As the quality of our food diminishes, so the humble multivitamin has become one of the most popular health supplements in the world. Yet, taking supplements can be expensive. One option is to buy low-dose multis from large, reputable manufacturers that are able to price their products competitively and, being more in the public eye, may feel more obliged to offer a quality product.
But low-dose multis are just that - low dose - containing 100 per cent, or less, of the Recommended Daily Allowance of a nutrient. At this level, you get enough to stave off a deficiency disease (like scurvy), but not enough to have a therapeutic effect.
Because of this, some consumers contemplating a low-dose supplement may well ask the very reasonable question: will it do me any good?
Where's the evidence?
Surprisingly, even though specific nutrients such as vitamins C and E, zinc, calcium and magnesium have been widely studied, data on the benefits of taking multivitamin/mineral supplements of any kind are sparse.
It is important to remember that multivitamins are not targeted nutrients, but simply provide a broad base to support other healthy practices. A recent study found that taking multis with or without extra vitamin E did not prevent or improve respiratory tract infections among the elderly (JAMA, 2002; 288: 715-21). But had the subjects exercised or cleared their homes of known allergens in addition to taking supplements, the results may have been different.
Other problems associated with vitamin studies include the fact that the study population may be using different kinds of multis containing varying amounts of nutrients, and that the use of a multi may reflect a generally healthier individual who takes care of himself in other ways as well.
A study of the heart-protective benefits of multis in a group of healthy US physicians is testimony to this, showing as it did that, in such subjects, a daily multi did not significantly reduce the risk of heart disease (Arch Intern Med, 2002; 162: 1472-6).
However, data do show a trend towards benefit even with low-dose multis, especially among populations with poor nutrition. Multis containing 100 per cent of the RDA of a range of nutrients can improve B-vitamin levels in elderly persons in just eight weeks (J Nutr, 2000; 130: 3090-6), an important benefit, as it is associated with lower levels of homocysteine, a chemical that increases the risk of heart disease and stroke.
Other studies confirm that a low-dose daily multi is associated with a reduced risk of many chronic diseases in older adults (J Am Coll Nutr, 2000; 19: 613-21).
For instance, a daily multi in combination with extra vitamins C, E and A can reduce the risk of heart and cardiovascular disease by as much as 15 per cent in some older people (Am J Epidemiol, 2000; 152: 149-62). Multis are also associated with a lower risk of cataracts (Am J Ophthalmol, 2001; 132: 19-26).
In women of childbearing age, a multivitamin at the time of conception and during pregnancy can help reduce the risk of birth defects and childhood brain tumours (Am J Epidemiol, 1999; 150: 675-82; Am J Med Genet, 1996; 62: 179-83; Int J Cancer Suppl, 1998; 11: 17-22).
Children can benefit, too. In a group of 'working-class' children in the US, a low-dose multi (with only 50 per cent of the RDA) resulted in dramatic gains in IQ (J Altern Complement Med, 2000: 6: 19-29).
The general population can also benefit. Daily low-dose multis can provide a modest reduction in prostate cancer risk (Cancer Epidemiol Biomarkers Prev, 1999; 8: 887-92), though not as much as high-dose, targeted nutrients like vitamins C and E, and zinc; multis containing folate combined with a healthy lifestyle can reduce the risk of colon cancer (Cancer Epidemiol Biomarkers Prev, 2002; 11: 227-34).
Daily low-dose multis (not unlike those in this survey) have been proved to combat the effects of stress in highly stressed individuals (South Afr Med J, 2000; 90: 1216-23), and to reduce the risk of cardiovascular disease (Am J Epidemiol, 2000; 152: 149-62). The ongoing Nurses' Health Study found that a daily multi containing the full RDA of folate reduced the risk of breast cancer particularly among women who drank more than 15 g of alcohol per day (JAMA, 1999; 281: 1632-7).
To find out what's in 'good-value' vitamins and which were the best buys, we endeavoured to compare like with like. As testing every substance in every tablet is a gargantuan task, we only looked at the vitamin C content. This vitamin degrades quickly, so its quantities provide a reasonable indication of whether the manufacturer has produced a quality product.
Our laboratory found that all the products in our road test included more than the stated amount of vitamin C - albeit by insignificant amounts in some cases.
When purchasing low-dose multis, there are several things to look out for. Most don't contain enough vitamins C and E, and are likely to be low in certain essential minerals, particularly calcium and magnesium. This was certainly the case with all of the products in our survey. In fact, because these nutrients take up a lot of space in a tablet, including 100 per cent of your RDA of these would make a tablet too big to swallow.
Cheap multis rarely contain important cofactors such as bioflavonoids, which aid vitamin C absorption. Indeed, only one of the products reviewed contained rutin. Similarly, none contained essential amino acids (though these could be manufactured from a well-balanced diet). And while the majority included a wide range of minerals, these were generally in the form of oxides and sulphates - not the most readily absorbable forms (see box above).
Cheap vitamins are also more likely to be made from synthetic sources, as was often the case here. While this may not be a problem with the water-soluble vitamins (C and B-complex), there is evidence that the fat-soluble vitamins (A, D, E and K) are better, and safer, from natural sources.
Finally, all of the supplements tested contained a range of fillers and additives, and many used unacceptable colours.
Taking cheap multis can be a false economy. Quality products such as Solgar's and BioCare's one-a-day vitamins, which got top marks from us (PROOF! vol 6 no 1), offer many times more of the expensive nutrients, such as the fat-soluble vitamins. For only 10 p more a day, you may get three times as much of many nutrients. But if you are on a tight budget, these products are certainly better than nothing.
EuRho Multivitamin and Mineral Tablets
Distributor: Lidl Stores
Price: lb3.59 (100 tablets)
Lidl discount supermarkets are popping up all over the UK, and these multis are among their own-brand products. They claimed 60 mg of vitamin C; our lab found 63 mg. The expiry date was Nov 04 so, by that time, it may have degraded considerably.
Its 800 mg of vitamin A is 25 per cent beta-carotene, vitamin D is the easily absorbed D3, and it has relatively good levels of magnesium and calcium - 100 mg and 162 mg, respectively. It delivers 1671 mg of vitamin C for your lb (the most in our road test) and costs only 4 p/day. Were it not for the coal-tar synthetic colouring 'sunset yellow', this might have earned top marks.
A-Z Multivitamins & Minerals
Price: lb3.29 (special offer; 60 tablets)
This product has a safety cap (only one of three that did) and no synthetic colours. It has a small amount of beta-carotene, but reasonably high levels of calcium (200 mg - among the highest we found) and magnesium (100 mg). It also uses the more easily absorbed vitamin D3. This was one of two products not to contain the trace element molybdenum.
The label claims 60 mg of vitamin C and our lab found 68 mg, not overly generous for a sell-by date of Dec 03. Nevertheless, you get 1094 mg of C to the lb, and taking this tablet will only cost you 5 p/day.
Centrum Complete From A to Zinc
Manufacturer: Wyeth Consumer Healthcare
Price: lb4.59 (30 tablets)
A comprehensive and popular supplement for adults, this product contains 31 nutrients. Its calcium and magnesium levels are reasonable - 162 mg and 100 mg, respectively. However, it is not clear from the label what the sources of vitamins A, D and E are - but 25 per cent of the vitamin A is beta-carotene, a reasonable proportion.
Centrum declared 60 mg of vitamin C; we found 63 mg. You get a very low 392 mg of vitamin C for your lb, at a cost of 15 p/day. Again, though, we would like to see the coal-tar-based 'sunset yellow' removed.
To all intents and purposes, this is the same product as Lidl's EuRho (see above) but, given the higher price tag, with considerably less value for your money.
A-Z Multivitamins + Minerals
Price: lb4.99 (60 tablets)
A clear label, but the vitamin E is a mix of natural and synthetic, vitamin A is synthetic retinyl acetate (including peanut oil, a potential allergen), and it uses vitamin D2, thought to be potentially more toxic. So, this gets points for clarity, but its content is not really up to scratch. Calcium and magnesium are reasonable at 162 mg and 100 mg, respectively, but it uses suspect colours like allura red and quinoline yellow.
The label declares 60 mg of vitamin C and we found 70 mg, giving you 721 mg of vitamin C for your lb at a cost of 8 p/day.
Manufacturer: Seven Seas Health Care
Price: lb4.59 (30 tablets)
The ingredients are printed on the throw-away box, not on the bottle, making it difficult to refer to them if necessary.
But plus points go to Seven Seas for including probiotics and for using vitamin D3 (cholecalciferol), the safest and most easily absorbed type. But the vitamin E is a mix of natural and synthetic (D,L-alpha-tocopherol), and it's not clear what the 'vitamin A preparation' is. As with others in this road test, many of the minerals are in the less absorbable oxide and sulphate forms.
It declares 60 mg of vitamin C; we found 77 mg. You get 392 mg of vitamin C for your lb, one of the least amounts in our survey (shared with Centrum), at a cost of 15 p/day.
Sanatogen Gold A to Z
Manufacturer: Roche Consumer Health
Price: lb4.39 (30 tablets)
Along with Seven Seas, Roche is one of the UK's largest manufacturers of over-the- counter medicines and supplements.
The label offers no clues as to the type of vitamins D or E used, but states 800 mg of vitamin A (source not identified) and 400 mg of beta-carotene, a tiny amount. But it also contains the eye-protecting carotenoid lutein, the only one in our survey to do so.
Roche claims 60 mg of vitamin C and we found 67 mg. With an expiry date of Oct 03, though, this product may be rapidly degrading. You get around 410 mg of vitamin C for your lb, at a cost of 15 p/day.
Complete Multi Vitamins and Minerals
Manufacturer: Boots Company PLC
Price: lb3.80 (30 tablets)
The labelling alone is a good reason to avoid this product. Instead of individual contents, the label lists the fillers (a considerable number), and states 'multimineral compound' and 'multivitamin compound' in the midst of all this. Calcium levels are high at 220 mg, but magnesium is low at 60 mg.
The label claims 60 mg of vitamin C; we found 79 mg. Rather pricey at 13 p/day, you only get 474 mg of vitamin C for your lb.
Multi Vitamins Plus Minerals
Manufacturer: Seven Seas Health Care
Price: lb5.99 (60 tablets)
A product specifically for vegetarians and vegans, we're not sure how this can satisfy their requirements. Vegetarians are often deficient in B vitamins, specifically B12 and, although levels here range from 175-300 per cent of the RDA, they are still very low. It has iron and zinc, but is missing important minerals and trace elements like potassium, magnesium, manganese and selenium. It uses vitamin D2, a synthetic derived from plants thought to be less well absorbed and more potentially toxic than D3.
The label promises 90 mg of vitamin C and we found 103 mg, giving you 901 mg for your lb, but at a cost of 10 p per day - expensive given how much is not in it.
Radiance Multivitamins & Minerals
Manufacturer: Holland & Barrett
Price: lb2.19 (60 tablets)
This value supplement doesn't contain the full range of vitamins/minerals and levels are generally less than the full RDA. Notably absent are B5, biotin, inositol, potassium, magnesium, manganese and selenium. Yet, this includes the flavonol rutin to aid the absorption/action of vitamin C, and brewer's yeast to boost B levels. Vitamin A is the synthetic retinyl acetate, but the vitamin E is from a natural source.
This claims 50 mg of vitamin C and we found 66 mg - good value at 1370 mg per lb and 4 p/day. But the brewer's yeast may not be suitable for those with Candida.
If you are perfectly healthy, have a good diet and no evidence of poor absorption, you may be able to get away with taking a low-dose multi. Adjusting your diet and adding high-dose, specific nutrients according to your personal needs may further improve your health. If you are taking a daily standard multivitamin/mineral tablet, the general advice is to take it with food so that your body can draw cofactors from your food resources to aid absorption.
Consider the following to help you choose the best supplements:
* Check the label. Make sure your chosen multi includes the full range of essential minerals as well as vitamins
* Check the label again. Look for the words 'citrate', 'picolinate', 'aspartate', 'glycinate', 'glutamate' and 'amino acid chelate'. These refer to the way the vitamin/mineral is processed (and usually follow the name of the nutrient, as in chromium picolinate) and are considered the easiest forms for the body to use. Compounds such as carbonates, sulphates and oxides are generally less well absorbed
* Look for the expiry date. Supplements can lose potency over time, especially in hot and humid climates. Choose supplements with an expiry date as far into the future as possible. If a supplement doesn't have an expiration date, don't buy it
* Reject junk. Watch out for excipients such as binders, fillings and coatings. In tablets, these are part of processing the supplement, but you can reject those with unnecessary additives such as artificial colours, and sweeteners such as glucose, lactose, mannitol and xylitol
* Buy from reputable shops and manufacturers. The bigger the shop and/or manufacturer, the more they are able to demand quality ingredients in their products
* Keep it simple. Avoid supplements that use a 'kitchen-sink' approach to formulation, with added herbs, such as ginseng, alfalfa, bee pollen and Ginkgo biloba. These are seldom present in therapeutic quantities and are usually only there to jack up the price. If you truly require these things, take them separately
* Avoid specialist formulas, such as 'women's formulas', 'men's formulas' or 'over-50s formulas'. These are not usually based on any solid science and are more expensive. The exception is for very young children, who may benefit from the lower doses of vitamins found in some children's products.
The Recommended Daily Allowance (RDA) is now an almost meaningless term since it refers to the minimum amount of each nutrient considered necessary to prevent a deficiency. There is often a huge gap between the RDA of a nutrient and its therapeutic amount.
To find out how much we should be getting of the main vitamins and minerals each day, we canvassed our PROOF! panel members. The table below sums up their advice. Remember that these amounts can come from food as well as supplements. Also, these are general guidelines for healthy adults and do not apply to children or pregnant women. Your individual requirements could be different from these. To determine what you should be taking, it is best to consult a qualified, experienced nutritionist before taking supplements.
Vitamin A 1600-2000 mgRE (5328-6660 IU)
Vitamin B1 (thiamine) 50 mg
Vitamin B2 (riboflavin) 50 mg
Vitamin B3 (as niacin) 50 mg
(as niacinamide) 100 mg
Vitamin B5 (panthothenic acid/pantothenate) 50-300 mg
Vitamin B6 (pyridoxine/pyridoxal) 50 mg
Folic acid 400-800 mg
PABA (para-aminobenzoic acid) 500 mg
Vitamin B12 (cobalamin) 100 mg
Biotin 200-1000 mg
Vitamin C at least 50 mg, preferably 1-3 g/day
Bioflavonoids 100-1000 mg
Vitamin D 400 IU (10 mg)
Vitamin E (D-alpha-tocopherol) 100-600 IU (70-420 mg)
Choline 500-700 mg
Inositol 600 mg
Boron 3 mg
Calcium 500 mg
Chromium 100 mg
Copper 2-3 mg
Iodine 500 mg
Iron 10 mg
Magnesium 200-400 mg
Manganese 5-25 mg
Potassium 300-600 mg
Selenium up to 200 mg
Zinc 15-30 mg