Dietary supplementation is being increasingly applied by athletes to maintain physical condition and improve performance. This brief review summarizes the classification and role of nutritional ergogenics in the requirements for energy, protein/amino acids, vitamins and minerals in sports. Guidelines are shown for the theory, effectiveness, safety, legal and ethical aspects to evaluate the claims made for ergogenic aids. Recommendations for using dietary supplements during a program of weight reduction, during vigorous training, and before and during exercise are described. The aspects of nutritional education and dietary support for the suitable use of supplements by young and adult athletes, and the role of sports dietitians are briefly described.
Dietary surveys of a population-based study have been beneficial to the National Nutrition Survey (NNS). Since 1995, the approximated proportion method (Method A) has been used in Japan for nutritional surveys conducted for the NNS. However, the estimated validity of the method has not been given sufficient consideration. Thirty-two students studying at a training facility for dietitians and 32 of their family members who were in charge of cooking were studied to identify the validity of Method A and the cause of the error observed between Method A and the individual-based food weighing method (Method B). Energy and macronutrient intake by individual subjects obtained through Method A showed a high correlation with those obtained through Method B (r=0.89-0.91). However, compared to Method B, Method A tended to systematically underestimate the mean value for energy intake by 94kcal/day. Method A causes excessive errors because it involves a large number of families and mixed dishes. A comparison of the two methods regarding energy intake from boiled rice indicated that values obtained through Method A are systematically low compared those obtained through Method B. Special attention should be given to the error for energy intake from boiled rice as it alone accounts for 50% of the underestimation.