When it comes to vitamin pills, some people just don't know when to pop
Peek into Amanda Ho's medicine cabinet and you'll notice countless bottles of vitamin and mineral supplements. The 33-year-old special education teacher pops several of these pills a day, claiming that they do everything from prevent colds to improve her eyesight and give her more energy.
Ho says that because she follows a balanced diet, she probably doesn't need half of these supplements, but she likes knowing that she has some kind of 'backup' in case her diet falls short of her nutritional requirements.
According to a recent report by the Australian Trade Commission, the vitamin and dietary supplement industry in Hong Kong was worth HK$3.2 billion last year, with combination dietary supplements the top sellers. Ho says she spends just more than HK$6,000 a year on her non-prescription vitamins and minerals. 'Having that peace of mind is worth every cent,' she says. 'I think of my supplements the same way I do health insurance.'
But are supplements necessary and are they for everyone? No, says dietitian Vivien Yu from privatedietitian.com. 'It really depends on your lifestyle needs, nutritional status, dietary habits, as well as physical health,' she says. 'If you don't eat a balanced diet, if you're pregnant, or if you suffer from nutritional deficiencies or have certain conditions that require you to consume supplements, then you probably need them.' If you aren't sure which supplements to take or if you should be taking any at all, it might be best to get advice from your health practitioner.
Daphne Wu, a freelance dietitian for Life Enrich Training & Consulting Centre, agrees. 'Supplements are meant to supplement your nutritional inadequacy,' she says, 'so you do not need any extra vitamins and minerals if you already have a balanced diet.' She adds that nutrient requirements differ across age groups, physical activity levels and even gender - for example, women need more calcium than men. Vegans and people with food intolerances or allergies might also need an extra dose of nutrients.
For healthy bones and teeth, Yu says that the average adult needs two to three servings of dairy products a day. Unfortunately, most of us do not get this amount, and so a calcium supplement might be required. 'Most adults need about 1,000 milligrams of calcium a day, but research has shown that we get just 400mg of this amount from food,' she says. 'Taking a calcium supplement of 600mg a day should be adequate. However, you'll need to increase this dosage if you are suffering from osteoporosis.'
If you're at a childbearing age or are pregnant and in your first trimester, you are advised to take a folate supplement. Folate is a B-vitamin that occurs naturally in foods like leafy green vegetables, citrus fruits and dried beans. Yu says about 600 micrograms (mcg) a day is recommended to prevent neural tube defects in babies.
Antioxidants, like vitamins A, C and E, and minerals zinc, selenium and manganese, help prevent cellular damage, which is believed to lead to cancer, ageing and a host of other diseases. Most people get enough antioxidants from food every day, says Yu, but if you smoke or do a lot of physical activities, you might need slightly more than the average person.
Smoking depletes your tissues and blood of vitamin C, so if you have yet to kick the habit, you should take a vitamin C supplement to counteract the damage that's been caused to your body.
It's a common belief that the more dietary supplements you consume, the more you get out of them. Unfortunately, there is such a thing as overdosing on vitamins and minerals. For example, long-term excessive intake (more than 1,000mg a day) of vitamin C, says Yu, may cause diarrhoea, lead to the formation of kidney stones, interfere with certain drugs, or cause iron overload in your system.
Over-consumption of vitamin D may lead to hypercalcemia, or excess calcium in the blood - the symptoms of which include constipation, nausea, frequent urination, pain in one side of the body between the abdomen and back, and even kidney damage.
And you might think you're building healthier blood cells by taking iron supplements religiously, but over-consumption over a long period can cause liver damage, adds Yu. Research has also shown a link between high calcium intake and the risk of prostate cancer, and high beta-carotene intake and lung cancer, Wu points out. So don't be tempted to take more than the recommended amount.
Another danger of an excess consumption of supplements is that specific nutrients can interact with others, hindering their absorption - animal studies show that high calcium intake appears to have a negative effect on iron absorption, says Wu. In addition, overdosing may mask the symptoms of other nutrients' deficiency - for example, high folic acid intake can mask the symptoms of vitamin B12 deficiency.
When shopping around for supplements, you might consider quality, brand, price and popularity. But, says Yu, what's more important is to check the dosage on the label. 'The dose per tablet or capsule should be within the recommended daily allowance,' she advises. 'You should only buy what your body needs, so avoid supplements that provide 'mega doses'.'
- Value (HK$ billions) of supplement/vitamin market in Hong Kong in 2010