DIETARY PROTEIN AND PROTEIN
SUPPLEMENTS
Protein is one of the most popular dietary
supplements marketed to athletes and physicallyactive
individuals. Protein supplements have been
recommended to athletes to enhance nitrogen
retention and increase muscle mass, to prevent
protein catabolism during prolonged exercise, to
promote muscle glycogen resynthesis following
exercise, and to prevent sports anemia by promoting
an increased synthesis of hemoglobin, myoglobin,
oxidative enzymes, and mitochondria during aerobic
training. However, whether or not athletes need more
protein is currently debatable. Based on available
research, the American College of Sports Medicine,
the American Dietetic Association, and the Dietitians
of Canada, in their recent joint position stand on
nutrition and athletic performance 1
, concluded that
protein requirements are higher in very active
individuals and suggested that resistance athletes
need 1.6-1.7 g protein/kg body weight while
endurance athletes need approximately 1.2-1.4 g
protein/kg, values that are about 150-200 percent of
the current United States Recommended Dietary
Allowances (RDA). Conversely, in its recent
presentation of the Dietary Reference Intakes (DRI)
for protein, the National Academy of Sciences 2
concluded that in view of the lack of compelling
evidence to the contrary, no additional dietary protein
is suggested for healthy adults undertaking resistance
or endurance exercise. Sports nutrition scientists do
note that even if athletes need more protein, the
recommended amounts are compatible with the
current Acceptable Macronutrient Dietary
Recommendations (10-35 percent of energy from
protein) and may be easily obtained from natural
foods in the diet 3,4. In general, protein supplements
are not necessary 5,6.
However, dietary protein is composed of 20 different
amino acids which, if ingested individually, have
been theorized to possess ergogenic potential and
have been marketed as sports supplements to
physically active individuals. Indeed, amino acids are
among the top five most popular sports supplements