Study: Cordyceps extract supports iron levels and muscle health in runners

The 16-week placebo-controlled, double-blind, parallel-group comparison trial tested the impact of supplementing Cordyceps militaris​ (CM) mycelium (produced by La Vie En Sante Ltd. Japan) extract, aka the caterpillar fungus, on blood markers for anemia—a common issue in long-distance runners.

The resulting data suggest that the supplement can maintain the hemoglobin and hematocrit levels in long-distance runners, possibly by suppressing the decrease in iron storage (reflected by serum ferritin) during pre-season training.

Furthermore, the creatine kinase levels—an enzyme found in the skeletal muscle, heart muscle and brain and a biomarker for tissue damage when found in the bloodstream—were significantly decreased in the CM group compared with those in the placebo group after 16 weeks of intervention.

"These results suggest that Cordyceps militaris​ mycelium extract exhibits a protective action on the muscle damage observed in long-distance runners and may suppress muscle injury," the researchers from Juntendo University, Japan wrote in the journal Nutrients​.

"Together, these observations suggest that Cordyceps militaris​ mycelium extract exhibits an improving effect on the markers for not only anemia but also muscle injury in long-distance runners during pre-season training."

Iron demand in athletes

Factors contributing to enhanced iron excretion include increased iron loss in sweat; increased excretion of red blood cells, hemoglobin and myoglobin in urine; and gastrointestinal bleeding. Notably, the half-life of iron is shorter in long-distance runners than in non-athlete controls, suggesting that iron turnover is enhanced in runners.

Iron demand is thought to increase in athletes, owing to increased blood volume and increased iron-containing enzymes and myoglobin in muscle. Moreover, it is possible that gastrointestinal function is decreased because of intense training, which may reduce iron absorption from the intestines.

Intense physical exercise such as endurance running induces an inflammatory response in muscle and results in muscle damage accompanied with an increase in serum creatine kinase (a biomarker for inflammatory response in muscle). In this context, it has been reported that the serum creatine kinase level is increased during or immediately after exercise in long-distance runners such as marathon runners.

Study details

A total of 22 healthy male long-distance runners between the ages of 18 and 24 were assigned to either a placebo or CM group and instructed to take six capsules per day (300 mg of Cordyceps militaris​ mycelium powder per capsule) for 16 weeks.

Participants were prohibited from taking any medications or supplements intended to improve anemia. They recorded adherence in a diary, which was more than 99% in both groups.

In addition to the baseline measurement performed at registration, blood tests and physical measurements (body weight, body mass index, body fat percentage, skeletal muscle percentage and basal metabolic rate) and dietary surveys were taken at four, eight and 16 weeks.

Dietary surveys indicated no significant difference in the dietary intake of iron and vitamin C between the two groups at all time points during the study period.

The total distance covered by the long-distance runners participating in this study was more than 1,600 km, and their 5,000 m running records were shortened in both the placebo and CM groups. Thus, it is assumed that the endurance performance of the subjects was increased, and the iron loss and demand were possibly enhanced in the long-distance runners during the study period.

The results indicated the change rates of serum ferritin levels were moderately increased in the CM group (n=11) but decreased in the placebo group (n=11), and the levels were significantly increased in the CM group compared with those in the placebo group at four weeks and eight weeks after the test food intake.

Moreover, the change rates of hemoglobin and hematocrit were significantly increased in the CM group compared with those in the placebo group at eight weeks after the test food intake.

Mechanism of action

Since Cordyceps sinensis​ contains substances with anti-inflammatory and antioxidant potential, the authors speculated that the Cordyceps militaris​ mycelium extract administered in this study exhibits anti-inflammatory and antioxidant actions on muscle, thereby protecting from muscle injury in long-distance runners during pre-season training.

Since the administration of the Cordyceps militaris​ mycelium extract significantly decreased the level of CK (a biomarker for inflammatory response in muscle), they further hypothesized that the extract exhibits anti-inflammatory action on injured muscle as evaluated by CK but not by C-reacting protein.

Source: Nutrients​
doi: 10.3390/nu16121835​
"Effect of the Administration of Cordyceps militaris Mycelium Extract on Blood Markers for Anemia in Long-Distance Runners"
Authors: Nakamura, A. et al.