There's a dietary supplement today for every ailment imaginable, but how did they become so popular and do they really work? Christina Larmer investigates.
Every year it seems an exciting new supplement that we can't live without hits the market. One year it was Echinacea for colds and flu, another it was fish oil for hyperactive kids.
Recently, everyone's raving about glucosamine, a so-called wonder treatment for osteoarthritis. In fact, sales of both fish oils and glucosamine helped make up a large part of Australia's $1 billion complementary medicine market, which grew by 7% in the past year.
What are supplements?
While homemade remedies have been around for thousands of years, manufactured supplements only emerged in Australia in the 1950s and even then, our grandmothers rarely went beyond cod liver oil and iron tonics. With changes in regulations, the market has boomed since the 1990s. Today, there are hundreds of supplements from anti-ageing formulas to zinc. Three out of four of us take at least one, with young women the biggest users (92% of women aged 20-24).
Why are they so popular?
"There's an awful lot of marketing now and supplements are promoted for just about everything," says dietitian Kate Marsh. "Plus people are also much more aware of their health these days."
We also want to boost wellness and slow down the ageing process. Many people would prefer to do this naturally but for others, it's about efficiency. Only 14% of us manage to consume the recommended five serves of vegies a day so supplements are seen as a reliable alternative in our fast-paced world.
Add to this the growing fear of nutrient-depleted soil, toxins in the environment, and the loss of natural nutrients through cooking and food processing, and you can see why they're so popular.
Are they a cure-all?
Most health experts agree, supplements should not be a substitute for food. While they can complement a regular diet, correct deficiencies and be useful in certain circumstances, supplements can't replicate all of the nutrients and benefits of whole foods. Supplements tend to work in isolation, while food has a complex source of vitamins, minerals and phytochemicals, all working together to boost health.
"In food, things are all in the right balance and the right amount," says Marsh. "Whereas in a supplement, if you start taking one thing in excess, then you can quite often interfere with the balance of other vitamins and minerals. You see people who come in with a whole bag of supplements and they haven't considered that they're doubling or tripling up on some ingredients, and they may be taking more than the amount that is considered safe."
Are they safe to take?
Because supplements are deemed natural, many people wrongly assume they're harmless. While some are water-soluble and the excess is excreted (vitamins B and C), others (vitamins A and D) are stored in our bodies and can be hazardous. Then there are those which are not well absorbed - up to 85% of some calcium supplements, for instance – so they remain undigested. It's a complex subject and not all supplements are created equal.
Your best defence is knowledge, says nutritionist Catherine Saxelby. Read the label carefully, avoid 'megadoses', check the expiry date, only take the suggested dosage, preferably with food for better absorption, and stick with reputable brands. "Cheaper brands may not have the most biologically-active form (for example, natural compared to synthetic vitamin E) or may have only tiny amounts," she says. "Check the amount you're getting. And be wary of exaggerated claims made on packs and in advertising."
The lowdown on our most popular supplements
Why do people take it? Iron is taken to treat anaemia, fatigue, and loss of appetite.
The risks: Excess iron can cause stomach upsets, nausea, heartburn and increased risk of cardiovascular disease. Severe toxicity can lead to vomiting, diarrhoea, intestinal damage and even death, particularly in children. Iron should not be taken with antacids or calcium.
Do you need it? Studies show iron supplementation may help some people with special needs (pregnant women, vegetarians, women who menstruate heavily, people with anaemia etc). For the general population, iron is best absorbed from foods.
Why do people take it? Women take it before and during pregnancy to reduce the risk of developing neural tube defects such as spina bifida in infants and to prevent folate deficiency anaemia.
The risks: It's water soluble, so the excess is excreted. There's some evidence that high levels of folic acid can cause seizures in patients on anti-convulsants. Excess folate can hide vitamin B12 deficiencies, cause diarrhoea, gastro problems and sleep disturbances.
Do you need it? Women should take extra folate daily if they are trying to fall pregnant, and for a month after conception.
Why do people take it? To relieve muscular aches and pains and improve healthy muscle function. Also to reduce muscle cramps and restless leg syndrome and as a treatment for migraines, PMS and insomnia. Sometimes used to treat heart disease by lowering homocysteine and depression due to its effects on neurotransmitters.
The risks: Excess magnesium causes nausea, diarrhoea, appetite loss, muscle weakness, dehydration, electrolyte imbalance and irregular heartbeat.
Do you need it? Evidence suggests magnesium may help regulate blood pressure and reduce your risk of developing type 2 diabetes, but this can usually be achieved through diet.
Why do people take it? To reduce the risk of cardiovascular disease, boost energy, relieve stress, depression and anxiety, alleviate headaches and PMS, and improve concentration.
The risks: The excess is usually excreted. However, extra vitamin B6 and niacin can sometimes cause side-effects (vitamin B6 can damage nerves in the fingers and toes).
Do you need it? Most people can get all they need from foods: except B12 if you're vegan; on medications that interact with it; or if you're elderly as you'll have trouble absorbing it. Vitamin B6 has been shown to be useful in treatment of Carpal tunnel syndrome and PMS. And folate (a B Group vitamin) reduces neural tube defects such as spina bifida.
Why do people take it? Bio ACE is an antioxidant formula that contains beta-carotene, vitamin C, vitamin E and zinc. People take it to protect the body from free radical damage (caused by stress, alcohol, smoking and pollution), and assist with general wellbeing.
The risks: Ascorbic acid may increase the risk of recurrence of kidney stones. Zinc may decrease the absorption and effectiveness of some medications.
Do you need it? Foods are the best way to boost antioxidant levels as they contain hundreds. Bio ACE is still undergoing clinical trials. Some research suggests supplements of antioxidants have no significant benefit.
Why do people take it? To help prevent heart disease, reduce triglycerides (a blood fat) and high blood pressure; reduce inflammation; improve eye function; and to help mental disorders like bipolar, depression, schizophrenia and ADHD.
The risks: Are mild and include occasional indigestion and nausea. If the oil is not properly distilled to remove all impurities there's some risk of contamination by pollutants such as mercury and PCBs (poisonous substances that are a bi-product of manufacturing processes). Very large doses can lead to decreased blood clotting.
Do you need it? Fish oils are good for people who don't eat fish, especially people with high blood fats, heart disease and arthritis. Avoid if on blood thinning medication. If allergic to fish, check with your doctor first.
Why do people take it? To treat calcium deficiency, reduce the likelihood of osteoporosis and strengthen bones.
The risks: Excess calcium inhibits iron absorption, as well as the absorption of some medications (antibiotics and blood pressure drugs). May cause gastrointestinal upsets (bloating, constipation). There is inconclusive evidence linking calcium supplements to heart disease.
Do you need it? Most people get their calcium needs from foods, however supplements may help those with extra requirements (young children, teenagers, post-menopausal women); those who do not eat dairy products or soy substitutes; or have a high salt diet. Calcium supplements are best absorbed with food. Low calcium intake has been shown to be a risk factor for osteoporosis.
Why do people take it? To 'top up' the nutrients in their diets. Especially people who have a poor diet.
The risks: Acute overdose of certain vitamins or minerals if taken in large amounts (eg excess vitamin A may cause birth defects in pregnant women).
Do you need it? Multivitamins can be valuable if you have a dietary imbalance but should be taken with care, especially by people with medical conditions and pregnant women. Some preparations contain more than the recommended dietary intake (RDI) of some vitamins and only a fraction of the RDI for others. Read the label carefully. There's no real evidence that multivitamin supplements are good for treating people with severe vitamin and mineral deficiency. However, there has been a lot of research that has linked an inadequate intake of some vitamins in general to the development of diseases like coronary heart disease, cancer and osteoporosis.
What the experts say...
Kate Marsh, Accredited Practising Dietitian
"Supplements can't replace a good diet. If you're eating well you probably don't need them, but there are some that are going to be useful in some cases."
Do you recommend any supplements to your clients? "For pregnant women or those trying to conceive, I recommend folate or a pregnancy or pre-conception multivitamin. Anyone on a vegan diet needs to take a vitamin B12 supplement. There are medications, such as the diabetes medication metformin, which can interfere with vitamin B12 absorption so anyone taking these should have their levels measured regularly and may need a supplement. Calcium for people who don't eat a lot of calcium-rich food; and vitamin D for those with low levels, particularly those with osteoporosis. If someone was anaemic, then in the short-term I'd recommend an iron supplement to build up stores and then try to maintain it with diet. I find most people with arthritis are already taking glucosamine."
Do you take any yourself? "I take vitamin B12 as I follow a vegan diet. If I'm starting to come down with a cold, I take a supplement with Echinacea, garlic, zinc and vitamin C. I don't know whether it's placebo but it seems to work."
Dr Caroline Johnson, General Practitioner
"They have a role but it's more limited than people think in Australian diets. As a GP I emphasise that having a healthy, well-balanced diet is the most important way of getting the nutrition you require. However, I recognise that for some people that's not always possible. It's a lot more complex thing than you might think when you read what's on the bottle and they're quite confusing for doctors and patients because of different issues about quality and dosage etc."
Do you recommend any supplements to your clients? "Calcium for women who don't have enough, don't like dairy products and are at risk of osteoporosis. Another is people who are low on iron, especially women with heavy periods and/or on vegetarian or vegan diets. But if they pay heed to iron content in food they can usually do without iron supplements. For pregnant women I recommend folic acid."
Do you take any yourself? "Not at the moment. At various times in my life I have, such as a fibre supplement to get the bowels going again after childbirth. When I was a child my mother used fluoride supplements and vitamin C. I have good teeth and I think the evidence is pretty strong that fluoride is beneficial unless taken in toxic amounts."
Dr Beres Joyner, General Practitioner
"There is a very limited role for supplements in treating older people regardless of whether they are well or have significant medical conditions."
Do you recommend any supplements to your older clients? "Calcium supplements and vitamin D for older people who have inadequate sunlight exposure. There is evidence to support their use in reducing the risk of fractures and falls in older people. Calcium supplements have a moderate effect in preventing polyps in the bowel. There is no evidence that people should take vitamin or mineral preparations to prevent age-related macular degeneration, or that antioxidant supplements will reduce mortality. There have been trials of B12 and folic acid to improve brain function and mood in older people, but there is no demonstrated benefit. There's probably a role for fish oil in arthritis."
NB: Dr Joyner does not recommend glucosamine. "For those people who choose to take it, there are no concerns regarding its safety."
Do you take any yourself? "None. I subscribe to a healthy lifestyle based on a healthy eating plan that includes plenty of fruit and vegetables, physical activity, and adequate sleep."
Catherine Saxelby, Accredited Practising Dietitian and Nutritionist
"I'd rather people eat food first and think about supplements second. Supplements can't give you the huge number of natural phytochemicals, vitamins, minerals and antioxidants, and they don't correct a diet that's got too much fat, salt and sugar. The nutrients we get from food are in the form that's biologically available, they're in the right amounts, they're combined with other complementary nutrients and there's very little risk of overdose."
Do you recommend any supplements to your clients? "I recommend people take fish oils if they don't eat the suggested two fish meals a week. For overall health, one capsule a day is fine but if you have a medical condition (such as arthritis or high triglycerides), then you need more."
Do you take any yourself? "I take fish oils for general health and to try and help the arthritis in my thumb joints. I also take B vitamins. If I feel a cold coming on I take a tablet that contains 500mg vitamin C, 10mg zinc and 1g echinacea, which I find helps."
Food is the best source of many vitamins and minerals. Here's a guide.
Iron: best absorbed from animal sources (red meats, fish, poultry). Also found in plant sources including cereals, green leafy vegies, nuts and seeds, lentils, dried beans and peas, tofu and dried fruit (prunes, apricots).
Multivitamins: found in each of the five food groups: vegetables; fruits; breads, grains and cereals; dairy products; and meat, poultry, fish, eggs, legumes, nuts and seeds.
Glucosamine: there are no food sources of glucosamine, although it is used in some sports drinks.
Magnesium: found in green vegetables, especially spinach, legumes (peas, beans), lentils, nuts and seeds, whole grains and cereals.
Bio ACE: you can get similar vitamins from different coloured fruits and vegies, nuts and seeds, whole grains, green tea.
Vitamin C: found in fruits (such as blackcurrants, citrus, guava, kiwifruit) and vegetables (broccoli, capsicum, sprouts).
Omega-3/fish oils: try oily fish (mackerel, salmon, sardines), or plant oils (flaxseeds, canola, soybean), walnuts, pumpkin seeds.
Calcium: from dairy foods (milk, yoghurt, cheese, buttermilk) and calcium fortified products (soymilk and cereals). Also, canned fish with bones (salmon, sardines), legumes, leafy green vegetables (broccoli, bok choy), tofu, nuts and seeds (almonds, dried figs).
B group vitamins: found in fruit, vegetables (peas, beans, Brussels sprouts, mushrooms), legumes, fortified cereals and breads, nuts, most meats, fish, eggs, dairy products (milk, cheese).