There is a major problem with reliance on placebos, like most vitamins and antioxidants. Everyone gets upset about Big Science, Big Pharma, but they love Big Placebo.Michael Specter
Study after study show vitamins do not lower cancer or heart-disease risk. In fact, they vitamins may be creating more problems than they solve.
More than half the population is regularly taking vitamins in CanadaMacleans (2015) – link and the USGallup (2013) – link, with similar levels across the rest of the Western world.Euromonitor (2015) – report (paywall) Most common is the multivitamin and mineral supplement (MVM), popularized in the US in 1941.American Journal of Clinical Nutrition (2007) – link. Multivitamins are now estimated to be consumed, regularly, by 1 in 3 Americans.NIH (2013) – link
Dietary supplements in the US alone make up an estimated $32.5 billion industry
Dietary supplements in the US alone make up an estimated $32.5 billion industry – $13.1 billion of which comes from vitamin and mineral supplements, $5.4 billion in multivitamin supplement format.
Multivitamin supplements typically are sold as once-daily pills that contain a long list of recognised vitamins and minerals. Some variation is seen in pills targeted to children or the elderly or tailored to a particular activity such as enhanced performance, improved immunity, aiding menopause symptoms or similar. What is common to all however, is that they generally contain levels close to or exceeding recommended dietary allowances (RDAs). In some cases, the levels actually exceed established tolerable upper intake levels.Journal of Nutrition (2011) – link
As vitamins and minerals are considered to be dietary supplements and not a formal medication, it means that they are significantly less regulated, with reduced legal safeguards in place. Obviously, all supplements are still required to be safe as a food stuff and meet all food safety standards. However, packaging can be much more liberal with its claims. For example, a combination of vitamin C, E, selenium and beta-carotene is often sold as an antioxidant formula rather than as an MVM supplement even though it contains multiple vitamins and minerals. This can make exact statistics difficult as the consumer does not necessarily realise their own intake.
The history of vitamins
The ancient Egyptians, 3500 years ago, recognised the value of certain foodstuffs in the curing of disease. They were aware that night blindness (resulting as a deficiency of vitamin A) could be easily cured simply by eating liver (rich in vitamin A).Handbook Clinical Neurology (2010) – link
Famously in 1747, the Scottish surgeon James Lind discovered that citrus foods helped prevent scurvy, a deadly disease, common in sailors where collagen cannot properly be synthesised (requiring vitamin C) causing poor wound healing, bleeding from the gums, severe pain before death. Lind’s findings were adopted by the Royal Navy and led to the nickname of “limey” for its sailors.
The first vitamin complex was isolated by a Japanese scientist Umetaro Suzuki in 1910, by extracting a water-soluble complex of nutrients from rice bran. However, when the original articleTokyo Kagaku Kaishi (1911) – PDF (Japanese) was translated into German, the translation failed to mention it was a newly discovered nutrient, so the article largely went unnoticed by the scientific community.
The term vitamin was coined by the Polish biochemist, Kazimierz Funk (commonly Anglicized as Casimir Funk)(great name!), as a contraction of “vital amine” when he first isolated, what is now called, vitamin B3 (niacin).Journal of Nutrition (1972) – PDF
Too much of a good thing?
If vitamins are therefore vital to life, as their name suggests, then where is the problem?
Well, the problem lies in quantities. As with so many things in life, it is all about balance and having the right level of something.
We all need water to live, but too much water can be deadly, we even have a word for it – drowning. Even controlled drinking of water can cause water intoxication and water poisoning as there are not enough electrolytes in the blood, it causes the cells of the brain to swell in size and increases the intracranial pressure and has been seen in competitive drinking competitions to occasionally cause death.
Many things be dangerous in high quantities, even vitamins
Too much oxygen causes muscle spasm, vertigo, drowsiness, severe vomiting and can kill with prolonged exposure.
So too can many things be dangerous in high quantities, even vitamins.
Most people will be familiar with the urban legend that eating a polar bear liver can kill you. The truth is, it can, and has.Biochemical Journal (1943) – link
As early as 1596, European explorers returned with accounts of horrible illness after consumption of polar bear liver. The severity often dependent upon how much was consumed but symptoms included drowsiness, sluggishness, irritability, severe headache, bone pain, blurred vision and vomiting. Perhaps the most horrific symptom they encountered was skin peeling. Even the thick skin on the bottom of the feet would peel away from the flesh. The worst cases ending in liver damage, coma and death.The official cause of death,
The official cause of death, acute hypervitaminosis A or too much vitamin A.
Why take vitamins?
Vitamins are essential in minimal amounts to maintain normal body function. Some vitamins are absolutely valid clinically, for example, folic acid (vitamin B9) is given to expectant mothers during pregnancy to ensure proper development of the nervous system in the foetus. Vitamin K can prevent diseases that cause haemorrhaging in newborns. Vitamin B12 and iron are given to patients with anaemia to ensure that they can carry oxygen in their blood.
In fact, almost all vitamins are taken as a preventative measure rather than as a treatment. Our own quotidian experience would seem to confirm this – when was the last time you saw someone with Rickets or scurvy?
However, absence of proof is not proof of evidence.
When faced with 50 years of society routinely self-administering a product and over 30 years of small scale clinical trials, what do you do?
Well if you work at Harvard and have the backing of the National Institutes of Health, you start a trial of 14,462 men and monitor what happens over 10 years as each man is randomly assigned a placebo, single vitamin or multivitamin.Public Health Study II (2007) – link
…we know that vitamin A, C and E have absolutely no protective effect to cancer
That trial began in August 1997. After 12 years of follow ups, we know that vitamin A, C and E have absolutely no protective effect to cancer.Annals of Internal Medicine (2013) – link
A similar trial in women with tens of thousands of patients over 10 years showed that vitamin C, D and E did not lower their risk of cancer.
Researchers out of the Kaiser Permanente Center for Health Research (Portland, US), systematically reviewed vitamin supplements, including 3 clinical trials of multivitamins and 24 single or paired vitamin trials of more than 400,000 participants. The authors concluded there was no evidence of a beneficial effect of supplements on all-cause mortality (any cause of death), cardiovascular disease or cancer.Annals of Internal Medicine (2013) – link
The problem with such large datasets is that they generate huge amounts of data it is often difficult to draw conclusions, especially outside the hypothesis you initially were looking at.
Hidden in the data are some worrying signs that vitamins might actually increase the cancer risk.
Evidence involving tens of thousands of people, randomly assigned in clinical trials show that increased dosages of beta-carotene, vitamin A and vitamin E increase mortality, whilst other antioxidants, folic acid, several B vitamins and multivitamin supplements had no benefit.Annals of Internal Medicine (2013) – link
Beta-carotene, vitamin E and likely vitamin A in the high doses seen in supplements are harmful. Other common place vitamins, minerals and antioxidants are ineffective in preventing any major chronic disease.
Water soluble vitamins such as vitamin C and the B-complexes, pose a lesser threat as the kidneys typically remove excess vitamins from the body. However, the fat-soluble vitamins A, D, E and K pose a problem of accumulating in the soft, fatty tissues.
Most [vitamin E] supplements are 400 IU, which is 20 times what you get with dietProf. Eliseo Guallar – Johns Hopkins
Which is really about 20 times what your body requires.
My problem is the people taking handfuls [of vitamin supplements], or the manufacturers that are putting incredibly high doses into single pills in a completely unregulated wayDr. Tim Byers – Associate Dean, Colorado School of Public Health
The fact of the matter is that, in the modern world where fresh food is available throughout the year a balanced diet is good enough to supply your body with everything it needs.
Do not forget the recommended dietary allowance (RDA) was established after World War 2, during rationing and was established to meet the requirements of 97.5 % of the population. If you are not in the top 2.5 % of the population, and most of us are not, the RDAs are more than you require.
Guallar and co-authors finish their editorial saying
…supplementing the diet of well-nourished adults with (most) mineral or vitamin supplements has no clear benefit and might even be harmful. These vitamins should not be used for chronic disease prevention. Enough is enough.
Food for thought.
References [ + ]
|1.||↑||Macleans (2015) – link|
|2.||↑||Gallup (2013) – link|
|3.||↑||Euromonitor (2015) – report (paywall)|
|4.||↑||American Journal of Clinical Nutrition (2007) – link|
|5.||↑||NIH (2013) – link|
|6.||↑||Journal of Nutrition (2011) – link|
|7.||↑||Handbook Clinical Neurology (2010) – link|
|8.||↑||Tokyo Kagaku Kaishi (1911) – PDF (Japanese)|
|9.||↑||Journal of Nutrition (1972) – PDF|
|10.||↑||Biochemical Journal (1943) – link|
|11.||↑||Public Health Study II (2007) – link|
|12.||↑||Annals of Internal Medicine (2013) – link|
|13.||↑||Annals of Internal Medicine (2013) – link|
|14.||↑||Annals of Internal Medicine (2013) – link|