The U.S. Department of Agriculture's (USDA) food pyramid system (www.mypyramid.gov) provides a good start by recommending that the bulk of your diet come from the grain group—this includes bread, cereal, rice and pasta— the vegetable group; and the fruit group. Select smaller amounts of foods from the milk group and the meat and beans group. Eat few—if any—foods that are high in fat and sugars and low in nutrients. The amount of food you should consume depends on your sex, age and level of activity.
To assure supplements have sufficient quality, standardization, and safety for public consumption, research efforts have focused on development of reference materials for supplement manufacturing and monitoring. High-dose products have received research attention, especially for emergency situations such as vitamin A deficiency in malnutrition of children, and for women taking folate supplements to reduce the risk of breast cancer.
Dietary supplements are complex products. The FDA has established good manufacturing practices (GMPs) for dietary supplements to help ensure their identity, purity, strength, and composition. These GMPs are designed to prevent the inclusion of the wrong ingredient, the addition of too much or too little of an ingredient, the possibility of contamination, and the improper packaging and labeling of a product. The FDA periodically inspects facilities that manufacture dietary supplements.