Is there any benefit from taking a vitamin or mineral supplement?

Millions of the population take them, but are they really needed?

There are many variants available; once daily products with most of the vitamins and minerals provided in amounts close to the RDA, or a product specifically aimed to a target market (menopausal women, men/women over 50, teenagers, improved immunity, weight control, healthier skin, more energy, better sporting performance). Around a third of the population has been said to be taking these products, with women, the elderly, those with university education, those with higher income, lower body weights and those with already healthier lifestyles and diets taking them most often. And those less likely are smokers, those with a higher body weight (BMI ≥ 30kg/m2) and those with a less healthy diet. So ironically, without even looking at the data , it seems that those who don’t need it, take them, and those who may benefit from them, don’t. As is usually the story with these kinds of products…

The majority of people take these supplements (from experience with discussing the topic with my patients) to ‘top themselves up’, therefore basically as a kind of nutritional insurance. This is usually without any thought as to which vitamin or mineral they may be lacking in, without a great deal of knowledge of what these vitamins and minerals do in the body, and whether they might be able to change their eating habits to suit these nutritional needs instead of taking the supplement. After all, in a society where everything is wanted quickly and easily, this seems like the easiest way to be ‘healthy’.

The recent evidence

A study was recently published in the Annals of Internal Medicine (Fortmann et al. 2013) which systematically reviewed the benefit and risk of vitamin and mineral supplements in community-dwelling, nutrient-sufficient adults for the primary prevention of CVD and cancer.

It concluded that limited evidence is available to support any benefit in already healthy individuals, however in many cases data were insufficient to draw any conclusion. Two multivitamin trials found a lower overall total cancer incidence in men (Hercberg et al. 2004; Sesso et al. 2012), however this effect was borderline, and displayed no benefit for women. It was also found that additional β-carotene supplementation increased lung cancer risk in smokers.

Although there are many in vitro and animal studies available to suggest that additional supplementation of a single or range of vitamins or/and minerals is beneficial to certain disease, it can prove very difficult to replicate, and even to expect similar effects in the human body.

When are supplements recommended? 

NICE (The National Institute for Health and Clinical Excellence) recommends the following:

  • Folic acid – all women thinking of having a baby and pregnant women up until week 12 of the pregnancy.
  • Vitamin D – all pregnant and breastfeeding women, children aged six months to five years, people aged 65 and over and people who are not exposed the sunlight much (people who cover up their skin for cultural reasons, people who are housebound, or those who cover up in the sun for medical reasons).
  • A supplement containing vitamins A, C and D – all children aged six months to four years. This is a precaution because growing children may not get enough, especially those not eating a varied diet, such as fussy eaters.

Conclusions

The general recommendation given by medical professionals is that if you have a healthy, balanced and varied diet then vitamin and mineral supplementation will be of no benefit to you. If anything, it may prove a risk in some cases. Fat-soluble vitamins present the risk of building up to toxic levels, and water-soluble vitamins in excess to the metabolic absorption rate will simply come out in waste products. If you are worried about being deficient in a specific nutrient, being in an ‘at-risk’ population group for deficiency, or not receiving a balanced-diet then it is best to consult your GP who can perform any necessary blood tests, or refer you to see a dietitian.

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