By Jane Nicholson,
Director of University News, Appalachian State University
A recent study by David Nieman, DrPH, director of the Appalachian State University Human Performance Laboratory at the N.C. Research Campus (NCRC) in Kannapolis, found that a special type of carbohydrate, raffinose, found in pistachio nuts and other foods reduced athletic performance when consumed prior to intense exercise.
Nieman is also a professor in Appalachian’s College of Health Sciences.
The study “Influence of pistachios on performance and exercise-induced inflammation, oxidative stress, immune dysfunction, and metabolite shifts in cyclists: a randomized, crossover trial” was published November 19 in PLOS ONE, a peer-reviewed, open-access resource from the Public Library of Science.
Because pistachios are nutrient-dense nuts that contain a unique nutrient profile of proteins and carbohydrates, Nieman and his research team hypothesized that ingesting three ounces of pistachio nuts a day for two weeks before and on the day of intense cycling would support performance compared to water only, and would attenuate inflammation, oxidative stress, and immune dysfunction for 21 hours afterwards.
However, since humans cannot digest raffinose, which is found in foods such as onions, soybeans, chickpeas and pistachios, athletes who ate the pistachio nuts increased the amount of raffinose in the colon. When they cycled for 75 kilometers at high intensity, performance time slowed by 4.8 percent compared to when pistachios were not ingested.
Using a sophisticated tracking technology called metabolomics that measures all detectable small molecules present in biological samples such as biofluids or tissues, Nieman discovered that raffinose leaked out of the gut during exercise, which caused the immune system to release a toxin that impaired energy production in the muscles.
Nieman clarified that the results of the study do not indicate that athletes should eliminate foods containing raffinose from their regular diets. “Pistachio nuts, beans, oat bran and other foods that contain raffinose are extremely nutritious and essential to a healthy diet,” he said. “When athletes are training for intense competitions like long-distance cycling or marathons, this study suggests they should limit some of these raffinose-containing foods during the week prior to competition to maximize their overall performance.”
“The net result,” Nieman said, “is that, if confirmed by other research groups, I believe a new sports nutrition policy will be developed that will recommend that athletes avoid foods containing raffinose in the days prior to endurance competition.
“I consider this paper to be among the top five discoveries of my research career,” he continued, “and it represents the type of research that the NCRC was established to advance.”
Nieman, a Fellow of the American College of Sports Medicine, is recognized as an expert in exercise physiology and sports nutrition. He has authored more than 300 published scientific papers on the topic. He collaborated with Durham-based Metabolon and the UNC Charlotte Bioinformatic Services Division at the N.C. Research Campus on the study.
Other members of the research team were Johannes Scherr, Department of Prevention and Sports Medicine, University of Munich; Beibei Luo, Department of Physiology, Second Military Medical University in Shanghai; Mary Pat Meaney, Human Performance Lab, N.C. Research Campus; Didier Dréau, Charlotte Research Institute and Department of Biological Sciences, UNC Charlotte; Wei Sha, Bioinformatics Services Division, UNC Charlotte, N.C. Research Campus; Dustin Dew, Human Performance Lab, N.C. Research Campus; Dru Henson, Department of Biology Immunology Laboratory, Appalachian State University; and Kirk Pappan, Metabolon Inc., Durham.
Past research conducted by Nieman and researchers affiliated with NCRC and Appalachian’s Human Performance Lab have found that:
- Sick days with the common cold among physically active people are cut nearly in half due to enhanced circulation of key immune cells and improved killing of viruses and bacteria.
- Ingesting carbohydrate, either from sports drinks or bananas, during a race can help counter the negative impact of stressful exercise on the immune system.
- Physically active, lean elderly individuals have T-cells (i.e., the immune cell group most negatively affected by aging) that function at levels found in much younger women.
- Marathon competition increases the odds of getting sick due to a transient but disturbing downturn in immune function and elevation in stress hormones.
- Ibuprofen use is common among endurance athletes, but causes the release of bacteria from the colon, amplifying inflammation and oxidative stress. A mixture of quercetin, green tea extract and fish oil works better than ibuprofen and reduces inflammation and oxidative stress post-exercise, but only when ingested for two weeks or longer.
- A 45-minute exercise bout in a metabolic chamber increased metabolism for 19 hours post-exercise with an extra energy expenditure of 190 calories above resting levels.
For information about this study or other findings, contact David Nieman, DrPH.