Diet Therapy Health Article

Definition

Diet therapies are specially designed and prescribed for medical and/or general nutritional reasons.

Purpose

Diet therapy promotes a balanced selection of foods vital for good health. By combining foods appropriate for each individual and drinking the proper amount of water, one can help maintain the best possible health. Eating the proper diet is critical for the health of individuals, groups with special medical and dietary needs, and entire populations afflicted with malnutrition.

Precautions

A particular modified diet is prescribed specifically for each individual. Those individuals who have medical conditions or who are sensitive to certain foods need to be very compliant and cautious about what they eat.

Individuals should not follow a "fad" diet without first consulting a registered dietitian or physician. Popular (but sometimes dangerous) low-carbohydrate diets, for example, may deprive the body of the glucose it needs for central nervous system and brain functions.

Description

Nutrition is the science concerned with the human body's use of nutrients and food substances. Proper nutrition decisions are important for the optimal health of each individual. This is especially true for those individuals with specific dietary needs and acute or chronic diseases. The nutrients necessary to maintain normal growth and health include proteins, carbohydrates, fats, vitamins, and minerals. Included in these nutrients are eight amino acids the body cannot produce but that must be derived from proteins, four fat-soluble and ten water-soluble vitamins, ten minerals, and three electrolytes.

Nutrient classes

PROTEIN. Protein is important for building body tissue and synthesizing enzymes. Enzymes are specialized organic substances that act to regulate the speed of chemical reactions in human metabolism. Twenty amino acids of the 100 or more occurring in nature make up proteins. Animals and plants are quick and available sources of what are termed "essential" amino acids; they are called essential because the body cannot build them internally. Normal growth and health are dependent upon these essential amino acids. Dietitians recommend that a healthy diet includes 10–20% of daily calories from protein (poultry, fish, dairy, and vegetable sources).

CARBOHYDRATES. Carbohydrates provide most of the energy in the majority of human diets. Foods rich in carbohydrates are usually the most abundant and cheapest. The carbohydrates containing the most nutrients are the complex carbohydrates, such as unrefined grains, tubers, vegetables, and fruits. Simple carbohydrates or sugars should be eaten in moderation, since they are high in calories but low in nutrients.

Carbohydrates are needed in the form of glucose by the brain and central nervous system (CNS). A minimum of 1.6 oz (50 g) of glucose is required daily for proper functioning of the CNS. If the body is denied carbohydrates, it will use ketone bodies for energy, but this is not a good energy source for the body, and may have unfavorable health effects.

FATS. Fats supply energy and essential fatty acids and promote absorption of the fat-soluble vitamins A, D, E, and K. The accumulation of body fat has become a serious health concern; over 50% of Americans are considered overweight. Fats are compact fuels efficiently stored in the body for later use when carbohydrates are in short supply. Fats produce more than twice as much energy as carbohydrates, approximately 9 Kcals/gram versus about 4 Kcals/gram for carbohydrate and protein. Dietary fats are broken down into fatty acids that pass into the blood. These fatty acids are either saturated or unsaturated (mono-unsaturated, polyunsaturated, or trans-unsaturated). Saturated fats, derived mostly from animal sources, have been found to raise the level of total cholesterol in the bloodstream, and certain unsaturated fats tend to lower the level of total cholesterol in the blood stream. For example, mono-unsaturated fats like oleic acid in olive oil reduce low-density lipoprotein cholesterol (bad cholesterol) and increase high-density lipoprotein cholesterol (good cholesterol), thus reducing the risk of heart disease. Saturated and trans-unsaturated fatty acids both raise serum cholesterol; in contrast, neither mono-unsaturated nor polyunsaturated fats have this effect.

INORGANIC MINERAL NUTRIENTS. Inorganic mineral nutrients are required to build tissues. They are also important for muscle contractions, nerve reactions, and blood clotting. All of these mineral nutrients must be supplied in the diet. Minerals are categorized as major elements or trace elements. Major elements consist of calcium, phosphorus, magnesium, iron, iodine, and potassium. Trace elements include copper, cobalt, manganese, fluorine, and zinc.

VITAMINS. Vitamins increase the breakdown and absorption of proteins, carbohydrates, and fats. Certain vitamins help form blood cells, hormones, nervous system chemicals, and genetic materials. Vitamins are classified into two groups: fat-soluble vitamins, such as A, D, E, and K; and water-soluble vitamins, such as vitamin C and the B-vitamin complex. Fat-soluble vitamins are usually found in foods that contain fat. Because excess amounts are stored in the body's fat and in the liver and kidneys, fat-soluble vitamins do not have to be consumed every day. The water-soluble vitamins, C and B complex, cannot be stored and must be consumed daily to replenish the body's supply.