Mortality and Lifespan of the Inuit

One of the classic counter-arguments that's used to discredit accounts of healthy hunter-gatherers is the fallacy that they were short-lived, and thus did not have time to develop diseases of old age like cancer. While the life expectancy of hunter-gatherers was not as high as ours today, most groups had a significant number of elderly individuals, who sometimes lived to 80 years and beyond. Mortality came mostly from accidents, warfare and infectious disease rather than chronic disease.

I found a a mortality table from the records of a Russian mission in Alaska (compiled by Veniaminov, taken from Cancer, Disease of Civilization), which recorded the ages of death of a traditionally-living Inuit population during the years 1822 to 1836. Here's a plot of the raw data:

Here's the data re-plotted in another way. I changed the "bin size" of the bars to 10 year spans each (rather than the bins above, which vary from 3 to 20 years). This allows us to get a better picture of the number of deaths over time. I took some liberties with the data to do this, breaking up a large bin equally into two smaller bins. I also left out the infant mortality data, which are interesting but not relevant to this post:


Excluding infant mortality, about 25% of their population lived past 60. Based on these data, the approximate life expectancy (excluding infant mortality) of this Inuit population was 43.5 years. It's possible that life expectancy would have been higher before contact with the Russians, since they introduced a number of nasty diseases to which the Inuit were not resistant. Keep in mind that the Westerners who were developing cancer alongside them probably had a similar life expectancy at the time. Here's the data plotted in yet another way, showing the number of individuals surviving at each age, out of the total deaths recorded:


It's remarkably linear. Here's the percent chance of death at each age:


In the next post, I'll briefly summarize cancer data from several traditionally-living cultures other than the Inuit.

Cancer Among the Inuit

I remember coming across a table in the book Eat, Drink and Be Healthy (by Dr. Walter Willett) a few years back. Included were data taken from Dr. Ancel Keys' "Seven Countries Study". It showed the cancer rates for three industrialized nations: the US, Greece and Japan. Although specific cancers differed, the overall rate was remarkably similar for all three: about 90 cancers per 100,000 people per year. Life expectancy was also similar, with Greece leading the pack by 4 years (the data are from the 60s).

The conclusion I drew at the time was that lifestyle did not affect the likelihood of developing cancer. It was easy to see from the same table that heart disease was largely preventable, since the US had a rate of 189 per 100,000 per year, compared to Japan's 34. Especially since I also knew that Japanese-Americans who eat an American diet get heart disease just like European-Americans.

I fell prey to the same logic that is so pervasive today: the idea that you will eventually die of cancer if no other disease gets you first. It's easy to believe, since the epidemiology seems to tell us that lifestyle doesn't affect overall cancer rates very much. There's only one little glitch... those epidemiological studies compare the sick to the sicker.

Here's the critical fact that modern medicine seems to have forgotten: hunter-gatherers and numerous non-industrial populations throughout the world have unusually low cancer rates. This idea was widely accepted in the 19th century and the early 20th, but has somehow managed to fade into obscurity.  Allow me to explain.

I recently read Cancer, Disease of Civilization by Vilhjalmur Stefansson (thanks Peter). Stefansson was an anthropologist and arctic explorer who participated in the search for cancer among the Canadian and Alaskan Inuit. Traditionally, most Inuit groups were mostly carnivorous, eating a diet of raw and cooked meat and fish almost exclusively. Their calories came primarily from fat. They alternated between seasons of low and high physical activity, typically enjoyed an abundant food supply yet also periodically faced famines.

Field physicians in the arctic noted that the Inuit were a remarkably healthy people. While they suffered from a tragic susceptibility to European communicable diseases, they did not develop the chronic diseases we now view as part of being human: tooth decay, overweight, heart attacks, appendicitis, constipation, diabetes and cancer. When word reached American and European physicians that the Inuit did not develop cancer, a number of them decided to mount an active search for it. This search began in the 1850s and tapered off in the 1920s, as traditionally-living Inuit became difficult to find.

One of these physicians was captain George B. Leavitt. He actively searched for cancer among the traditionally-living Inuit from 1885 to 1907. Along with his staff, he claims to have performed tens of thousands of examinations. He did not find a single case of cancer. At the same time, he was regularly diagnosing cancers among the crews of whaling ships and other Westernized populations. It's important to note two relevant facts about Inuit culture: first, their habit of going shirtless indoors. This would make visual inspection for external cancers very easy. Second, the Inuit generally had great faith in Western doctors and would consult them even for minor problems. Therefore, doctors in the arctic had ample opportunity to inspect them for cancer.

A study was published in 1934 by F.S. Fellows in the US Treasury's Public Health Reports entitled "Mortality in the Native Races of the Territory of Alaska, With Special Reference to Tuberculosis". It contained a table of cancer mortality deaths for several Alaskan regions, all of them Westernized to some degree. However, some were more Westernized than others. In descending order of Westernization, the percent of deaths from cancer were as follows:


Keep in mind that all four of the Inuit populations in this table were somewhat Westernized. It's clear that cancer incidence tracks well with Westernization, although other factors could be involved in producing this result (such as poorer diagnosis in less Westernized regions). By "Westernization", what I mean mostly is the adoption of European food habits, including wheat flour, sugar, canned goods and vegetable oil. Later, most groups also adopted Western-style houses, which incidentally were not at all suited to their harsh climate.

In the next post, I'll address the classic counter-argument that hunter-gatherers were free of cancer because they didn't live long enough to develop it.

Cancer and the Immune System

My understanding of cancer has changed radically over the past few months. I used to think of it as an inevitable consequence of aging, a stochastic certainty. The human body is made of about 50 trillion cells, many of which replicate their DNA and divide regularly. It's only a matter of time until one of those cells randomly accumulates the wrong set of mutations, and loses the molecular brakes that restrict uncontrolled growth.

Strictly speaking, the idea is correct. That is how cancer begins. However, there's another check in place that operates outside the cancer cell itself: the immune system. A properly functioning immune system can recognize and destroy cancerous cells before they become dangerous to the organism. In fact, your immune system has probably already controlled or destroyed a number of them in your lifetime.

I recently read a fascinating account of some preliminary findings from the lab of Dr. Zheng Cui at Wake Forest university. His group took blood samples from 100 people and purified a type of immune cell called the granulocyte. They then evaluated the granulocytes' ability to kill cervical cancer cells in a cell culture dish. They found that it varied dramatically from one individual to another. One person's granulocytes killed 97% of the cancer cells in 24 hours, while another person's killed 2%.

They found some important trends. Granulocytes from people over 50 years old had a reduced ability to kill cancer cells, as did granulocytes from people with cancer. This raises the possibility that cancer is not simply the result of getting too old, but a very specific weakening of the immune system.

The most important finding, however, was that the granulocytes' kung-fu grip declined dramatically during the winter months. Here's Dr. Cui:

Nobody seems to have any cancer-killing ability during the
winter months from November to April.

Hmm, I wonder why that could be?? Vitamin D anyone??

Celiac and Fat-Soluble Vitamins

One of the things I've been thinking about lately is the possibility that intestinal damage due to gluten grains (primarily wheat) contributes to the diseases of civilization by inhibiting the absorption of fat-soluble vitamins. If it were a contributing factor, we would expect to see a higher incidence of the common chronic diseases in newly-diagnosed celiac patients, who are often deficient in fat-soluble vitamins. We might also see a resolution of chronic disease in celiac patients who have been adhering faithfully to a long-term, gluten-free diet.

One thing that definitely associates with celiac disease is bone and tooth problems. Celiac patients often present with osteoporosis, osteopenia (thin bones), cavities or tooth enamel abnormalities (thanks Peter).

An Italian study showed that among 642 heart transplant candidates, 1.9% had anti-endomyosal antibodies (a feature of celiac), compared with 0.35% of controls. That's more than a 5-fold enrichment! The majority of those patients were presumably unaware of their celiac disease, so they were not eating a gluten-free diet.

Interestingly, celiac doesn't seem to cause obesity; to the contrary. That's one facet of modern health problems that it definitely does not cause.

The relationship between cancer and celiac disease is very interesting. The largest study I came across was conducted in Sweden using retrospective data from 12,000 celiac patients. They found that adult celiac patients have a higher overall risk of cancer, but that the extra risk disappears with age. The drop in cancer incidence may reflect dropping gluten following a celiac diagnosis. Here's another study showing that the elevated cancer risk occurs mostly in the first year after diagnosis, suggesting that eliminating gluten solves the problem. Interestingly, celiac patients have a greatly elevated risk of lymphoma, but a lower risk of breast cancer.

There's a very strong link between celiac and type I diabetes. In a large study, 1 in 8 type I diabetic children had celiac disease. This doesn't necessarily tell us much since celiac and type I diabetes are both autoimmune disorders.

One last study to add a nail to the coffin. Up to this point, all the studies I've mentioned have been purely observational, not able to establish a causal relationship. I came across a small study recently which examined the effect of a high-fiber diet on vitamin D metabolism in healthy (presumably non-celiac) adults. They broke the cohort up into two groups, and fed one group 20g of bran in addition to their normal diet. The other group got nothing extra. The bran-fed group had a vitamin D elimination half-life of 19.5 days, compared to 27.5 for the control group. In other words, for whatever reason, the group eating extra bran was burning through their vitamin D reserves 30% faster than the control group.

Unfortunately, the paper doesn't say what kind of bran it was, but it was probably wheat or oat (**Update- it's wheat bran**). This is important because it would determine if gluten was involved. Either way, it shows that something in grains can interfere with fat-soluble vitamin status, which is consistent with the staggering negative effect of refined wheat products on healthy non-industrialized cultures.

Add to this the possibility that many people may have some degree of gluten sensitivity, and you start to see a big problem. All together, the data are consistent with gluten grains interfering with fat-soluble vitamin status in a subset of people. As I discussed earlier, this could contribute to the diseases of civilization. These data don't prove anything conclusively, but I do find them thought-provoking.

Thanks to Dudua for the CC photo

The Seat of Power

Have you ever wondered why the buttocks is one of the most attractive parts of the body on both sexes?

The shape of the buttocks comes mostly from the gluteal muscles (maximus and medius), superimposed by a layer of fat. The 'glutes' are some of the strongest muscles in the body, due to their large size and efficient leverage. Thrusting doesn't even come close to tapping into the glutes' tremendous power. What does? Heavy lifting. Sprints. Jumps. In short, some of the most functional full-body movements we perform as humans.

In any full-body movement, the hips are the central source of power. The strongest muscles surround the hips, and muscle strength diminishes progressively as you move further from them. A shapely buttocks is typically a strong buttocks, and a strong buttocks generally means a strong person. So if you want to decide at a glance whether a person is capable of sprinting and jumping after large prey, and then carrying it home, the buttocks is a good place to look.

The buttocks is also a storage area for fat. Humans tend to store a disproportionate amount of fat near their center of gravity: in the abdominal cavity, on the hips and on the buttocks. The right amount of fat indicates a healthy individual. A shapely buttocks is typically attached to someone who is strong and well-nourished. It's not so hard to imagine why we find it attractive.

Meditation

Meditation is the single most effective tool I've ever found for cultivating calmness, positivity and self-acceptance. It's an ancient technique that's simple and free. In fact, it's so simple, I'm about to teach it to you in five minutes over the internet. I personally practice Zen meditation
several times a week, by myself and with a sitting group. Meditation is not fundamentally a religious practice, although it has been used by spiritual people in every major religion. Don't think you're patient enough for meditation? That's exactly why you should be doing it!

Let's start with posture. The main purpose of the meditation posture is to allow you to remain still for long periods of time without discomfort. I'll discuss two postures: cross-legged and kneeling. Before you elevate your mind though, you have to elevate your backside. Find something you can sit on- a firm cushion or a folded blanket will work well. Your pelvis should be at least four inches above the ground. Now cross your legs. Your knees should be lower than your pelvis. Adjust your posture until you can maintain a straight back without any muscle tension. You'll have to rotate the top of your pelvis forward slightly, curving your lower back in toward your stomach.

Now put your hands together so that your left fingers rest on top of your right ones, just above your lap. Your palms should face up. Now touch your thumbs lightly together. That's it! You are now sitting in a very nice meditation posture. It will get more comfortable over time as you adjust to it.

The kneeling posture is the same except you kneel and put the support under your pelvis, between your legs. Wooden 'seiza' benches work well for this, but are not necessary. Your pelvis should be at least six inches off the ground so that you don't hurt your knees. This is my preferred posture, but I'm admittedly in the minority.

Now that you know the posture, face a blank wall three or four feet away. You can also look at the floor (while keeping your head and neck straight) or anything else that isn't likely to capture your interest.

Try breathing 'into your stomach'. To do this, breathe using only your diaphragm, in such a way that it makes your stomach rise and fall rather than your chest. Breathe slowly and deliberatley, pausing after each exhale. Bring your full attention to the rise and fall of your stomach. That's it, you're meditating! Really. Don't get fancy: it's counterproductive to try to actively relax yourself or achieve some different mental state.

In Zen, we call meditation 'sitting'. We use such a simple word because that's all it is: paying full attention to the moment, while you sit. Just bring your attention to your breath. If your mind drifts, gently bring it back. Don't try to stifle your thoughts, just acknowledge them and come back to your breath. If you can't focus, that's normal.

Try this for 15 minutes at first. Every day is best, but do what you can. When you're more comfortable with the technique, increase your time to 30 minutes. Meditation is a practice that changes and ripens with time.

The Dhamma Brothers

I saw a movie a few nights ago called 'The Dhamma Brothers'. It's about a meditation program at Donaldson correctional facility in Alabama, one of the most violent prisons in the country. Two Bhuddist teachers of Vipassana meditation led a 10-day silent retreat for a volunteer group of inmates. They got up at dawn and meditated for several hours each day. Some of the inmates went through an amazing transformation.

They were forced to confront and accept the horrible crimes they had committed. When you aren't allowed to talk for 10 days, and all you have are your thoughts to keep you company, it's hard to ignore your feelings. Many of them had breakdowns as they felt the full force of their own suffering for the first time.

At first, the warden was skeptical that the prisoners were just acting to get parole; "fake it 'til you make it". Then he started noticing major changes in the inmates' behavior. They became less violent and easier to deal with. Some of them left their gangs. Even after the program was discontinued thanks to an overzealous chaplain, many of the "Dhamma brothers" continued meditating on their own.

It's hard to doubt a grown man's sincerity when you see tears running down his cheeks. These men were hardened criminals, most of them serving life sentences for murder, who rediscovered perspective and humanity simply by spending focused time with themselves.

Meditation is a powerful tool. There are two types of knowledge: intellectual and visceral. You can read books until you're cross-eyed and you will never connect with the fundamental, animal, visceral side of living. We like to think of ourselves as rational, conscious beings. It's reassuring to us. We're in control of our minds and therefore our lives. But that's more illusion than reality.

Neuroscience and meditation have shown us that the human mind is like a monkey riding an elephant. The monkey is our conscious and the elephant is our subconscious. The monkey can tell the elephant where to go, but ultimately the elephant is going to do what it wants. The monkey likes to be in charge however, so it retroactively decides it was the one that chose the direction.

To illustrate the point, imagine doing a simple algebra problem. Do you have to go over everything you ever learned about algebra in your head to solve that problem? No, your subconscious navigates the strata of accumulated knowledge and practically hands you the answer. What happens when you decide on an entree at a restaurant? Do you make a pro/con list for each item and weigh them accordingly? Or do you decide based on a feeling? Where does that feeling come from?

Meditation is plugging back into the vastness of human experience. It's acknowledging that your conscious, declarative mind is only a small slice of the pie.