In the study, male and female participants who ate 57 g of almonds a day for a month had more of the beneficial fatty acid 12,13-dihydroxy-9Z-octadecenoic acid (12,13-DiHOME) in their blood immediately after a meal. intense exercise session than those control participants who did not take almonds.
The study’s lead author, dr David C Niemanprofessor and director of the Human Performance Laboratory at Appalachian State University Research Campus in North Carolina, explains: “Volunteers who consumed 57 g of almonds daily for a month reported feeling less fatigue and tension, more strength in the legs and less muscle damage after intense exercise than those who took cereal bars.”
How the study was done
The clinical trial involved 38 men and 26 women between the ages of 30 and 65, who were not participating in training on a regular basis. About half were randomly assigned to the almond diet group and the other half to the control group, which ate a daily cereal bar with the same calories. The researchers took blood and urine samples before and after the four-week period of dietary supplementation. Performance measures included a 30-second Wingate anaerobic test, a 50-meter round trip test, and vertical jump strength exercises, weight bench training. Additional blood and urine samples were taken immediately after this 90 minute eccentric exercise session and daily for the following four days.
After each blood draw, participants completed a Profile of Mood States (POMS) questionnaire to quantify their mental state and rated their delayed-onset muscle soreness, that is, the pain and stiffness felt after a strenuous or unaccustomed exercise, on a 10 -interval scale.
As expected, the 90-minute exercise led to an increase in the volunteers’ self-reported sensation of muscle damage and muscle soreness, as well as an increase in the POMS score, indicating decreased vigor and increased energy. self-reported fatigue, anxiety, and depression.
Exercise also resulted in transiently elevated levels of proinflammatory cytokines such as IL-6, IL-8, IL-10, and MCP-1 in the blood, consistent with minor muscle damage. However, these changes in cytokines were the same in the almond and cereal bar groups.
Differences in both groups
The study highlights that immediately after exercise, the concentration of the beneficial 12,13-DiHOME was 69% higher in the blood plasma of participants in the almond group than in participants in the cereal bar group. 12,13-DiHOME is known to increase fatty acid transport and uptake by skeletal muscle, with the overall effect of promoting metabolic recovery after exercise.
The reverse pattern was found for another oxylipin, the mildly toxic 9,10-dihydroxy-12-octadecenoic acid (9,10-diHOME), which was 40% higher immediately after exercise in the blood of the control group than in the almond group.
The key is in the skin
Nieman and his colleagues concluded that daily consumption of almonds leads to a change in metabolism, downregulates inflammation and oxidative stress from exercise, and allows the body to recover faster.
“We concluded that almonds provide a unique and complex blend of nutrients and polyphenols that can support metabolic recovery from stressful levels of exercise. Almonds have high amounts of protein, types of healthy fats, vitamin E, minerals, and fiber. And the brown skin of almonds it contains polyphenols that end up in the large intestine and help control inflammation and oxidative stress,” Nieman said.