Does "Metabolically Healthy Obesity" Exist?

Obesity is strongly associated with metabolic alterations and negative health outcomes including diabetes, cardiovascular disease, and some types of cancer (1, 2, 3, 4).  Excess body fat is one of the primary causes of preventable health problems and mortality in the United States and many other affluent nations, ranking in importance with cigarette smoking and physical inactivity.  Obesity is thought to contribute to disease via the metabolic disturbances it causes, including excess glucose and lipids in the circulation, dysregulated hormone activity including insulin and leptin, and inflammatory effects.  This immediately raises two questions:

1. Does metabolically healthy obesity exist?
2. If so, are metabolically healthy obese people at an elevated risk of disease and death?

Does metabolically healthy obesity exist?

Read more »

Atherosclerosis in Ancient Mummies Revisited

Many of you are already aware of the recent study that examined atherosclerosis in 137 ancient mummies from four different cultures (1).  Investigators used computed tomography (CT; a form of X-ray) to examine artery calcification in mummies from ancient Egypt, Peru, Puebloans, and arctic Unangan hunter-gatherers.  Artery calcification is the accumulation of calcium in the vessel wall, and it is a marker of severe atherosclerosis.  Where there is calcification, the artery wall is thickened and extensively damaged.  Not surprisingly, this is a risk factor for heart attack.  Pockets of calcification are typical as people age.

I'm not going to re-hash the paper in detail because that has been done elsewhere.  However, I do want to make a few key points about the study and its interpretation.  First, all groups had atherosclerosis to a similar degree, and it increased with advancing age.  This suggests that atherosclerosis may be part of the human condition, and not a modern disease.  Although it's interesting to have this confirmed in ancient mummies, we already knew this from cardiac autopsy data in a variety of non-industrial cultures (2, 3, 4, 5).

Read more »

The Kitavans: Wisdom from the Pacific Islands

There are very few cultures left on this planet that have not been affected by modern food habits. There are even fewer that have been studied thoroughly. The island of Kitava in Papua New Guinea is host to one such culture, and its inhabitants have many profound things to teach us about diet and health.

The Kitava study, a series of papers produced primarily by Dr. Staffan Lindeberg and his collaborators, offers a glimpse into the nutrition and health of an ancient society, using modern scientific methods. This study is one of the most complete and useful characterizations of the diet and health of a non-industrial society I have come across. It's also the study that created, and ultimately resolved, my cognitive dissonance over the health effects of carbohydrate.

From the photos I've seen, the Kitavans are beautiful people. They have the broad, attractive faces, smooth skin and excellent teeth typical of healthy non-industrial peoples.

Like the Kuna, Kitavans straddle the line between agricultural and hunter-gatherer lifestyles. They eat a diet primarily composed of tubers (yam, sweet potato, taro and cassava), fruit, vegetables, coconut and fish, in order of calories. This is typical of traditional Pacific island cultures, although the relative amounts differ.

Grains, refined sugar, vegetable oils and other processed foods are virtually nonexistent on Kitava. They get an estimated 69% of their calories from carbohydrate, 21% from fat, 17% from saturated fat and 10% from protein. Most of their fat intake is saturated because it comes from coconuts. They have an omega-6 : omega-3 ratio of approximately 1:2. Average caloric intake is 2,200 calories per day (9,200 kJ). By Western standards, their diet is high in carbohydrate, high in saturated fat, low in total fat, a bit low in protein and high in calories.

Now for a few relevant facts before we really start diving in:

• Kitavans are moderately active. They have an activity level comparable to a moderately active Swede, the population to which Dr. Lindeberg draws frequent comparisons.
  


• They have abundant food, and shortage is uncommon.
  


• Their good health is probably not related to genetics, since genetically similar groups in the same region are exquisitely sensitive to the ravages of industrial food. Furthermore, the only Kitavan who moved away from the island to live a modern life is also the only fat Kitavan.
  


• Their life expectancy at birth is estimated at 45 years (includes infant mortality), and life expectancy at age 50 is an additional 25 years. This is remarkable for a culture with limited access to modern medicine.
  


• Over 75% of Kitavans smoke cigarettes, although in small amounts. Even the most isolated societies have their modern vices.

The first study in the series is provocatively titled "Apparent absence of stroke and ischaemic heart disease in a traditional Melanesian island: a clinical study in Kitava." In it, Dr. Lindeberg presents data from interviews and electrocardiograms (ECG) suggesting that heart disease and stroke are absent or extremely rare on Kitava. The inhabitants are entirely unfamiliar with the (characteristic) symptoms of heart attack and stroke, despite the sizable elderly population. This is confirmed by the ECG findings, which indicate remarkable cardiovascular health. It also agrees with data from other traditional cultures in Papua New Guinea. Lindeberg states:

For the whole of PNG, no case of IHD or atherothrombotic stroke has been reported in clinical investigations and autopsy studies among traditionally living Melanesians for more than seven decades, though an increasing number of myocardial infarctions [heart attacks] and angina pectoris in urbanized populations have been reported since the 1960s.

Dementia was not found except in in two young Kitavans, who were born handicapped. The elderly remained sharp until death, including one man who reached 100 years of age. Kitavans are also unfamiliar with external cancers, with the exception of one possible case of breast cancer in an elderly woman.

Overall, Kitavans possess a resistance to degenerative diseases that is baffling to industrialized societies. Not only is this typical of non-industrial cultures, I believe it represents the natural state of existence for Homo sapiens. Like all other animals, humans are healthy and robust when occupying their preferred ecological niche. Our niche happens to be a particularly broad one, ranging from near-complete carnivory to plant-rich omnivory. But it does not include large amounts of industrial foods.

In the next few posts, I'll discuss more specific data about the health of the Kitavans.

Vitamin K2, menatetrenone (MK-4)

Weston Price established the importance of the MK-4 isoform of vitamin K2 (hereafter, K2) with a series of interesting experiments. He showed in chickens that blood levels of calcium and phosphorus depended both on vitamin A and K2, and that the two had synergistic effects on mineral absorption. He also showed that chickens preferred eating butter that was rich in K2 over butter low in K2, even when the investigators couldn't distinguish between them. Young turkeys fed K2-containing butter oil along with cod liver oil (A and D) also grew at a much faster rate than turkeys fed cod liver oil alone.

He hypothesized that vitamin A, vitamin D and vitamin K2 were synergistic and essential for proper growth and subsequent health. He particularly felt that the combination was important for proper mineral absorption and metabolism. He used a combination of high-vitamin cod liver oil and high-vitamin butter oil to heal cavities, reduce oral bacteria counts, and cure numerous other afflictions in his patients. He also showed that the healthy non-industrial groups he studied had a much higher intake of these fat-soluble, animal-derived vitamins than more modern cultures.

Price found an inverse correlation between the levels of K2 in butter and mortality from cardiovascular disease and pneumonia in a number of different regions. A recent study examined the relationship between K2 (MK-4 through 10) consumption and heart attack risk in 4,600 Dutch men. They found a strong inverse association between K2 consumption and heart attack mortality risk. Men with the highest K2 consumption had a whopping 51% lower risk of heart attack mortality and a 26% lower risk of death from all causes compared to men eating the least K2! Their sources of K2 MK-4 were eggs, meats and dairy. They obtained MK-5 through MK-10 from fermented foods and fish. The investigators found no association with K1, the form found in plants.

Perigord, France is the world's capital of foie gras, or fatty goose liver. Good news for the bon vivants: foie gras turns out to be the richest known source of K2. Perigord also has the lowest rate of cardiovascular mortality in France, a country already noted for its low CVD mortality.

Rats fed warfarin, a drug that inhibits K2 recycling, develop arterial calcification. Feeding the rats K2 completely inhibits this effect. Mice lacking matrix Gla protein (MGP), a vitamin K-dependent protein that guards against arterial calcification, develop heavily calcified aortas and die prematurely. So the link between K2 and cardiovascular disease is a very strong one.

Mammals can synthesize K2 MK-4 from K1 to some degree, so dietary K1 and other forms of vitamin K may contribute to K2 MK-4 status. 

The synergism Weston Price observed between vitamins A, D and K2 now has a solid mechanism. In a nutshell, vitamins A and D signal the production of some very important proteins, and K2 is required to activate them once they are made. Many of these proteins are involved in mineral metabolism, thus the effects Price saw in his experiments and observations in non-industrialized cultures. For example, osteocalcin is a protein that organizes calcium and phosphorus deposition in the bones and teeth. It's produced by cells in response to vitamins A and D, but requires K2 to perform its function. This suggests that the effects of vitamin D on bone health could be amplified greatly if it were administered along with K2. By itself, K2 is already highly protective against fractures in the elderly. It works out perfectly, since K2 also protects against vitamin D toxicity.

I'm not going to go through all the other data on K2 in detail, but suffice it to say it's very very important. I believe that K2 is a 'missing link' that explains many of our modern ills, just as Weston Price wrote. Here are a few more tidbits to whet your appetite: K2 may affect glucose control and insulin release (1, 2). It's concentrated in the brain, serving an as yet unknown function.

Hunter-gatherers didn't have multivitamins, they had nutrient-dense food. As long as you eat a natural diet containing some vegetables and some animal products, and lay off the processed grains, sugar and vegetable oil, the micronutrients will take care of themselves.

Vitamin K2, MK-4 is only found in animal products. The best sources known are grass-fed butter from cows eating rapidly growing grass, and foie gras. K2 tends to associate with beta-carotene in butter, so the darker the color, the more K2 it contains (also, the better it tastes). Fish eggs, other grass-fed dairy, shellfish, insects and other organ meats are also good sources. Chris Masterjohn compiled a list of food sources in his excellent article on the Weston Price foundation website. I highly recommend reading it if you want more detail. K2 MK-7 is found abundantly in natto, a type of fermented soybean, and it may be partially converted to MK-4.

Finally, you can also buy K2 supplements. The best one is butter oil, the very same stuff Price used to treat his patients. I have used this one personally, and I noticed positive effects on my skin overnight. Thorne research makes a synthetic liquid K2 MK-4 supplement that is easy to dose drop-wise to get natural amounts of it. Other K2 MK-4 supplements are much more concentrated than what you could get from food so I recommend avoiding them. I am generally against supplements, but I've ordered the Thorne product for a little self-experimentation. I want to see if it has the same effect on my skin as the butter oil (update- it does).

Nature's Laws

Last night I was watching a little video clip of the Jack LaLanne show. LaLanne was an advocate of strength training and whole foods nutrition whose TV show ran from the 1950s through the 1980s. In the clip, he describes how his father died an early death due to heart and liver disease. A quote that really stuck with me was when he said his father died due to "disregarding nature's laws". That pretty much sums up my philosophy. Live in a way that generally mimics what our genes evolved to thrive on. Why did our paleolithic ancestors have strong, healthy bodies? Why are there still cultures that are free of chronic disease to this day, even into old age? Because they are following nature's laws. Break the law at your own risk.

Jack LaLanne and I do differ a bit on what constitutes a natural diet. For example, I don't throw out my egg yolks... But hey, the man is 94 and going strong. Here's another quote of his: "If man made it, don't eat it". Words to live by. Quite literally.

Genetics and Disease

There is a lot of confusion surrounding the role of genetics in health. It seems like every day the media have a new story about gene X or Y 'causing' obesity, diabetes or heart disease. There are some diseases that are strongly and clearly linked to a gene, such as the disease I study: spinocerebellar ataxia type 7. I do not believe that genetics are the cause of more than a slim minority of health problems however. Part of this is a semantic issue. How do you define the word 'cause'? It's a difficult question, but I'll give you an example of my reasoning and then we'll come back to it.

A classic and thoroughly studied example of genetic factors in disease can be found in the Pima indians of Arizona. Currently, this population eats a version of the American diet, high in refined and processed foods. It also has the highest prevalence of type II diabetes of any population on earth (much higher than the US average), and a very high rate of obesity. One viewpoint is that these people are genetically susceptible to obesity and diabetes, and thus their genes are the cause of their health problems.

However, if you walk across the national border to Mexico, you'll find another group of Pima indians. This population is genetically very similar to the Arizona Pima except they have low rates of obesity and diabetes. They eat a healthier, whole-foods, agriculture-based diet. Furthermore, 200 years ago, the Arizona Pima were healthy as well. So what's the cause of disease here? Strictly speaking, it's both genetics and lifestyle. Both of these factors are necessary for the health problems of the Arizona Pima. However, I think it's more helpful to think of lifestyle as the cause of disease, since that's the factor that changed.

The Pima are a useful analogy for the world in general. They are an extreme example of what has happened to many if not all modern societies. Thus, when we talk about the 'obesity gene' or the 'heart disease gene', it's misleading. It's only the 'obesity gene' in the context of a lifestyle to which we are not genetically adapted.

I do not believe that over half of paleolithic humans were overweight, or that 20% had serious blood glucose imbalances. In fact, studies of remaining populations living naturally and traditionally have shown that they are typically much healthier than industrialized humans. Yet here we are in the US, carrying the very same genes as our ancestors, sick as dogs. That's not all though: we're actually getting sicker. Obesity, diabetes, allergies and many other problems are on the rise, despite the fact that our genes haven't changed.

I conclude that genetics are only rarely the cause of disease, and that the vast majority of health problems in the US are lifestyle-related. Studies into the genetic factors that predispose us to common health problems are interesting, but they're a distraction from the real problems and the real solutions that are staring us in the face. These solutions are to promote a healthy diet, exercise, and effective stress management.