Category Archives: Diet

Sugar’s Gotta Go Somewhere

A recent paper published in the journal Neurology shows that, for patients with a history of Alzheimer’s disease (but, interestingly, not vascular dementia), the risk of cancer was reduced. And for patients with a history of cancer, their risk of Alzheimer’s disease was reduced. If their risk profiles demonstrate this level of dependence, what ties them together?

Assume two things are true (which is certainly a big assumption as there is preliminary evidence accompanied by unanswered questions for both):

  1. Cancer is, in some way, shape or form, promoted by chronically elevated blood sugar.
  2. Alzheimer’s is, in some way, shape or form, a consequence of chronic neural uptake of high levels of glucose from the bloodstream and/or the dysregulation of inflammation caused by chronically elevated insulin levels.

Then this trade off in disease risk begins to make sense. On a diet high in sugar, the body begins to react by decreasing sensitivity to insulin in muscle tissue (normally a prime consumer of blood glucose).  Neural tissue and the tissues in the eyes, however, do not have the luxury of insulin resistance (as they use a different glucose transporter) and maintain their uptake of very high levels of glucose. This is likely why Type II diabetics often struggle with diabetic retinopathy and neuropathy.

Just how high a level of glucose uptake is maintained is probably quite individual. In people whose neural tissues can absorb large quantities of sugar from the bloodstream, total blood sugar may remain near ‘normal’ but the neural tissue is forced to deal with high concentrations of glucose and the resulting metabolic by-products. Long term, this struggle may lead to Alzheimer’s disease.

In individuals whose neural tissue accepts glucose uptake at a lower level, blood sugar stays elevated and the resulting diffusion of glucose throughout the body likely results in global intercellular glucose levels higher than in those individuals with high neural glucose uptake. If sugar concentrations really do contribute to cancer, globally elevated tissue glucose (which, to my knowledge, isn’t routinely measured) would be an excellent way to stack the deck in favor of cancer, i.e. should a cell lose control of its growth process, in a high-sugar environment it would grow like mad.

We measure gross capacity for uptake of blood glucose (without regard to where it goes) via the usual oral glucose tolerance test but there’s currently no way to assess an individual’s neural glucose uptake capacity. And given that the options are Alzheimer’s or cancer, I’ll choose to just avoid sugar intake whenever possible.


Carbohydrates – Survival’s Friend

This continues a series of basic posts each focusing on a single key topic that, in modern society on an average diet, has gone badly awry with negative consequences. As I am not by any stretch of the imagination the first to discuss these topics, the majority of these posts will simply be referring you to excellent background resources.

Both fats and carbohydrates can be used by the body as sources of energy for movement, thought and the basic processes that keep us alive and procreating (protein, while able to be used for energy when necessary, plays a largely structural role under ideal nutritional conditions). The real question, then, is how much of each to consume. Assuming that your goal is to maximize both health and longevity, I and many others would argue that we are designed to function best on a diet high in fat. Carbohydrates were most often available to our pre-historical ancestors in the form of seasonal grains and seeds. These were hardy, could be gathered and stored, and kept us alive through winters’ shortage of tasty, fat-laden critters. This reliance on high-carbohydrate foods, however, was (and in many impoverished areas around the world still is) about survival.

In moving to agriculture, we accepted subsistence on carbohydrate-laden foods and in return we no longer were required to travel nomadically, following herds of whatever we thought most likely to ensure our survival. Keep in mind that this move to subsistence farming may have been driven more by our eating all the megafauna rather than by some particular innate desire to be farmers. This was then a Faustian bargain: continued human survival in exchange for reduced lifespans. Note that this reduction wasn’t universal and populations with a long-term reliance on grain-based diets certainly developed protective mutations. Just because your genetic stock may have a few compensatory mechanisms, however, doesn’t particularly mean subsisting primarily on carbohydrates is good for you. And most modern carbohydrates (pasta, white bread, pizza crust, sugary cereals, etc.) hardly resemble what our ancestors may have chosen to eat when all else failed.

Personally, given the evidence to date, I try to keep my carbohydrate intake below 100g/day and, when I do eat carbohydrates, I seek to minimize the glycemic index (and enjoy informative musings on the same) of anything I eat (particularly by avoiding sugars and heavily refined flour-based items).

Five chunks of related blogosphere wisdom:

  1. You are what your ancestors ate, part I
  2. Arrested adaptation and “diseases of civilization”
  3. The Vegetarian Myth
  4. Paleopathology at the Origins of Agriculture
  5. How to Eat Grains

Wheat – Historical Friend; Modern Threat

This continues a series of basic posts each focusing on a single key topic that, in modern society on an average diet, has gone badly awry with negative consequences. As I am not by any stretch of the imagination the first to discuss these topics, the majority of these posts will simply be referring you to excellent background resources.

Western civilization was very literally built on wheat. It powered the Egyptians that built the pyramids. It was grown by European peasants during the middle ages and paid as taxes to their feudal lords. Wheat has played a major role in human history and we owe it a debt of gratitude.

This gratitude, however, does not extend to endorsing eating wheat in the modern era when other options are available. Some people seem to be able to consume abundant quantities of wheat without consequence. Others have clear, obvious medically significant responses to eating wheat (e.g. celiac disease). What is less obvious, however, are the myriad, seemingly unrelated health problems that in many people can clear up on wheat elimination diets.

Most of these reactions seem to share a common cause in the effect of gliadin, a gluten protein found in wheat. Per the usual, Wikipedia has an excellent summary of these effects:

Upon exposure to gliadin, and certain other prolamins, the enzyme tissue transglutaminase modifies the protein, and the immune system cross-reacts with the small-bowel tissue, causing an inflammatory reaction. That leads to a truncating of the villi lining the small intestine (called villous atrophy). This interferes with the absorption of nutrients, because the intestinal villi are responsible for absorption.

It can also lead to ‘leaky gut’ in which the inflamed intestinal tissue is no longer able to provide a seal to keep the contents of the intestines from seeping through into the body cavity. This seepage of all manner of compounds and organisms can itself be an additional, powerful inflammatory stimulator.

While I grew up loving all manner of pizza, pasta and their delicious, wheat-based brethren (wheat beer, how I miss thee!), the evidence is remarkably clear that, for most people, wheat consumption is a bad idea. And for those who believe themselves just fine, thank you, keep in mind it is nearly impossible to determine that you suffer no ill effects given the disconnect in most people between their diet and their various chronic health problems and irritations. Have you always “just had oily skin” or “just had acne”? Or have you always just eaten wheat? There’s an easy way to find out: eliminate wheat from your diet for 30 days and see what happens!

Five chunks of related blogosphere wisdom:

  1. This is your brain on wheat 
    (summarizes 30 years of studies on human wheat consumption!)
  2. Wheat Belly
  3. A wheat-free 2010
  4. Celiac Disease and Osteoporosis
  5. The Thing with Grains