Multivitamins review and compare

Do you really need to take one?
 
Learn more
 
 
 
 
 
  • Updated:6 Jan 2005
 

01 .Introduction

Multivitamins

In brief

  • There’s evidence that multivitamin/mineral supplements can be beneficial for some people, particularly if your general diet is inadequate, though they can’t replace the benefits of changing your diet to a healthier mix.
  • Believe it or not, multivitamins are a complementary medicine and may interfere with the absorption or function of prescription medicines, so tell your doctor you’re taking one, or planning to.

Not if you have a good diet. Research makes it clear that a balanced diet is still the best way to get your vitamins and minerals, and studies show that diets high in whole grains, vegetables and fruit reduce the risk of cancers and other diseases.

Please note: this information was current as of January 2005 but is still a useful guide today.


A good diet beats supplements because:


  • Whole foods are complex, containing not only the major nutrients but also a wide variety of vitamins, minerals and other micronutrients.
  • Whole foods provide dietary fibre, which is important for digestion and has a role in preventing cancer, diabetes and heart disease.
  • Whole foods contain other substances, called phytochemicals, which may also protect us against cancer, heart disease, diabetes and high blood pressure.
  • Whole foods usually contain vitamins and minerals in different forms — for example, vitamin E occurs in nature in eight different forms — but supplements usually contain just one. The different forms may be absorbed better or not as well by the body (this is known as their bioavailability), and absorption may depend on other things in the food too. Improving your diet to include a variety of food sources gives your body a much better chance of absorbing enough of a vitamin in all the available forms.
 
 

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02.Who might need one?

 

There’s also a case for some people taking supplements:

  • Many adults — and particularly those who are elderly, ill or alcohol-dependent — don’t have an adequate diet and so can be at risk of vitamin deficiency. For example, a national nutrition survey by the Australian Bureau of Statistics found that most Australian women over 40 were eating less zinc and calcium than they needed.
  • One trial involving elderly people showed that taking a multivitamin/multimineral supplement reduced the number of days of illness due to infections by half.
  • Women who are pregnant, likely to become pregnant or who are breastfeeding may benefit from a multivitamin. The most important vitamin here is folate — eating more than 400 micrograms (µg) a day has been shown to reduce neural tube defects like spina bifida in the developing foetus. Pregnant and breastfeeding women also need more of other nutrients, particularly iron and calcium. But pregnant women should avoid multis high in vitamin A, as this vitamin has been linked to an increased risk of birth defects. It’s probably worth looking for a multivitamin especially formulated for pregnancy, but talk to your doctor about it first.
  • Research also shows that multivitamins may lower the risk of coronary heart disease, colon cancer and breast cancer, particularly among regular consumers of alcohol. In fact in 2002, researchers from Harvard who’d undertaken a review of multivitamin studies concluded that it would be prudent for all adults to take a daily multivitamin.

03.Important vitamins and minerals

 

These are the ones most people probably need to be concerned about if their diet isn’t as good as it could be.

Calcium

Calcium supports the structure of bones and teeth and helps to regulate blood pressure, as well as being needed by muscles, blood vessels and hormones and for sending messages throughout the nervous system. Inadequate levels of calcium, as well as vitamin D, contribute to the development of osteoporosis and fractures, so it’s a particularly important mineral for seniors, especially women.

However, you won’t find calcium at a 100% RDI dose in a multivitamin — it’s so bulky the pill would be too big to swallow. So if you want to increase your calcium intake, you’re better off doing it in your diet or looking for a specific supplement.

  • Main food sources: Dairy products, fish with bones (especially salmon and sardines), nuts, legumes (beans, including baked beans, lentils), tofu (if it’s made with calcium sulphate). It’s also found in smaller amounts in broccoli and leafy greens.

Iron

Iron is essential for oxygen transportation in the body and a deficiency can result in fatigue, poor work performance and decreased immunity. Prior to menopause it’s an important mineral for women to keep an eye on, and vegetarians and endurance athletes might benefit from a supplement. But most other adults get plenty of iron from their diet and don’t need supplements — in fact too much iron can cause or mask other health problems.

Ferrous iron salts (ferrous fumarate, ferrous sulphate and ferrous gluconate) are the forms of iron supplements that the body can absorb best. Absorbing iron from non-meat sources like supplements is boosted by vitamin C, so take them with a glass of orange juice.

  • Main food sources: Iron comes in two forms — haem iron and non-haem iron. The haem form is absorbed more readily by the body: sources include liver, red meat and chicken, and fish to a lesser extent. Good sources for non-haem iron are nuts, legumes, apricots and whole grains.

Zinc

Zinc helps protect the body’s immune system and is important, particularly for men, for the reproductive system. It’s also thought useful for promoting wound healing.

  • Main food sources: Oysters and other seafood, meat, liver and eggs are the best sources. It’s also found in nuts, legumes and whole grains.

Vitamin A

An important antioxidant, vitamin A comes in two main ways: either as ready-to-go preformed vitamin A (such as retinol) found only in animal foods; or pro-vitamin A, which is turned into vitamin A in the body and is mainly found in plant foods (for example, beta carotene, which is most common). Pregnant women shouldn’t take it in the retinol form, as this is linked to a risk of birth defects. Excessive retinol (over 1500 µg/day) has also been implicated in reduced bone density or increased hip fracture risk. Two studies have suggested that men who are smokers and take high-dose beta carotene supplements have an increased risk of lung cancer.

  • Main food sources: It’s chiefly found in liver and cod liver oil; some is also in oily fish, eggs, milk, butter and cream. The body can also easily convert it from the beta carotene in dark green vegetables and orange and red fruits and vegetables. It’s usually added to margarines.

Vitamins B6, B12

Vitamin B6 is needed to make haemoglobin to carry oxygen and also help to maintain normal blood sugar and serotonin levels. Vitamin B12 is needed to make DNA. Along with folate, low levels of vitamins B6 and B12 are risk factors for cardiovascular heart disease, and can result in anaemia and neurological disturbances. Taking a supplement of B6 may also reduce the severity of PMT and morning sickness.

  • Main food sources: For B6, wheatgerm, fish, bananas, meat, legumes and nuts. And per milligram, Vegemite is one of the richest sources of B6. For B12, liver, kidney sardines, oysters, egg yolk, fish, meat, cheese and milk.

Folate (Folic Acid)

One of the B vitamins, folate (or its synthetic form, folic acid) is especially important for pregnant women (in fact for all women who might get pregnant) as it’s been proven to help reduce the level of neural tube defects (like spina bifida) in the developing foetus. Low levels may also be a risk factor for cardiovascular heart disease and colon and breast cancer. Clinical trials are currently under way to determine whether folate supplementation can lower the risk of coronary heart disease.

  • Main food sources: Fresh green leafy vegetables, asparagus, organ meats, legumes, oranges, nuts and folate-fortified cereals.
    More on folate ...

Vitamin C

We need to eat vitamin C on a regular basis, as humans are one of the few species of animal that can’t make it. It’s also one of the most important antioxidant substances in the body, maintains the body’s connective tissue, and is essential for the formation of collagen, the major element of blood vessels, skin, tendons, cartilage and teeth.

Some studies suggest that taking vitamin C supplements long-term may help prevent heart disease. It may also play a role in cancer prevention. Any role vitamin C might have in the prevention and treatment of the common cold remains hotly debated, but a recent Cochrane Review analysis of 29 vitamin C studies concluded that it doesn’t appear to prevent colds, but may have a modest role in reducing their duration and severity.

  • Main food sources: It’s in many fruits and vegetables, the most concentrated sources being blackcurrants, red capsicum, guava, pawpaw, oranges and strawberries.

Vitamin D

Vitamin D is made in the body by exposure to sunlight. Along with calcium, low levels of vitamin D contribute to the development of osteoporosis and fractures, so this is important for seniors, particularly women. There’s no Australian RDI for vitamin D (because there’s thought to be little danger of anyone not getting enough exposure to the sun). However, anyone who’s housebound or not exposed to direct sunlight for at least one to two hours a week is recommended to take a supplement of 10 µg/day. Elderly people in particular should make sure their diet contains enough. Pregnant women shouldn’t take large doses.

  • Main sources: Apart from exposure to sunlight, small amounts are also found in oily fish like herring, salmon, tuna and sardines, beef liver, fortified margarine, eggs and cod liver oil.

Vitamin E

This is considered to be the most important and potent fat-soluble antioxidant. It’s best known for its effects on the cardiovascular system and may have a role to play in preventing cardiovascular disease, though recent research suggests having enough in your diet is better than supplements. High-dose vitamin E supplements have also been tested in clinical trials for pain relief of rheumatoid arthritis and osteoarthritis, with varying results.

  • Main food sources: Vegetable oils, particularly wheatgerm oil, nuts and seeds. It’s also found in eggs, soya beans, and fruit and vegetables to a lesser extent.
Some vitamins, such as A, C and E, are antioxidants, which help prevent cell damage in the body. Oxidative cell damage is caused when ‘free radicals’ attack cells in the body. This type of attack is called oxidation: it harms cells and, among other things, may weaken the immune system. Free radicals are formed in the body as by-products when the body converts oxygen into energy, and by environmental causes. Antioxidants prevent oxidation by getting rid of free radicals before damage occurs. Fruits and vegetables are notable sources of antioxidants.

A recent Danish study looked at whether fruit and veg or a vitamin supplement was more effective, by comparing three groups of people: one on a fruit and veg diet, one taking supplements and one taking a placebo.

It found that both the fruit-and-veg and supplement groups had less cell damage than the placebo group, but the fruit-and-veg eaters fared best of all, with significantly less damage than those in the supplement group.

05.What your body can and can’t store

 
  • Water-soluble vitamins, including vitamin C, biotin and the seven B vitamins aren’t stored in your body in significant amounts. Because surplus water-soluble vitamins are simply excreted in your urine, ‘megadoses’ of these are mostly a waste of money.
  • Fat-soluble vitamins (like A, D and E) that aren’t immediately used by your body are stored in your body fat and liver. High doses over a long period are potentially toxic, even though studies of high-dose vitamin E have produced conflicting reports of possible benefits for some conditions. And because vitamins E and K affect blood clotting, talk to your doctor before taking a supplement that contains either if you’re also taking a blood thinner such as warfarin. Supplements of fat-soluble vitamins should be taken with a meal or your body won’t properly absorb them.