Dietary supplement industry use has grown drastically around the globe for the past decades, with sales increasing from 135 billion USD in 2016 to 205 billion USD in 20211. The premise of taking a pill to fulfil our daily nutrition requirements is captivating, but the underlying evidence is in conflict to this narrative.
One study says, "Dietary supplementation with folic acid to lower homocysteine levels had no significant effects within five years on cardiovascular events or on overall cancer or mortality in the populations studied." 2 Another says, "Calcium supplements with or without vitamin D increased the risk of cardiovascular events, particularly myocardial infarction." 3 The Selenium and Vitamin E Cancer Prevention Trial, showed that “Vitamin E supplements could increase the risk of prostate cancer among healthy men.” 4
Most published studies show no overall benefits and some even point towards deleterious effects5. However, the sales of dietary supplements have increased steadily in the past few years, with market sales predicted to surpass 308 billion USD by the year 20281. On the flip side, dietary inadequacy is still a major concern across the world.
“In 2017, 11 million deaths and 255 million DALYs (disability-adjusted life year) were attributable to dietary risk factors. High intake of sodium (3 million deaths and 70 million DALYs), low intake of whole grains (3 million deaths and 82 million DALYs), and low intake of fruits (2 million deaths and 65 million DALYs) were the leading dietary risk factors for deaths and DALYs globally and in many countries”. 6 * DALY (Disability-Adjusted Life Years) is a measurement that examines years of healthy life lost due to disability.
Why are we forgoing a wholesome and healthy diet in favour of the masses adopting dietary supplements? Have dietary supplements filled the gaps in our diet? Whether or not they work, dietary supplements have managed to grow popular over the years.
Dietary supplements are products taken in addition to the normal diet and may include7:
- Vitamins and pro-vitamins
- Minerals and trace elements
- Fatty acids, protein components
- Herbs or other botanical products
- A concentrate, metabolite, constituent, or extract
- Others like brewer's yeast, algae, and probiotics
The use of dietary supplements can be traced back to an era in the past century where overt nutritional deficiency diseases were predominant. Food supplementation became favoured as people found the need to supplement B-group vitamins that were destroyed during food processing of white flour, white bread, and white rice. The widespread use of dietary supplements and the perceived benefits of vitamin C in scurvy or the benefit of cod liver oil in rickets continue to influence people’s perception of dietary supplements as an important constituent of a healthy diet because processed food products have become a way of life. But easy access to food products has also led to overconsumption, and people question whether eating food is better than focused intake of missing nutrients as supplements.8
Aggressive marketing of dietary supplements and their claims of numerous health benefits have succeeded in convincing the public, though the benefits are sometimes misleading. For example, using a Harvard study which showed an inverse association between prostate cancer and dietary lycopene -- the pigment found in deep-red ripe tomatoes, one brand promoted the use of their MVMs, MultiVitamin/Mineral supplements containing lycopene, though it contained many other constituents that might affect the user. The study was neither randomized nor tracked the effect of lycopene on overall health5.
The allure that a chemical compound can compensate for deficiencies in the diet stems from the original vitamin studies, but also from today's fast and disposable lifestyle filled with machines that move with fuel. “Prescription is more convenient than proscription.” It is easier to shift an imbalance by perceiving it as a deficiency that can be compensated by a supplement than to face the idea that an imbalance is due to tasty unhealthy foods. Rather than cutting down on junk foods, fast foods, fun foods, and our ill dietary habits, it is easier to take a pill.
- Statista. 2022.Dietary supplements market size worldwide 2028 forecast | Statista. [online] Available at: <https://www.statista.com/statistics/828514/total-dietary-supplements-market-size-globally/>.
- Clarke R, Halsey J, Lewington S, Lonn E, Armitage J, Manson JE, et al. Effects of lowering homocysteine levels with B vitamins on cardiovascular disease, cancer, and cause-specific mortality: Meta-analysis of 8 randomized trials involving 37 485 individuals. Arch Intern Med.2010;170:1622– –31.
- Bolland MJ, Grey A, Avenell A, Gamble GD, Reid IR. Calcium supplements with or without vitamin D and risk of cardiovascular events: Reanalysis of the Women's Health Initiative limited access dataset and meta-analysis. BMJ. 2011;342:d2040.
- Klein EA, Thompson IM, Jr, Tangen CM, Crowley JJ, Lucia MS, Goodman PJ, et al. Vitamin E and the risk of prostate cancer: The Selenium and Vitamin E Cancer Prevention Trial (SELECT) JAMA.2011;306:1549–56.
- Kamangar F, Emadi A. Vitamin and mineral supplements: do we really need them?. Int J Prev Med. 2012;3(3):221-226.
- GBD 2017 Diet Collaborators (2019). Health effects of dietary risks in 195 countries, 1990-2017: a systematic analysis for the Global Burden of Disease Study 2017. Lancet (London, England), 393(10184), 1958–1972. https://doi.org/10.1016/S0140-6736(19)30041-8.
- InformedHealth.org [Internet]. Cologne, Germany: Institute for Quality and Efficiency in Health Care (IQWiG); 2006-. What are dietary supplements? 2008 Jun 25 [Updated 2016 Sep 8]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK279425/
- Lentjes MAH. The balance between food and dietary supplements in the general population. Proc Nutr Soc. 2019;78(1):97-109. doi:10.1017/S0029665118002525