It is well established that a healthy diet helps prevent chronic diseases.
Studies have consistently found that a diet based on vegetables and fruits, whole grains, a variety of healthy proteins and fats is linked to a lower risk of heart disease, stroke, Alzheimer’s disease and certain cancers.
However, if your diet is less than stellar, you may be inclined to take a daily vitamin supplement to protect your long-term health.
If this is the case, an updated review of the evidence suggests that you are wasting your money.
This is what you need to know about vitamin and mineral supplementation.
Updated supplement guidelines
To update its 2014 supplement recommendation statement, the U.S. Preventive Services Working Group (USPSTF) commissioned a group of independent experts to review 84 studies, including 52 new studies published since 2014.
The researchers tried to determine whether taking single nutrient supplements (e.g., folic acid, vitamin D, vitamin E), even nutrient supplements (e.g., calcium + vitamin D, folic acid + B12), or multivitamins reduced the risk of disease. cardiovascular, cancer. or premature death.
According to the new USPSTF guidelines, published June 21 in the Journal of the American Medical Association, there is no evidence that multivitamins, single supplements, or paired supplements help prevent cardiovascular disease or cancer in adults. pregnant, otherwise, healthy.
For most of the supplements reviewed, there was little or no evidence of serious harm.
However, the USPSTF specifically recommends not taking a beta-carotene supplement due to the possible increased risk of lung cancer and cardiovascular death. The updated guidelines also discourage the use of vitamin E, presumably because vitamin E supplements showed no benefit in protecting against cardiovascular disease, cancer, or premature death.
These findings do not surprise me at all.
Whole foods contain a mixture of vitamins, minerals, phytochemicals, fiber and other nutrients, dietary components designed to work together to deliver health benefits. This orchestrated network of beneficial compounds does not exist in isolated vitamin and mineral pills.
However, this does not mean that nutritional supplements are useless. Under the right circumstances, they can offer benefits.
When supplements are helpful
While I recommend trying to meet the daily nutrient needs of whole foods, in some cases this is not always feasible.
Some supplements are helpful in overcoming dietary nutrient gaps. They are also needed to treat vitamin and mineral deficiencies.
Women who are planning to become pregnant or who may become pregnant should take a daily multivitamin that provides 0.4 mg of folic acid to help prevent neural tube defects, birth defects that affect the brain, and the brain. spinal cord.
If you are on a vegan diet, taking a multivitamin and mineral supplement is an important way to get your daily iodine, a mineral found in dairy and seafood that is needed to produce thyroid hormones as well as vitamin B12.
B12 of natural origin is only found in foods of animal origin. It is needed to maintain healthy nerve function and to produce red blood cells and DNA.
Vegetarian or not, it is recommended that adults over the age of 50 get most of their daily vitamin B12 from a supplement, such as a multivitamin or B complex, or fortified foods. This is because many older adults do not produce enough gastric acid (stomach) needed to absorb B12 from food.
I also recommend a daily multivitamin for people taking a medication that can reduce the absorption of vitamin B12 from the diet (e.g., gastric acid inhibitors and metformin).
If you follow a low-calorie diet to lose weight or eat a very limited diet, a multivitamin and mineral supplement can provide some nutrient coverage.
A daily vitamin D supplement is needed to maintain a sufficient level of vitamin in the bloodstream. Osteoporosis Canada recommends vitamin D supplements for adults year-round, as it is almost impossible to get enough nutrients from food alone.
Vitamin D plays an important role in calcium absorption, bone health, muscle performance and balance.
Bottom line
Vitamin supplements are often considered completely benign. It’s not always like that, though. When taken in high doses, many nutrients can have adverse effects.
For example, in moderate doses vitamin A can reduce bone density and high doses can be toxic to the liver. Taking too much iodine can cause some of the same symptoms of an iodine deficiency, including an enlarged thyroid gland (e.g., goiter).
Supplementation with too much zinc can have consequences such as impaired immune function, reduced HDL (“good”) cholesterol levels, loss of appetite, diarrhea, headaches, and abdominal pain.
To supplement properly and safely, consult your healthcare provider.
Leslie Beck, a Toronto-based private practice dietitian, is director of food and nutrition at Medcan. Follow her on Twitter @LeslieBeckRD
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