Vitamin D deficiency, seasonal depression, and diseases of civilization

George Hamilton admits that he has been addicted to sunbathing for much of his life. The photo below (from: phoenix.fanster.com), shows him at the age of about 70. In spite of possibly too much sun exposure, he looks young for his age, in remarkably good health, and free from skin cancer. How come? Maybe his secret is vitamin D.

Vitamin D is a fat-soluble pro-hormone; not actually a vitamin, technically speaking. That is, it is a substance that is a precursor to hormones, which are known as calcipherol hormones (calcidiol and calcitriols). The hormones synthesized by the human body from vitamin D have a number of functions. One of these functions is the regulation of calcium in the bloodstream via the parathyroid glands.

The biological design of humans suggests that we are meant to obtain most of our vitamin D from sunlight exposure. Vitamin D is produced from cholesterol as the skin is exposed to sunlight. This is one of the many reasons (see here for more) why cholesterol is very important for human health.

Seasonal depression is a sign of vitamin D deficiency. This often occurs during the winter, when sun exposure is significantly decreased, a phenomenon known as seasonal affective disorder (SAD). This alone is a cause of many other health problems, as depression (even if it is seasonal) may lead to obesity, injury due to accidents, and even suicide.

For most individuals, as little as 10 minutes of sunlight exposure generates many times the recommended daily value of vitamin D (400 IU), whereas a typical westernized diet yields about 100 IU. The recommended 400 IU (1 IU = 25 ng) is believed by many researchers to be too low, and levels of 1,000 IU or more to be advisable. The upper limit for optimal health seems to be around 10,000 IU. It is unlikely that this upper limit can be exceeded due to sunlight exposure, as noted below.

Cod liver oil is a good source of vitamin D, with one tablespoon providing approximately 1,360 IU. Certain oily fish species are also good sources; examples are herring, salmon and sardines. For optimal vitamin and mineral intake and absorption, it is a good idea to eat these fish whole. (See here for a post on eating sardines whole.)

Periodic sun exposure (e.g., every few days) has a similar effect to daily exposure, because vitamin D has a half-life of about 25 days. That is, without any use by the body, it would take approximately 25 days for vitamin D levels to fall to half of their maximum levels.

The body responds to vitamin D intake in a "battery-like" manner, fully replenishing the battery over a certain amount of time. This could be achieved by moderate (pre-sunburn) and regular sunlight exposure over a period of 1 to 2 months for most people. Like most fat-soluble vitamins, vitamin D is stored in fat tissue, and slowly used by the body.

Whenever sun exposure is limited or sunlight scarce for long periods of time, supplementation may be needed. Excessive supplementation of vitamin D (i.e., significantly more than 10,000 IU per day) can cause serious problems, as the relationship between vitamin D levels and health complications follows a U curve pattern. These problems can be acute or chronic. In other words, too little vitamin D is bad for our health, and too much is also bad.

The figure below (click on it to enlarge), from Tuohimaa et al. (2009), shows two mice. The one on the left has a genetic mutation that leads to high levels of vitamin D-derived hormones in the blood. Both mice have about the same age, 8 months, but the mutant mouse shows marked signs of premature aging.

It is important to note that the skin wrinkles of the mice on the left have nothing to do with sun exposure; they are associated with excessive vitamin D-derived hormone levels in the body (hypervitaminosis D) and related effects. They are a sign of accelerated aging.

Production of vitamin D and related hormones based on sunlight exposure is tightly regulated by various physiological and biochemical mechanisms. Because of that, it seems to be impossible for someone to develop hypervitaminosis D due to sunlight exposure. This does NOT seem to be the case with vitamin D supplementation, which can cause hypervitaminosis D.

In addition to winter depression, chronic vitamin D deficiency is associated with an increased risk of the following chronic diseases: osteoporosis, cancer, diabetes, autoimmune disorders, hypertension, and atherosclerosis.

The fact that these diseases are also known as the diseases of civilization should not be surprising to anyone. Industrialization has led to a significant decrease in sunlight exposure. In cold weather, our Paleolithic ancestors would probably seek sunlight. That would be one of their main sources of warmth. In fact, one does not have to go back that far in time (100 years should be enough) to find much higher average levels of sunlight exposure than today.

Modern humans, particularly in urban environments, have artificial heating, artificial lighting, and warm clothes. There is little or no incentive for them to try to increase their skin's sunlight exposure in cold weather.

References:

W. Hoogendijk, A. Beekman, D. Deeg, P. Lips, B. Penninx. Depression is associated with decreased 25-hydroxyvitamin-D and increased parathyroid hormone levels in old age. European Psychiatry, Volume 24, Supplement 1, 2009, Page S317.

P. Tuohimaa, T. Keisala, A. Minasyan, J. Cachat, A. Kalueff. Vitamin D, nervous system and aging. Psychoneuroendocrinology, Volume 34, Supplement 1, December 2009, Pages S278-S286.

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Cancer patterns in Inuit populations: 1950-1997

Some types of cancer have traditionally been higher among the Inuit than in other populations, at least according to data from the 1950s, when a certain degree of westernization had already occurred. The incidence of the following types of cancer among the Inuit has been particularly high: nasopharynx, salivary gland, and oesophageal.

The high incidence of these “traditional” types of cancer among the Inuit is hypothesized to have a strong genetic basis. Nevertheless some also believe these cancers to be associated with practices that were arguably not common among the ancestral Inuit, such as preservation of fish and meat with salt.

Genetic markers in the present Inuit population show a shared Asian heritage, which is consistent with the higher incidence of similar types of cancer among Asians, particularly those consuming large amounts of salt-preserved foods. (The Inuit are believed to originate from East Asia, having crossed the Bering Strait about 5,000 years ago.)

The incidence of nasopharynx, salivary gland, and oesophageal cancer has been relatively stable among the Inuit from the 1950s on. More modern lifestyle-related cancers, on the other hand, have increased dramatically. Examples are cancers of the lung, colon, rectum, and female breast.

The figure below (click on it to enlarge), from Friborg & Melbye (2008), shows the incidence of more traditional and modern lifestyle-related cancers among Inuit males (top) and females (bottom).

Two main lifestyle changes are associated with this significant increase in modern lifestyle-related cancers. One is increased consumption of tobacco. The other, you guessed it, is a shift to refined carbohydrates, from animal protein and fat, as the main source of energy.

Reference:

Friborg, J.T., & Melbye, M. (2008). Cancer patterns in Inuit populations. The Lancet Oncology, 9(9), 892-900.

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How to break a coconut

The coconut is often presented as a healthy food choice, which it is, as long as you are not allergic to it. Coconut meat has a lot of saturated fat, which is very good for the vast majority of us.

(I posted about this issue elsewhere on this blog: my own experience and research suggest that saturated fat is very healthy for most people as long as it is NOT consumed together with refined carbs and sugars from industrialized food products.)

Coconut water is a good source of essential minerals, particularly magnesium and potassium. So is coconut meat, which is rich in iron, copper, manganese, and selenium. Coconut meat is also an good source of folate and an excellent source of dietary fiber.

If you are buying coconuts at a supermarket, I suggest choosing coconuts that have a lot of water in them. They seem to be the ones that taste the best. Just pick a coconut up and shake it. If it feels heavy and full of water, that’s the one.

First you need to make some holes on the coconut shell to extract the water. I recommend using a hammer and screwdriver. The screwdriver should be used only for this purpose, so you can keep it clean. Nails can be too thin. Place the coconut over a mitten or towel, and make holes on the dark spots (usually three) using the hammer and screwdriver.

Once you puncture the coconut, move the screwdriver a bit to enlarge each hole. Then place the coconut on a cup or thermos, with the holes pointing downwards, and let the water flow out of it. Normally I use a thermos, so that I can keep the coconut water fresh for later consumption.

As soon as all the coconut water is out, hold the coconut with a mitten in one hand, and strike it with the hammer with the other hand. The key here is to hold the coconut with your hand. You need to strike it hard. It is a good idea to do this inside or right above a kitchen sink so that the shell pieces fall into it.

Do not place the coconut against a hard surface (e.g., ceramic tiles), otherwise you can either break that surface or send pieces of the coconut flying all over the pace. Strike different areas of the coconut until it breaks into 5 to 7 pieces.

Finally, remove the meat of the coconut with a butter knife. The hand that holds the knife should be protected with a mitten, because you will have to apply pressure with it.

Store the coconut water in a sealed thermos, and the coconut meat pieces in a sealed container, both in the refrigerator, to preserve their freshness.

Coconut water and meat have a slightly sweet taste because of their sugar content, which is small and packed in with a lot of fiber. 100 g of coconut meat has about 15 g of carbs, of which 9 g is dietary fiber; that is, 100 g of coconut meat has only 6 g of net carbs.

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Talking rubbish in the big wide world

This week has seen an interruption to my usual online witterings. I've spent most of my week away from the computer, talking rubbish elsewhere.

It's actually been a very exciting week, beginning with the opportunity on Tuesday to meet the Seven Suffolk Streets project team and the door-knockers, a team of volunteer master composters who are tasked with drumming up residents' support for the Waste Reduction Fortnight that's taking place in March. I'll be joining them soon, knocking on doors across different areas of Suffolk to talk rubbish with other folk who live in my county. So watch this space for further news.

Yesterday, I'd also been invited to speak at Inspire East's community champion event, which launched their community empowerment programme. It was a really inspiring event and as well as having the chance to promote the idea of reducing waste and the results of last year's Recycle Week challenge in Moreton Hall, I also had the opportunity to meet some fabulous people and explore the value of working with your local community to promote other sustainable ideas. If you live in the East of England and would like more support on how to empower people in your community to do more, I really recommend you visit the Inspire East website.

And on the subject of communities, tomorrow I'll be speaking at the Zero Waste Community event in Norwich about my Zero Waste challenge, as well as hosting a workshop on how to set up a Zero Waste household.

It looks like it will be a very exciting day, featuring Richard Anthony from the Zero Waste Alliance, San Diego, Jim Mclaughlin from the Community Recycling Network and Furniture Recycling Network, Maxine Narburgh, Director of the Bright Green Consultancy and member of Zero Waste Europe and Ralph Ryder from Communities Against Toxics.

The topics that will be covered include: Zero Waste Communities and Principles; An introduction to climate change Zero Waste and jobs; How to be a Zero Waste home and the Impact of Incineration in Communities. Workshops will include how to develop campaigns for zero waste within your community and how to run community reuse and recycling projects.

If you happen to live in the region and would like to attend the Norwich event, you can find the link to the original flyer here. It's an all day programme that runs from 9.30am to 4pm. The latest schedule has since been altered and my presentation has been slotted in at 12pm.

So I am afraid with all these to-ings and fro-ings, I've been far too busy gadding around the region or having my head down in preparing PowerPoint presentations that I've hardly had any time to work on my personal declutter challenge. So there's no major update on that today.

However, I did go through my jewellery box to select a whole host of things for my car boot collection. It only took me about 30 minutes and I was truly amazed at the surplus of jewellery I've been given, made or have bought over the last decade. This is only half of it and I couldn't help wondering how many other women have got collections like this, where most of their items go to waste without use.



Maybe if you've got half an hour to spare, you could go through yours too and donate the pieces that you no longer wear to charity or sell online. As well as eBay, there are other fabulous sites such as wicycle-it or even JumbleAid, which helps you support your favourite charity. Alternatively you could keep it in your local community with sites such as Freegle or Freecycle.

I knew I was a bit of a magpie but I now intend to be more careful about what I collect in future. At least with my passion for vintage jewellery, there'll be far fewer mass-manufactured adornments from wherever.

So I'll be back soon to catch up with all the lovely comments that you've kindly left, but for now, I've got to get my head back down to prepare for tomorrow.

While I'm away, if you haven't seen it yet - check out our very own Mrs Green's appearance on BBC news this week. It was excellent and very exciting. You can catch one of the broadcasts here:

http://news.bbc.co.uk/local/gloucestershire/hi/people_and_places/newsid_8482000/8482762.stm


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The low modern potassium-to-sodium ratio: Big problem or much ado about nothing?

It has been argued that the diets of our Paleolithic ancestors had on average a much higher potassium-to-sodium ratio than modern diets (see, e.g., Cordain, 2002).

This much lower modern ratio is believed by some to be the cause of a number of health problems, including: high blood pressure, stroke, heart disease, memory decline, osteoporosis, asthma, ulcers, stomach cancer, kidney stones, and cataracts.

But, is this really the case?

The potassium-to-sodium ratio in ancient and modern times

According to some estimates, our Paleolithic ancestors’ daily consumption was on average about 11,000 mg of potassium and about 700 mg of sodium (salt). That yields a potassium-to-sodium ratio of about 16. Today’s ratio in industrialized countries is estimated to be around 0.6.

Just for the sake of illustration, let us compare a healthy Paleolithic diet food, walnuts, with a modern industrialized food that many believe to be quite healthy, whole-wheat bread. The table below (click on it to enlarge) compares these two foods in terms of protein, carbohydrate, fat, vitamin, and mineral content.

Walnuts have a potassium-to-sodium ratio of about 205. The whole-wheat bread’s ratio is about 0.5; much lower, and close to the overall ratio estimated for industrialized countries mentioned above.

At the same time, walnuts provide a better nutritional value than whole-wheat bread, including a good amount of omega-3 fatty acids (2.5 g; of α-linolenic acid, or ALA). However, walnuts have a fairly high omega-6 fat content.

Also, many diabetics experience elevated blood glucose levels in response to whole-wheat bread, in spite of its glycemic index being supposedly lower than that of white bread. Walnuts do not seem to cause this type of problem, even though several people are allergic to walnuts (and other tree nuts).

Health effects of the potassium-to-sodium ratio

So, the potassium-to-sodium ratio appears to have been much higher among our Paleolithic ancestors than today. It is important to stress that, even though this is a possibility, we do not know this for sure. Animals go to great lengths to find salt licks, and then consume plenty of sodium in them. Our ancestors could have done that too. Also, we know that sodium deficiency can be deadly to both animals and humans.

As for the many negative health effects of a low potassium-to-sodium ratio in modern humans, we have reasons to be somewhat skeptical. One has to wonder if the studies that are out there do not conflate the effects of this ratio with those of other factors, such as smoking, heavy alcohol consumption, or consumption of industrialized high carb foods (e.g., cereals, pasta, refined sugars).

Another possible confounding factor is potassium deficiency, not the potassium-to-sodium ratio. Potassium deficiency, like other deficiencies of essential minerals, including sodium deficiency, is associated with serious health problems.

If potassium is deficient in one’s diet, it is also likely that the potassium-to-sodium ratio will be low, unless the diet is also equally deficient in sodium.

Let us take a look at a study by Ikeda et al. (1986), which included data from 49 regions in Japan, a country known for high consumption of sodium.

This study found a significant association between the potassium-to-sodium ratio and overall mortality and heart disease, but only among men, and not among women.

One wonders, based on this, whether another uncontrolled factor, or factors, might have biased the results. Examples are smoking and heavy alcohol consumption, which could have been higher among men than women. Another is chronic stress, which could also have been higher among men than women.

The researchers report that they found no association between the potassium-to-sodium ratio and mortality due to diabetes, liver disease, or tuberculosis. This ameliorates the problem somewhat, but does not rule out the biasing effect of other factors.

It would have been better if the researchers had controlled for the combined effect of covariates (such as smoking, alcohol consumption etc.) in their analysis; which they did not.

Moreover, the study found no association between the potassium-to-sodium ratio and blood pressure. This is a red flag, because many of the diseases said to be caused by a low potassium-to-sodium ratio are assumed to be mediated by or at least associated with high blood pressure.

Regarding the possible confounding effect of industrialized high carb foods consumption, it seems that many of these foods have a low potassium-to-sodium ratio, as the example of whole-wheat bread above shows. Thus, some of the health problems assigned to the low potassium-to-sodium ratio may have actually been caused by heavy consumption of industrialized high carb foods.

It is also possible that the problem is with the combination of a low potassium-to-sodium ratio and industrialized high carb foods consumption.

At the time the study was conducted, Japan was somewhat westernized, which is why industrialized high carb foods consumption might have been a factor. The US strongly influenced the Japanese after World War II, as it helped rebuild Japan’s economy.

In conclusion, the jury is still out there regarding whether the low modern potassium-to-sodium ratio is a big problem or much ado about nothing.

References:

Cordain, L. (2002). The Paleo Diet: Lose weight and get healthy by eating the food you were designed to eat. New York, NY: Wiley.

Ikeda, M., Kasahara, M., Koizumi, A., and Watanabe, T. (1986). Correlation of cerebrovascular disease standardized mortality ratios with dietary sodium and the sodium/potassium ratio among the Japanese population. Preventive Medicine, 15(1), 46-59.

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The Rubbish Diet Challenge: Week 3, Waste Not Want Not

Welcome to Week 3 of The Rubbish Diet Challenge, where this week I am taking you into the kitchen to find out how much food gets thrown in your bin.

Managing food waste is one of the most important areas of waste reduction. Not only has it huge potential for slimming your bin, but by reducing what you throw away can save you money and provide environmental rewards too.

According to WRAP's LoveFoodHateWaste campaign if we all stop wasting food we could have eaten, the CO2 impact is the equivalent of taking 1 in 4 cars off the road. That's a startling statistic and when I first heard it, it really made my jaw drop in surprise.

So in Week 3, I will be revealing what type of food waster I was, in the hope that even the least careful of folk will see that there is light at the end of the tunnel. And I've included tricks for using up leftovers as well as advice about portions and ways of dealing with waste if you just can't simply eat any more.

And if you're a stranger to the kitchen with the exception of visiting the microwave, I hope to inspire you to grab your apron, or lab coat and start experimenting with food. There's so much more to being a rubbish cook, than simply being rubbish in the kitchen. You never know, you may even be tempted to have a go at making pasta or bread as an alternative way to cut down on packaging.

So if you're ready to crack on with Week 3 of the Rubbish Diet Challenge, find out what you're in for at:

http://tinyurl.com/TheRubbishDietWeek3

Oh and I almost forgot, I did a spot of reminiscing today and if you didn't catch it at the time, here's one of the recordings I did for BBC Radio 4's Woman's Hour a couple of years ago.



STOP PRESS

iPhone users - there's an exciting new app available from www.wasteawarelovefood.org.uk, which will help you plan your meals from your phone with a recipe finder and portion planner. You can download it directly from the itunes store.

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Eating fish whole: Sardines

Different parts of a fish have different types of nutrients that are important for our health; this includes bones and organs. Therefore it makes sense to consume the fish whole, not just filets made from it. This is easier to do with small than big fish.

Small fish have the added advantage that they have very low concentrations of metals, compared to large fish. The reason for this is that small fish are usually low in the food chain, typically feeding mostly on plankton, especially algae. Large carnivorous fish tend to accumulate metals in their body, and their consumption over time may lead to the accumulation of toxic levels of metals in our bodies.

One of my favorite types of small fish is the sardine. The photo below is of a dish of sardines and vegetables that I prepared recently. Another small fish favorite is the smelt (see this post). I buy wild-caught sardines regularly at the supermarket.

Sardines are very affordable, and typically available throughout the year. In fact, sardines usually sell for the lowest price among all fish in my supermarket; lower even than tilapia and catfish. I generally avoid tilapia and catfish because they are often farmed (tilapia, almost always), and have a poor omega-6 to omega-3 ratio. Sardines are rich in omega-3, which they obtain from algae. They have approximately 14 times more omega-3 than omega-6 fatty acids. This is an excellent ratio, enough to make up for the poorer ratio of some other foods consumed on a day.

This link gives a nutritional breakdown of canned sardines; possibly wild, since they are listed as Pacific sardines. (Fish listed as Atlantic are often farm-raised.) The wild sardines that I buy and eat probably have a higher vitamin and mineral content that the ones the link refers to, including higher calcium content, because they are not canned or processed in any way. Two sardines should amount to a little more than 100 g; of which about 1.6 g will be the omega-3 content. This is a pretty good amount of omega-3, second only to a few other fish, like wild-caught salmon.

Below is a simple recipe. I used it to prepare the sardines shown on the photo above.

- Steam cook the sardines for 1 hour.
- Spread the steam cooked sardines on a sheet pan covered with aluminum foil; use light olive oil to prevent the sardines from sticking to the foil.
- Preheat the oven to 350 degrees Fahrenheit.
- Season the steam cooked sardines to taste; I suggest using a small amount of salt, and some chili powder, garlic powder, cayenne pepper, and herbs.
- Bake the sardines for 30 minutes, turn the oven off, and leave them there for 1 hour.

The veggies on the plate are a mix of the following: sweet potato, carrot, celery, zucchini, asparagus, cabbage, and onion. I usually add spinach but I had none around today. They were cooked in a covered frying pan, with olive oil and a little bit of water, in low heat. The cabbage and onion pieces were added to the mix last, so that in the end they had the same consistency as the other veggies.

I do not clean, or gut, my sardines. Normally I just wash them in water, as they come from the supermarket, and immediately start cooking them. Also, I eat them whole, including the head and tail. Since they feed primarily on plant matter, and have a very small digestive tract, there is not much to be “cleaned” off of them anyway. In this sense, they are like smelts and other small fish.

For about a year now I have been eating them like that; and so have my family (wife and 4 kids), of their own volition. Other than some initial ew’s, nobody has ever had even a hint of a digestive problem as a result of eating the sardines like I do. Maybe the Kock family members share a common crocodile-like digestive system, but I think most people will do fine following the same approach. This is very likely the way most of our hominid ancestors ate small fish.

If you prepare the sardines as above, they will be ready to store, or eat somewhat cold. There are several variations of this recipe. For example, you can bake the sardines for 40 minutes, and then serve them hot.

You can also add the stored sardines later to a soup, lightly steam them in a frying pan (with a small amount of water), or sauté them for a meal. For the latter I would recommend using coconut oil and low heat. Butter can also be used, which will give the sardines a slightly different taste.

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Decluttering: A space to eat

You won't believe it but what you're witnessing at this very point in time is a rare occurrence.

No, I don't mean the messy table! Oh No! The rare occurrence is that for once I am indeed speechless!

And as I write, I am experiencing nervous bouts of laughter and moments of shame as I introduce the state of my dining room to a whole bunch of strangers on the Internet, including online friends, recycling officers and academics from all across the world. Revealing this photo feels worse than showing how much rubbish we used to throw away. The only thing I find reassuring is that I might show at least one person that there is a glimmer of hope.

I took the photograph shown above last weekend before we started to declutter, but I have to be honest and say the dining room hasn't always looked like this.

Before Christmas, it looked like this:




Haha, I bet you didn't expect to see that did you?! Talk about an immovable force, but I promise I did at least tidy up before my sister and her family arrived for Christmas.

But my nervous laughter is now reaching decibels of immense proportions, especially as not even my best friend gets to see the house in such a condition. I make sure I shut the dining room door before I open the front door to her and all other visitors. So if she's reading this blog she'll soon get the shock of her life. And she'll now know why I haven't invited her and her husband - or indeed anyone else - to dinner for a long-long time.

People may think I'm being anti-social, but the truth is I've been too embarrassed to admit that since writing this blog I've been far too busy to keep on top of all domestic functions. However, I reckon there are hundreds and thousands of houses just like this across the country, also suffering from too much stuff, too much to do and insufficient space and time to do it all in.

And the problem I've had with our dining room is that is is actually not just a dining room. It's also a hobby room, Little T's craftroom, a homework room, a filing room and a "temporary" storage room. It's also where we permanently store odds and ends like cables and replacement bulbs in various cupboards and drawers.


So it really is a room that has multiple functions and is constantly in use by a very busy multi-tasking but time-poor family, trying to juggle too many balls at once.

If this all sounds similar, you'll recognise the signs of the clutter magnet that takes effect.

For example you'll be going great guns in keeping a clear space. Then momentarily, you'll take your eye off the ball and put something down on a table. And that's your first mistake, because what follows is the law of attraction. Out of nowhere, everybody else adds "their thing" next to "your thing" and before you know it, you're all taking it in turns like a game of buckaroo by stealth as the free space gets taken over by a multitude of clutterbug sins.

And have you noticed that things appear that you've never even seen before, making you wonder whether your neighbours have heard the rumour and have sneaked in with their bits of crap too? Then if you're clearing out another room, like the kitchen for instance and have nowhere else to dump the stuff that you're collecting for a car boot sale, the dining room table is often the easiest place to put it all.

No wonder Mr A despairs and threatens to throw all sorts of stuff in the rubbish bin. A sight like this can easily drive someone to chuck it all away, which used to happen frequently before I started the Zero Waste challenge. But I can assure you that there is no-one who stresses about this more than me and I know I have to become more efficient and organised on the home front to regain more control and therefore greater mental freedom.

So, on my latest decluttering mission, the first thing I did was grab a HUGE box to create a designated spot for all the items that we are going to sell at the car boot sale in the spring. Immediately, this cleared half the amount of stuff off the dining table.



The next job was to simply tidy all the other things away into their proper homes, including the Christmas fabric that I'd bought to replace paper for wrapping family Christmas presents.



That was the easy bit!

However I think the dining room is probably going to need a lot more work than we've had time to dedicate so far, especially when sorting out the drawers full of cables and leads. We just need to work out which items are still needed and take the remainder to the Household Waste Recycling Centre for recycling with all the other Waste Electrical and Electronic Equipment (WEEE).

But in the meantime, our box of car booty is growing all the time and has expanded to include a plastic ugly bug, a redundant kitchen towel holder, a fabric bun holder, an over sized vodka bottle and several little ornaments. I've got a feeling that by the time I've finished, there will be a small number of old DVDs too as well as boxes of old beads that I've discovered in a cabinet drawer.

When I showed the photo of my dining room to Clare Baker of the ClutterClearing consultancy, she reassured me that I am nowhere near a clutterholic and that it would be easy to restore order. That was a real relief and it was simply a case of time and following the tips on her website to create categories for the items that we were decluttering.

With this in mind I also took the opportunity to sort the drawers of the Welsh dresser, separating things into stationery and craft items in one drawer, tableware linen in another and I've left the last drawer for personal mementos such as photos. Having done this will also be of benefit when I work on other rooms, as we now have a central storage point for transferring stuff.

I could go on, but I bet you can't wait to see the results of our efforts. I say "our" because it was indeed a team effort by me and Mr A, who is naturally more organised in this area than me. So without further ado, here it is:

Our dining room in all its glory......



And now it's all clear, I can now enjoy some of my favourite things, such as this funky plastic flower that I made at the Aldeburgh Food Festival, accompanied by one of the gorgeous felt flowers from Henry & Jayne.





But my favourite decluttered view of all is of the vintage tea-set that I picked up last summer for just £15.




I have found it's worth taking time out to appreciate these objects while I've got a good view and recognise this moment as one of the key incentives for keeping space clutter-free in future. It's almost impossible to enjoy lovely things when they're surrounded by other distractions such as a multi-pack of chopped tomatoes and a set of ice-lolly moulds that have lost their lids.

So if you want to come around for dinner, we've now got somewhere to eat, drink and be merry.

Now talking of incentives, another useful tip I picked up from Clare Baker this week was to make sure I reward myself for the efforts I've made to free up my space. So seeing as it's a Friday evening, I think it's going to have to be a nice glass of wine.

Yep, it's time to dig out the Chablis. Well, it is a special occasion of course. Not only was it my second blogaversary yesterday, but at last I can now get to the other end of the table to reach the wine glasses to celebrate and properly thank you for all the lovely comments that you sent.

And if you're a blogger sorting out your own clutter and are showing off the results on your own blog, I've added a Mr Linky to this blogpost so you can link up your efforts too.

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Applied evolutionary thinking: Darwin meets Washington

Charles Darwin, perhaps one of the greatest scholars of all time, thought about his theory of mutation, inheritance, and selection of biological traits for more than 20 years, and finally published it as a book in 1859.  At that time, many animal breeders must have said something like this: “So what? We knew this already.”

In fact George Washington, who died in 1799 (many years before Darwin’s famous book came out), had tried his hand at what today would be called “genetic engineering.” He produced at least a few notable breeds of domestic animals through selective breeding. Those include a breed of giant mules – the “Mammoth Jackstock” breed. Those mules are so big and strong that they were used to pull large boats filled with coal along artificial canals in Pennsylvania.

Washington learned the basic principles of animal breeding from others, who learned it from others, and so on. Animal breeding has a long tradition.

So, not only did animal breeders, like George Washington, had known about the principles of mutation, inheritance, and selection of biological traits; but they also had been putting that knowledge into practice for quite some time before Darwin’s famous book “The Origin of Species” was published.

Yet, Darwin’s theory has applications that extend well beyond animal breeding. There are thousands of phenomena that would look very “mysterious” today without Darwin’s theory. Many of those phenomena apply to nutrition and lifestyle, as we have been seeing lately with the paleo diet movement. Among the most amazing and counterintuitive are those in connection with the design of our brain.

Recent research, for instance, suggests that “surprise” improves cognition. Let me illustrate this with a simple example. If you were studying a subject online that required memorization of key pieces of information (say, historical facts) and a surprise stimulus was “thrown” at you (say, a video clip of an attacking rattlesnake was shown on the screen), you would remember the key pieces of information (about historical facts) much better than if the surprise stimulus was not present!

The underlying Darwinian reason for this phenomenon is that it is adaptively advantageous for our brain to enhance our memory in dangerous situations (e.g., an attack by a poisonous snake), because that would help us avoid those situations in the future (Kock et al., 2008; references listed at the end of this post). Related mental mechanisms increased our ancestors’ chances of survival over many generations, and became embedded in our brain’s design.

Animal breeders knew that they could apply selection, via selective breeding, to any population of animals, and thus make certain traits evolve in a matter of a few dozen generations or less. This is known as artificial selection. Among those traits were metabolic traits. For example, a population of lambs may be bred to grow fatter on the same amount of food as leaner breeds.

Forced natural selection may have been imposed on some of our ancestors, as I argue in this post, leading metabolic traits to evolve in as little as 396 years, or even less, depending on the circumstances.

In a sense, forced selection would be a bit like artificial selection. If a group of our ancestors became geographically isolated from others, in an environment where only certain types of food were available, physiological and metabolic adaptations to those types of food might evolve. This is also true for the adoption of cultural practices; culture can also strongly influence evolution (see, e.g., McElreath & Boyd, 2007).

This is why it is arguably a good idea for people to look at their background (i.e., learn about their ancestors), because they may have inherited genes that predispose them to function better with certain types of diets and lifestyles. That can help them better tailor their diets to their genetic makeup, and also understand why certain diets work for some people but not for others. (This is essentially what medical doctors do, on a smaller time scale, when they take a patients' parents health history into consideration when dispensing medical advice.)

By ancestors I am not talking about Homo erectus here, but ancestors that lived 3,000; 1,000; or even 500 years ago. At times when medical care and other modern amenities were not available, and thus selection pressures were stronger. For example, if your no-so-distant ancestors have consumed plenty of dairy, chances are you are better adapted to consume dairy than people whose ancestors have not.

Very recent food inventions, like refined carbohydrates, refined sugars, and hydrogenated fats are too new to have influenced the genetic makeup of anybody living today. So, chances are, they are bad for the vast majority of us. (A small percentage of the population may not develop any hint of diseases of civilization after consuming them for years, but they are not going to be as healthy as they could be.) Other, not so recent, food inventions, such as olive oil, certain types of bread, certain types of dairy, may be better for some people than for others.

References:

Kock, N., Chatelain-Jardón, R., & Carmona, J. (2008). An experimental study of simulated web-based threats and their impact on knowledge communication effectiveness. IEEE Transactions on Professional Communication, 51(2), 183-197.

McElreath, R., & Boyd, R. (2007). Mathematical models of social evolution: A guide for the perplexed. Chicago, IL: The University of Chicago Press.

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Two years old today and Mr A has the last word on the matter.

1 week's rubbish, circa January 2008

It's been so busy of late, the fact that this blog is two years old today almost passed me by. So do excuse me for a moment while I grab a now defunct party blower to celebrate and give it a WhoopeyTootToot!

Yes indeed. Two years old. Whoop whoop. Toot toot!

Who'd have thought it, eh!

It's no secret that when I typed up my first blog post on 21st January 2008, I only intended to write about my run-up to St Edmundsbury's zero waste challenge and document the big week itself.

Just eight weeks, that's all.

At the time I had no idea what the heck I was doing or what I'd got myself into. But when I discovered the urgency of it all, I found I had less time to dedicate to blogging about other stuff or making money from things like this...

...because of a new-found determination to reduce the burden of this:


From designing beautiful tiaras to designing out stinky old waste, now that's what I would call a tale of chalk and cheese!

But I can certainly say that despite there being more money in tiaras than there is in blogging about bin bags, I really haven't looked back...

...except for last night, when I sat down with my husband, aka Mr A. And while we reminisced I decided to ask him what he really thought about my rubbish blog and our personal measures to reduce our family's waste. For new readers who aren't familiar with my husband's reputation, perhaps I should say now that he is rather masterful in the sport of filling bin bags with whatever crap that gets in his way.

"Just like that!"

So it's fair to say that he took some warming up on the issue and when I asked if the reputation I've given him on this blog was appropriate, he just smiled and said that it was for me to judge because all he did was "follow my draconian rules".

Now now Mr A. More enthusiasm please! I'm the gentle love-of-your-life not some haughty Miss Whiplash! Although this paragraph is beginning to make me sound like the latter.

So with a little more patience, this is what I managed to tease out of the man who's had to put up with my rubbish reducing antics for two whole years. This is what he really thinks about life in the Almost Average Household...

"I suppose it hasn't been that difficult to deal with the waste we create and it has made me think about what I buy. These days I hardly ever go shopping to the supermarket because I can't pick up anything without the thought police reminding me about packaging waste."

"And it's great to see how well things are working, whether it means me refusing new bags at the shops or seeing the success of home-composting."

Well so far so good! But with my hands almost over my ears, I thought I'd enquire about his key frustrations too....

"Well, I find it really annoying that things destined for the black bin are snaffled away and relocated to a corner of the house in a way that resembles a mini waste-transfer-station, and that they are then left to hang around on a long-term promise of being taken off to a charity shop".

Ouch! I suppose I really do need to get myself more organised.

"AND there are certain rules of the recycling industry that are hard to understand, e.g. why Weetabix wrappers end up in the black bin when other plastic film can be recycled at the Bury St Edmunds recycling centre."

I agree and well spotted. I'd forgotten about those - and indeed Weetabix will be getting back to me later to tell me what they're made of...........So is that all?

"No, there's having to put up with that plastic bag hanger on the wall, which I think is ugly and PLEASE don't get me started on having to wash up butter wrappers."

Oh dear, slightly going a bit pear-shaped there. Perhaps I have gone a step too far, but you've seen those bulging bags of plastic film that we had beforehand. So that bin has been a huge help.

But surely it's not all hassle on the domestic front?

"I have to admit the wooden toothbrushes were great and so are the washing balls that have replaced the constant need for laundry powder."

Phew, that's music to my ears and a surprise too. So anything else to say on the matter Mr A?

"Well all I can say is, who would have known that a blog could become a full-time occupation eh! And I would NEVER have guessed that family holidays would feature sightseeing visits to recycling centres!"

Now I could swear there was a smile when he mentioned the bit about the holidays. Could it be sarcasm? I suppose I'll ask him later.

But seriously, if it wasn't for the support of my husband, I could never have kept this blog going for so long. And he has had to put up with my determination in rescuing all sorts of things from the bin, such as old wooden toilet seats, unwanted slippers and cans of shaving foam. And the times I've stamped my foot crying "It's not rubbish it's a resource" is really nobody's business.

However, don't ever think that it's me who wears the trousers around here. Having given up tiara-making for writing about waste, I am now under very strict instructions to finally sort out my old bead-kit and I have also been told to buck up my ideas about rehoming my clutter too before it is too late.

So Mr A really does have the last word around this neck of the woods, honestly.

Well, that is until I remind him of the small matter, that since I took over the management of our waste, he's never had to put the rubbish bin out in all that time! Not once, in two whole years - it's me who's had to wheel it out, but then half-a-dozen times is hardly a hardship.

That's blimmin' good service is it not and surely it's worth the odd hassle? I ask him and he most definitely agrees.

So all's well that ends well and here's a toast to many more rubbish reducing adventures to come. Thank you to everyone who has been following the blog, to old friends and new. Even if you feel that the rest of your household isn't quite on your wavelength, I hope this reassures you that they can come round in time.

So to celebrate, I'm turning my attention back to decluttering. If you can, please come back tomorrow to see how I've got on!

What's that Mr A...? I'd better take it all off to the charity shop before you get back from work, or you might just chuck it in the bin?

Oh...dear!

At least you get to see what I'm up against! Actually, I'm saving it up for a boot sale!

Well there's no time for arguing about it now - I've got to get on and it's time for a sing-song as I go.

"Happy birthday dear blog, Happy birthday dear blog, Happy birthday dear blo-og, Happy birthday dear blog!"

Hoorah.

WhoopeyTootToot!

Whoop whoop. Toot toot!

Oh and I nearly forgot....here's a photo of our latest week's rubbish, all dressed for the occasion.



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Who is really behind these posts?

Acknowledgement: In addition to the references provided at the end of several posts, I would like to acknowledge that I also regularly consult with the most interesting man in the world, especially in connection with complex scientific matters. (YouTube link below, if you must know the identity of this incredibly modest and low-key person.)

http://www.youtube.com/watch?v=PVwG1t-NVAA

No need to refer to him as The Most Interesting Man in the World (i.e., capitalized), because, as he notes: "There is only one most interesting man in the world."

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How long does it take for a food-related trait to evolve?

Often in discussions about Paleolithic nutrition, and books on the subject, we see speculations about how long it would take for a population to adapt to a particular type of food. Many speculations are way off mark; some think that even 10,000 years are not enough for evolution to take place.

This post addresses the question: How long does it take for a food-related trait to evolve?

We need a bit a Genetics 101 first, discussed below. For more details see, e.g., Hartl & Clark, 2007; and one of my favorites: Maynard Smith, 1998. Full references are provided at the end of this post.

New gene-induced traits, including traits that affect nutrition, appear in populations through a deceptively simple process. A new genetic mutation appears in the population, usually in one single individual, and one of two things happens: (a) the genetic mutation disappears from the population; or (b) the genetic mutation spreads in the population. Evolution is a term that is generally used to refer to a gene-induced trait spreading in a population.

Traits can evolve via two main processes. One is genetic drift, where neutral traits evolve by chance. This process dominates in very small populations (e.g., 50 individuals). The other is selection, where fitness-enhancing traits evolve by increasing the reproductive success of the individuals that possess them. Fitness, in this context, is measured as the number of surviving offspring (or grand-offspring) of an individual.

Yes, traits can evolve by chance, and often do so in small populations.

Say a group of 20 human ancestors became isolated for some reason; e.g., traveled to an island and got stranded there. Let us assume that the group had the common sense of including at least a few women in it; ideally more than men, because women are really the reproductive bottleneck of any population.

In a new generation one individual develops a sweet tooth, which is a neutral mutation because the island has no supermarket. Or, what would be more likely, one of the 20 individuals already had that mutation prior to reaching the island. (Genetic variability is usually high among any group of unrelated individuals, so divergent neutral mutations are usually present.)

By chance alone, that new trait may spread to the whole (larger now) population in 80 generations, or around 1,600 years; assuming a new generation emerging every 20 years. That whole population then grows even further, and gets somewhat mixed up with other groups in a larger population (they find a way out of the island). The descendants of the original island population all have a sweet tooth. That leads to increased diabetes among them, compared with other groups. They find out that the problem is genetic, and wonder how evolution could have made them like that.

The panel below shows the formulas for the calculation of the amount of time it takes for a trait to evolve to fixation in a population. It is taken from a set of slides I used in a presentation (PowerPoint file here). To evolve to fixation means to spread to all individuals in the population. The results of some simulations are also shown. For example, a trait that provides a minute selective advantage of 1% in a population of 10,000 individuals will possibly evolve to fixation in 1,981 generations, or 39,614 years. Not the millions of years often mentioned in discussions about evolution.

I say “possibly” above because traits can also disappear from a population by chance, and often do so at the early stages of evolution, even if they increase the reproductive success of the individuals that possess them. For example, a new beneficial metabolic mutation appears, but its host fatally falls off a cliff by accident, contracts an unrelated disease and dies etc., before leaving any descendant.

How come the fossil record suggests that evolution usually takes millions of years? The reason is that it usually takes a long time for new fitness-enhancing traits to appear in a population. Most genetic mutations are either neutral or detrimental, in terms of reproductive success. It also takes time for the right circumstances to come into place for genetic drift to happen – e.g., massive extinctions, leaving a few surviving members. Once the right elements are in place, evolution can happen fast.

So, what is the implication for traits that affect nutrition? Or, more specifically, can a population that starts consuming a particular type of food evolve to become adapted to it in a short period of time?

The answer is yes. And that adaptation can take a very short amount of time to happen, relatively speaking.

Let us assume that all members of an isolated population start on a particular diet, which is not the optimal diet for them. The exception is one single lucky individual that has a special genetic mutation, and for whom the diet is either optimal or quasi-optimal. Let us also assume that the mutation leads the individual and his or her descendants to have, on average, twice as many surviving children as other unrelated individuals. That translates into a selective advantage (s) of 100%. Finally, let us conservatively assume that the population is relatively large, with 10,000 individuals.

In this case, the mutation will spread to the entire population in approximately 396 years.

Descendants of individuals in that population (e.g., descendants of the Yanomamö) may posses the trait, even after some fair mixing with descendants of other populations, because a trait that goes into fixation has a good chance of being associated with dominant alleles. (Alleles are the different variants of the same gene.)

This Excel spreadsheet (link to a .xls file) is for those who want to play a bit with numbers, using the formulas above, and perhaps speculate about what they could have inherited from their not so distant ancestors. Download the file, and open it with Excel or a compatible spreadsheet system. The formulas are already there; change only the cells highlighted in yellow.

References:

Hartl, D.L., & Clark, A.G. (2007). Principles of population genetics. Sunderland, MA: Sinauer Associates.

Maynard Smith, J. (1998). Evolutionary genetics. New York, NY: Oxford University Press.

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Go see your doctor, often

As I blog about health issues, and talk with people about them, I often notice that there is a growing contempt for the medical profession.

This comes in part from the fact that many MDs are still providing advice based on the mainstream assumption that saturated fat is the enemy. Much recent (and even some old) research suggests that among the main real enemies of good health are: chronic stress, refined carbs, refined sugars, industrial trans-fats, and an omega-6/omega-3 imbalance caused by consumption of industrial vegetable oils rich in omega-6 fats.

Because of this disconnect, some people stop seeing their doctors regularly; others avoid doctors completely. Many rely exclusively on Internet advice, from health-related blogs (like this) and other sources. In my opinion, this is a BIG mistake.

A good MD has something that no blogger who is not an MD (like me) can have. He or she has direct access to a much larger group of people, and to confidential information that can clarify things that would look mysterious to non-MDs. They cannot share that information with others, but they know.

For example, often I hear from people that they did this and that, in terms of diet a lifestyle, and that their lab tests were such and such. Later I find out that what they told me was partially, or completely, wrong. That is, they distorted the truth, maybe subconsciously.

I have never met an MD who completely ignored hard facts, such as results of lab tests and common health-related measurements. I have never met an MD who tried to force me to do anything either; although I have to admit that some tend to be a bit pushy.

I see a doctor who does not agree with me; e.g., he wanted me to take statins. No problem; that is the way I like it. If my doctor will agree 100% with all I say, do I need to see that doctor?

My doctor does not question lab results though, and maybe I am changing a bit the way he thinks. He wanted me to take statins, but once I told him that I wanted to try a few other things first, he said: no problem. When the results came, he had that look on this face - maybe u wuz royt eh!?

Many, many patients are under the mistaken assumption that they need to please their doctors. A subconscious assumption for most, no doubt. I guess this is part of human nature, but I don’t think it is helpful to doctors or patients.

Patients actually need to work together with their doctors, see them often, do their own research, ask questions, and do those things that lead to health improvements – ideally measurable ones.

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Bags of bags in bags and even more bags!

Geez, being a trolley pulling reusable bag carrying veteran, I'd forgotten how many plastic bags could potentially come with a weekly shop.

But look! Here's my latest shopping that arrived home today from the supermarket! And just look at those bags. There are blimmin' lots of them!

But as you can probably guess, it wasn't me doing the shopping today. This isn't how my shopping looks when I normally bring it through the door. For the first time in absolutely yonks I'd ordered my groceries online, thanks to my car being immobile and needing an urgent mega top-up of stuff. I would have normally gone on the bus, but I've also been too busy of late to make regular trips into town.

Ordering online may have been convenient but it meant there was no escape from the plazzie bag and its many friends, which is utterly ironic because only ten minutes before the delivery van arrived, I'd got a call from BBC Three Counties Radio to appear on the JVS show later to discuss the topic of carrier bags. Timing is everything, wouldn't you say!

A few years ago I wouldn't have given this picture a second thought, but these days I look at the amount of plastic and think, what a potential waste! And there were even more bags than you see here, but I'd quickly unpacked them and gave them back to the driver along with a bag full of plastic packaging I'd been collecting for recycling.

At least these bags are in good hands. It's not quite the end of their life just yet. Many people would just throw them in the bin, where they would take decades to break down in landfill, not to mention those that get blown away and harm wildlife. However these will be reused as bin bags for all the plastic film packaging that I'll collect over the year and each month will be recycled together with the contents. I guess they'll probably come back as plastic lumber or something similar!

But plastic bags aren't the only problem when it comes to the amount of rubbish that gets generated by shopping. There's so much other rubbish that a trip to the supermarket can create too. So if you'd like to find out more about what else you can do to reduce waste, be sure to check out my latest guide for Week 2 of The Rubbish Diet challenge, which was published online just yesterday.

And if you really need some extra help with remembering to take your reusable bags to the shops, take a look at the YouTube video below featuring Dave Chameides from 365 Days of Trash. Email subscribers can find the link directly to the video here.



More advice is also available in Dave's article, that accompanies his video, entitled Plastic Bags: Stop being part of the problem.

And the good news is, after this tiny blip in usual proceedings, I will be back to the shops next week with more reusable bags than you can shake a stick at!
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Thanks to Stephanie of @Facing_South on Twitter for sharing the link to Dave Chameides' article. And if you're interested in further discussons on plastic bags, listen into BBC Three Counties Radio today (19th Jan) between 1-2pm where JVS will be discussing this very topic on his show.
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The evolution of costly traits: A challenge to a strict paleo diet orientation

The fundamental principle of the paleo diet movement is that we should model our diet on the diet of our ancestors. In other words, for optimal health, our diet should be as close to the diet of our ancestors as possible. Following this principle generally makes sense, but there are a number of problems with trying to follow it too strictly.

Some of those problems will have to wait for other posts. Examples are: our limited knowledge about what our ancestors really ate (some say: lean meat; others say: fatty meat); the fact that evolution can happen fast under certain circumstances (a few thousand years, not millions of years, thus recent and divergent adaptations are a possibility); the fact that among our ancestors some, like Homo erectus, were big meat eaters, but others, like Australopithecus afarensis, were vegetarians … Just to name a few problems.

The focus of this post is on traits that evolved in spite of being survival handicaps. These counterintuitive traits are often called costly traits, or Zahavian traits (in animal signalling contexts), in honor of the evolutionary biologist Amotz Zahavi (Zahavi & Zahavi, 1997). The implication for dieting is that our ancestors might have evolved some eating habits that are bad for human survival, and moved away from others that are good for survival. And I am not only talking about survival among modern humans; I am talking about survival among our human ancestors too.

Here is the most interesting aspect of these types of traits. Our ancestors may have acquired them through genetic mutation and selection (as opposed to genetic drift, which may lead some traits to evolve by chance). That is, they emerged not in spite, but because of evolutionary pressures.

The simple reason is that evolution maximizes reproductive success, not survival. If that were not the case, mice species, as well as other species that specialize in fast reproduction within relatively short lifespans, would never have evolved.

In fact, excessive longevity is akin to quasi-cloning through asexual reproduction, from an evolutionary perspective. It is bad because species need genetic diversity to exist in a constantly changing environment, and genetic diversity is significantly increased by sexual reproduction; the more, the better. Without plenty of death to match that, overpopulation would ensue.

Death is one of evolution’s main allies.

Genes code for the expression of phenotypic traits, such as behavioral (e.g., aggressiveness) and morphological (e.g., opposing thumbs) traits. Costly traits are phenotypic traits that evolved in spite of imposing a fitness cost, often in the form of a survival handicap.

In non-human animals, the classic example of costly trait is the peacock’s train, used by males to signal good health to females. This trait is usually referred to, wrongly, as the male peacock’s tail. Both males and females have tails, but only the males have the large trains, which are actually tail appendages.

What about humans?

One example is the evolution of testosterone markers in human males. Testosterone markers (facial masculinity) have been hypothesized to be handicaps evolved in part by human males to signal to females that they are healthy, essentially because testosterone suppresses the immune system. This apparently bizarre idea is known as the immunocompetence-handicap hypothesis (Rhodes et al., 2003).

This idea will sound bizarre to some, because of the notion that testosterone helps build muscle mass (which it does, together with other hormones, such as insulin), and arguably muscle mass helped our ancestors hunt and fight off predators. Yet, consider the following questions: If muscularity was so useful for hunting and fighting, why are humans so weak compared with other animals of similar size? Why are not females as muscular as males? Why is it so hard to gain muscle mass, compared to fat mass?

Another example is the evolution of oral speech in humans. The evolution of oral speech is one of the most important landmarks in the evolution of the human species, having happened relatively recently in our evolutionary history. However, the new larynx design required for oral speech also significantly increased our ancestors’ chances of death by choking during ingestion of food and liquids, and of suffering from various aerodigestive tract diseases such as gastroesophageal reflux, among other survival-related problems.

Yet, oral speech evolved because it enhanced overall reproductive success, in part by enabling knowledge communication (Kock, 2009), and also due to sexual selection (Miller, 2000). As Miller put it in his book The Mating Mind, ancestral women could gauge a man’s overall health by his ability to speak intelligently, in addition to other traits, such as testosterone markers.

Most of the sexual selection pressure during human evolution was placed by females on males, not the other way around. Ancestral women were more selective than men about who they had sex with; so are modern women, Sex and the City notwithstanding.

Now let us look at the connection with strict paleo dieting.

Paleo man may have consumed certain types of food to help with his testosterone handicap, increasing his reproductive success. As far as evolution is concerned, this is fine – the genes are selfish, and could not care less about the host (Burt & Trivers, 2006; Dawkins, 1990). The guy will mate, but will not live as long as he would like, past reproductive age. Given this possibility, does eating exactly like paleo man make sense for a 50 year old married male today? That is where too much of a focus on a paleo diet may be a problem.

Of course "paleo man" is really a metaphor. There was no "one" paleo man. There are at least three hominid species in the Paleolithic period that differed significantly from each other: Homo sapiens, Homo erectus, and Homo habilis. If you go back in time a little further, we encounter other hominid species, such Australopithecus afarensis and Australopithecus africanus, who were mostly, if not strictly, vegetarians.

Evolution is very useful as a unifying principle to help us understand what is healthy today and what is not. But it cannot completely replace empirical research on nutrition. Some of that research will undoubtedly uncover nutrition habits that increase longevity and improve health today, even though they were not practiced by our paleo ancestors.

We know that highly refined carbs (e.g., white bread with no fiber) and sugars (e.g., table sugar) are too recent an addition to the human diet for us to have evolved to use them optimally for nutrition. So their association with the metabolic syndrome makes sense, from an evolutionary perspective. But there are very gray areas where paleo nutrition speculations cannot tell us much, and what they tell us may be misleading.

References:

Burt, A. & Trivers, R. (2006). Genes in conflict: The biology of selfish genetic elements. Cambridge, MA: Harvard University Press.

Dawkins, R. (1990). The selfish gene. Oxford, UK: Oxford University Press.

Kock, N. (2009). The evolution of costly traits through selection and the importance of oral speech in e-collaboration. Electronic Markets, 19(4), 221-232.

Miller, G.F. (2000). The mating mind: How sexual choice shaped the evolution of human nature. New York, NY: Doubleday.

Rhodes, G., Chan, J., Zebrowitz, L.A., & Simmons, L.W. (2003). Does sexual dimorphism in human faces signal health? Proceedings of the Royal Society of London: Biology Letters, 270(S1), S93-S95.

Zahavi, A. & Zahavi, A. (1997). The Handicap Principle: A missing piece of Darwin’s puzzle. Oxford, England: Oxford University Press.

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