An apple a day keeps the doctor away, so the old saying goes. But in today's world, vitamin pills seem to do the trick.

Cookery author Sylvia Tan, 60, takes an arsenal of health products, from multivitamins for women to supplements such as calcium, phytoestrogen, flax seed oil, garlic and horse radish.

'I'm less stressed and fall ill less often,' she says of the pill-popping regimen, which costs her roughly over $100 a month.

She considers herself well-informed regarding her supplements intake. She learns about them from family friends and her own reading.

Get it naturally

Vitamin A What for: Healthy skin, eyes, hair and mucous membranes. Helps in bone formation and resistance to infection. Found in: Eggs, liver, spinach, broccoli, dark leafy vegetables, deep orange fruit (apricots, papaya), carrots, sweet potatoes, pumpkin Vitamin B Complex What for: Healthy metabolism and energy production Found in: Dairy products, lean meat, green leafy vegetables, liver, oatmeal, wheatgerm, beans and nuts Vitamin C What for: Collagen production. Helps in healing and aids iron absorption. Found in: Citrus fruit (orange, grapefruit, lime), strawberries, mangoes, peppers, lettuce, tomatoes Calcium What for: Healthy bones, teeth, and proper nerve functions. Found in: Dairy products, sardines eaten with bones, anchovies, tofu, greens (broccoli) Iron What for: Healthy muscle function, red blood cells and supply of oxygen to other cells. Found in: Red meat, liver, shellfish, egg, dried fruit, legumes Zinc What for: Promotes protein, sperm production and insulin. Important for DNA synthesis and healing. Found in: Meat, fish, shellfish, poultry, grains, legumes For more information, see Patient's Resources, Health Bites at www.nuh.com.sg

She is one of many Singaporeans spending $100 or more a month on vitamin pills and supplements, making it a booming industry here.

Singaporeans spent US$270 million (S$374 million) on health supplements in 2006, according to latest figures from the Health Supplements Industry Association of Singapore (HSIAS).

This was about a 42 per cent jump from the figure for 2003.

The market is growing at 12 to 15 per cent a year, says the association.

Major pharmaceutical chain Guardian Health and Beauty has seen a 15 per cent increase in its health-supplement sales over the past two years, while Unity, the retail-pharmacy arm of NTUC Healthcare, says its increase is over 20 per cent.

Over at the retail chains, global health food line GNC says it has seen an annual increase of 10 per cent in local sales.

Industry sources say the best-selling products are multivitamins and bone supplements such as calcium and glucosamine.

They don't come cheap - a 1,000mg bottle of Omega-3 supplements can cost $66.90.

Are pill takers overdoing it? Some doctors LifeStyle spoke to say that supplements are actually not needed if a person is in good health.

Sometimes, taking pills may even be harmful if they interfere with medication.

In general, health supplements are not as strictly regulated as medicine. Singapore's Health Sciences Authority (HSA) says at the moment, as happens in countries such as the United States, products in Singapore are not tested before they go on the market.

But with the Health Products Act introduced last year, which will see tighter controls on the health-supplements market, the HSA says that changes involving regulations of different categories of health products will be implemented 'in phases'.

Still, businessman Ong S. P., 35, who takes five different kinds of supplements, from antioxidants to Omega-3 nutrients, says: 'It's up to ourselves to read up more and do our own research. Consumers nowadays are getting smarter and smarter.'

On the variety of products available, Ms Huang Shu Yin, 27, a communications executive, says: 'This just means more choice. I don't find it confusing at all.'

She has been taking a Swiss product that is a combination of multivitamins and minerals for three years now, and claims she rarely catches a cold or a cough.

Besides that, she is also into evening primrose oil, 'good for maintaining healthy skin and nails, and for regulating the menstrual cycle'. She has also started taking glucosamine sulphate for joint-ache prevention.

Dr Tan See Lin, a general practitioner from the Pacific Medical Clinic, notes that as a rule of thumb, 'supplements are not to replace medication'.

Ms Rita Lye, a nutritionist from health retail chain Nature's Farm, adds: 'Supplements can't cure health problems, but can help to support the healthy function of our bodies.'

Also, more is not always better. Experts point out that there may be overlap of ingredients in different supplements that a person is consuming.

Generally, though, the ceiling for vitamins and supplements is high, say doctors. Vitamin C is generally safe up to 1,000mg, but high doses of around 10,000mg (10g) per day can cause stomach upset and diarrhoea, they say. The recommended daily allowance may range from 15mg to 90mg, depending on age group.

More importantly, if you are on medication, watch out because some supplements may interact with the drug you are consuming. This applies especially to cancer patients.

The general advice is to always seek help from a pharmacist or your family doctor if you are unsure.

Also, the literature on health-supplements research is fraught with debate. In 2007, a study by Danish scientists rocked the world of Vitamin E and antioxidant lovers by concluding that these supplements, taken by millions to fight disease, may actually send you to the grave earlier.

The research was later slammed by critics who said it was inaccurate because it was based on people who were already chronically ill before the intake of supplements.

Meanwhile, many health professionals say that as long as someone is on a balanced diet and does not have any pre-existing deficiencies, health supplements are not needed.

'The whole idea that you must meet some vitamin and mineral target every day of your life is a marketing myth,' says Ms Nehal Kamdar, a dietitian at Raffles Hospital.

But for those who insist on health supplements, the advice is to use established brands. Always read the labels and look out for details such as warning statements, pharmaceutical grades (some products have indications of good manufacturing practices by authorities) and recommendations for use.

And don't think that just because something costs a lot, it is the best product around. Says chief pharmacist at Alexandra Hospital and vice-president for the Pharmaceutical Society of Singapore, Dr M K Fatimah: 'Higher cost is generally associated with the branding and country of manufacture.'

This article was first published in The Sunday Times on Apr 6, 2008.