Ashwaganda (Withania somnifera (L.) Dunal) is a plant that has been safely used in Ayurveda for over 3,000 years. The main active substances from the roots are the withanolides common in the nightshade family. The highest concentrations are found in ashwaganda. These steroids have a similar effect as the main active ingredients of ginseng. Hence why ashwagandha is also called ‘Indian ginseng’. The roots of the shrub also contain various alkaloids.
The Technical University of Denmark (DTU) conducted a risk assessment of the plant for the Danish Veterinary and Food Administration in 2020. Building on their negative review in 2008, DTU noted a few studies showing adverse effects on thyroid and sexual function after consumption of unspecified extracts from the root and other plant parts. They concluded that its consumption has negative effects on sex hormones and reproduction. In addition, the plant could affect the metabolism, the immune system, and the central nervous system. DTU concluded that it could not establish a safe lower limit for intake of the root or extracts from it. Therefore, ashwagandha was banned in Denmark. [1]
Other countries are considering following this ban. In September 2022, the Swedish Food Agency announced that the Danish risk assessment can also be applied in Sweden, but that the municipalities decide in individual cases. Poland already took the decision in 2020 to only allow root powder with a maximum of 3 g and 10 mg withanolides, and to ban it for children, pregnant and breastfeeding women.
Several experts have criticized the report for not objectively assessing safety.
The main problem is that no distinction is made between leaf and root. In the Ayurvedic tradition, the leaves or stem (which contain higher concentrations of withaferin A, withanone, and alkaloids compared to the root) are used externally, but rarely internally.
Based on small studies with heterogeneous results for the levels of active substances in different plant parts, the DTU concluded that no distinction could be made between the plant parts. However, the risk assessment mentions a difference by a factor of 30 for the content of withaferin A in the root (0.032%) and in the leaf (0.9-1%). An indication that they do have different safety profiles. This was also confirmed in other studies. In 2021, the Indian Ministry of AYUSH issued official guidelines against using leaves in Ayurvedic formulations.
These recent studies were not included in the assessment. DTU referred to 8 studies (4 animal studies) evaluating the effect of the root on sex hormones, 7 of which showed normalized levels of sex hormones, – “normalizing” or “balancing” the body’s hormones is one of the functional features of ashwagandha -while one 2002 animal study showed a reduced willingness to mate. However, DTU did not report in its review that the authors themselves concluded that this was “not due to changes in testosterone levels or toxicity, but may be attributed to […] the sedative activities of the extract”, among other possible causes such as effects of GABA or serotonin.
In addition, no distinction was made between different extraction methods and solvents. The traditional method is water extraction. With methanol or ethanol, other profiles are obtained.
DTU also refers to 2 studies conducted with one specific extract, while there were already 10 published double-blind studies confirming safety available at the time.
The WHO published a monograph in 2020 and the plant is also in the British and American Pharmacopoeia.
In addition, in 2023, World Ashwagandha Council published a comprehensive review of DTU’s risk assessment, stating that a large number of well-conducted studies have been published since 2020 in relation to safety. [2]
In conclusion, several questions arise about the robustness of the DTU assessment.
Comments are closed, but trackbacks and pingbacks are open.