Do supplements really work? Here's what you need to know

Walk into any pharmacy, and the bottles of vitamins and supplements occupy some serious shelf space. There’s an alphabet of choices from vitamin A to zinc. They come in tablets, capsules, liquids and gummies, in formulations for women, men, kids, seniors and athletes, with claims like:

“Helps maintain a healthy heart.”
“May reduce the risk of osteoporosis.”
“Supports urinary and bladder health.”
“Boosts energy and stamina levels.”
“Aids in the conversion of food into energy.”

The messages are so compelling that Australians are spending an estimated $1.3 billion on vitamin and mineral supplements every year, according to a report by market researcher, Ibisworld. One in three Australian women take them and one in four Aussie men, according to the latest National Health Survey (NHS). But the burning question is, do we really need them or are we wasting our money? So accepted are supplements that for most of us the word vitamin conjures an image of pills in bottles rather than the fruit and vegetable aisle in the supermarket. Vitamins, of course, are the chemical compounds in foods that provide health benefits. Vitamin supplements contain these compounds synthesised and isolated. In an ironic twist, multivitamin use is more common among people with healthier lifestyles and diets, and lower BMIs, according to the NHS. For many of them, vitamin supplementation is as much a part of a healthy lifestyle as eating whole grains and fresh produce. Since 1999, more than $250 million a year has been invested on supplement research, in particular, their ability to prevent chronic diseases. “So far there is no clear evidence that any supplement is effective, but there is evidence that some can be harmful,” says epidemiologist Dr Eliseo Guallar, who has been studying the affect of vitamin supplements on cardiovascular health.

Megadose mania

While a multivitamin may benefit some people who have nutritional deficiencies, megadoses are another story altogether. We’re not designed to take in large quantities of vitamins at once and we would never get those quantities from food. For example, to consume 1,000 mg of vitamin C, you would have to eat 14 oranges — more than the body was meant to handle at one time. “Based on limited evidence, there don’t appear to be any significant risks associated with most supplements. But some single vitamins or minerals when taken in higher doses such as selenium, may result in toxicity,” says Joanna Harnett, lecturer in complementary medicines at the Faculty of Pharmacy at Sydney University. “There is also some evidence of a ‘sick user risk’ where supplements such as beta-carotene may be detrimental to people with conditions like some types of cancer.” Megadoses can also cause ‘relative deficiency’ – when taking too much of one single nutrient for prolonged periods causes imbalances in others. While excess soluble vitamins such as C and the B complex are excreted in urine if you take too much, “Fat soluble nutrients such as vitamin D, A, E and K can build up to toxic levels when taken in high amounts for prolonged periods of time,” says Melanie McGrice, dietitian and Director of Nutrition Plus clinics in Melbourne. “Side effects from megadoses may not always be obvious, including constipation (from iron supplements), and heart issues (from calcium supplements) or B12 deficiency, which can be masked by taking too many folate supplements.” In addition, when people take numerous different supplements, other related vitamins (for example, B6 which can cause nerve damage at elevated doses) may be included, causing megadoses that the person has no idea they are taking. And since many people are already getting most of the vitamins they need from food, taking “extra” vitamins can bump their intake far beyond recommended daily levels. By contrast, no-one has ever overdosed on vitamins from eating too much salad – it’s almost impossible to get too many from eating food.

Mixed messages

The Australian Therapeutic Goods Administration (TGA) evaluates the quality and safety of complementary medicines, such as vitamin and mineral supplements. It prohibits labels from stating that supplements can cure, manage or prevent any disease, disorder or condition. The TGA recently reviewed the accepted claims that supplement labels are permitted to make, and allows words such as ‘maintains’, ‘supports’, ‘enhances’, ‘relieves’ and ‘reduces risks’, when describing their supposed benefits so long as their is evidence to support the claim. “Advertisements about supplements are not vetted for accuracy, leaving the door open for fraudulent claims about what they can do for your health,” says John Dwyer, founder of the Australian Health Care Reform Alliance and Emeritus Professor at the UNSW Sydney. As a result, according to Dwyer, Australians are bombarded with misleading advertising that suggests “wellness” is available from nutritional supplements. “These claims, which are not backed up by studies, are irresponsible and dilute the really important message that it’s a healthy lifestyle and not something out of a bottle, that produces ‘wellness’,” Dwyer says. “As a result, Australians spend on average $60-80 a month on supplements and vitamins they don’t need.”

We’re healthier than we think

Today, vitamins and minerals are baked into breads and cereals, added to dairy products and pumped into sports drinks. Thanks to all of this, true vitamin and mineral deficiencies are rare in Australia. “People who are healthy generally don’t need vitamin and mineral supplements,” says Aloysa Hourigan, spokesperson for Nutrition Australia. You know the drill – eat whole foods, fresh vegetables and fruit, lean protein, low fat dairy and healthy oils. “If you enjoy a range of foods across all the core food groups and follow the Australian Dietary Guidelines, you can obtain all the nutrients you need.”

Food also kickstarts different processes in your body, that are not triggered in the same way by supplements. Eating food affects hunger (by triggering the release of appetite suppressing hormones). “Also, the process of smelling, seeing and chewing food sets off responses in your mouth, brain and stomach that help you absorb all the nutrients your body needs from the food and also impacts on chemicals in your brain,” explains McGrice. The process of chewing also triggers digestive enzymes in your mouth, stomach and pancreas. “These enzymes and stomach acids are critical to some nutrients being properly utilised by your body,” McGrice says. “For example, vitamin B12 requires gastric acid in order to be fully absorbed. So simply swallowing a supplement might not stimulate enough of that acid to ensure you absorb it well.”

When supplements are helpful

Of course there are some legitimate medical uses for supplements. For example, in medically diagnosed deficiencies of iron and zinc. “Long-term treatment with acid-supressing medicines may result in vitamin B12 or magnesium deficiency in older people,” says Harnett. “ Supplementation with folic acid during pregnancy has been shown to reduce the risk of neural tube defects and people who follow a vegetarian or vegan diet sometimesneed supplementation with vitamin B12.” Yet according to Harnett, the supplement paradox persists, with the ‘worried well’, taking vitamins and minerals they don’t need. One thing is certain: “There are no studies showing that without a healthy diet, vitamin and mineral supplements can help you live longer or healthier,” McGrice says. “But there is plenty of evidence showing that a healthy diet can reduce risk of heart disease, diabetes and cancer.” Research from the University College of London shows that eating 5 x 2 or more portions of fruit and vegetables a day (which is the recommended guidleines) reduces your risk of early death by 42 per cent. “Instead of handing over good money for supplements," McGrice suggests, "adding more plant foods to your supermarket trolley and dinner plate is a far better investment in your health.”

Pack your plate with nutrients

A colourful plate is a good way to boost your nutrient intake. To help you get the right mix of vitamins and minerals, dietitian Melanie McGrice gives us the rundown on their best food sources.

Vitamins

B Group Good sources are in most core food groups:

B1 (thiamine) - wholemeal cereal grains, seeds (especially sesame seeds), legumes, wheatgerm, nuts.
B2 (riboflavin) - milk, yoghurt, cottage cheese, egg white.
B3 (niacin) - wholegrain breads and cereals, nuts, mushrooms, all protein-containing foods.
B5 (pantothenic acid) - meats, milk, kidneys, eggs, peanuts, legumes.
B6 (pyridoxine) - cereal grains and legumes, green and leafy vegetables.
B7 (biotin) - cauliflower, egg yolks, mushrooms.
B9 (folate) - found in green leafy vegetables, legumes, cereals.
B12 (cyanocobalamin) - mainly meats, liver, milk, cheese, eggs.
C - Fruit and vegetables such as red and yellow capsicums, guava, orange and papaya. Grains, proteins and dairy products also contain a small amount.
D - We get most of our vit D from sunlight as food sources contain a limited amount. Moderate sources include: oily fish, milk, egg yolks and fortified foods.
E - Nuts, seeds (and their oils), oily fish, dark green vegetables (eg spinach and chard)

Minerals

Potassium - some vegetables (English spinach, potato, pumpkin) and some fruits (custard apple, banana, nectarine).
Magnesium - high-fibre cereals, nuts and seeds, soy products and oily fish.
Zinc - seafood (oysters being the best source), red meat.