What you need to know about vitamin and mineral supplements
Are you up to scratch with your knowledge of the A-Zs of vitamins? Pamela Mason provides the latest information on vitamin and mineral supplements
Vitamins and minerals are essential for life. They play well established biochemical roles, particularly as co-factors for various enzymes or as structural substances in tissues such as bone and blood.
Between them, these nutrients are important for the health of every cell in the body. Lack of vitamins is associated with a range of adverse effects, from deficiency diseases, such as scurvy, rickets and anaemia, to chronic conditions, depending on the nutrient concerned, including cardiovascular disease and eye disease, as well as poor immune function, which may be reflected in poor overall health.
All essential vitamins and minerals can be obtained from the diet, but the UK national nutrition and diet survey, which began in 1992 and is published by the Department of Health, continues to show that significant numbers of the British population do not achieve recommended intakes. Basically, the most recent data from this survey1 show that the UK diet has not improved over the past 10 years. Intakes of minerals are particularly worrying in young women, but low intakes of nutrients occur across several age ranges, including children.
In particular, intakes of iron were below the reference nutrient intake (RNI) among 58 per cent of girls aged 11 to 18 years and 79 per cent of women aged 19 to 64 years. Mean intake of iron fell below the lower reference nutrient intake (LRNI) among 44 per cent of girls aged 11 to 18 years and 22 per cent of women aged 19 to 64 years. Mean intakes of both magnesium and selenium were below the LRNI in 50 per cent of girls aged 11–18 years.
Poor vitamin D status is the subject of many reports. Among those population groups where an RNI is set (ie, children, older people, pregnant and breast-feeding women), dietary intakes are low. Among older men (>65 years) mean intake of vitamin D is just 39 per cent of the RNI. Among older women, the figure is 29 per cent. Only 27 per cent of children (aged one-and-a-half to three years) achieve the RNI for vitamin D.
Everyone should be encouraged to eat a healthy diet based on grains, vegetables and fruit, with moderate amounts of meat, fish or beans and dairy foods (preferably low in fat). Given that many people do not appear to be able to achieve this and maintain an intake of vitamins and minerals in reference amounts (see Table), a multivitamin and mineral preparation containing a wide variety of vitamins and minerals can be recommended to help maintain good health. People who are most likely to be at risk of deficiency and could benefit from a multivitamin supplement are shown in the Panel below (“People who may benefit from supplementation”).
Studies in adults,2,3 toddlers4 and teenagers5 have shown that supplement use can make a significant contribution to vitamin and mineral intake. In addition, supplementation with vitamins and minerals can improve plasma levels of micronutrients and reduce the prevalence of suboptimal plasma concentrations.6–8
People who may benefit from supplementation
The following groups of people could benefit from taking vitamin and mineral supplements:
The Healthy Start scheme provides free vitamin supplements (folic acid, vitamins C and D) formulated for pregnant women and free vitamin drops (vitamins A, C and D) for young children. Maternal supplements are free to all eligible women who are pregnant or have an infant under 12 months of age, while children’s vitamin drops are free to all eligible children (those aged six months or over). Pharmacists should provide information on the Healthy Start scheme and ensure that the products are available.
Women eligible for Healthy Start
Women who are eligible for Health Start are those who are at least 10 weeks pregnant or have a child under four-years old, and the family receives income support; or income-based job seeker’s allowance; or income-related employment and support allowance; or child tax credit; and the family has an annual family income of £16,190 or less (2011–12). Pregnant women under the age of 18 also qualify.
Multivitamins are the most popular dietary supplements in the UK, and can be recommended for providing a wide range of micronutrients for people consuming a poor diet.
Although multivitamins are not intended for use in the prevention of chronic conditions, there is some epidemiological evidence for an inverse link between use of multivitamins and cardiovascular disease9,10 and cataract.11 Evidence for benefit of multivitamins in reducing risk of infection is weak and conflicting. Recent analyses have shown no association between use of vitamin supplements and various types of cancer, including breast12 and prostate13 cancer. Few controlled intervention trials have been conducted with multivitamins but two studies have shown reduced antisocial behaviour in prisons14 and in children15 with vitamins and minerals.
Lack of vitamin D is the subject of a huge amount of research. This is due to findings of suboptimal blood levels, deficiency and in northern countries such as the UK, the re-emergence of vitamin D deficiency disease (eg, rickets). Vitamin D is obtainable from few foods and in northern countries exposure to sunlight is unlikely to be adequate to produce optimal blood levels.
Lack of vitamin D has been associated with a range of different conditions, such as osteoporosis, cancer, cardiovascular disease, multiple sclerosis, diabetes mellitus and poor immune function.16 A recent systematic review of cohort studies concluded that low baseline serum 25-hydroxy vitamin D levels predict increased risk of fractures, colorectal cancer, CVD and all-cause mortality.17 Vitamin D deficiency has recently been associated with the deaths of 45 children (mostly under the age of 12 months) of natural causes.18 Three recent meta-analyses have shown that vitamin D supplementation is associated with reduced mortality.19–21
In light of concerns about vitamin D deficiency, the UK’s chief medical officers have written to health professionals reminding them about this issue. The Department of Health recommends that a daily vitamin D supplement should be taken by various groups of people, including:
• All pregnant and breast-feeding women
• Breastfed babies from the age of six months (or earlier if the mother’s vitamin D status is not adequate)
• Formula-fed babies receiving less than 500ml infant formula a day
• All children aged one to four years.
• All people over the age of 65 years
• People who are not exposed to much sun
• People with darker skins.
In an article published in The Pharmaceutical Journal earlier this year,18 Oliver Gillie, director of Health Research Forum, London, suggested that vitamin D supplementation should begin in week 1 for all babies and that Government advice, which recommends the need for supplementation only after the age of six months, should be changed.
Fish oils are used as supplements mainly on the basis of their content of long-chain n-3 polyunsaturated fatty acids (LC n-3 PUFAs), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Traditionally, fish oils have been most often used for the alleviation of joint stiffness in arthritic conditions. Today, however, evidence links the use of LC n-3 PUFAs with benefits in a wider range of conditions, particularly cardiovascular disease, principally through reducing the tendency of the blood to clot and reducing blood levels of triacylglycerols. Evidence of value of LC n-3 PUFAs in cognitive function and childhood behavioural disorders is also increasing.
Recent studies continue to add to the data base on these fatty acids in different population groups. Experimental studies have suggested that LC n-3 PUFAs may reduce the risk of atrial fibrillation (AF), but evidence from studies attempting to link intake data with AF have been conflicting. However, a new study in 3,326 US adults that evaluated circulating levels of omega-3 fatty acids as a more objective measure of exposure found that higher blood levels of LC n-3 PUFA were associated with lower risk of incident AF.22
Several studies have demonstrated differences in omega-3 fatty acid composition in plasma and in erythrocyte membranes in patients with attention deficit-hyperactivity disorder (ADHD) compared with unaffected controls. Results from randomised controlled trials (RCTs) have been conflicting, but these have evaluated a range of doses of omega-3 fatty acids in different types of child behavioural disorders. A new meta-analysis of 10 RCTs involving 699 children with ADHD found that omega-3 fatty acid supplementation, particularly with higher doses of EPA than DHA, was modestly effective in the treatment of ADHD.23
The use of zinc lozenges for reducing the duration of the common cold has been widely advocated. Trials conducted since 1984 have produced mixed results, but a recent Cochrane review of 13 therapeutic trials and two prevention trials concluded that zinc administered within 24 hours of onset of cold symptoms reduces the duration and severity of the common cold in healthy people. When subjects were supplemented for at least five months, zinc was also found to reduce cold incidence, school absenteeism and the need of prescribing of antibiotics in children. The authors suggest that further evidence is required before firm recommendations can be made on doses and formulations for different populations.24
Iodine deficiency is the most common cause of preventable mental impairment worldwide, but this issue has received scant attention in the UK in recent times. However, findings from three recent UK studies suggest that the UK does have a problem with iodine deficiency. A cross-sectional survey among 14- to 15-year-old schoolgirls found that indicators of mild iodine deficiency were present in 51 per cent of the participants, with moderate deficiency present in 16 per cent and severe deficiency in 1 per cent.25
A survey of 100 pregnant women in the south east of England found that only 18 per cent of the women had intakes that satisfied the World Health Organization criteria for pregnancy.26 Since developing fetuses are the most susceptible to adverse effects of iodine deficiency and even mild perturbations of maternal and fetal thyroid function have an effect on neurodevelopment, these findings are of potential major public health importance.
Vitamins and minerals play well established biochemical roles at the cellular level and are essential for life. Although essential nutrients can be obtained from the diet, surveys continue to show that significant numbers of the British population, particularly young women, do not achieve recommended intakes.
In circumstances where nutrient intake from diet is inadequate, a multivitamin or mineral supplement may be recommended. Specific people who might benefit from supplements include infants and children, pregnant and breastfeeding women, older people, people taking several medicines, and those on restricted diets. Poor vitamin D status is a particular cause for concern and the DoH has re-emphasised its advice to health professionals that pregnant and breast-feeding women, children aged one to four years, people over the age of 65 years, people with darker skin and those not exposed to sunlight should take a supplement.
The DoH advice also includes the need for vitamin D supplementation in all breast-fed babies from the age of six months, and all bottle-fed babies receiving less than 500ml infant formula each day.
However, the suggestion has been made that all babies should receive a vitamin D supplement from the start and that the DoH advice should be changed.
A range of other nutrients continue to attract attention, in particular omega-3 fatty acids for cardiovascular health and their use in ADHD, as well as zinc for the reduction in the incidence of the common cold. More recently, deficiency of iodine has been shown in the UK, including among pregnant women, which could be potentially serious for the neural development of the unborn child.
Pharmacists should emphasise the importance of eating a healthy diet wherever possible, but a supplement containing recommended amounts of nutrients may be useful where maintenance of health due to nutrient inadequacy is in doubt.
1 Bates B, Lennox A, Bates C et al. National Diet and Nutrition Survey. Headline results from year 1 and 2 (combined) of the Rolling Programme (2008/2009-2009/2010). A survey carried out on behalf of the Food Standards Agency and the Department of Health. Available: http://www.dh.gov.uk/prod_consum_dh/groups/dh_digitalassets/documents/digitalasset/dh_128550.pdf and: http://www.dh.gov.uk/prod_consum_dh/groups/dh_digitalassets/documents/digitalasset/dh_128556.pdf.
2 Henderson L, Irving K, Gregory J et al. The National Diet and Nutrition Survey: adults aged 19 to 64 years. Volume 3. Vitamin and mineral intake and urinary analysis. London: Stationery Office; 2003.
3 Troppmann L, Gray-Donald K, Johns T. Supplement use: is there any nutritional benefit? Journal of the American Dietetic Association 2002;102:818–25.
4 Briefel R, Hanson C, Fox MK et al. Feeding Infants and Toddlers Study: do vitamin and mineral supplements contribute to nutrient adequacy or excess among US infants and toddlers? Journal of the American Dietetic Association 2006;106(1 Suppl 1):S52–65.
5 Sichert-Hellert W, Wenz G, Kersting M. Vitamin intakes from supplements and fortified food in German children and adolescents: results from the DONALD study. Journal of Nutrition 2006;136:1329–33.
6 Girodon F, Blache D, Monget AL et al. Effect of a two-year supplementation with low doses of antioxidant vitamins and/or minerals in elderly subjects on levels of nutrients and antioxidant defense parameters. Journal of the American College of Nutrition 1997;16:357–65.
7 Navarro M, Wood RJ. Plasma changes in micronutrients following a multivitamin and mineral supplement in healthy adults. Journal of the American College of Nutrition 2003;22:124–32.
8 Wolters M, Hermann S, Hahn A. Effects of 6-month multivitamin supplementation on serum concentrations of alpha-tocopherol, beta-carotene, and vitamin C in healthy elderly women. International Journal for Vitamin and Nutritional Research 2004;74:161–8.
9 Holmquist C, Larsson S, Wolk A et al. Multivitamin supplements are inversely associated with risk of myocardial infarction in men and women ? Stockholm Heart Epidemiology Program (SHEEP). Journal of Nutrition 2003;133:2650–4.
10 Rautiainen S, Akesson A, Levitan EB et al. Multivitamin use and the risk of myocardial infarction: a population-based cohort of Swedish women. American Journal of Clinical Nutrition 2011;92:1251–6.
11 Kuzniarz M, Mitchell P, Cumming R et al. Use of vitamin supplements and cataract: the Blue Mountains Eye Study. American Journal of Ophthalmology 2001;132:19–26.
12 Chan AL, Leung HW, Wang SF. Multivitamin supplement use and risk of breast cancer: a meta-analysis. Annals of Pharmacotherapy 2011;45:476–84.
13 Stratton J, Godwin M. The effect of supplemental vitamins and minerals on the development of prostate cancer: a systematic review and meta-analysis. Family Practice 2011;28:243–52.
14 Gesch CB, Hammond SM, Hampson SE et al. Influence of supplementary vitamins, minerals and essential fatty acids on the antisocial behaviour of young adult prisoners. Randomised, placebo-controlled trial. British Journal of Psychiatry 2002;181:22–8.
15 Schoenthaler SJ, Bier ID. The effect of vitamin-mineral supplementation on juvenile delinquency among American schoolchildren: a randomized, double-blind p lacebo-controlled trial. Journal of Alternative and Complementary Medicine 2000;6:7–17.
16 Holick MF. Vitamin D deficiency. New England Journal of Medicine 2007;357:266–81.
17 Scragg R. Vitamin D and public health: an overview of recent research on common diseases and mortality in adulthood. Public Health Nutrition 2011;14:1515–32.
18 Gillie O. Vitamin D deficiency in dead babies shows why official advice is misleading. The Pharmaceutical Journal 2012;288:137.
19 Autier P, Gandini S. Vitamin D supplementation and total mortality: a meta-analysis of randomized controlled trials. Archives of Internal Medicine 2007;167:1730–7.
20 Bjelakovic G, Gluud LL, Nikolova D et al. Vitamin D supplementation for prevention of mortality in adults. Cochrane Database of Systematic Reviews 2011;6:CD007470.
21 Zittermann A, Iodice S, Pilz S et al. Vitamin D deficiency and mortality risk in the general population: a meta-analysis of prospective cohort studies. American Journal of Clinical Nutrition 2012;95:91–100.
22 Wu JH, Lemaitre RN, King IB et al. Association of plasma phospholipid long-chain omega-3 fatty acids with incident atrial fibrillation in older adults: the Cardiovascular Health Study. Circulation 2012;2012:26.
23 Bloch MH, Qawasmi A. Omega-3 fatty acid supplementation for the treatment of children with attention-deficit/hyperactivity disorder symptomatology: systematic review and meta-analysis. Journal of American Academy Child and Adolescent Psychiatry 2011;50:991–1000.
24 Singh M, Das RR. Zinc for the common cold. Cochrane Database of Systematic Revviews 2011;16:CD001364.
25 Vanderpump MP, Lazarus JH, Smyth PP et al. Iodine status of UK schoolgirls: a cross-sectional survey. The Lancet 2011;377:2007–12.
26 Bath S, Wright J, Taylor A et al. Iodine deficiency in pregnant women living in the south-east of the UK. Proceedings of the Nutrition Society 2010;69(OCE6):null-null.
Citation: The Pharmaceutical Journal URI: 11099947
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