Thursday, January 29, 2009

Seafood and Vitamin K2

In his travels around the globe, Dr. Weston Price found that the most robust groups were often those who had access to marine and freshwater foods. For example, Polynesian groups had a tooth decay prevalence as low as 0.6% of teeth. That's roughly one in 5 people with even a single cavity, in a population that doesn't brush its teeth, drink fluoridated water or go to the dentist. These individuals had broad dental arches, straight teeth, and fully erupted wisdom teeth as well.

As soon as they adopted white flour and sugar as dietary staples, the tooth decay prevalence of Polynesian groups went as high as 33.4% of teeth, or about 11 cavities per person. This represents a 5,600% increase in the prevalence of tooth decay. The next generation to be born also suffered from characteristic facial and skeletal abnormalities that are common in modern societies to varying degrees.

This leads me to ask the question, what is unique about seafood that allows it to support excellent development and maintenance of the human body? Seafood has a lot of advantages. It tends to be very rich in minerals, particularly iodine which can be lacking in land foods. It's also a good source of omega-3 fatty acids and low but adequate in linoleic acid (omega-6). This impacts development and maintenance in a number of ways, from fat mass to dental health.

As I wrote in the last post and others, I believe that one of the major determinants of proper development and continued health is the diet's content of the fat-soluble vitamins A, D and K2. K2 in particular is rare in the modern diet. We're also deficient in vitamin D because of our indoor lifestyles and use of sunscreen. Polynesians didn't have to worry about vitamin D because they spent much of the day outside half naked.

How about K2? Is seafood a good source? At first glance, it doesn't appear to be. Mackerel is the best source I came across on NutritionData, with one serving delivering 5.6 micrograms of vitamin K. It wasn't specified, but only a portion of that will be vitamin K2 MK-4, with the majority probably coming from K1. Most other types of fish have very low levels of vitamin K.

But we have to probe deeper. Nutrition information for fish refers to muscle tissue. Muscle is a poor source of K2 in mammals, could that be the case in fish as well? It turns out, the organs are the best source of K2 MK-4 in fish, just as they are in mammals. It's most concentrated in the liver, kidneys, heart and gonads. This loosely resembles the situation in mammals, which also retain MK-4 in their kidneys and gonads (along with pancreas, salivary glands, and brain).

I don't know how frequently traditional non-industrial cultures ate fish organs. My guess is they discarded most of them as do modern cultures, because they smell funny and putrefy rapidly. There are some exceptions, however. Certain traditional cultures ate fish livers, cod for example. Price described a dish eaten by a healthy, isolated Gaelic group in Nutrition and Physical Degeneration:
An important and highly relished article of diet has been baked cod's head stuffed with chopped cod's liver and oatmeal.
Gonads are one of the richest sources of K2 MK-4 in fish, containing 5-10 micrograms of MK-4 per kilogram of tissue in a few different species (according to this paper). Even that is not really an impressive concentration.

One thing that is universally relished by traditional groups is fish eggs, which of course develop from the gonads. A number of cultures dried fish eggs, sometimes trading them far into the interior. Although they haven't been analyzed for MK-4 content in modern times, Price found fish eggs to be a rich source of K2. Speaking of vitamin K2, he said: "its presence is demonstrated readily in the butterfat of milk of mammals, the eggs of fishes and the organs and fats of animals". Unfortunately, Price's assay was not quantitative so we don't have numbers.

As mainstream medicine slowly catches up to the importance of vitamin K2 MK-4 that Price described in the 1940s, more foods are being tested. I think we'll see values for fish eggs in the near future. This will allow us to discriminate between two possibilities: 1) seafood is a good source of K2, or 2) the human requirement for K2 is not particularly high in the context of an otherwise healthy diet.

Tuesday, January 27, 2009

Vitamin K2 and Cranial Development

One of the things Dr. Weston Price noticed about healthy traditional cultures worldwide is their characteristically broad faces, broad dental arches and wide nostrils. Due to the breadth of their dental arches, they invariably had straight teeth and enough room for wisdom teeth. As soon as these same groups adopted white flour and sugar, the next generation to be born grew up with narrow faces, narrow dental arches, crowded teeth, pinched nostrils and a characteristic underdevelopment of the middle third of the face.

Here's an excerpt from Nutrition and Physical Degeneration, about traditional and modernized Swiss groups. Keep in mind these are Europeans we're talking about (although he found the same thing in all the races he studied):
The reader will scarcely believe it possible that such marked differences in facial form, in the shape of the dental arches, and in the health condition of the teeth as are to be noted when passing from the highly modernized lower valleys and plains country in Switzerland to the isolated high valleys can exist. Fig. 3 shows four girls with typically broad dental arches and regular arrangement of the teeth. They have been born and raised in the Loetschental Valley or other isolated valleys of Switzerland which provide the excellent nutrition that we have been reviewing.

Another change that is seen in passing from the isolated groups with their more nearly normal facial developments, to the groups of the lower valleys, is the marked irregularity of the teeth with narrowing of the arches and other facial features... While in the isolated groups not a single case of a typical mouth breather was found, many were seen among the children of the lower-plains group. The children studied were from ten to sixteen years of age.
Price attributed this physical change to a lack of minerals and the fat-soluble vitamins necessary to make good use of them: vitamin A, vitamin D and what he called "activator X"-- now known to be vitamin K2 MK-4. The healthy cultures he studied all had an adequate source of vitamin K2, but many ate very little K1 (which comes mostly from vegetables). Inhabitants of the Loetschental valley ate green vegetables only in summer, due to the valley's harsh climate. The rest of the year, the diet was limited chiefly to whole grain sourdough rye bread and pastured dairy products.

The dietary transitions Price observed were typically from mineral- and vitamin-rich whole foods to refined modern foods, predominantly white flour and sugar. The villagers of the Loetschental valley obtained their fat-soluble vitamins from pastured dairy, which is particularly rich in vitamin K2 MK-4.

In a modern society like the U.S., most people exhibit signs of poor cranial development. How many people do you know with perfectly straight teeth who never required braces? How many people do you know whose wisdom teeth erupted normally?

The archaeological record shows that our hunter-gatherer ancestors generally didn't have crooked teeth. Humans evolved to have dental arches in proportion to their tooth size, like all animals. Take a look at these chompers. That skull is from an archaeological site in the Sahara desert that predates agriculture in the region. Those beautiful teeth are typical of paleolithic humans and modern hunter-gatherers. Crooked teeth and impacted wisdom teeth are only as old as agriculture. However, Price found that with care, certain traditional cultures were able to build well-formed skulls on an agricultural diet.

So was Price on to something, or was he just cherry picking individuals that supported his hypothesis? It turns out there's a developmental syndrome in the literature that might shed some light on this. It's called Binder's syndrome. Here's a description from a review paper about Binder's syndrome (emphasis mine):

The essential features of maxillo-nasal dysplasia were initially described by Noyes in 1939, although it was Binder who first defined it as a distinct clinical syndrome. He reported on three cases and recorded six specific characteristics:5

  • Arhinoid face.
  • Abnormal position of nasal bones.
  • Inter-maxillary hypoplasia with associated malocclusion.
  • Reduced or absent anterior nasal spine.
  • Atrophy of nasal mucosa.
  • Absence of frontal sinus (not obligatory).
Individuals with Binder's syndrome have a characteristic appearance that is easily recognizable.6 The mid-face profile is hypoplastic, the nose is flattened, the upper lip is convex with a broad philtrum, the nostrils are typically crescent or semi-lunar in shape due to the short collumela, and a deep fold or fossa occurs between the upper lip and the nose, resulting in an acute nasolabial angle.
Allow me to translate: in Binder's patients, the middle third of the face is underdeveloped, they have narrow dental arches and crowded teeth, small nostrils and abnormally small sinuses (sometimes resulting in mouth breathing). Sound familiar? So what causes Binder's syndrome? I'll give you a hint: it can be caused by prenatal exposure to warfarin (coumadin).

Warfarin is rat poison. It kills rats by causing them to lose their ability to form blood clots, resulting in massive hemmorhage. It does this by depleting vitamin K, which is necessary for the proper functioning of blood clotting factors. It's used (in small doses) in humans to thin the blood as a treatment for abnormal blood clots. As it turns out, Binder's syndrome can be caused by
a number of things that interfere with vitamin K metabolism. The sensitive period for humans is the first trimester. I think we're getting warmer...

Another name for Binder's syndrome is "warfarin embryopathy". There happens to be
a rat model of it. Dr. Bill Webster's group at the University of Sydney injected rats daily with warfarin for up to 12 weeks, beginning on the day they were born (rats have a different developmental timeline than humans). They also administered large doses of vitamin K1 along with it. This is to ensure the rats continue to clot normally, rather than hemorrhaging. Another notable property of warfarin that I've mentioned before is its ability to inhibit the conversion of vitamin K1 to vitamin K2 MK-4. Here's what they had to say about the rats:
The warfarin-treated rats developed a marked maxillonasal hypoplasia associated with a 11-13% reduction in the length of the nasal bones compared with controls... It is proposed that (1) the facial features of the human warfarin embryopathy are caused by reduced growth of the embryonic nasal septum, and (2) the septal growth retardation occurs because the warfarin-induced extrahepatic vitamin K deficiency prevents the normal formation of the vitamin K-dependent matrix gla protein in the embryo.
"Maxillonasal hypoplasia" means underdevelopment of the jaws and nasal region. Proper development of this region requires fully active matrix gla protein (MGP), which I've written about before in the context of vascular calcification. MGP requires vitamin K to activate it, and it seems to prefer K2 MK-4 to K1, at least in the vasculature. Administering K2 MK-4 along with warfarin prevents warfarin's ability to cause arterial calcification (thought to be an MGP-dependent mechanism), whereas administering K1 does not.

Here are a few quotes from a review paper by Dr. Webster's group. I have to post the whole abstract because it's a gem:
The normal vitamin K status of the human embryo appears to be close to deficiency [I would argue in most cases the embryo is actually deficient, as are most adults in industrial societies]. Maternal dietary deficiency or use of a number of therapeutic drugs during pregnancy, may result in frank vitamin K deficiency in the embryo. First trimester deficiency results in maxillonasal hypoplasia in the neonate with subsequent facial and orthodontic implications. A rat model of the vitamin K deficiency embryopathy shows that the facial dysmorphology is preceded by uncontrolled calcification in the normally uncalcified nasal septal cartilage, and decreased longitudinal growth of the cartilage, resulting in maxillonasal hypoplasia. The developing septal cartilage is normally rich in the vitamin K-dependent protein matrix gla protein (MGP). It is proposed that functional MGP is necessary to maintain growing cartilage in a non-calcified state. Developing teeth contain both MGP and a second vitamin K-dependent protein, bone gla protein (BGP). It has been postulated that these proteins have a functional role in tooth mineralization. As yet this function has not been established and abnormalities in tooth formation have not been observed under conditions where BGP and MGP should be formed in a non-functional form.
I think there's a good case to be made that most people in modern societies exhibit some degree of "Binder's syndrome" due to subclinical vitamin K2 deficiency during growth. I believe the evidence suggests that prenatal vitamin K2 MK-4 deficiency is behind narrow dental arches, crooked teeth, underdevelopment of the face and jaw, underdevelopment of the sinuses with mouth breathing in some cases, and poor tooth development resulting in a high susceptibility to dental cavities.

These symptoms are so common they are viewed as normal in industrial societies. There is no other single factor that so elegantly explains these characteristic changes in cranial form.
Rickets (vitamin D deficiency during growth) also causes cranial malformations, but they are distinct from those caused by K2 deficiency.

Humans do not efficiently convert K1 into K2 MK-4 (unlike rats), so we require a ready source of K2 in the diet. Our hunter-gatherer ancestors had a relatively high intake of K2 MK-4 from the organs of wild animals (particularly brain, pancreas, and marrow), insects and seafood. Our food supply today is depleted of K2, due to our avoidance of organ meats and poor animal husbandry practices. K2 MK-4 is found only in animal products. Pastured dairy is the most convenient source of K2 MK-4 in the modern diet, just as it was for the villagers of the Loetschental valley when Dr. Price visited them. Dairy from grain-fed cows contains much less K2.

Price felt that to ensure the proper development of their children, mothers should eat a diet rich in fat-soluble vitamins both before and during pregnancy. This makes sense in light of what we now know. There is a pool of vitamin K2 MK-4 in the organs that turns over very slowly, in addition to a pool in the blood that turns over rapidly. Entering pregnancy with a full store means a greater chance of having enough of the vitamin for the growing fetus. Healthy traditional cultures often fed special foods rich in fat-soluble vitamins to women of childbearing age and expectant mothers, thus ensuring beautiful and robust progeny.

Sunday, January 25, 2009

The Tokelau Island Migrant Study: The Final Word

Over the course of the last month, I've outlined some of the major findings of the Tokelau Island Migrant study. It's one of the most comprehensive studies I've found of a traditional culture transitioning to a modern diet and lifestyle. It traces the health of the inhabitants of the Pacific island Tokelau over time, as well as the health of Tokelauan migrants to New Zealand.

Unfortunately, the study began after the introduction of modern foods. We will never know for sure what Tokelauan health was like when their diet was completely traditional. To get some idea, we have to look at other traditional Pacific islanders such as the Kitavans.

What we can say is that an increase in the consumption of modern foods on Tokelau, chiefly white wheat flour and refined sugar, correlated with an increase in several non-communicable disorders, including overweight, diabetes and severe tooth decay. Further modernization as Tokelauans migrated to New Zealand corresponded with an increase in nearly every disorder measured, including heart disease, weight gain, diabetes, asthma and gout. These are all "diseases of civilization", which are not observed in hunter-gatherers and certain non-industrial populations throughout the world.

One of the most interesting things about Tokelauans is their extreme saturated fat intake, 40- 50% of calories. That's more than any other population I'm aware of. Yet Tokelauans appear to have a low incidence of heart attacks, lower than their New Zealand- dwelling relatives who eat half as much saturated fat. This should not be buried in the scientific literature; it should be common knowledge.

Overall, I believe the Tokelau Island Migrant study (among others) shows us that partially replacing nourishing traditional foods with modern foods such as processed wheat and sugar, is enough to cause a broad range of disorders not seen in hunter-gatherers but typical of modern societies. Changes in vitamin D status between Tokelau and New Zealand may have also played a role, due to the more indoor lifestyle of migrants.

The Tokelau Island Migrant Study: Background and Overview
The Tokelau Island Migrant Study: Dental Health
The Tokelau Island Migrant Study: Cholesterol and Cardiovascular Health
The Tokelau Island Migrant Study: Weight Gain
The Tokelau Island Migrant Study: Diabetes
The Tokelau Island Migrant Study: Asthma

Saturday, January 24, 2009

The Tokelau Island Migrant Study: Gout

Gout is a disorder in which uric acid crystals form in the joints, causing intense pain. The body forms uric acid as a by-product of purine metabolism. Purines are a building block of DNA, among other things. Uric acid is normally excreted into the urine, hence the name.

On Tokelau between 1971 and 1982, gout prevalence fell slightly. In migrants to New Zealand, gout prevalence began at the same level as on Tokelau but increased rapidly over the same time period. Here are the prevalence data for men, from Migration and Health in a Small Society: the Case of Tokelau (I don't have data for women):

This paper found that the age-standardized risk of developing gout was 9 times higher in New Zealand than on Tokelau for men, and 2.7 times higher for women.

Gout is usually treated by taking drugs and avoiding purine-rich foods. According to Wikipedia's entry on purines, these include:
sweetbreads [calf thymus or pancreas], anchovies, sardines, liver, beef kidneys, brains, meat extracts (e.g Oxo, Bovril), herring, mackerel, scallops, game meats, and gravy. A moderate amount of purine is also contained in beef, pork, poultry, fish and seafood, asparagus, cauliflower, spinach, mushrooms, green peas, lentils, dried peas, beans, oatmeal, wheat bran and wheat germ.
Those include some of the most nutritious foods available! The idea that the human body would not have evolved to tolerate most of the foods listed above is beyond comprehension, given our species' carnivorous tendencies. As a matter of fact, the only controlled trial I found suggests that a diet high in purines from animal protein has no effect on the uric acid concentration in the blood, because the body simply excretes any excess. In any case, like cholesterol, the majority of purines in the body are synthesized on-site, rather than coming from the diet. The only thing I found in support of the purine-gout hypothesis was a prospective study from 2004 that found an association between dietary purines and gout. I think we need to consider other possibilities.

Is there anything else that elevates uric acid in humans? Ah, sugar, one of my favorite punching bags. You never let me down, old friend. Refined sugar (sucrose) increases serum uric acid under controlled conditions, as does fructose when compared to starch. This has never been demonstrated for purine-rich foods that I could find.

Another clue comes from a disorder called "hereditary fructose intolerance". These patients are missing an enzyme required for metabolizing fructose, and must avoid it or risk becoming very ill. Some of the relatives of these patients are "heterozygous" for the mutation, meaning they have one mutated copy of the gene and one normal copy. They can metabolize fructose, but at a slower rate than someone with two functional copies. And they also have a very high incidence of gout.

Tokelauan migrants to New Zealand consumed significantly more sugar than Tokelauans on Tokelau during this study period (13 vs. 8 percent of calories in 1982). This explanation makes much more sense to me than the idea that gout is caused by the very foods that have sustained us as long as our species has existed.

There is one piece that doesn't fit, however. If sugar is causing gout, then why didn't gout incidence increase on Tokelau as their sugar consumption increased? I don't know. Perhaps there is another factor involved as well. Any thoughts?

The Tokelau Island Migrant Study: Background and Overview
The Tokelau Island Migrant Study: Dental Health
The Tokelau Island Migrant Study: Cholesterol and Cardiovascular Health
The Tokelau Island Migrant Study: Weight Gain
The Tokelau Island Migrant Study: Diabetes
The Tokelau Island Migrant Study: Asthma

Wednesday, January 21, 2009

The Tokelau Island Migrant Study: Asthma

Asthma is another disease of civilization. Between 1980 and 2001, its prevalence more than doubled in American children 17 years and younger. The trend is showing no sign of slowing down (CDC NHANES surveys).

The age-standardized asthma prevalence in Tokelauan migrants to New Zealand age 15 and older, was 2 - 6 times higher than in non-migrants from 1976 to 1982, depending on gender and year. The highest prevalence was in New Zealand migrant women in 1976, at 6.8%. The lowest was in Tokelauan men in 1976 at 1.1%.

A skeptic might suggest it's because these adults grew up around certain types of pollen or other antigens, and were exposed to new ones later in life. However, even migrant children in the 0-4 age group, who were most likely born in NZ, had more asthma than on Tokelau.

What could contribute to the increased asthma prevalence upon modernization? I'm not particularly knowledgeable about the mechanisms of asthma, but it seems likely to involve a chronic over-activation of the immune system ("inflammation"). In the case of Tokelauans, this could result from wheat gluten, an excessive sugar intake, and/or insufficient vitamin D. All three are potential culprits in my opinion. Stress may also play a role.

Anecdotally, many people report freedom from asthma and allergies after adopting a "paleolithic"-style or low-carbohydrate diet. I feel that's consistent with the effects of a good diet on inflammation. If you reduce or eliminate the chief offenders-- wheat, sugar, industrial vegetable oil and other processed food-- you will most likely reduce your level of chronic inflammation, which seems to be tied to many modern disorders.

The Tokelau Island Migrant Study: Background and Overview
The Tokelau Island Migrant Study: Dental Health
The Tokelau Island Migrant Study: Cholesterol and Cardiovascular Health
The Tokelau Island Migrant Study: Weight Gain
The Tokelau Island Migrant Study: Diabetes

The Tokelau Island Migrant Study data in this post come from the book Migration and Health in a Small Society: The Case of Tokelau.

Thanks to the EPA and Wikipedia for the graph image (public domain).

Monday, January 19, 2009

The Tokelau Island Migrant Study: Diabetes

This post will be short and sweet. Diabetes is a disease of civilization. As Tokelauans adopted Western industrial foods, their diabetes prevalence increased. At any given time point, age-standardized diabetes prevalence was higher in migrants to New Zealand than those who remained on Tokelau:

This is not a difference in diagnosis. Tokelauans were examined for diabetes by the same group of physicians, using the same criteria. It's also not a difference in average age, sice the numbers are age-standardized. On Tokelau, diabetes prevalence doubled in a decade. Migrants to New Zealand in 1981 had roughly three times the prevalence of diabetes that Tokelauans did in 1971. I can only imagine the prevalence is even higher in 2008.

We don't know what the prevalence was in Tokelauans when their diet was completely traditional, but I would expect it to be low like other traditional Pacific island societies. I'm looking at a table right now of age-standardized diabetes prevalence on 11 different Pacific islands. There is quite a bit of variation, but the pattern is clear: the more modernized, the higher the diabetes rate. In several cases, the table has placed two values side-by-side: one value for rural inhabitants of an island, and another for urban inhabitants of the same island. In every case, the prevalence of diabetes is higher in the urban group. In some cases, the difference is as large as four-fold.

The lowest value goes to the New Caledonians of Touho, who are also considered the least modernized on the table (although even their diet is not completely traditional). Men have an age-standardized diabetes prevalence of 1.8%, women 1.4%. At the other extreme are the Micronesians of Nauru, affluent due to phosphate resources, who have a prevalence of 33.4% for men and 32.1% for women. They subsist mostly on imported food and are extremely obese.

The same patterns can be seen in Africa, the Arctic and probably everywhere that has adopted processed Western foods. White rice alone (compared with the combination of wheat flour and sugar) does not seem to have this effect.

The data in this post are from the book Migration and Health in a Small Society: the Case of Tokelau.

The Tokelau Island Migrant Study: Background and Overview

The Tokelau Island Migrant Study: Dental Health
The Tokelau Island Migrant Study: Cholesterol and Cardiovascular Health
The Tokelau Island Migrant Study: Weight Gain

Sunday, January 18, 2009

Insulin, Leptin, Aging and Health

I recently read an article by Dr. Ron Rosedale that I found through commenter Stan's blog. Dr. Rosedale is one of those rare individuals who is capable of taking a truly big-picture view of health and aging, incorporating evolutionary biology, genetics and medicine into a coherent whole. The article discusses the role of the master hormones insulin and leptin in aging, health and disease.

I don't agree with everything he says, but I think it's a great article to read if you want a general orientation on the role of these hormones in health.

If you've read it, here are my main points of disagreement:
  1. Dr. Rosedale says that insulin's ability to regulate blood sugar is a minor role, and that other hormones do the same thing. Tell that to a type 1 diabetic. Excessive blood glucose is Not Good, and that's what you get if there isn't enough insulin around.
  2. I'm not convinced by the theory that organisms balance reproduction and repair, emphasizing one at the expense of the other. The amount of energy it takes to fuel cellular repair processes is negligible compared to the amount it takes to maintain body temperature, fuel the brain and contract skeletal muscles. Why not just have the organism eat an extra half-teaspoon of mashed potatoes to fuel the heat-shock proteins and make a little extra catalase? I think the true reasons behind lifespan extension upon caloric restriction will turn out to be more complex than a balance between reproduction and repair.
  3. I disagree with the idea that carbohydrate itself is behind elevated fasting insulin and leptin. Just look at the Kitavans. They get 69% of their calories from high-glycemic-load carbohydrates, with not much fat (21%) or protein (10%) to slow digestion. Yet, they have low fasting insulin and remarkably low fasting leptin. I believe the fasting levels of these hormones are more responsive to macronutrient quality than quantity. In other words, what matters most is not how much carbohydrate is in the diet, but where the carbohydrate comes from. The modern Western combination of carelessly processed wheat, sugar and linoleic acid-rich vegetable oil seems to be particularly harmful.

Friday, January 16, 2009

The Tokelau Island Migrant Study: Weight Gain

Between 1968 and 1982, Tokelauans in nearly all age groups gained weight, roughly 5 kilograms (11 pounds) on average. They also became slightly taller, but not enough to offset the gain in weight. By 1980-82, migrants to New Zealand had become especially heavy, with all age groups weighing more than non-migrants by about 5 kg (11 lb) on average, and 10 kg (22 lb) more than Tokelauans did in 1968.

The body mass index (BMI) is a rough estimate of fat mass (although it can be confounded by muscle mass), and is the weight in kilograms divided by the square of the height in meters [BMI = weight / (height^2)]. A BMI of 25 to 30 is considered overweight; 30 and over is considered obese.

The graphs I'm about to present require some explanation. The data in each graph were collected from the same individuals over time (15-69 years old). That means some weight gain is expected, as this population normally gains weight into middle age (then loses weight). What's interesting to note is the difference in the rate of weight change between migrants and non-migrants. The first two data points in 1968 are baseline, and compare non-migrants with "pre-migrants" still living on Tokelau. The second two data points in 1981-82 compare the same individual migrants in New Zealand with the same non-migrants.
Unless they all decided to become body builders, migrants to New Zealand gained more fat mass than Tokelauans between 1968 and 1982. The rate of weight gain in New Zealand was more than twice as fast for men and more than 50% faster for women than on Tokelau.

Why did Tokelauans and especially migrants to New Zealand gain weight? I can't say for sure, but this is a blog so I get to speculate. I've noticed an interesting association between the appearance of wheat and weight gain in a number of cultures, even if it replaces another refined carbohydrate such as rice. Sugar, although it may not cause weight gain directly, contributes to insulin resistance and leptin resistance, which may interfere with the body's ability to regulate weight. The introduction of wheat and sugar, at the expense of coconut and traditional carbohydrate sources, was the main change to the Tokelauan diet during this time period. See this post for a graph.

Finally, there's the question of exercise. Did a change in energy expenditure contribute to weight gain? The study didn't collect data on exercise during the time period in question, so all we have are anecdotes. During this time, men living on Tokelau progressively adopted outboard motors for their fishing boats, replacing the traditional sails and oars. Their energy expenditure probably decreased.

But what about women? Tokelauan women traditionally perform household tasks such as weaving mats and preparing food. Their energy expenditure probably didn't change much over the same time period. Since both men and women on Tokelau gained weight, it would be hard to argue that exercise was a dominant factor.

How about migrants to New Zealand? Here's a quote from Migration and Health in a Small Society: the Case of Tokelau:
Overall it is our belief that most of the migrants expend greater energy in their work than is currently the case in Tokelau.
I don't think exercise is the key to reaching or maintaining a healthy weight. The key is maintaining the biological feedback loops that normally keep fat mass in a tight range. They function by regulating the balance between energy intake and energy expenditure. I believe they are most influenced by diet, although exercise also contributes. I'll write more about this another time.

Wednesday, January 14, 2009

The Tokelau Island Migrant Study: Cholesterol and Cardiovascular Health

Let's get right to the meat of this study. It's a direct test of the idea that saturated fat is a cause of cardiovascular disease. If you were to design the perfect experiment to determine if saturated fat causes heart disease, and ethics were not a concern, how would you do it? You would stuff one group of people with as much saturated fat as they would eat for their entire lives, while feeding far less to a genetically identical group. Ideally, you would keep everything else about the diet and lifestyle the same. Then, you would measure some marker of cardiovascular disease, or even better, count actual heart attacks.

The Tokelau Island Migrant study isn't a perfect experiment, but it's about as close as we're going to get. Tokelauans traditionally obtained 40-50% of their calories from saturated fat, in the form of coconut meat. That's more than any other group I'm aware of, even topping the roughly 33% that the Masai get from their extremely fatty Zebu milk.

So are the Tokelauans dropping like flies of cardiovascular disease? I think most of the readers of this blog already know the answer to that question. I don't have access to the best data of all: actual heart attack incidence data. But we do have some telltale markers. In 1971-1982, researchers collected data from Tokelau and Tokelauan migrants to New Zealand on cholesterol levels, blood pressure and electrocardiogram (ECG) readings.

The Tokelauan diet, as I've described in detail in previous posts, is traditionally based on coconut, fish, starchy tubers and fruit. By 1982, their diet also contained a significant amount of imported flour and sugar. Migrants to New Zealand had a much more varied diet that was also more typically Western: more carbohydrate, coming chiefly from wheat, sugar and potatoes; more processed sweet foods and drinks; more red meat; more vegetables; more dairy and eggs. Sugar intake was 13 percent of calories, compared to 8 percent on Tokelau. Saturated fat intake in NZ was half of what it was on Tokelau, while total fat intake was similar. Polyunsaturated fat intake was higher in NZ, 4% as opposed to 2% in Tokelau. I don't have data to back this up, but I think it's likely that the n-6:n-3 ratio increased upon migration.

Blood pressure did not change significantly over time in Tokelau from 1971 to 1982, if anything it actually declined slightly. It was consistently higher in NZ than in Tokelau at all timepoints. Men were roughly three times more likely to be hypertensive in NZ than on Tokelau at all timepoints (4.0% vs. 12.0% in the early 1970s). Women were about twice as likely to be hypertensive (8.1% vs. 15.0%).

On to cholesterol. Total cholesterol in male Tokelauans was a bit lower on average than in New Zealand, but neither was particularly elevated (182 vs. 199 mg/dL). LDL was also a bit higher in NZ males (119 vs. 132 mg/dL). Get these guys on Lipitor!! Triglycerides were lower in Tokelauan men than in NZ (80 vs. 114 mg/dL). There were no differences in total cholesterol, LDL cholesterol or triglycerides between Tokelauan and NZ women.

These data would make Dr. Uffe Ravnskov smile (actually I'm sure he's aware of them). Much of the hoopla surrounding saturated fat is due to the fact that in controlled clinical trials, it seems to elevate blood cholesterol (by elevating both LDL and HDL). What Dr. Ravnskov and others have pointed out is that the correlation between saturated fat intake and blood cholesterol is weak, and in any case, so is the correlation between blood cholesterol and cardiovascular disease. This study lends support to the idea that saturated fat is not a major determinant of total cholesterol or LDL.

But does it cause heart attacks? The best data I have from this study are ECG readings. These use electrodes to monitor the electrical activity of the heart. There are certain ECG patterns that suggest that a person has had a heart attack (Minnesota codes 1-1 and 1-2). The data I am going to present here are all age-standardized, meaning they are comparing between groups of the same age. On Tokelau in 1982, 0.0% of men 40-69 years old showed ECG readings that indicated a probable past heart attack. In NZ in 1980-81, 1.0% of men 40-69 years old showed the same ECG readings. In Tecumseh U.S.A. in 1965, 3.5% of men 40-69 years old showed the same ECG pattern. I don't have data for women.

These data don't prove that no one ever has a heart attack on Tokelau. They do sometimes, and they also have strokes (at least in modern times). But they do allow us to compare in quantitative terms between genetically similar people living in two different environments.

This is consistent with what has been observed on Kitava and other traditional Pacific island cultures: a vanishingly small incidence of cardiovascular disease while they retain their traditional diet and lifestyle (and sometimes even when some processed Western food has been introduced). When diets and lifestyles become modern, there is invariably a rise in the incidence of chronic disease.

I don't believe that saturated fat contributes to cardiovascular disease. The best data available have never supported that hypothesis, even from the very beginning. The Tokelau Island Migrant study, among many others, should have put it out of its misery long ago. Tokelau underlines the fact that the most important determinant of health is a diet based on whole, natural foods that are familiar to the human metabolism, prepared in traditional ways that maximize their digestibility and nutritional value.

Unless otherwise noted, the data in this post are from the book Migration and Health in a Small Society: the Case of Tokelau.

Sunday, January 11, 2009

Back on Line

Hi folks. I've been battling some security problems with my Google account (among other accounts), hence the temporary absence. I think I have it under control now. You may have noticed that my photo keeps disappearing. That was not my doing.

Incidentally, if anyone has tried to contact me and hasn't gotten a response, try again. I may not have received your e-mail, so don't feel snubbed!

A few people have also complained of comments disappearing. The only time I ever delete a comment is if it's highly disrespectful (to myself or another commenter) or if it's an advertisement. I've only deleted one comment for being disrespectful, and it was a threat to another commenter. I don't believe in censorship here. Anyone is free to disagree with me at any time, as long as they can back it up. I value this blog as a forum for intelligent people to brainstorm together, and that inherently involves disagreement. So if you typed a civil comment and it disappeared, it's a glitch.

Tuesday, January 6, 2009

The Tokelau Island Migrant Study: Dental Health

I'm always on the lookout for studies that can confirm or deny the information in Nutrition and Physical Degeneration. Traveling around the world in the 1920s and 1930s, Dr. Weston Price found a number of non-industrial cultures that had excellent dental and overall health, including a high resistance to tooth decay, perfectly straight teeth, and wisdom teeth that erupted without impacting. These same cultures developed extreme dental problems, including severe dental decay and crooked teeth in the younger generation, upon adopting modern European foods. These foods always included white flour and refined sugar, with variable contributions from canned goods and vegetable oils.

I have detailed information on the Tokelauan diet beginning in 1968 and ending in 1982. The traditional diet until the 1960s consisted of coconut, fish, breadfruit, pulaka, fruit, pigs, chickens and wild fowl. These are typical Polynesian foods. From the 1960s through the 1980s, Tokelauans gradually adopted flour and sugar as major carbohydrate sources, partially displacing starchy breadfruit and pulaka intake as well as coconut. They also began eating low-quality canned meats that partially replaced fish in their diet. Total calorie intake fluctuated between 1,500 and 2,000 kilocalories but did not trend in any particular direction over time. Here's a graph of macronutrient changes:

I found a study on the dental health of Tokelauans that I thought would be a fitting way to kick off this series. It's titled "Changed oral conditions, between 1963 and 1999, in the population of the Tokelau atolls of the South Pacific". I was only able to get my hands on the abstract, but that was enough. In 1963, Tokelauans were consuming roughly 15 lb of white flour and 10 lb of sugar per person per year. By 1980, the numbers were 60 lb and 69 lb for flour and sugar, and the trend was showing no sign of slowing down (see the graph in the previous post). I don't have numbers for 1999, but they're likely to be higher than in 1980, given the trend. For comparison, in 2006, the average American ate 117 lb of flour per year.

Let's look at a graph. This represents the DMF score (decayed, missing or filled teeth) of Tokelauans 15-19 and 35-44 years old, in 1963 and 1999. I've connected the two data points with lines to give an idea of the trend.

Dental decay increased eight-fold in adolescents and more than four-fold in adults. I don't know what their dental health was like before 1963, but I can only guess it was better than when this study was conducted, due to the fact that the Tokelauan diet was already partially modernized in 1963. The authors conclude "a serious decline in oral health has occurred over the past 35 years."

Does this sound familiar? It should be, because it's been known at least since the 1930s. Here's a quote from Nutrition and Physical Degeneration, describing the Tongan islanders, another Polynesian group:
The limited importation of foods to the Tongan Islands due to the infrequent call of merchant or trading ships has required the people to remain largely on their native foods. Following the war, however, the price of copra went up from $40.00 per ton to $400.00, which brought trading ships with white flour and sugar to exchange for the copra. The effect of this is shown very clearly in the condition of the teeth. The incidence of dental caries [cavities] among the isolated groups living on native foods was 0.6 per cent, while for those around the port living in part on trade foods, it is 33.4 per cent. The effect of the imported food was clearly to be seen on the teeth of the people who were in the growth stage at that time [i.e., they developed crooked teeth]. Now the trader ships no longer call and this forced isolation is very clearly a blessing in disguise. Dental caries has largely ceased to be active since imported foods became scarce, for the price of copra fell to $4.00 a ton. The temporary rise in tooth decay was apparently directly associated with the calling of trader ships.
0.6 percent is one tooth in every 167. In other words, less than one in five people had even a single cavity. That's without the benefit of tooth brushing, fluoride or any of the tools of modern dentistry. 33.4 percent tooth decay in Tongans living on modern foods means they had 11 cavities per person, a bit less than Tokelauans had in 1999.

Weston Price's anecdote above is remarkably similar to something that happened on Tokelau in 1979. The atolls didn't receive their normal shipments of European foods for a five-month period, during which they resorted to traditional foods. Here's an excerpt from the New Zealand Herald from June 11, 1979:
What will happen the day the country runs out of fuel and the ships stop bringing those "essential" foods like sugar and flour? Tokelauans recently found out what the answer to that question was- they got healthier. One of the victims of cyclone Meli earlier this year was the passenger cargo ship Cenpac Rounder, chartered five times per year by the Tokelau Affairs office in Apia. Left high and dry on a reef South of Fiji it was badly damaged and could not be moved. So ever since January the three Tokelau atolls have not received fresh supplies. Late last month the first ship called in, chartered by the Tokelau Affairs office. The Secretary of the office said that when the ship arrived the atolls had run out of fuel. So the fishermen had returned to the traditional sail, a sight on the lagoon that had almost been forgotten, thanks to the outboard motor. There was no sugar, flour, tobacco and starch foods either- and the atoll hospitals reported a shortage of business during the enforced isolation. It was reported that the Tokelauans had been very healthy during that time and had returned to the pre-European diet of coconuts and fish. Many people lost weight and felt very much better including some of the diabetics.

Sunday, January 4, 2009

The Tokelau Island Migrant Study: Background and Overview

Tokelau's troubles began in 1765 with its 'discovery' by British commodore John Byron. Traditionally, residents of the three small coral atolls collectively called Tokelau (Nukunonu, Fakaofo and Atafu) lived an isolated subsistence lifestyle, relying almost exclusively on coconut, seafood, wild fowl and fruit for food. The first reliable account of the Tokelauan population, by an American expedition in 1841, found the people there healthy and happy. Here's an excerpt from Migration and Health in a Small Society: the Case of Tokelau (1992):
The expedition considered the people living there to be healthy and handsome... They all appeared to be thriving on their 'meager diet' of fish and coconut, for no evidence of cultivation was seen... People of both sexes were tattooed with geometric designs and figures of turtles and fish. The numerous reports and journals of the Expedition leave the impression of a generally admirable people - amiable (though cautious), peaceful, orderly, and resourceful.
Between 1841 and 1863, the population of Tokelau was reduced to a fraction of its original size by epidemics and kidnapping by slave ships. The old social and religious order was broken, and the inhabitants were converted to Christianity by overzealous and competing Protestant and Catholic missionaries. During this time, Tokelauans also gained new food sources from other Polynesian islands, including breadfruit trees, pulaka (a starchy tuber), pigs and chickens. Breadfruit is a starchy fruit used like plantain.

Tokelau became a territory of New Zealand in 1925, and Tokelauans were granted New Zealand citizenship in 1948. In 1963, a government-assisted migration program was established to (voluntarily) bring Tokelauans to the New Zealand mainland, as the population of Tokelau had reached a cozy 1,870 people. When a cyclone devastated coconut and breadfruit crops in 1966, Tokelauans began taking advantage of the assisted migration program in earnest. By 1971, roughly half of Tokelauans lived on the New Zealand mainland.

There are two reasons why the Tokelau Island Migrant study is unique. First, it's one of the best-documented transitions from a traditional to a modern lifestyle, studied over decades on Tokelau and in New Zealand. Regular visits by physicians recorded the health of the population as it shifted from a relatively traditional diet to a more Western one. The second thing that makes this population unique is they traditionally have an extraordinarily high saturated fat intake from coconut. They derive between 54 and 62 percent of their calories from coconut, which is 87% saturated. This gives them perhaps the highest documented saturated fat intake in the world. This will be a test of the "diet-heart hypothesis", the idea that dietary fat, cholesterol and especially saturated fat contribute to cardiovascular disease!

Through the late 1960s, cargo ships visited Tokelau every three months, making only small contributions to the islanders' diets. In 1968, just two percent of Tokelauans' calories came from sugar. By 1978, the number had risen to 8 percent, and by 1982, 14 percent. The increase came chiefly from refined sugar and sweetened imported foods. In 1961, ships brought 12 lb of flour per person per year to Tokelau, increasing to 60 lb per year by 1980. During this time, importation of low-quality canned meats such as "mutton flaps" and chicken backs, and sweets also increased. Rice imports declined in the 1970s. The diet of migrants to New Zealand rapidly became highly Westernized, containing a higher proportion of refined carbohydrates such as flour and sugar, more red meat and poultry, and less coconut and seafood.

Here's a nice quote from Migration and Health in a Small Society: the Case of Tokelau, to set the tone for the rest of the posts in this series:
In the mid- and late twentieth century, 'Western diseases'- that is, diseases of affluence (Trowell and Burkitt 1981)- have become the major health risk for Polynesians, because of exposure to cosmopolitan diet patterns and life-style.
The varying cultures and resource bases of islands in the Pacific have influenced the degree to which their populations have been modernized and thus exposed to Western diseases. At one end of the spectrum are relatively traditional subsistence societies such as those on Tokelau and on the low islands- for example Pukapuka, Manihiki, and Rakahanga in the Northern Cook Islands. These atolls are characterized by the almost complete absence of soil, by the inhabitants' dependence on coconut in varied forms, and by a bountiful supply of fish as a major part of the traditional diet. Their populations are notable for their low levels of blood pressure, high rates of infectious disease, and low rates of coronary heart disease, obesity and diabetes. At the other end of the spectrum are those Polynesian societies, such as the Hawaiians and the Maori of New Zealand, who were submerged by 'Western' settlers and the dominating cultures they brought with them. These populations have inevitably acquired the diseases of the 'West', sometimes to an exaggerated degree.
That quote could have been straight out of Nutrition and Physical Degeneration, despite being published 60 years later. Good science is timeless. Join me in future posts as I explore the health of Tokelauan society as it transitions from a traditional diet and lifestyle to a modern one.

Lard Retraction!

Folks, I have to apologize. It appears I was wrong about the high vitamin D content of lard. An astute reader pointed out to me that my reference for that was not very solid. Upon double checking it, I found that he was right. Lard from pasture-raised pigs (and tallow from pasture-raised cows) has about as much vitamin D as summer butter, which is enough to prevent rickets but not enough to make a major contribution to an optimum intake. So while pasture-raised leaf lard is still on my list of good fats, please don't rely on it to provide vitamin D. I'll be correcting my earlier posts. Sorry for the mistake.

Saturday, January 3, 2009

Vitamin D and Cancer

I'd like to point readers to a couple of posts by Richard Nikoley over at Free the Animal, on the relationship between vitamin D status and various types of cancer. The epidemiology consistently shows an inverse relationship between vitamin D levels and cancer incidence. A few intervention trials also support a protective role of vitamin D against cancer. Increased sunscreen use has not reduced melanoma incidence, to the contrary. I've discussed this before as well. Richard got his graphs from the website GrassrootsHealth.

Vitamin D deficiency and All Cancer

Melanoma, Sun and its Synthetic Defeat (sunscreen)

Vitamin D is not just another vitamin. It's a hormone precursor that plays a fundamental role in the regulation of numerous bodily processes. Sunlight is an essential nutrient for physical and mental health.

Here are the best natural sources of vitamin D:
  • Sunlight
  • High-vitamin cold liver oil
  • Summer blood from animals raised outdoors (for example, blood sausage)
  • Fatty fish
Vitamin D is one of the few nutrients that may be worth supplementing during wintertime. Make sure to buy D3 and take at least 2,000 IU if you are going to bother.

Thursday, January 1, 2009

More on Hydrogenated Fat

I stumbled on an interesting history of hydrogenated vegetable oil on the website Soy Info Center. It turns out, margarine was made out of animal fat before 1915. Hydrogenated vegetable shortening (Crisco) was introduced in 1911. Before that our intake of trans fat was very low, coming chiefly from dairy and meat (not the same as synthetic trans fats). Here's an excerpt from the website:
In 1909 Procter & Gamble in Cincinnati acquired the US rights to the Normann patent from Crosfield's and in 1911 they began marketing Crisco, the first hydrogenated shortening, which contained a large amount of cottonseed oil. In America, however, six other firms had been working since 1915 according to the patents of C.E. Kayser (1910) and Carleton Ellis (1912), and with a number of other processes, most of which were never published. After a long period of litigation, initiated by Procter & Gamble, for alleged infringement of patent rights, a US court decision held the 1915 Burchenal patent (US Patent 1,135,351), under whose broad claims P&G's shortening was then being made, to be invalid. This opened the way for a number of firms to begin manufacture of hydrogenated shortenings and, from 1915, margarines.
Hydrogenated vegetable oil wasn't widely eaten until 1920:
Before the use of hydrogenation, the production of shortening and margarine had been entirely dependent on animal fats as a source of raw materials. Increased demand soon caused these to grow scarce and expensive. Thus hydrogenation liberated shortening and margarine from their dependence on animal fats and made it possible for cooks to have products resembling lard and butter made from vegetable oils. Nevertheless it was not until after 1920 that hydrogenated vegetable oils were widely used in margarine and shortening. During the 1930s the use of hydrogenation worldwide took a quantum leap forward, as production increased greatly.

By the late 1970s roughly 60% of all edible oils and fats in the US were partially hydrogenated (Dutton, in Emken and Dutton 1979). And an estimated 75% of the soy oil used in the US was hydrogenated to make shortening and margarine, as well as large amounts of lightly hydrogenated soy cooking and salad oils (Kromer 1976).

Rizek et al. (1974) estimated that in the period from 1937 to 1972 per capita annual consumption of trans fatty acids increased by 81%, from 6.3-11.4 gm. During the same period per capita consumption of vegetable oils and fats increased by only 64% (from 36-59 gm).
Death from coronary heart disease was rare until 1925. It peaked in the 1950s, remaining high through the 1970s and diminishing only due to modern medical interventions. Coincidence? I don't know, but it's awfully suspicious.

Here is a description of the hydrogenation process. Makes my mouth water:
Typically, a mixture of refined oil and finely powdered nickel catalyst (comprising 0.05-0.1% of the weight of the oil) is pumped into a cylindrical pressure reactor of 5-20 tons capacity. It is heated by heating coils to 120-188°C (248-370°F) at 1-6 atmospheres pressure. Hydrogen is pumped into the bottom of the reactor and dispersed by a stirrer, continuously, as bubbles into the oil... After hydrogenation is completed to the desired degree, the oil is filtered to remove the catalyst (which may be reused) then pumped to a storage tank; it may later be blended with other harder or softer fats or oils to make margarine or shortening.
Who in his right mind would think this stuff is suitable for human consumption? Hydrogenated vegetable oil is ubiquitous in processed food, because of its low cost and long shelf life, although the amounts are diminishing since the FDA required it to be included on nutrition labels in 2006. The implication here is that consumers know it's unhealthy, but manufacturers aren't going to stop putting it in foods until someone shines a spotlight on them.

It will be interesting to see if CHD incidence drops with decreasing trans fat intake. The obesity epidemic does seem to be leveling off in the U.S. This also corresponds with other recent dietary improvements such as a small decrease in sugar, wheat and vegetable oil consumption (see this post).