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).