For over 40 years, much of the dietary guidance for Americans has focused on messages that encourage people to think of foods as “good” or “bad.” However, this overly simplistic approach has more than a few flaws that can harm health when taken to extremes. It ignores the many complexities of the human body and its need for a great variety of nutrients to support growth during youth and optimal function throughout life.
Question: If foods should not be considered “good” or “bad,” how should we think about what to eat?
Answer: First and foremost, good nutrition requires eating combinations of foods that provide an adequate supply of about 60 essential nutrients — vitamins, minerals, amino acids, fatty acids, etc. These chemicals called essential nutrients support thousands of chemical reactions in the body required for life and ongoing health. Without an adequate supply of just one of them, serious problems can develop over time.
Nutrient-dense foods (foods that contain plenty of key nutrients relative to their calories) make it easier to meet nutrient needs. Diets that are simply low in calories, however, often are low in one or more of the essential nutrients. Also, it is important to keep in mind that we must be able to absorb nutrients from food into the body. Some foods that are high in fiber also contain compounds that inhibit the absorption of various essential minerals. In addition, consuming excess amounts of some “good” foods or “superfoods” on an ongoing basis can result in toxic intake of an essential mineral like manganese.
Q: What foods meet these nutrient guidelines?
A: Based on accumulating research, health-promoting diets include a wide variety from all of the food groups. Certainly, fruits, vegetables, grains, nuts and beans are healthful components of the diet. Although animal foods like milk products, eggs and meat are often maligned because of calories, saturated fat and cholesterol, they contribute many essential nutrients that can be missing, low or poorly absorbed from plant food. New research also is indicating that saturated fat and cholesterol are not causing diseases as previously thought.
Q: How did the scientists get it wrong?
A: It has become clear that certain key research findings were not published until recently. The exact reason for this is unknown because many of these researchers are no longer alive. It does appear that the unpublished data disagreed with previously published research, showing how complex the study of nutrition science can be.
Q: So what foods should we eat?
A: The simple answer is everything. A variety from all food groups greatly improves your chances of getting all essential nutrients needed without too much of anything. If any of the food groups are eliminated from the diet, nutrient deficiencies can develop; some develop within several weeks, others over decades.
Also, keep in mind that many things change with age. For example, as people age they generally lose muscle and bone structure. This loss accelerates when the diet is too low in protein. So, even though calorie needs decline with age, it is important to maintain an adequate amount of protein in the diet.
Having a normal serving of animal protein daily also provides essential minerals like iron and zinc that tend to be low in the diets of older people. Of course, all plant foods are important, but having a high-protein food as part of every meal is likely to keep senior citizens stronger longer.
