A study suggests an intensive exercise program boosts cognitive performance and physical fitness in United States Air Force personnel. A nutritional supplement may also have some additional benefits.
While exercise is known to improve health and cognition, combining it with a nutritional supplement that mimics a Mediterranean diet may provide further advantages.
Scientists at the University of Illinois in Urbana-Champaign, Abbott, and the U.S. Air Force Research Lab found that volunteers who consumed the supplement before and after training sessions had an edge in some measures of fitness and cognition 3 months later.
However, intensive exercise alone improved strength and endurance more than intensive training with the supplement.
On two cognitive performance measures, both the placebo group and the supplement group showed a slight reduction in performance, while other measures improved.
“The physical and mental health benefits of exercise are well known, but this study demonstrates how optimal nutrition can help boost brain function as well,” says study leader Chris Zwilling, a postdoctoral researcher at the University of Illinois.
“We are excited by the results because they provide critical insights into how simple dietary changes can make a big difference in helping people be as efficient and productive as possible in today’s world,” he adds.
The research appears in the journal Scientific Reports.
The scientists recruited 148 active-duty male and female Air Force personnel from Wright Patterson Air Force Base in Dayton, OH, and randomly assigned them to two groups.
Both groups underwent a 12-week exercise program involving five daily sessions of 45 minutes, including rotating sessions of high-intensity interval training, aerobic fitness, and strength training each week.
One group drank the specially formulated nutritional supplement 30 minutes before and 1 hour after each session, while the second group consumed a placebo drink that looked and tasted the same. The supplement contained 267 calories of energy, while the placebo contained 100 calories.
Neither the researchers nor the participants knew who drank the special supplement and who drank the placebo.
The high-protein supplement contained a wide range of nutrients, including:
- lutein, a carotenoid vitamin related to beta-carotene and vitamin A found in kale, spinach, avocados, and eggs
- omega-3 fatty acids, found in oily fish such as mackerel and sardines
- phospholipids, an essential component of cell membranes
- beta-hydroxy beta-methylbutyrate, a supplement that helps increase muscle mass and aids recovery after exercise
- folic acid
- B vitamins
- vitamin D
Participants took a series of cognitive and physical fitness tests before and after the exercise program. The cognitive tests assessed their memory, fluid intelligence — the ability to solve novel reasoning problems, executive function, and reaction time.
The exercise-only group had positive improvements in 5 out of 6 physical fitness measures and 4 out of 8 cognitive functioning measures. The research team recorded cognitive functioning increases in:
- short-term memory
- episodic memory
- executive function reaction time
- fluid intelligence and processing efficiency
The group who also took the supplement had improvements in all six fitness measures and 6 out of 8 cognitive measures. Compared with exercise alone, taking the supplement was associated with significant additional enhancements:
- working memory increased
- fluid intelligence reaction time decreased
- lean muscle mass increased
- resting heart rate, a measure of physical fitness, decreased
However, some of the figures in the study abstract were inaccurate. The authors have provided updated figures to Medical News Today and the journal.
Furthermore, the figures in the abstract were determined using raw data, which the paper did not provide. There were also some errors in rounding. Therefore, MNT is cautious about the study’s findings while the authors and the journal update the figures.
Matt Kuchan, a research fellow and brain health scientist at Abbott and a co-author of the study, was impressed by the improvement in working memory among participants who took the supplement.
Working memory is a finite, temporary information store that predicts an individual’s ability to multitask and is often impaired in stressful situations. For example, it allows a person to remember a telephone number long enough to dial it or write it down.
“This is a really big deal,” says Kuchan. “First, because working memory is hard to improve. And secondly, because it is relevant to everybody.”
Strangely, two measures of cognitive function were slightly worse after the intervention for both the supplement and the placebo group: short-term memory and executive function accuracy.
It could be that these small performance decreases were due to test anxiety or chance.
The investigators say they did not design the study to determine which nutrients improved physical and cognitive performance. They also remain unsure if the enhanced cognition was due to the supplement, improvements in physical fitness, or a combination of both.
The study also took just 3 months, and therefore, it is not certain that real-life health programs could maintain these enhancements.
The research team discovered a link between the supplements and improvements that could not be explained by exercise in only 5 out of the 23 analyzed measures of cognitive health.
In addition, they made no adjustments in the statistical analysis to assess many variables in a single and relatively small study.
They also believe there may have been further benefits by using whole foods to deliver the nutrients, rather than supplements.
However, this would have presented several challenges in designing the study, for example, how to deliver exact quantities of several different nutrients.
The study provides evidence that intensive cardiovascular and resistance training offer rapid improvement in fitness, and in line with previous research, is associated with improvements in some measures of cognition.