The Base of the Pyramid
The base of the dietary component includes the bread, pasta, rice, couscous, polenta, and other whole grains and potatoes group. This group should be consumed in greater quantities than the other groups. If you wish to monitor your weight, keep in mind that although this group is at the base of the pyramid, it does not mean that the portion sizes should be ignored. Huge portions mean huge amounts of calories. The portion sizes often seen in the United States are not indicative of healthful portion sizes; the portion sizes that the Mediterranean people consume are much smaller than portion sizes in the United States.
This group is made up primarily of starch, fiber, a small amount of protein, vitamins, minerals, and phytochemicals. Starches, also known as complex carbohydrates, are considered one of the three macronutrients. The other two are proteins and fats. The body will primarily use this type of macronutrient as an energy source. Energy is provided by breaking down the complex carbohydrates into simple carbohydrates and then into glucose. Glucose is your primary source of energy. The body uses glucose to maintain the functional integrity of the nerve tissue, and under normal circumstances it is the sole source of energy for the brain. If the body is given more carbohydrates than it needs (in other words, overeating) then carbohydrates are converted and stored as fat. That is why although carbohydrates are essential and healthy, eating too many of them will cause weight gain.
Fiber is found only in plant foods such as whole grains, vegetables, fruits, legumes, nuts, and seeds. Soluble and insoluble fibers are components in food that our bodies do not digest. Soluble fiber can aid in protecting against heart disease and diabetes. Good sources of soluble fiber from this group are oats and barley. Insoluble fiber can help to prevent or delay onset of stomach problems and decrease risk of colon and rectal cancers. Whole-wheat products, wheat and corn bran, potatoes, and oats are all good sources of insoluble fiber. With their added bulk, these miracle substances add to a feeling of fullness in the stomach. Fiber also slows gastric emptying, so you feel full longer.
Protein is made up of amino acids that are used as building blocks to build and repair tissue in your body. There is a small amount of protein found in this group. Protein is not stored well by our bodies; because of this it is important to consume protein on a daily basis.
Vitamins and Minerals
Complex carbohydrates contain a variety of the B vitamins. A vitamin is a compound that the body needs in small amounts to control metabolic processes, such as digestion. With the exception of vitamins D and K, vitamins are considered essential nutrients because the body cannot produce them by itself; they must be obtained through consuming foods. B vitamins are water soluble. The body does not store them well, so it is important to eat foods rich in B vitamins daily. The B vitamins that are found in these groups are as follows: thiamin (B1), riboflavin (B2), niacin (B3), and pyridoxine (B6). Grain products may be fortified with folic acid.
A mineral is a compound that the body needs to consume in very small amounts. Minerals are part of many cells and play an important role in many body processes. One example of a mineral is iron. Other minerals that are found in whole grains are zinc, chromium, copper, phosphorus, and selenium.
Iron comes from a wide variety of foods, of both animal and plant origin. Most of the iron from meat, poultry, and fish is heme iron. Heme iron is part of the hemoglobin and myoglobin (similar to hemoglobin in humans) in animal tissue. Foods of plant origin contain only nonheme iron. Egg yolks have mostly nonheme iron. A deficiency in iron can cause iron-deficiency anemia.
You can enhance your body's ability to absorb nonheme iron. Food rich in vitamin C (e.g., bell peppers, broccoli, potatoes, tomato products, citrus fruits) and foods with heme iron (e.g., fish, poultry, meat) aid the absorption of nonheme iron.
Heme iron is absorbed into your body more readily than nonheme iron. Depending on how much iron you already have stored in your body, 15 to 35 percent of heme iron gets absorbed.
Phytochemicals are naturally occurring substances in plant foods that are thought to promote wellness and decrease the risk of many different types of diseases. Phytochemicals are different from vitamins because the lack of a phytochemical does not cause a deficiency disease. For example, a vitamin C deficiency causes scurvy, or a vitamin D deficiency can cause rickets. Phytochemicals aid in preventing diseases such as cancer, diabetes, heart disease, and hypertension. More than 900 different phytochemicals have been identified and each year more are being discovered. Phytochemicals present at the base of the pyramid include saponins and phytates found in oats, barley, brown rice, and whole-wheat flour.
The nutritional importance of the grain group can't be emphasized enough. However, on the other side of the coin the portion sizes of grains cannot be emphasized enough. Rule of thumb is a 1/3 to ½ cup of a grain is 1 serving and a 1-inch slice of bread is 1 serving.