When it comes to supplements, it’s not just what you take, but how you take them, that counts. Fiona Marsden investigates

Get Supplement Smart

Even with the healthiest eating habits, there may be times in life when your nutrition needs extra help. Menstruation, pregnancy and menopause can all increase your need for certain nutrients. Taking supplements can boost your intake when you can’t get enough from food alone.

But before you pop those pills, it’s worth stopping to consider how and when you take them. Some supplements can interfere with each other, while certain substances in food and drink can affect your absorption of supplements. What’s more, taking large doses of single-nutrient supplements may increase your consumption to unsafe levels, particularly during pregnancy.

So what is the most effective way to take supplements at key times in your life?


If you’re menstruating, particularly if your periods are prolonged or heavy, you could be at risk of iron deficiency. The National Health and Medical Research Council (NHMRC), which sets Recommended Dietary Intakes (RDIs) for Australia and New Zealand, believes women aged 19 to 50 should be getting 18 milligrams of iron per day.

"Some women may struggle to meet this RDI through food alone, especially if they don’t eat red meat," says Tania Ferraretto, Accredited Practising Dietitian and spokesperson for the Dietitians Association of Australia.

If you do take a supplement, be aware that the amount of iron varies considerably between different formulations. Single-nutrient supplements, for example, may contain much more iron than multi-vitamins. High doses of iron can cause stomach pains and constipation in some people, so Ferraretto cautions against using high-dose supplements unless you are advised by a pharmacist or other health professional.

If you do experience side effects, says Ferraretto, "it might be worth adjusting your diet to include three meals with red meat per week, instead of taking a supplement." You’ll get around 7-8mg of iron from a small steak. And there’s a bonus: iron from meat is absorbed more efficiently than iron from a supplement or plant-based food.


When you’re pregnant, your body needs more of certain nutrients because it has to provide for the needs of the growing foetus as well as your own.

According to the Victorian government’s Better Health Channel, the developing foetus draws enough iron from the mother to last it through the first five or six months after birth. This means the RDI for iron during pregnancy is much higher than usual, at 27mg per day, so taking a supplement may help.

An adequate intake of folate (also known as folic acid) is also important when you’re planning pregnancy, and throughout the first trimester. "Numerous studies have shown that folate reduces the incidence of neural tube defects like spina bifida," says Ferraretto. If you’re planning pregnancy, she recommends taking a folate supplement as soon as you stop using contraception, or at least a month before you become pregnant.


During pregnancy, the RDI for folate from dietary sources alone is 600mg per day. Good sources of folate include spinach, broccoli, avocado and citrus foods, along with folate-fortified foods like yeast extract and some breakfast cereals.

This RDI does not include the amount required to minimise the risk of neural tube defects. To do this, says the NHMRC, you need an additional 400mg per day from folate-fortified foods or folate supplements.

Ferraretto advises taking a supplement specifically designed for use during pregnancy, rather than a more generic kind. "It will have higher levels of the nutrients you need," she says, "without the nutrients that can be harmful in excess amounts." For example, too much Vitamin A is thought to cause birth defects.


Dr Gary Deed, President of the Australasian College of Nutritional and Environmental Medicine, says our ability to absorb nutrients decreases with age because we produce less stomach acid. This can particularly affect the absorption of B-group vitamins in some people, making supplementation a useful tool.

Ironically, at the same time as your ability to absorb some nutrients decreases, your need for them increases. For example, women need more calcium in the post-menopausal years, to help offset the increased rate of bone loss that can lead to osteoporosis. The RDI for women aged 51 and older is 1,300 milligrams per day, compared with 1,000 milligrams for younger women. If you can’t get your RDI from food alone, a supplement may help—provided you take it in the right way.

"Calcium tends to be better absorbed at night," says Tania Ferraretto, "so it’s best to take it at bedtime." The caffeine and tannin in coffee and tea can affect the absorption of calcium, so don’t be tempted to slosh down your supplement with a cuppa. This applies to anyone taking a calcium supplement, not just post-menopausal women.

Ditch the drink

Alcohol reduces the body’s ability to absorb nutrients, so try to minimise or avoid drinking whilst you’re taking supplements. "Otherwise," says Dr Gary Deed, "you’re just taking nutrients in and excreting them straight out."

(If you’re pregnant, drinking alcohol is unwise anyway, because it could pose risks to your unborn baby. The NHMRC advises that if you’re pregnant or planning to be, the safest option is to avoid alcohol completely.)

What about the common practice of taking a Vitamin B supplement to help ease a hangover? Does it work? Tania Ferraretto is unconvinced. "The B-group vitamins are water soluble, so they’re not harmful in large doses because you’ll excrete what you don’t need," she says. "But our bodies are designed to keep our nutrient levels consistent, so taking a single big dose of Vitamin B after a big night may have more of a placebo effect than anything else."

A word about fibre

It’s relatively well known that some high fibre foods, particularly the psyllium husks used to ease constipation, can hamper our assimilation of iron. What’s less known is that it can also bind calcium, making it unavailable for absorption. "If you’re using single, large-dose supplements of iron or calcium, it’s a good idea to take them separately from eating high fibre foods," says Ferraretto.

Food for thought

No matter what your stage of life, experts believe food should always be your primary source of nutrients, with supplements playing an occasional support role.

"Studies from around the world show that, on the whole, people who eat a healthy diet with plenty of fruit, vegetables and wholegrains will get the nutrients they need," says Tania Ferraretto. "This is particularly the case in Australia, where we have a healthy and varied food supply."

The nutrients in food come in a combination which facilitates assimilation by the body, says Dr Deed. By contrast, taking supplements of certain nutrients in combination can compromise absorption.

What’s more, supplements lack the anti-oxidants and fibre found in healthy foods. "Nature has packaged food in a certain way to give us what we need," says Ferraretto. "You can’t replicate these factors in a pill."

For more information

Australasian College
of Nutritional and
Environmental Medicine

www.acnem.org — lists nutritionally qualified health professionals in your local area.

Better Health Channel

www.betterhealth.vic.gov.au — general advice on a range of health and wellness issues.

Dietitians Association of Australia

www.daa.asn.au — lists Accredited Practising Dietitians in your area.

Healthy Eating Club

www.healthyeatingclub.org — nutrition information written by qualified professionals.

Fiona Marsden is a freelance health and wellbeing writer. Visit her blog at www.healthierwealthierwiser.wordpress.com

Supplementation do’s and don’ts

Minerals: take before meals.

Iron: take with Vitamin C to enhance absorption, and not with tea or coffee.

Calcium: take at bedtime, and not with tea or coffee.

Vitamin A: avoid large doses during pregnancy.

Vitamin B12 and folate: depend on each other to work effectively. If you’re taking a B-vitamin supplement, make sure you take enough folate too.

Vitamin D and calcium: taking large doses together can increase the risk of kidney stones.

Fish oil and evening primrose oil: take with food to enhance absorption, but separately from mineral-based supplements.


Sources: Dr Gary Deed, ACNEM and Tanya Ferraretto, DAA.