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 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 at Johns Hopkins University conducted a meta-analysis (a research study that pools the results of the best-quality studies) to examine the effects of vitamin E supplements on the risk of death.
The meta-analysis showed that people taking high doses of vitamin E (400 IU per day or more) had an increased risk of death (approximately 4 extra deaths for every 1000 people taking vitamin E at these doses). The researchers noted that most of the studies of high-dose vitamin E were done in people with chronic diseases, so it’s unknown whether these results apply to healthy people.
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!
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 can 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 a NTD, should take 5 mg of folic acid daily under doctor’s supervision.
Once you’re positive that you’re pregnant, you should boost your daily folic acid intake to at least 0.6 mg, but don’t take more than 1 mg without checking with your doctor first. You’ll need more 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.
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, three 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? Babies, children and adults under 50 need 400 IU (international units) per day. Adults over 50 should get 800 IU daily.
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.
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