In the last several years, many new diets have been introduced, most if not all of which claim to be the solution to one (e.g. obesity), many, or even all of the health problems inflicting Americans. Most of these diets differ radically and yet each one declares that it is the most suitable for the human race. The promoters of each of these diets promise unbelievable results as a consequence of adopting their dietary principles. It seems that never in the past have we had to choose between so many conflicting messages. The Flat Belly diet, Paleo diet, Cabbage Soup diet, Raw Food diet, Gandhi’s diet, Hollywood diet, Russian Air Force diet, Hallelujah diet, Beverly Hills diet, Jerusalem diet, Metabolic diet, Zone diet, Atkins diet, Optimal diet, the Seventh Day diet, Brain diet, and the Leptin diet are just a few examples of many more diets available for those who are willing to adopt them. Which diet is the best: a low or high carbohydrate diet, low or high protein diet? Are products cooked in a microwave fit for human consumption? Should we eat only organic products? Are soy products healthy? What about genetically modified products? Should we consume dietary supplements? If so, which ones? What principles truly constitute healthy eating?
A healthy diet can be described in simple principles. The first of them is: eat a variety of whole grain products. The importance of grains in the human diet has been known for thousands of years. For example, Biblical manuscripts and writings found in Egyptian tombs clearly indicate that grains constituted a staple food in ancient Palestine and Egypt. In the Bible we find records of individual grains and a bread recipe. For example, in the fifth book of the Bible entitled Deuteronomy, we read in the description of the Promised Land that God led the Israelites to “a land of wheat, barley, (…) a land in which you will eat bread without scarcity, (…)” Similarly, in the book of Ezekiel we read the injunction of God to the prophet Ezekiel: “take for yourself wheat, barley, (…) millet, and spelt; put them into one vessel, and make bread of them for yourself.” Bread made with the above formula can be purchased in American grocery stores today. Archaeologists found round flat loaves in the tombs of Egyptian officials. On the walls of tombs in Luxor and in other locations archaeologists also found paintings that illustrate the process of making bread. In making bread the Egyptians used whole grain flour, which they produced using stone which was slid across the floor. The finished product resembled today’s multigrain bread. The importance of grain consumption in ancient Egypt illustrates the biblical story of Joseph, the son of Israel, recorded in the Book of Genesis. It describes a seven-year period of drought, which both the Egyptians and people living in neighboring countries, survived thanks to the grain stocks accumulated by Joseph in the years prior to the period of drought.
Consuming of a variety of products is a fundamental principle of healthy eating. In the case of grains, a variety means consumption of products made of wheat, rye, barley, oats, buckwheat, millet and other grains. Of course this does not mean that all of these products should be consumed at each meal. This means having different grain products over a period of several days or a week.
To understand the importance of consumption of whole grains versus refined grain products we must understand the structure of the grains. A grain kernel is composed of three layers. The first is the outer shell, composed mainly of fiber. In addition to fiber, it also contains various nutrients and phytochemicals. The second is the germ, which contains large amounts of vitamins and minerals. The third layer is the endosperm, consisting chiefly of starch and protein. When a whole grain is refined, (as in making white flour or white rice) both the outer layer and the germ are removed from the endosperm. As a result, compared to whole grain flour, white flour is composed primarily of starch and protein with a small amount of micronutrients (vitamins and minerals), fiber and phytochemicals. For example, making white flour reduces the fiber content by nearly 80 percent compared to whole wheat flour. Similarly, white flour contains just 7 percent of vitamin E, and only about 26 percent of potassium in comparison to whole grain flour.
Some countries mandate that some vitamins and minerals lost in the refining process be added back into the while flour or white rice. In the United States, it is mandatory that food manufacturers add five nutrients to refined grain products. They include vitamins B1, B2, niacin, folic acid and the mineral iron. When these nutrients are added back to the refined flour it is then called enriched flour. Yet, in comparison to flour made of whole grains, it is still a nutrient-deprived product. The graph below shows the nutrient content in refined and whole grain flours.
Figure 1. Nutrient content of white wheat flour compared to whole wheat flour.
In addition to fiber and micronutrients, grains are a source of other important compounds such as stanols and sterols. Studies have shown that these compounds are effective in lowering blood cholesterol. Also, grains are a good source of magnesium and iron. Higher intake of magnesium is associated with lower blood pressure, and consequently a lower risk of stroke. In the United States, grains provide 30 to 50 percent of iron consumed, which means that they provide more iron than any other food group. It is precisely because of the relatively large amounts of fiber content, micronutrients, and other compounds including sterols and stanols that grains play an extremely important role in human nutrition and in the prevention of diseases.
Studies consistently showed that whole grains have a beneficial effect on the prevention of virtually all chronic health conditions including cardiovascular disease (e.g. heart attack, hypertension), cancer and diabetes. Whole grains may also play a significant role in the treatment of some of these health problems. An example of such a study is the Health Professionals Follow-Up Study conducted by researchers from Harvard University. It involved more than 51,000 men aged 40 to 75 years. This study has shown that individuals with an average consumption of whole grains in the amount of 46 grams per day had a 19 percent lower risk of being diagnosed with high blood pressure compared with those individuals who on average consumed only 3.3 grams.
Consumption of whole grains reduces the risk of other health problems. For example, results of the previously mentioned Health Professionals Follow-up Study showed that regular consumption of whole grains was associated with lower body weight. Therefore, the consumption of whole grains is an effective way of preventing obesity. Prospective studies have shown a lower risk of type 2 diabetes among people who consume higher amounts of these products. According to the Framingham Offspring Cohort study, people with the highest intake of whole grains had a 32 percent lower risk of being diagnosed with metabolic syndrome compared to those with the lowest intake. Similar results were reported by researchers from Iran. A meta-analysis based on 40 studies showed a 21 to 43 percent lower risk of bowel cancer among people who consumed higher amounts of whole grains compared to individuals with lower intake. The Kaiser Permanente Retrospective Study showed a 30 percent lower risk of colorectal cancer among those with the highest intake of whole grains compared to those with the lowest intake.
In addition to the positive impact of whole grains on the prevention of many chronic diseases, in countries where grain products are fortified with vitamin B1, B2, niacin and folic acid, grains are also essential in the prevention of other health problems including Beri Beri, pellagra, or neural tube defects. Unfortunately, today in most developed and developing countries, the vast majority of consumed grains are refined grains. Until recently, in the United States, on average only about 2 percent of the approximately 70 kg of wheat flour consumed per capita per year was accounted by whole grains. Similarly, the vast majority of consumed rice was white rice, which is subject to the same refining process described above.
Foods made with whole grains are one of the main sources of nutrients, such as fiber, vitamin E, magnesium, iron and phytochemicals such as plant sterols and stanols. Whole grain products should be consumed each day. In many grocery stores in America whole grains are available as breads, cereal, pizza dough, brown rice and in other forms. Their consumption is associated with a lower incidence of lifestyle diseases including cardiovascular disease and some cancers.
In order to find whole grains in a grocery store look for the word “whole” in the “Ingredients” section on the food label. Foods manufactured and/or sold in America that are made of multiple ingredients must contain a food label with a list of ingredients a given product was made of. Since the list of ingredients must reflect their predominance by weight (from the most to the least predominant by weight), unless the first ingredient listed contains the word “whole” (e.g. whole wheat flour, whole oat flour, whole barley flour, etc.), it is not a whole grain product. If a product is made of just one ingredient (e.g. oats) it will not have the “Ingredients” section. Instead, in the front of the package it should say “whole oats” or “100% whole oats.”