Whole grains for health
Moore Report Summer 2016
Nowadays, it is easy to find a diet book for every occasion, every medical condition and every political taste. The bookstore shelves are full of books touting the cave man diet, the all carbohydrate diet, the all meat and fat diet and the ketogenic diet, plus many others. The truth is that while everyone is eating their favorite fad diet, the American population is becoming less healthy. Americans are getting fatter and diabetes is on the rise. These conditions, along with uncontrolled high blood pressure, have been increasing in the U.S. population since the mid-1990s. Most of these diseases are diet driven.
What constitutes a healthy diet has been known for decades. Good diets consist of fruits, vegetables, nuts, whole grains and fish. Recently, some scientific-sounding books authored by medical doctors have sold the idea that eating whole grains leads to poor health and is especially damaging to the brain. This notion is not supported by the whole of scientific evidence. However, it is not surprising that people would come to that conclusion. The idea that grains are detrimental to a person's health probably arises from studies showing that simple carbohydrates, like sugars and starches, are associated with increased inflammation of body organs, including the brain. These simple carbohydrates are the basic ingredient found in a large portion of processed foods and are derived from highly refined wheat, rice, corn or potatoes.
In contrast to diets that confuse refined flours with whole grains, there is increasing evidence that the whole grain foods are especially wholesome and beneficial. Once you investigate the biology of grains the reason for their high nutrient value becomes clear. A grain is a seed, and a seed is the plant equivalent of an egg. Seeds and eggs both contain nutrients for early development. For example, each grain of wheat, called a berry, contains layers of tissue that carry nutritious compounds that, once planted, provide sustenance for the developing plant and, if eaten, to people. The outer layer, the bran, is rich in Vitamins A, C and B6 (pyridoxine) and potassium. Bran is also a good source of dietary fiber, iron, magnesium, calcium and other minerals. The bulk of the berry is the endosperm, which contains starch and some protein. The region toward the bottom of the berry is the germ, the portion of the berry that will germinate to form the plant. It contains Vitamin E, folate, minerals like phosphorus, zinc, and magnesium, thiamin, as well as essential fatty acids (healthy lipids). Foods that use flours after the bran and germ have been removed (white flour), contribute little to a nutritious diet and may cause more harm than benefit. However, it is the starchy portion of the berry that contains the protein gluten that allows dough to be elastic as the basis for many types of bread and pastries. In wheat, two groups of proteins, gliadins and glutenins, come together and form what we call gluten (Shewry et al. 1986). Gluten is a good source of amino acids, but causes harm in people who have celiac disease.
What evidence is there that eating whole grains will offer nutritional benefit? A recent study showed decreasing rates of diabetes mellitus were associated with increasing levels of whole grain consumption. Another study showed increased egg quality in women seeking the use of reproductive technology to become pregnant associated with increasing levels of whole grains in their diets. Studies like these add to the already substantial body of literature showing that people who enjoy consuming whole grains will benefit by having fewer chronic diseases as they age.
Director, OHSU Moore Institute for Nutrition & Wellness
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