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.

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.

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.

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.

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.

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).