The intake of plant-based
supplements especially among athletes is common nowadays. Herbal supplements are often claimed to provide health benefits and at
the same time be extremely safe. But they do have their side effects, as
demonstrated by a recent study
published in the Journal of International Society of Sports Nutrition
Among the natural
supplements used by athletes, those that contain plant-derived hormones such as
ecdysteroids, phytoestrogens and sterols, or substance with hormone modulating
properties such as Tribulus terrestris constitute the preferred list.
The published study was
carried out in Italy to evaluate knowledge regarding plant-derived nutritional
supplements among physically active people and to evaluate the side effects
following intake of these supplements.
The study was conducted in
740 trained subjects, which included 420 body builders, 70 cyclists, and 250
fitness athletes. These subjects had been training regularly for at least 1
Among these study participants,
26 declared that they used plant-derived supplements and 23 of them gave their
consent for the blood sample collection.
The study found that the participants knew very little regarding
plant-derived nutritional supplements. In fact, 45% of the 740 individuals did
not know any of the substances provided in the list.
Blood tests in the 23 athletes who took plant-derived supplements
revealed that 15 athletes (65%) showed alteration in sex hormone levels like
estrogen, progesterone and testosterone. However, there were no clinical manifestations of
Individuals with high
estrogen levels reported excessive intake of soy protein. Individuals with
abnormal estrogen and high progesterone levels had consumed products containing
ecdysteroids. Those with high testosterone levels had consumed high dosages of
soy protein, and products containing ecdysteroids and Tribulus terrestris.
A disadvantage of this study
was that it included only a small number of individuals taking plant-based
supplements. Further studies are necessary in this field to establish the side
effects of these plant-based supplements.
Paolo Borrione et al. Consumption
and biochemical impact of commercially available plant-derived nutritional
supplements. An observational pilot-study on recreational athletes. Journal of
the International Society of Sports Nutrition 2012, 9:28