Recent media attention has suggested that vitamin and mineral supplements offer no health benefits from their consumption. An article published in the Daily Mail reported two studies in which long-term use of vitamin and mineral supplements appeared to provide little if any protection against cognitive decline or developing cardiovascular disease.
A quick look at the studies
The Physicians’ Health Study II, a randomised, double-blind, placebo-controlled trial, started in 1997 to test the balance of benefits and risks of three widely used supplements (vitamin E, vitamin C, and a multivitamin) for the primary prevention of cardiovascular disease, cancer, age-related eye disease, and cognitive decline. The cognitive function sub-study began in 1998 with up to 4 repeated cognitive assessments by telephone interview and completed over 12 years. The study participants were male physicians aged 65 years or older and the study looked at test performance (not at the actual development of dementia) and found no significant difference in cognitive test scores between vitamin users and those taking a placebo. The second study, a review of 24 randomised, controlled trials and 2 cohort studies of community-dwelling adults for the primary prevention of cardiovascular disease (CVD) and cancer, found no evidence to suggest a protective effect of individual vitamins or multivitamin and mineral supplementation on cardiovascular disease risk. So here we have two studies that suggest that general multivitamins and mineral supplements do not prevent us from developing cognitive decline or cardiovascular disease. The subsequent media message to the public was that supplement users are simply wasting their money.
Before we all reach to the supplement drawer to ditch our multivitamins is it fair to judge the benefits (or lack of) of multivitamin and minerals on these two studies? Firstly, whilst the latter study reported no benefits to cardiovascular disease risk, it did include two large trials that reported lower cancer incidence in men taking a multivitamin for more than 10 years. Interestingly, additional findings from The Physicians’ Health Study II found that those men in the multivitamin group had an 8% lower risk of developing cancer compared to those on placebos. So both studies actually suggest that there are benefits derived from multivitamin and mineral supplementation, certainly in relation to a possible role in cancer prevention. What about other studies out there that support the use of supplements?
A 2012 meta-analysis of ten trials assessing the effects of multivitamins on cognitive performance indicated that multivitamins were effective in improving immediate free recall memory  and that multivitamins may reduce the risk of colorectal adenoma in women  and, further, that multivitamin and mineral supplementation may even have beneficial effects on many aspects of mood, stress and mild psychiatric symptoms in healthy individuals. Studies on the use of multivitamins and minerals in health and disease are regularly published, creating a myriad of often conflicting results. With many of these studies there are variables such as bioavailability of the nutrients, population target, study design and length, nutritional status of the participants, disease state (or not) that can affect outcomes. To choose two studies from the bank of studies that have been conducted and from these tell the public to avoid multivitamins and minerals is, frankly, sloppy and weak advice.
Can we meet our nutrient requirements via a ‘normal healthy diet’?
As a nutrition scientist, I advocate good nutrition with the best nutrition-based strategy for promoting optimal health and reducing the risk of chronic disease, focusing around wise choices from a wide variety of nutrient-rich foods.
Additional nutrients from supplements can help some people meet their nutrition needs as specified by science-based nutrition standards such as the Recommended Daily Allowance (RDA). As such, I actively encourage those I meet to adopt good eating habits, consume their ‘5-a-day’, get plenty of fibre and so on. Whilst eating patterns and nutrient intake are dependent on numerous factors, it is generally accepted that if people have access to a sufficient quantity and a good variety of quality foods, they will meet, in large part, their nutritional needs. In general, when advising on the use of multivitamins and minerals I focus on food first, as supplements of this nature are really designed to ‘top-up’ where food may fail. As the name suggests, they are not really formulated to treat, or prevent disease, but rather ‘supplement’ the diet to ensure the RDA is met. The RDA itself represents levels of intake of essential nutrients considered to be adequate to meet the known needs of practically all healthy people. The RDA does not take into account the nutritional requirements of individuals with health issues or of disease states, or even during pregnancy where multivitamin, and especially folate, supplementation is actively encouraged due to the impact on reducing the occurrence of neural-tube defects. The nutrient requirements of those who are ill differ significantly from healthy individuals and it is often the case that the role of individual nutrients must be addressed.
Food as a source of nutrients
How do we ensure our diets are providing the key nutrients for ‘normal everyday’ functioning? For a food to deliver optimal nutrients it must be nutritionally rich when consumed. The issue here is that health benefits derived from consuming food will be compromised by any time gap that arises between the moment a food is picked or produced and its consumption. Nutrient losses can occur between harvesting, during processing and distribution as well as during storage. To ensure the food we consume is at its most nutritionally ‘active’ we should choose food that is, in an ideal world, organic, free-range (where appropriate), grown in nutrient rich-soil, locally sourced, freshly picked and optimally stored. Many nutrients are also highly influenced by cooking (don’t even MENTION microwaves), so consuming food raw where possible will certainly help retain vital nutrients.
We also should avoid foods that are either processed or refined, as these steps are known to strip them of key nutrients either by direct removal as part of the process or through loss due to sensitivity to heat, light and oxygen. Many cereals, for example, require fortification with key nutrients to avoid deficiencies that may arise as a consequence of processing methods. There are also numerous factors that may influence nutrient uptake. Phytates and oxalates are, for example, antioxidant compounds found in whole grains, legumes, nuts and seeds (and those cups of tea you drink!). The issue with these compounds is that they bind to certain dietary minerals including iron, zinc and manganese and, to a lesser extent, calcium, and slow or inhibit their absorption. So the message here is that there’s a lot to think about when considering how to optimise nutrient intake and avoid potential avenues that may give rise to sub-optimal nutrient levels. It is also worth noting that that the RDA is the daily dietary intake level of a nutrient considered sufficient by the Food and Nutrition Board to meet the requirements of 97.5% of healthy individuals in each life-stage and sex group. Indeed nutrient requirements will change if a ‘healthy’ individual becomes ‘unhealthy’! The RDA is also based on the assumption that the population has access to those foods needed to supply nutrients and that they adopt good eating practices In addition, there are individuals, those of economic restrictions, those with poor food choices or those with higher nutrient requirements (as in some disease states), for example, where levels of certain micronutrients may not be met from food alone. For example, vitamin D deficiency is a growing concern and NHS figures suggest that the number of under-18s who have been admitted to hospital in England for rickets has soared by 25% in the last 9 years. As such, the government’s chief medical officer Dame Sally Davies has recently suggested that all low-income families and all children under the age of five receive free vitamin and mineral supplements to help reduce the growing incidence of nutrient-deficiency related conditions.
For many of us, supplementing the diet with multivitamins and minerals is seen as merely a method to ‘top-up’ our levels of nutrients that we feel may often be missing from our normal diets. Vitamins and other dietary supplements are not intended to be a food substitute and they cannot replace all of the nutrients and benefits of whole foods. There may be occasions or lifestyle changes that can increase our nutrient needs or influence absorption from food sources, thus warranting popping the odd multi-vit. Some drugs can impede absorption, for example, corticosteroids, often prescribed to reduce inflammation, decrease absorption of calcium and vitamin D. Long-term stress can result in the body being on constant, low-grade ’fight or flight’ status, which can influence digestion and absorption of nutrients. Regular alcohol and coffee consumption can also decrease absorption rates and exercise, whilst good for the body and mind, can actually increase the body’s nutrient requirements.
For those that do choose to supplement, quality is usually reflected by the price. Ensuring the active ingredients are in bioavailable forms will significantly improve any potential health benefits. Chelation, for example, involves attaching a mineral to an amino acid so that the body can more easily absorb it. Chelated magnesium such as magnesium citrate is significantly more soluble and bioavailable than the oxide form which is often found in many cheap, poor quality health supplements. So when choosing a supplement, a little research goes a long way and if in doubt about what to choose, your friendly nutritionist or health store can provide invaluable information.
- Gaziano JM, Sesso HD, Christen WG, Bubes V, Smith JP, MacFadyen J, Schvartz M, Manson JE, Glynn RJ, Buring JE: Multivitamins in the prevention of cancer in men: the Physicians’ Health Study II randomized controlled trial. JAMA : the journal of the American Medical Association 2012, 308:1871-1880.
- Grodstein F, O’Brien J, Kang JH, Dushkes R, Cook NR, Okereke O, et al. Long-term multivitamin supplementation and cognitive function in men. A randomized trial. Annals of internal medicine 2013; 159:806-14.
- Grima NA, Pase MP, Macpherson H, Pipingas A: The effects of multivitamins on cognitive performance: a systematic review and meta-analysis. Journal of Alzheimer’s disease : JAD 2012, 29:561-569.
- Massa J, Cho E, Orav EJ, Willett WC, Wu K, Giovannucci EL: Long-term use of multivitamins and risk of colorectal adenoma in women. British journal of cancer 2014, 110:249-255.
- Long SJ, Benton D: Effects of vitamin and mineral supplementation on stress, mild psychiatric symptoms, and mood in nonclinical samples: a meta-analysis. Psychosomatic medicine 2013, 75:144-153.
- Czeizel AE, Dudas I, Vereczkey A, Banhidy F: Folate deficiency and folic acid supplementation: the prevention of neural-tube defects and congenital heart defects. Nutrients 2013, 5:4760-4775.