By consulting this new reference, consumers and their doctors can learn which nutritional supplements may improve health and which supplements may interact with foods or prescription or nonprescription medicines. About 75 percent of Americans use nutritional supplements including vitamins, minerals, amino acids, proteins, hormonal products, fatty acids, nucleic acids and probiotics. With few exceptions, nutritional supplements marketed for weight loss and the promotion of lean body mass and athletic endurance have little or no data to support the claims. Creatine, one of the most popular supplements, may be of some help to elite athletes, but little scientific evidence exists that it benefits anyone else, including the thousands of high school athletes that use it to enhance physical performance.
Safety is also an issue.
Very little long-term safety data exist and there is some concern regarding its effects on the kidneys, particularly among those with compromised renal function. Pyruvate and bromelain are among the few supplements that may benefit some athletes. Pyruvate has shown some ability to enhance athletic endurance and bromelain may speed recovery from athletic injuries, in some instances. For weight loss, there is preliminary evidence that green tea catechins may increase energy expenditure and promote fat oxidation leading to weight loss. According to the PDR for Nutritional Supplements, a number of nutritional supplements may be effective in fighting cancer.