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IS IT REALLY WORTH TAKING MULTIVITAMINS?

People spend billions of dollars on vitamins and mineral supplements globally each year.1 Is everybody taking multivitamins in blind faith, or do they really know what they are taking, and why?

If you have ever searched for a multivitamin product, you will know that there are thousands of formulations on the market and the choice can be overwhelming. Deciding which multivitamin is right for you is not an intuitive exercise. Most of us do not know where to start when comparing supplements. Maybe you take a multivitamin as a type of nutritional insurance policy – back-up for those days when you might have missed some essential nutrients  in your diet. On the other hand, you may have heard someone’s assertion that multivitamins are just expensive urine – a waste of money, but is that really true?

Some research seems to indicate that if you are specifically trying to reduce your risk of a specific chronic disease, like cardiovascular disease, then a multivitamin is not the answer.2 Other research shows that multivitamin supplements do offer real benefits to many people, and that there are low risks associated with using them.3,4,5,6,7

While the best advice for tackling a nutritional health issue is to speak directly to your doctor or dietitian, we can draw on existing research to understand whether or not you are one of those individuals who might benefit from a multivitamin supplement, and if so, how to pick the right one.

What is a multivitamin?

There is currently no consensus or criteria guiding the formulation of multivitamins, and there are several definitions of multivitamins.8 This variation in definition explains why it becomes so confusing to select one. According to the National Institutes of Health panel, the definition of a multivitamin is simply “any supplement containing 3 or more vitamins and minerals, but no herbs, hormones, or drugs, with each component at a dose less than the Tolerable Upper Intake Level (UL)”, whereas other definitions suggest that a multivitamin supplement should contain at least 100% of the RDA for at least 9 vitamins and minerals.1,8 The National Institutes of Health also classifies multivitamins into 3 categories:

  • “Once daily” formulations, providing most or all essential vitamins and minerals at levels close to the Recommended Dietary Allowance (RDA) or Adequate Intake (AI).
  • Special formulations designed for subgroups of the population, such as pregnant women.
  • “Specialized” formulations that might contain higher concentrations of vitamins and minerals that exceed the RDA and sometimes approach or exceed the UL.8

Essentially, a multivitamin is a dietary supplement that is designed to be taken regularly – usually daily – to provide a relatively concentrated dose of multiple essential micronutrients (vitamins and minerals), but since multivitamins come in various formulations and formats, we need to know more before we can decide what to take.

Prevention of deficiency: Do we really need more micronutrients?

Public health nutrition guidelines like the South African food-based dietary guidelines (FBDGs) are based on the understanding that eating a variety of food is the best way to get the broad spectrum of micronutrients we need to maintain health and protect against developing noncommunicable diseases.9 In South Africa you might argue that poor nutrition for many individuals could be attributed to affordability and a basic inability to follow the FBDGs. In this situation, spending a significant amount of money on a dietary supplement to meet requirements is unrealistic, which is partly why the mandatory fortification of staple foods was implemented in South Africa. The FBDGs are also specifically designed around affordability and access to food, so following the FBDGs and eating fortified staples is a relatively affordable way to cover your nutrition bases.

It is certainly best to buy healthy food instead of a supplement if you must make the choice. However, even for individuals who do have the resources to purchase enough healthy foods and improve their dietary diversity, there are assumptions made about the nutritional adequacy of those diets that are not necessarily accurate. Do we all make healthy choices when we can afford it? The trouble is that even if we know what types of food we should be eating, many of us still struggle to eat well consistently because of demanding schedules, easy availability of poor-quality convenience foods or simple lack of motivation to eat better. Research shows us that while improved financial status can positively impact dietary diversity and quality, it is also linked to increased consumption of more indulgent (and less nutritious) food choices such as cookies, sweets and salty snacks.10

Another area of research indicates that our food is gradually becoming less nutritious over time because the demand for increased yields of vegetables and fruit has created intensive farming methods that also disrupt the balance of nutrients in the soil. This results in lower levels of nutrients in the harvested crops. One example is that regularly tilled cabbage was shown to contain significantly lower levels of micronutrients – including several B vitamins, calcium and vitamins K and E – than cabbage grown and harvested through more regenerative farming practices that protect the soil.11 If declining soil quality results in lower quality crops, we may find that we need to eat more and more healthy food over time to reach the same level of micronutrient intake. This is not great news for those of us who already struggle to eat enough vegetables.

A multivitamin could never fulfil all the roles of a consistently healthy diet, but it could support dietary intake of micronutrients and potentially fill in the gaps created by suboptimal food choices.

Prevention of disease – can multivitamins help?

In support of the 2012 Physicians’ Health Study II, which showed that daily multivitamin supplementation “modestly but significantly” reduced total cancer risk,3 the 2022 evidence review from the US Preventive Services Task Force showed a slightly lower risk of cancer with multivitamin use, however the researchers concluded that there is simply not enough evidence to make strong recommendations about using multivitamins to prevent against cardiovascular disease, cancer and death.12 Part of the challenge in interpreting multivitamin research is that multivitamin supplements are often already used by individuals who practice other healthy lifestyle habits.1

Apart from the recommendations around noncommunicable disease, there is expert consensus that long term use of multivitamin supplements is safe in healthy adults, provided they do not exceed the upper limit of recommended intake levels.8 There is also agreement that multivitamin supplements should be considered in select groups where there is known benefit, for example:

  • Pregnant women, where multivitamin supplementation enables adequate folic acid and iron intake and is linked to improved outcomes for both the mother and baby.4,5
  • Elderly individuals, where multivitamin supplementation is linked to a substantial decrease in likelihood or advancement of cataracts.14 and improvements in cognitive function6,7, as well as providing a helpful source of nutrition, which is often compromised as people age and become more dependent.13
  • Individuals with compromised nutrient intake, such as those with conditions that interfere with absorption, or those with increased requirements.8,14

There is another concept that requires more research, but that has emerged recently regarding micronutrient status. Some researchers suggest that when there is low intake of micronutrients, certain metabolic processes are prioritised at the expense of long-term health. This is effective for immediate survival and does not necessarily manifest as a deficiency state, but it could be linked to accelerated ageing and long-term health problems.15

 

The risks: Is taking multivitamins safe?

The use of multivitamin supplements is generally considered safe.8 There are a few cases where multivitamin use should be approached with caution:

  • Smokers should avoid large amounts of beta carotene or vitamin A, because research has pointed towards an increased risk of lung cancer associated with these nutrients.14
  • Pregnant women should be cautious of excessive vitamin A (not beta carotene) which can increase risk of birth defects.14
  • Healthy adult males and postmenopausal women should not take repeated high doses of iron beyond requirements.14,15

It is worth remembering that while we are usually trying to get enough, it is also possible to take too many supplements and to exceed the tolerable upper level of micronutrient intake by mistake. Water-soluble vitamins (the B vitamins) can be excreted relatively easily, so it is common to see supplements with quite high levels of B vitamins, but there are minerals and some vitamins, like vitamin A, that tend to build up over time and can become toxic when taken in excess.15 If your dietary intake is relatively good, you may not have to take a supplement every single day. You may wish to take a multivitamin every other day, or occasionally when you travel, or if you have a particularly busy week and your food choices are different.

How to compare multivitamins

The quality of multivitamin supplements that make it onto shelves in South Africa is not always controlled. It is important to select a multivitamin that has been manufactured safely to ensure that it contains what it says on the label, and no additional harmful or toxic substances. A good way to check this is to note whether a manufacturer is licensed with the South African Health Products Regulatory Authority (SAHPRA) as the principle regulatory body of South Africa, established by the Medicines Act, which ensures that health products available to the public are safe, effective and of good quality. SAHPRA governs manufacturers to have a Good Manufacturing Practice (GMP) system in place that ensures products are consistently produced and controlled according to specific required quality standards.

Once you feel confident that you are comparing high quality and safe supplements, you can then assess the actual formulation and decide what quantity of nutrients would work for you.

The Nutrient Reference Value (NRV) is a good place to start when comparing supplements.  The NRV is a value used in food labelling in South Africa that is related to Recommended Dietary Allowances (RDAs) which meet the needs of 97-98% of healthy individuals to prevent nutrient deficiencies. These values are considered to be the minimum amounts necessary to achieve and maintain optimum nutritional status which will assist in the reduction of disease, specifically degenerative diseases of lifestyle.16

Given that the NRV is a baseline and average requirement, individuals with more demanding lifestyles or specific conditions may therefore require more nutrients than the NRV suggests.16 The NRV also does not account for the difference in requirements for different genders or life stages, so you may want to consider formulations that are designed to address these differences. For example, in general, women have higher demands for iron than men do, and for women of child-bearing age folic acid intake is also a priority, so a multivitamin for women should ideally provide these nutrients at suitable levels.

Be aware that most multivitamin tablets or capsules are limited in size, so they are unlikely to contain the full NRV for every micronutrient because they would be far too big to swallow, so it is important to consider the range of nutrients your multivitamin does provide and perhaps add additional supplements if you need more of one specific nutrient. This is particularly important if you are trying to correct a known deficiency, in which case you may need a significantly higher dose than a multivitamin provides. This type of high dose supplementation should be supervised by a health professional and based on blood tests that are performed to guide treatment.

Vital NRV Table

A note from Vital’s experts:

The Vital MultitimeTM range is a collection of expertly formulated multivitamin and mineral blends. From the foundational nutrient blend provided by Vital Multivitamin 100% NRV through to highly specialised products such as Vital Eye Health, there is targeted nutrition support for different ages and health requirements. Within the range, there is also a clearly differentiated offering for men and for women to address gender-specific health priorities at various life stages. The Vital manufacturing site (including the onsite lab) has been audited by the South African Health Products Regulatory Authority (SAHPRA) and certified to meet the requirements of Good Manufacturing Practice (GMP).

references

  1. National Institutes of Health State-of-the-Science Panel. National Institutes of Health State-of-the-Science Conference Statement: Multivitamin/mineral supplements and chronic disease prevention. Am J Clin Nutr. 2007 Jan;85(1):257S-264S
  2. Sesso HD, Christen WG, Bubes V, Smith JP, MacFadyen J, Schvartz M, et al. Multivitamins in the prevention of cardiovascular disease in men: The Physicians’ Health Study II randomized controlled trial.JAMA 2012;308:1751-60. 
  3. Gaziano JM, Sesso HD, Christen WG, Bubes V, Smith JP, MacFadyen J et al. multivitamins in the prevention of cancer in men: The Physicians’ Health Study II randomized controlled trial. 2012; 308(18): 1871–1880.
  4. International Alliance of Dietary/Food Supplement Associations. Multiple micronutrient supplementation: Improving the quality of nutrition for mothers in low- and middle- income countries. 2023.
  5. Gomes F, Agustina R, Black RE, Christian P, Dewey KG, Kraemer K et al. Multiple micronutrient supplements versus iron-folic acid supplements and maternal anemia outcomes: an iron dose analysis. Ann N Y Acad Sci. 2022 Jun;1512(1):114-125.
  6. Baker LD, Manson JE, Rapp SR, Sesso HD, Gaussoin SA, Shumaker SA, Espeland MA. Effects of cocoa extract and a multivitamin on cognitive function: A randomized clinical trial. Alzheimers Dement. 2023 Apr;19(4):1308-1319.
  7. Yeung LK, Alschuler DM, Wall M, Luttman-Gibson H, Copeland T, Hale C et al. Multivitamin supplementation improves memory in older adults: A randomized clinical trial. Am J Clin Nutr. 2023 Jul;118(1):273-282.
  8. Blumberg JB, Cena H, Barr SI, Biesalski HK, Dagach RU, Delany B et al. The use of multivitamin/multimineral supplements: A modified Delphi consensus panel report. Clin Ther. 2018; 40(4):640-657.
  9. Vorster HH, Badham JB, Venter CS. An introduction to the revised food-based dietary guidelines for South Africa. S Afr J Clin Nutr 2013;26(3):S1-S164.
  10. Madlala SS, Hill J, Kunneke E, Kenge AP, Peer N, Faber M. Dietary diversity and its association with nutritional status, cardiometabolic risk factors and food choices of adults at risk for type 2 diabetes mellitus in Cape Town, South Africa. 2022 Aug; 14(15): 3191.
  11. Montgomery DR, Bikle A, Archuleta R, Brown P, Jordan J. Soil health and nutrient density: preliminary comparison of regenerative and conventional farming. 2022 Jan 27;10:e12848. doi: 10.7717/peerj.12848
  12. O’Connor EA, Evans CV, Ivlev I, Rushkin MC, Thomas RG, Martin A, Lin JS. Vitamin and mineral supplements for the primary prevention of cardiovascular disease and cancer Updated evidence report and systematic review for the US Preventive Services Task Force. 2022;327(23):2334-2347.
  13. Marais ML. Malnutrition in older persons: Underestimated, underdiagnosed and undertreated. S Afr J Clin Nutr.2017;30(2):4–6.
  14. Ward E. Addressing nutritional gaps with multivitamin and mineral supplements.
    Nutr J. 2014 Jul 15;13:72.
  15. Ames BN. Low micronutrient intake may accelerate the degenerative diseases of aging through allocation of scarce micronutrients by triage. Proc Natl Acad Sci U S A. 2006 Nov 21;103(47):17589-94.
  16. Department of Health. 2010. R.146. Regulations relating to the labelling and advertising of foodstuffs. Foodstuffs, cosmetics and disinfectants act, 1972 (Act 54 of 1972).