Plant-based Supplements Not Entirely Safe

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 theJournal 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 year. 
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 the same. 
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. 
Reference: 
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 doi:10.1186/1550-2783-9-28