The US vitamins market is valued at 30 billion dollars, and two-thirds of American adults take them. Are they really necessary, however? It turns out that the evidence is very mixed – vitamins can be good for some, bad for others, and useless to most.
The birth of the vitamin illusionThe vitamin industry owes its existence to the great chemist and Nobel laureate Linus Pauling. Later in his life, Pauling became convinced that antioxidant vitamins, especially vitamin C, could cure anything – from a cold to cancer. He kept dosing himself with huge quantities of vitamin C … until he died of cancer. So popular were his books on vitamins, however, that the industry flourished – and eventually doctors and patients alike were convinced that you have to take multivitamins.
Opinions are dividedWhat the general public is convinced of is not always true, however. While vitamins are touted as the best prevention measure for heart disease, cancer, and cognitive issues, research rarely supports these claims.
- Heart disease. Since cardiovascular disease is the main cause of death worldwide, it is natural that people eagerly consume multivitamins that are supposed to reduce the risks of heart disease. However, researchers disagree: the largest study, which followed 14000 men for many years, did not find any decrease in the risk of heart attack among those who took vitamins.
- Cancer. Just like with heart disease, recent large-scale studies did not show any decrease in cancer risk among multivitamin users (see details here), while other research suggests that some vitamin supplements can actually increase the risk of cancer (for example, vitamin A and beta-carotene may lead to lung cancer in smokers).
- Cognitive function. While omega-3 and omega-6 fatty acids are indeed necessary for the brain and can be taken as supplements, the same cannot be said about normal multivitamins. Studies agree that vitamin pills do not have any noticeable effect on memory and cognition (more info here).
The issues with multivitamins
- Poor regulation of supplements. You can never know if the contents of the pill correspond to what’s written on the label. Some vitamins can be stated but not present at all, while others can be included in much higher or lower quantities than prescribed by the recommended norms.
- Overdoses. Fat-soluble vitamins, such as A and D, are accumulated in the fat tissue, so an overdose is possible. Vitamin A, in particular, can be deadly over a certain limit (interestingly, Antarctic explorer Xavier Mertz died of a vitamin A overdose after eating some dog liver – one of the richest sources of this vitamin – while stranded in the ice in 1913). Vitamins D and E can also be toxic in high doses (more info here).
- Bioavailability. Vitamins in pills are not the same thing as vitamins in food. In fact, many multivitamins can disintegrate too fast or too slowly for some vitamins to be absorbed, and additives (like sweeteners, binders, and wax covering) can prevent proper absorption. The debate on how bioavailable vitamins in pills are is still open (more on the matter here).
What to do?Some categories of people do require specific supplements: extra B12 is needed for vegans, vitamin D for older people, omega-3 and omega-6 for most of us, etc. However, multivitamin pills have not been proven efficient and definitely cannot replace a varied diet. Our advice? Stop buying the pills and spend that money on fruit, vegetables, lean meat, fish and seafood, whole grains, nuts and seeds, and quality dairy.