New Under the Sun:
Volume 6, Issue 8
Premier Nutrition: Part 2
Last month we began the topic of the type of nutrition for which humans are adapted by discussing the negative effects of dairy products. We continue this month by looking at grains.
Nutrition models have changed over the past thirty or so years from the 4 Squares to the pre-2005 Pyramid to the current pyramid version called My Pyramid. In all three models, grain products play an important role. Grains include wheat, oats, barley, rye, millet, rice, and corn/maize, among others. Because corn is often packaged as a vegetable (for instance, in a bag of frozen peas, carrots, and corn), many do not realize that it is actually a grain product, until they are reminded of tortillas and corn bread.
As I discussed in a previous newsletter, grains initially became an important part of the diet only when there was little other option. Later, when it was realized that grain crops could be grown in quantities large enough to provide for future needs, many other populations began to adopt agriculture. However, grains have been a widespread part of the human diet for only the past 2,000 – 5,000 years: a mere blink of the eye in terms of human history. Our bodies are not adapted to a diet in which grains play a major role. If we want to model appropriate nutrition in terms of a pyramid, then the base or largest section of the pyramid should be composed of fruits, tree nuts, and vegetables, of which we need to eat at least ten servings per day.
Grains and grain products play such a major role in our diets because they are relatively cheap, versatile, and filling. This last is quite important. For instance, one-quarter cup of un-popped corn kernels costs only pennies, but will pop to fill a large bowl and an empty belly. Unfortunately, there isn’t much nutrition in a bowl of popcorn, but if I am very poor and very hungry, my major concern is to stop the gnawing hunger pangs, not with whether my “meal” is well balanced or not. Throughout history, those who were well off were always able to enjoy a better diet, but the poor had little choice but to rely on cheap, filling grains, even if the long-term effects on their health were negative.
Health of Early Agriculturalists
The grain-based diet of the original agriculturalists resulted in reduced stature and a weakened body easily conquered by contagious diseases. We can see other negative effects of a grain-based diet when we examine the teeth of these early agriculturalists. The teeth show signs of rapid and severe wear, dental caries (cavities), and tooth loss. Tooth wear was due to the bits of grit that became part of the flour/meal as the grains were ground on stone. We no longer worry about grit in our meal, but dental caries and tooth loss continue to be a problem. Grains form a paste in our mouths when moistened by saliva. This paste sticks to our teeth and gums, providing a nourishing habitat for micro-organisms, leading to dental decay. When grains are eliminated from the diet and hard fruits and vegetables such as apples and carrots are added, teeth stay much cleaner and dental decay is greatly reduced.
Analysis of the skull and long bones indicates that these early agriculturalists suffered from malnutrition and disease. Porous skull bones, particularly of the eye sockets, are associated with anemia and poor health. Pits and ridges on the teeth (hypoplasias) and lines perpendicular to the axis of long bones (Harris lines) indicate that during childhood the individual suffered episodes when growth ceased, and later resumed. These episodes would have been caused by malnutrition and/or disease.
Health Effects of Grain-Based Diets on Modern Humans
As with research on dairy products, much of the research on grain products is supported by the agriculture/foods industry. Again, this does not mean that the research is inappropriate, but it does mean that the results should be carefully scrutinized. There is an automatic acceptance, based on the past few thousand years during which grains formed a major component of the diet, that grains must be beneficial for human health. However, the main benefit of grains and grain products is, and has been, as a filler: grain fills the empty stomach and pads out a meal that includes a small portion of meat and/or vegetables. Although grains are highlighted as a source of fiber, most grain products eaten in modern societies are made of refined flours that provide little, if any, fiber. The best sources of fiber are in fruits and vegetables which also provide many other nutrients and micronutrients important to the maintenance of our health.
Carbohydrates provide a necessary base to the diet, but when grains form the major portion of carbohydrates eaten, nutrition suffers. The carbohydrates from grains (and white potatoes) have a high glycemic index which is associated with an increased risk of coronary heart disease. On the other hand, the carbohydrates from fruits and vegetables have a low glycemic index, providing heart-healthy benefits. Grain products cannot adequately substitute for the carbohydrates and numerous other nutrients obtained from fruits, vegetables, and nuts.
Increased amounts of grain are frequently used to replace protein from meat in the diet. But using grains as a protein substitute requires a careful matching of foods so that all the required amino acids are obtained. For instance, you can combine peas and rice, or beans and corn tortillas. Children fed a primarily grain-based vegetarian diet with little or no protein from animal sources will tend to fail to reach their full potential in height. Height is a complex trait involving the interaction of perhaps dozens of genes and the environment. Identical twins with the same genetics, but raised on very different diets, one with adequate protein and amino acids and one without, will be unlikely to achieve the same height when they reach adulthood. The impact of diet on stature can be easily seen in the children of immigrant parents who after moving to the United States adopted a western diet containing more protein than was typical of the diets of their homeland: the children tend to be several inches taller than their parents. This is not a recommendation for adopting a western style diet since there are health problems associated with it, as discussed here. However, it is a recommendation for the inclusion of adequate levels of low-fat, high quality proteins in the diet such as can be obtained from eggs, fish, and shellfish. Remember, our ancestors prior to the development of agriculture and a heavy reliance on grains were tall: males averaged 5’10” and females 5’6” in stature; heights we are only now regaining after thousands of years of agriculture.
Unlike dairy products which are fairly easy to eliminate from the diet, it is much more difficult to wholly eliminate grains since they quite literally form the base of most main meals in most modern cultures. It can be done, however, if you keep in mind that the largest section of the Food Pyramid should be fruits, tree nuts, and vegetables, and that grain products are fillers. Instead of a plate of pasta with a little sauce, have a little pasta with a large amount of a tomato-based sauce rich in other vegetables and some low-fat meat such as chicken. Do the same with other grain-based dishes. Eventually, you will realize you do not need the pasta or rice or whatever grain to feel full and to be healthy. If you wish to continue to have grains in your diet, then they should be whole grain products, but these are more difficult to obtain; whole wheat bread is not the same as whole grain bread. Read the labels carefully.
played little or no role in the diet of our ancient ancestors.
are relatively cheap and easy to grow and can be stored for future use.
The subject of Premier Nutrition will continue in next month’s newsletter.
© 2001-2009 Kathleen E. Fuller, PhD. All rights reserved.