There's been a lot of excitement about antioxidants – nutrients that protect the body from damage due to "free radicals," which are compounds produced by environmental toxins and normal body processes. Free radicals can damage cells throughout the body. There have been many claims about what antioxidants can do for our health, including protecting us from heart disease, cancer, and Alzheimer's disease. Vitamins C and E, beta-carotene (vitamin A), and the mineral selenium are well-researched antioxidants.

Early studies showed that people who ate lots of fruits and vegetables – foods rich in antioxidants – were less likely to develop such diseases than those who shunned these foods. Next, people already taking antioxidant pills were compared to others who weren't taking such supplements. Again, the antioxidants seemed to be protective. But were they really? Taking a closer look at these studies, it's likely that people who choose to eat lots of fruits and vegetables or take supplements are more health-conscious than those who don't; this may explain these impressive results. Also, fruits and vegetables offer many more nutrients than the few antioxidants we know about.

The best studies are "clinical trials," where a large group of people are randomly assigned either antioxidants or a placebo (a dummy tablet). That way, the only difference between the two groups is whether they're getting the antioxidant or not – participants (and usually researchers as well) don't know which group they're in. As it turns out, the latest clinical trials on vitamins C and E and beta-carotene supplements didn't find that they protected against heart disease and cancer. In several studies, smokers in the group taking beta-carotene pills had a higher risk of lung cancer than smokers taking a placebo. Researchers conducted a meta-analysis (a research study that pools the results of the best-quality studies) to examine the effects of antioxidant supplements on the risk of death and showed that they did not prevent death in healthy people or in people with diseases. In fact, people taking beta-carotene and vitamin E were at an increased risk of death.

Other studies have investigated antioxidants like coenzyme Q10 for Parkinson's disease or traditional antioxidants for the treatment of arthritis but have yet to find any evidence to support antioxidants for treating these conditions. However, there's still so much research going on to settle this question. Meanwhile, Mom was right – eat your fruits and veggies, because they're good for you!

Bone-building buddy

Our bodies need vitamin D to absorb calcium, the major building block of bone. It boosts the body's ability to absorb calcium by up to 80%. Vitamin D becomes especially important as we get older, when calcium is less efficiently absorbed. Together, calcium and vitamin D can prevent osteoporosis, a condition where bones become thin and brittle and break easily.

Vitamin D is often called "the sunshine vitamin," since our bodies can actually produce it themselves when exposed to sunlight. In the summer, having our arms, face, and hands out in the sun for just 10-15 minutes a day, 3 times per week, can make enough vitamin D to meet the body's requirements.

Unfortunately, the sun may not be the safest or most reliable way to get enough of this vitamin. Using sunscreens to prevent skin cancer blocks the rays needed to produce vitamin D. Dark-skinned people absorb less sunlight than those with light skins, putting them at risk of vitamin D deficiency. Also, many people, especially the elderly, are at risk, as they spend more time indoors. Finally, the long, cold, and dark Canadian winters mean that the skin's vitamin D production shuts down from early October until late March every year.

So how can we get enough vitamin D – and just how much do we need? Infants under 1 year of age should get 400 IU (international units) per day. Children over 1 year of age and adults under 70 (who do not have osteoporosis) need between 600 IU and 1000 IU per day. Adults over 70 should get at least 800 IU daily. Some doctors recommend up to 2000 IU per day for certain individuals.

In Canada, a glass of milk (250 mL) is enriched with 100 IU of vitamin D, making it a good source of this nutrient. Small amounts of vitamin D are in margarine, eggs, chicken liver, salmon, sardines, herring, mackerel, swordfish, and fish liver oil. It may be hard to get enough vitamin D from food alone, though, so you may opt to take a supplement. Remember that most multivitamins contain 400 IU of vitamin D, which is enough for most people. Don't be tempted to take higher doses – too much vitamin D can lead to loss of calcium from bone, too much calcium in the blood, and kidney problems.

It's especially important that babies and children get enough vitamin D. Kids who are short on this vitamin can get rickets, a disease affecting bone development. Infant formulas are already fortified with vitamin D, so bottle-fed babies don't need supplements. Breast-fed babies, on the other hand, may need a vitamin D supplement since breast milk is usually low in vitamin D. Breast milk is still the perfect food for babies but, if you're breast-feeding, talk to your doctor about whether your baby needs extra vitamin D.

Folic acid

If you're pregnant – or even planning to have a baby – you need to know about folic acid. This type of vitamin B is crucial in preventing certain birth defects in the brain and spinal cord called neural tube defects (NTDs). The neural tube starts out as a flat sheet of cells that normally folds into a tube and goes on to form the brain and spinal cord. The tube closes by the 29th day after conception – before many women even realize they're pregnant – but if it doesn't close properly, NTDs are the result. That's why it's so important to start getting extra folic acid before you become pregnant.

Healthy women who are planning to become pregnant should take a vitamin supplement containing 0.4 mg (400 micrograms) of folic acid every day. Most women only get about 0.2 mg of folic acid from foods, like grains, green vegetables (spinach, broccoli), meat (liver), and legumes (lentils and beans), so a supplement is the only way to be sure you're getting enough. Women with diabetes, epilepsy, or a family history of NTDs, or who have already had an infant with an NTD, or are obese (BMI > 35) should take 5 mg of folic acid daily under doctor's supervision, starting at least 3 months before trying to conceive.

Once you're positive that you're pregnant, you should continue taking your daily dose of folic acid. If your doctor initially recommended 5 mg of folic acid daily, speak to your doctor before changing your routine. You'll continue to need folic acid during pregnancy to help produce added blood cells and allow the fetus and placenta to grow rapidly. If you plan on breast-feeding, you should keep taking extra folic acid after delivery.

Shopping for supplements

Nutrition experts agree: the best way to stock up on vitamins and minerals is by eating right. Popping a pill is no substitute for a balanced diet. But if, like millions of Canadians, you decide to take a vitamin and mineral supplement, here are some tips:

  • Don't waste your money on "natural" vitamins. Your body can't tell the difference between synthetic (man-made) vitamins and so-called "natural" ones, but synthetics are usually cheaper. The exception to this rule is vitamin E: your body absorbs the natural form better than the synthetic version, although vitamin manufacturers add enough to synthetic vitamin E to make up for the difference (and it's still cheaper). Also remember that generic and other reasonably priced brands are just as good as more expensive ones.
  • Read the label to make sure the expiry date hasn't passed. Like foods, supplements should not be used after their expiry dates. Look for a Drug Identification Number (DIN) or Natural Health Product (NHP) number, usually on the front label, which shows that the product was approved by Health Canada.
  • Don't assume that more is better. In fact, vitamins A and D, iron, zinc, and selenium can be toxic in high doses, while others can have unpleasant or serious side effects. Your safest bet is to look for supplements that provide no more than the recommended daily dose of each nutrient.
  • Keep supplements away from children. Those pills may look and taste like candy to a child – but they can be deadly. Iron supplements cause more poisoning deaths in children than any other substance.
  • Tell your doctor about all of the vitamins, minerals, and other supplements you're taking. Some vitamins and minerals can interfere with certain medications.