Eating used to be simple. As long as the food was tasty, looked reasonably appetizing and was plentiful, we were content. But then science came to dinner, and all of a sudden sitting down at the table became a laboratory experience, and a confusing one at that. Eat fish, we were told, it’s chock full of omega-3 fats. Be careful, urged another report, fish may harbour “good” fats, but it’s also loaded with PCBs and mercury. We switched to margarine from butter because it had fewer saturated fats. But then came accusations that the trans fatty acids it contained clogged arteries just like saturated fats. Eat soy, we were told, it lowers your cholesterol. Don’t eat soy, it affects thyroid function. Drink milk, you need the calcium. Don’t drink milk, it forms mucus. Drink coffee, it is full of antioxidants. Don’t drink coffee, it raises blood pressure. Then there are those little gems that “they” say. Stay away from MSG. Don’t touch foods preserved with nitrites. Or with sulphites. Beware of pesticide residues. Ban foods that contain genetically modified organisms. Don’t cook in Teflon pots. Or in microwave ovens. Stay away from sugar. And don’t even think about artificial sweeteners! But just who are “they”? We’ve been advised to load up on foods like oats, flax, mangosteen juice, garlic and oregano because some researchers showed each of these to be of some benefit. Whole-grain bread may be in one day—lots of useful fibre and vitamins—but out the next because acrylamide, a purported carcinogen, was detected in the crust.
Many people throw up their arms in bewilderment at all this confusing nutritional information, and go back to their old dietary regimens. And that is too bad. Nutrition is important. The challenge is to separate the wheat from the chaff, and come to some practical conclusions about what to eat, based not on hearsay but on sound science.
This is not easy to do, especially when we consider that the human body is the most complex machine on the face of the earth. The diversity of its molecular components is so astounding that by comparison, computers, medical scanners and space vehicles are simple devices. What we call life is really the result of astonishingly complex molecular activity that goes on in every cell in our body every second of the day. And where do the molecules that engage in these intricate gymnastics come from? One way or another, they come from the food we eat.
It seems obvious then that the composition of our diet can affect our molecular makeup, and consequently our health. But the relationship between diet and health is not a simple one. Food is chemically very complex. An apple, for example, is composed of over 300 different compounds. A single meal can flood the body with thousands of compounds, many of which have never been isolated or identified. While nutrition is obviously an important determinant of health, it is folly to think that one can introduce something as complicated as food into something as complex as the human body and make easy predictions about the outcome. Curing disease by dietary manipulation must therefore be looked at with a healthy degree of skepticism. But preventing disease by modifying our diet is realistic. The question is: how? These are all fascinating issues. Now, onto the fun part: let’s try to digest them.