The position statement, released jointly by the American College of Sports Medicine, the Academy of Nutrition and Dietetics, and the Dietitians of Canada, represents an evidence-based analysis and synthesis of more than eight years of relevant nutritional research on important dietetic practice questions, including fluid and nutrient intake, nutrition strategies for exercise recovery, and the use of performance-enhancing supplements.
One of the lead authors, Travis Thomas, PhD, of the University of Kentucky College of Health Sciences, said the positions laid out in the paper have evolved over time, and represent the authors’ best estimation of the weight and quality of science backing the various aspects of dietary recommendations for athletes.
“This is an effort that has gone on for about two years,” Thomas told NutraIngredients-USA. “This is building on the last position paper that was published about eight years ago. We usually look at revising the position paper starting at somewhere from three to six years after publication depending on what evidence is coming in.”
Overall weight of evidence
As such, some of the research that has caused excitement in the sports nutrition end of the dietary supplement industry in recent years counted for less in this group’s evaluation, as some of the ingredients in the space have only a few, small-scale studies behind them, as opposed to the raft of studies supporting the effects of macronutrients. Thomas said the way science has come to be publicized in recent years might move the needle of opinion with certain subsets of consumers, but carries less weight with committees such as the one he was involved with that are tasked with evaluating the overall weight of evidence.
“We really have looked at lots of evidence and we were not open to changing the entire view on a topic based on one study. Unfortunately a lot of consumers will get caught up on certain articles that may present favorable outcomes, but those outcomes may not relate to them or to their specific training program. Many of these studies were low quality, with small numbers of participants,” Thomas said.
Thomas said the paper does contain recommendations on a number of micronutrients and five categories of supplement ingredients that appear in sports products. The micronutrients discussed are iron, vitamin D, calcium and antioxidants. In a table labeled “Sports Specific Supplements” the authors discussed creatine, caffeine, sodium bicarbonate, B-alanine and nitrate. The table lists the identified the benefits of consuming these ingredients along with cautions for their use, which can include gastrointestinal side effects and the toxicity concerns associated with over-consumption of caffeine.
Shift in protein focus
On the question of protein, the paper makes a significant shift away from recommendations based on activity type and more toward a focus on where an athlete might be in his or her training cycle. Previously it was thought that endurance athletes needed less protein, whereas more recent research suggests that a power cycle in training calls for a spike in protein consumption, whether it’s a 10,000 meter runner trying to boost his or her kick or a strength athlete going through a phase of maximum efforts.
“One of the key messages with protein is that we shouldn’t categorize athletes as endurance athletes or power athletes. Previously if you fell into one camp or another there was a difference in the total amount of protein recommended. Now we key it to the actual stage of their training,” Thomas said.
Protein intakes in general are set at 1.2 to 2.0 grams per kilogram of body weight. The paper recommends spacing this intake throughout the day, and says that more protein might be recommended if the athlete is seeking to shed body weight during training so as to better maintain lean body mass during that process. The paper places less emphasis on the widely popular notion that a large serving of protein consumed shortly after training is the best way to go.
“We recommend an even spacing of protein over the course of the day. As to whether a large serving post exercise is effective, we don’t believe we have all the answers to that,” Thomas said.
Nutrient dense carbohydrates
Dietitians as a class tend to come down hard on the side of whole foods as the best source of energy, and the committee’s position paper falls in line with that philosophy. Thomas said he was aware of some studies done on specific types of carbohydrate as ingredients in sports nutrition products, but again the overall weight of evidence was not conclusive in the authors’ evaluation.
“We are trying to promote more nutrient dense carbohydrates. When you look at where a specific carbohydrate falls on the GI scale and you are trying to relate that directly to performance there is not a lot of evidence to support that connection,” Thomas said.