Commonly Asked Questions About Vitamin and Mineral Supplements

Before taking any supplement it's important to talk to your dietitian or health care provider to discuss your individual needs.

1. Will vitamin and mineral supplements give you energy?

No. The energy that your body needs to think, work and play comes from calories. Vitamins and minerals in pill form do not provide calories. Calories come from the foods we eat.

2. Can vitamin and mineral supplements reduce stress?

No. Vitamin and mineral supplements don't reduce stress but eating well is one strategy that may help you cope with the stresses of daily living. A supplement will only provide some missing nutrients if you are not eating well. If you are feeling stressed it's important to find out the causes of your stress and get help from a health professional if needed.

3. Should I take vitamin and mineral supplements to make sure that I am getting what I need or give them to my kids when they don’t eat right?

Not necessarily. You and your family can get the nutrients you need by following the recommendations in Canada’s Food Guide. Vitamin and mineral supplements do not provide the benefits of food such as fibre, carbohydrate, fat, protein and calories. If you’re concerned about whether you or your children are getting enough nutrients, speak to your dietitian or health care provider.

4. Who should consider taking a supplement?

Here are some situations that may require a supplement. Remember, if you are concerned about your nutrient intake or think you may need a supplement, speak to your dietitian or health care provider.

1. Women of childbearing age who are thinking of getting pregnant should take a supplement that contains at least 400 ug (0.4 mg) of folic acid. This is to prevent neural tube defects such as spina bifida that can begin early in pregnancy even before many women realize they are pregnant.

2. Women who are pregnant need added folic acid and iron, which can be obtained from foods and with a multivitamin. Look for a prenatal vitamin that contains at least 400 ug (0.4 mg) of folic acid and 16 to 20 mg of iron.

3. People over the age of 50 should consider vitamin D and vitamin B12 supplements. Health Canada recommends a daily supplement of 400 IU of Vitamin D for both men and women over the age of 50. Also, adults over 50 may not be able to fully absorb vitamin B12 that occurs naturally in foods and should take a supplement.

4. People who don’t drink milk or  fortified plant-based beverages daily may need a vitamin D and/or calcium supplement. 

5. Vegetarians or Vegans. A well planned vegetarian or vegan diet will meet most nutrient needs. Vegans may need a source of vitamin B12 either from a supplement or foods fortified with vitamin B12. They may also benefit from a calcium and vitamin D supplement.

6. People with medical conditions. Some conditions such as anemia, inflammatory bowel disease or osteoporosis may need more of some nutrients. Or if you’ve had surgery or an infection you may require extra nutrients or a supplement until you regain your health. Your health care provider will advise you.

7. People with very restricted diets, such as those with poor appetite, very low calorie diet or food allergies may need a supplement.

8. People who smoke. Smoking increases the need for vitamin C. People who smoke should take a vitamin C supplement and eat vitamin C rich foods.

5. Can supplements be dangerous?

Sometimes. A daily multivitamin is usually safe.  However, some vitamins and minerals are dangerous when taken in large amounts if you take them as single nutrient supplements. For example, high intakes of vitamin A during pregnancy have been linked to birth defects. Also, vitamin D, niacin, calcium, iron and selenium are toxic in high doses.
 
For some supplements, if you take too much, you may experience unpleasant side effects. For example, having over 2000 mg of vitamin C may cause gut problems like diarrhea. Magnesium in higher doses may also cause diarrhea.  Large amounts of vitamin B6 may also have harmful side effects. Speak to your dietitian or health care provider before starting a higher dose supplement to make sure it is right for you.

6. Can taking a vitamin A or beta-carotene supplement help prevent cancer?

No. It is not recommended that vitamin A or beta-carotene supplements be used to prevent cancer. In fact, research has shown that in some cases, taking these supplements can increase the risk of some types of cancer.

7. Can taking vitamin C or zinc supplements boost my immunity?

Almost all nutrients help the immune system in one way or another. Some research suggests that vitamin C and zinc may help reduce the duration of a cold and the severity of some symptoms. For most people, however, there is no good evidence that taking more of these nutrients than what you can get from a nutritious diet will improve your immune system.
It’s best to check with your dietitian or health care provider before taking any supplements. Zinc can be toxic in high doses, and taking more than 2,000 mg of vitamin C per day can have side effects like diarrhea.

8. Can some nutrients delay or prevent dementia?

No. Several nutrients have been studied to see if they can help prevent dementia. These include antioxidants (such as vitamins A, C and E), B vitamins, and omega-3 fatty acids. Currently there is not enough evidence that shows that taking vitamin and mineral supplements will prevent dementia. 

9. Can taking a vitamin E supplement help prevent cancer or heart disease?

No. It is not recommended that you take a vitamin E supplement to help prevent chronic diseases like heart disease or cancer. In fact, some research has shown that in certain individuals (such as those who already have had heart disease, cancer or diabetes), high doses of vitamin E supplements can actually cause harm. More research is needed to know how vitamin E supplements can affect the risk of chronic disease.  Always speak with your health care provider before starting a vitamin E supplement.
 
Note: The amount of vitamin E found in a multivitamin is considered safe and appropriate for healthy individuals.

How can a dietitian help?

A dietitian can review what you are eating to make sure you are getting all the vitamins and minerals you need. If you are low in some, they can recommend foods to include, or a supplement. If you have medical conditions like allergies, osteoporosis, anemia or are recovering from surgery, a dietitian will advise you on any supplements you may need. Connect with a dietitian today!

Bottom line

In most cases, your best bet is to get the vitamin and minerals you need from food. Some people would benefit from taking a supplement, such women of childbearing age, pregnant women and people over the age of 50. Always check with your dietitian or health care provider before starting a supplement.

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This article was written and reviewed by dietitians from Dietitians of Canada. The advice in this article is intended as general information and should not replace advice given by your dietitian or healthcare provider.

Last Update – February 13, 2023