A British man recently ended up needing a liver transplant after taking green tea capsules. (1).(2).
Many people do not realise that supplements can be useless or even harmful.
Firstly, Dietary supplements may not always be helpful. Even though the Public Health team in England recommend vItamin D supplements, a large study published recently – found that Vitamin D supplements do NOT prevent fractures or falls in General population. (3) (4).
Secondly, Dietary supplements can be harmful. For example , a cancer prevention trial involving 35,533 North-American men reported that “Dietary supplementation with vitamin E significantly increased the risk of prostate cancer among healthy men”. (JAMA 2011; 306: 1549). Another cancer prevention trial in Finland involving 29,133 male smokers unexpectedly found a “higher incidence of lung cancer among the men who received beta carotene dietary supplements”. (NEJM 1994;330:1029 )
On the other hand, Vitamin are essential nutrients. Vitamin deficiency can be severely harmful to health. Vitamin D deficiency is common in colder parts of northern hemisphere. Vitamin D supplements are used in treatment and prevention of osteoporosis (5). Vitamin B12 deficiency is common in Vegans and Vitamin B12 supplements are used. (6).
So there is no clear cut answer ….
Always consider the possibility that “dietary supplements may actually have harmful as well as possible beneficial effects”.
- BBC News – Are supplements safe and do they work? https://www.bbc.com/news/health-45992725
- Daily mail: Green tea supplements may cause liver damage, warns EU watchdog. https://www.dailymail.co.uk/health/article-5629791/How-healthy-healthy-EU-warns-green-tea-supplements.html
- Public Health England recommends vitamin D supplements in autumn and winter. BMJ 354 doi:10.1136/bmj.i4061
- Guardian : Vitamin D supplements don’t help bone health, major study concludes. https://www.theguardian.com/society/2018/oct/04/vitamin-d-supplements-dont-help-bone-health-major-study-concludes
- Vitamin B12 and Health: http://www.lnds.nhs.uk/Library/Vitamin_B12_and_HealthOct2018LNDS123.pdf
- National Osteoporosis Guideline Group: https://www.sheffield.ac.uk/NOGG/mainrecommendations.html