Stroll through the supplement aisle in any pharmacy and you’ll be enticed by dozens and dozens of products that promise to “support cardiovascular health,” “improve brain function,” “reduce inflammation” and “metabolize carbohydrates, fat and protein.” These claims are alluring: just pop a little pill and voila! You’ll be protected from disease and living your best life with an optimally functioning body. But are supplements effective at doing what they say they will? Are they necessary? Are there risks or consequences?
As a registered dietitian, I can assure you there’s no question that vitamins and minerals are essential for keeping the physiologic and biochemical functions of our bodies operating at their best. They contribute to energy production, cell and tissue growth and repair and hormone synthesis, and help prevent such chronic diseases as diabetes, osteoporosis, hypertension, cardiovascular disease and cancer. But that doesn’t mean we should recommend that everyone take supplements.
So, should you take supplements?
According to the latest data from Statistics Canada, about 46 percent of Canadians take nutritional supplements. Ironically, research shows that people who have the most nutritious diets—and thus are less likely to have deficiencies—are more likely to take supplements.
Despite how common supplement use is, the majority of the population can get most or all of the nutrients they need from a nutritious diet alone. Vitamin and mineral supplements should never replace a healthy, balanced diet. Evidence has not conclusively proven that supplements are effective in preventing chronic disease in the same way nutrients from food are.
There are, however, some groups of people who may not be able to meet their nutritional requirements through diet alone. People at certain life stages with particular dietary restrictions or health conditions may benefit from a supplement. It’s best to discuss your particular needs with your doctor or dietitian.
Is it better to get your nutrients from food?
Food sources of nutrients have a greater benefit to the body than supplements for reasons scientists can’t fully explain. Something in the synergistic nature of all the elements contained within a food—vitamins, minerals, phytochemicals, antioxidants and fibre—makes it greater than the sum of its parts. It’s often the combinations of different foods we eat and their interactions with each other that enhance the functioning or absorption of the nutrients they contain. Separate those elements out and package them in a neat little capsule, and something is lost.
So instead, think of a healthy diet that’s rich in fruits and vegetables, whole grains, lean protein, beans and legumes and healthy sources of fat as your best defence. Then, if warranted, add supplements on top as an insurance policy.
How do you know if you need supplements?
Ask yourself these questions to help determine if supplements are something you should consider:
- Do you eat at least five servings of vegetables and fruit each day? Do you eat a wide variety, including plenty of leafy greens and orange vegetables and fruit? If not, you might be deficient in a number of vitamins or minerals.
- Do you consume dairy products or a fortified dairy alternative (e.g., soy or almond beverage) each day? If not, consider vitamin D and/or calcium supplements.
- Do you eat whole grains each day? If not, you might not be meeting your needs of B vitamins.
- Are you vegetarian or vegan? If so, vitamin B12 and iron might be a concern.
- Do you include sources of healthy fats every day (from foods like flaxseeds, chia seeds, hemp hearts, nuts, canola and soybean oils, and at least 2 servings of oily fish like salmon, mackerel and sardines per week)? If not, you might consider an omega 3 supplement, particularly if you have high LDL cholesterol or a family history of heart disease.
- Do you eat a restricted diet due to illness, low appetite or attempts to lose weight? If so, you might need a multivitamin.
Adults in certain life stages have increased nutrient needs or may have a higher risk of deficiency. Therefore, the following are recommended:
- Women of childbearing age should take 400 mcg folic acid to prevent neural tube defects.
- Pregnant women should take a prenatal multivitamin containing 16-20 mg iron and 400 mcg folic acid. Breastfeeding women should also take a multivitamin.
- Adults over 50 should take vitamin B12, vitamin D and calcium.
Some conditions may put you at risk of deficiency, including:
- Celiac, IBS, Crohn’s or colitis
- Osteoporosis or other bone conditions
- Age-related macular degeneration
- Recovery from surgery or illness
- Iron deficiency anemia
- Pernicious anemia
It’s impossible to give blanket recommendations on supplementation to the entire population, or even sub-groups, so talk to your doctor or dietitian for individualized advice. A blood test to determine your levels is the only way to know for sure if you’re deficient in a nutrient.
What supplements are most common?
In 2012, researchers from the University of Toronto analyzed nationally representative data from the Canadian Community Health Survey to find the prevalence of nutrient inadequacies. They found that Canadians were meeting most of their nutrient needs through diet alone, however the nutrients people most commonly fell short in were vitamin D, calcium, vitamin A and magnesium.
Do you need to take vitamin D supplements?
Most people know that vitamin D plays an important role in bone health, but it also has other functions, like promoting a strong immune system, reducing inflammation, reducing the risk of type 2 diabetes and protecting against cancer growth. The body makes vitamin D when skin is exposed to sunlight, which means that in northern countries like Canada most people don’t get enough exposure to meet their needs, especially in the winter.
Milk and dairy alternatives are fortified with vitamin D and fatty fish is a good source, but it can be difficult to get enough from diet alone. The 2012 study found that 93 percent of women ages 14 to 50 were deficient in vitamin D, which means it’s safe to say we should all be taking a supplement. The recommended dietary allowance for vitamin D is 600 IU per day for children and adults under 70 years, and 800 IU for adults over 70 years. Depending on your sunlight exposure, skin colour, age, body size and intake from food sources, you may need to take as much as 1,000 to 2,000 IU. The tolerable upper limit (the amount beyond which may be harmful) is 4,000 IU, so stay well below.
What about calcium?
About 85 percent of women over 50 are deficient in calcium. Considering calcium’s role in preventing osteoporosis, this is alarming and definitely cause to incorporate more sources of calcium in your diet or start taking a supplement. Adults 19 to 50 need 1,000 mg of calcium each day, which rises to 1,200 mg for women over 50 and men over 70. Each cup of milk or fortified dairy alternative provides about 300 mg, as does 3/4 cup yogurt and 1 1/2 oz. of cheese. Soybeans, fortified tofu, canned salmon with bones, white beans, navy beans and leafy greens like kale and bok choy also contain calcium. We get about 300 mg of calcium from our diet without incorporating any high calcium foods. If you aren’t getting enough, consider supplementing with calcium that provides 300 to 350 mg per tablet. Split supplements up throughout the day as the body can only absorb about 500-600 mg at a time.
What are the potential risks associated with supplements?
If taken in excess, water-soluble vitamins will simply pass through the body and be excreted in your urine. Not a major concern, except if you consider the cost that gets flushed down the toilet each day. There is however potential for toxicity from fat soluble vitamins (A, D, E and K) because they stay in the body and can build up over time and may have adverse effects. For example, people who smoke should avoid beta carotene supplements due to an increased risk of lung cancer. High doses of vitamin E have been shown to have harmful side effects, for example it can reduce the body’s ability to form blood clots, may increase the risk of prostate cancer, and may interact with chemotherapy and radiation in cancer patients. The other risk is drug-nutrient interactions as certain supplements can change the effectiveness of medications (for example vitamin K affects blood-clotting medications such as warfarin). Some supplements also interact with each other (for example calcium inhibits the absorption of iron). It’s imperative that you discuss any supplements you’re taking with your health care provider.
The bottom line
So while the world of supplements may seem overwhelming, the best advice boils down to this:
- Aim to eat a healthy, balanced diet that provides all the nutrients you need through food.
- Everyone should take a vitamin D supplement (at least 600-800 IU), especially in the winter months.
- Consider other supplements if you’re at risk of deficiency based on your dietary intake, stage of life or health conditions.
- Always discuss all the supplements you’re taking with your doctor and/or dietitian.
Emily Kichler is a registered dietitian in Norfolk County, Ont.