Monday, November 05, 2007

Thoughts On Meat And Cancer

Some diagnoses of cancer have hit my family in the last few months. It's been a trying time. I've been especially keen to understand why, so I've been pouring over research. One dietary item keeps popping up ... meat. I don't know what it is about meat ... heme-iron, hormones, a type of fat, environmental toxins that are dissolved in animal fat, carcinogens produced via cooking, etc. But the association is common in my reading.

We can't ethically feed meat to someone until they get cancer. So there aren't clinical trials, just epidemiological studies, and those can always be devalued. Even I question some of their conclusions. Still, over and over, cancer is seen in populations that eat the most meat. And the mechanisms of action hypothesized for this link make sense to me.

In the absence of a clear, indisputable guideline, and in the presence of this association, how is someone with cancer to eat?

Fitting Low-Carb Into The Picture

I believe in the health benefits derived from eating a low-carb diet. That's not to say I believe in eating a low-carb diet. As I've said before, I don't believe carbohydrates are the problem. The problem is blood glucose and hormones (e.g. insulin). Since carbohydrates have such an impact on them, I can understand where the idea of limiting carbs came from. However, we still don't know the long-term effect of this dietary choice.

While science elucidates further the meat:cancer link, I think it would be prudent to reduce my meat intake, an intake that has risen to at least once-a-day since discovering my impaired glucose tolerance. Once-a-day meat intake has been linked to some of the highest rates of cancer. I respect that some find this link tenuous bordering on meaningless. I'm not willing yet to discard its implication.

How can I derive the benefits of eating low-carb, but still eat carbohydrates -- a situation I'm faced with when I cut back on meat?

The problem to me is not carbohydrates per se. The problem is:
  • The type of carbohydrate.
    • Stay away from refined products such as flour and sweeteners (e.g. HFCS) which are digested quickly. Choose vegetables and seeds (that would include grains which are seeds) in their whole form and containing starch-types that are more slowly digested, e.g. amylose instead of amylopectin, resistant starch, etc. These qualities are reflected in a food's glycemic index.
  • The amount of carbohydrate eaten at one time.
  • The speed of digestion and absorption, the slower the better.
    • Digestion is slowed by the presence of fiber and fat in a meal.
    • Digestion is slowed by the temperature of a meal, e.g. cold foods pass through quickly, hot foods slowly.
    • Digestion is slowed by the fluidity of a meal, e.g. liquids pass through quickly, dry foods slowly.
  • The frequency of carbohydrate-containing meals.
    • Not every 2 hours! Or as Michael, one of our commenters said, "Wait until there is some space in the tank before refilling."
  • Activity after a carb-containing meal.
    • Exercise has been shown to accelerate post-meal glucose clearance.
The worst scenario, that is, the worst of all of the above combined, can be found in the consumption of a cold, liquid, high-fructose-corn-syrup sweetened beverage consumed every few hours. You may as well have an IV of sugar hooked up to your arm.

In my mind, eating a "low-carb" diet -- one that virtually eliminates foods that contain carbohydrates, and one that is rich in foods like meat, fish, dairy, and eggs -- is a patch, a symptom-alleviator, not necessarily or unquestionably the best way to eat.

Update: See Meat and Cancer, Part 2 for more on the meat/cancer link.

No comments: