Nutrition for Athletes - Commonwealth Games Federation

athletes’ medical informationSupplements andsports foodsAthletes look to nutritional supplementsfor many benefits, including:• promoting adaptations to training• increasing energy supply• allowing more consistent and intensivetraining by promoting recovery betweentraining sessions• maintaining good health and reducinginterruptions to training due to chronicfatigue, illness or injury• enhancing competitive performanceSupplement use is widespread amongsportsmen and women, but few of theseproducts are supported by a sound researchbase and some may even be harmful to theathlete. Athletes should look carefully at therisks and rewards of individual supplementsbefore trying them.Where there is a demonstrated deficiencyof an essential vitamin or mineral, and anincreased intake from food is not possible,a supplement may be helpful. The use ofsupplements, however, does not compensatefor poor food choices and an inadequate diet.Many athletes ignore the need for caution insupplement use and take supplements indoses that are not necessary, and may evenbe harmful.Protein powders and supplementsProtein supplements, high-protein bars andamino acid preparations are among the biggestsellingsports nutrition products. An adequateintake of protein is essential for muscle growthand repair, but this can easily be achieved fromeveryday foods and extra protein is seldomrequired (see pages 12-13).Protein-carbohydrate supplements mayhave a role as part of a post-exercise recoveryplan, but whole proteins have advantages overindividual amino acids.Fat reduction and muscle buildingA huge array of supplements is on sale withclaims that they can reduce body fat levels andbuild bigger and stronger muscles — claimsthat appeal to athletes and non-athletes alike.The reality is that many of the productsthat are effective in doing this are either onthe banned list or are associated with serioushealth risks (or both).Compounds in the muscle-building categoryinclude chromium, boron, hydroxymethylbutyrate(HMB), colostrum and others. Based on currentresearch, none of these has anything worthwhileto offer the athlete.Increasing energy supplySupplements in this category include pyruvateand ribose as well as some more exotic herbalpreparations. None of these is likely to improveperformance and, in spite of advertising claims,none is supported by good independentevidence. There is now limited evidence thatcarnitine can affect exercise metabolism insome circumstances, but the evidence forperformance effects is not convincing.26