Astragalus extract balances rowers’ immune systems in study

By Hank Schultz

- Last updated on GMT

©Getty Images - Alistair Berg
©Getty Images - Alistair Berg

Related tags astragalus immune function

A recent study found that supplementation with an astragalus extract benefited the immune systems of elite class rowers participating in a heavy training cycle.

Suppression of immune system response is a well known side effect of intense training.  Over time athletes and coaches have found different strategies to deal with this, but every year there are at least a few athletes whose dreams are shattered by an ill timed respiratory infection or intestinal complaint that blunts their performance edge.  On the other hand, an immune system overstimulated by heavy workouts can cause an excessive inflammatory response that hinders performance and training adaptation all on its own.

Seeking balance

So sports authorities are always in the market for supplements or OTC preparations that can balance out this response and that don’t violate WADA guidelines.  The latest substance to be studied in this regard is what the researchers involved were calling an Astragalus Membranaceus Root (AMR), which was standardized to 0.5% 3-hydroxy 7-methoxy isoflavonoids.  Astragalus is one of the immunity ingredients that has seen a surging demand​ since the start of the global pandemic.

The research, which was published last week in the Journal of the International Society of Sports Nutrition​, was performed by a team associated with two institutions in Poland.  Their subjects were 18 rowers of the Polish national team who were participating in an intensive six week training camp.

The rowers were all young men, with an average age of about 21, and most were in the heavyweight rowing group, with only four lightweight rowers.  The rowers all supplemented with 1 gram/day of the extract or a cornstarch placebo formulated as capsules.  The rowers ate their standard training diet during the study, but did refrain from other supplements or medications during the study period.

Balancing components of the immune system

The rowers performed a 2,000 meter sprint rowing ergometer test before and at the end of the training camp.  To assess the before and after states of the immune system, the researchers drew blood from the rowers and tested it for levels of immunomodulatory cytokines IL2, IL4, IL10, IFN-ɣ, and T regulatory lymphocytes [CD4+/CD25+/CD127–] (Treg), cytotoxic lymphocytes [CD8+/TCRαβ+] (CTL), natural killer cells [CD3−/CD16+/CD56+] (NK), and TCRδγ-positive (Tδγ).

The rowers were training about 16 hours a week.  The training camp consisted of a blend of longer distance workouts, shorter intensive sessions and strength training on land.  They were divided into a 10-member group receiving the astragalus extract and an 8-member placebo group.

The prime outcome was a measurement of the shift in the ratio of two immune system components, T helper 1 and T helper 2 cells.  An immune system response characterized by more Th2 cells has been associated with some disease states, such as chronic fatigue syndrome​ or chronic inflammatory disorders​.

The researchers concluded that the astragalus extract successfully balanced the rowers’ immune systems in such a way that excessive Th2 expression was avoided.

“AMR stabilizes the immune system in athletes by restoring the immunological balance towards Th1 response during restitution after strenuous exercise.  . . . The discovered immuno-tonic effect gives the hope to use AMR in athletes’ daily routine to protect them against Th2-shift related illnesses,”​ they concluded.

Source: Journal of the International Society of Sports Nutrition
18​, Article number: 57 (2021)
Standardized astragalus extract for attenuation of the immunosuppression induced by strenuous physical exercise: randomized controlled trial
Authors: Latour E, et al.