Should I be taking a multivitamin?
By Leonie O’Sullivan, July 18 2023—
A key memory from my undergraduate studies is when my biochemistry professor told the class to take the money our parents were giving us for vitamins and spend it on a night out instead. They implied that by paying for multivitamins the most we would be getting out of it was expensive urine. This recollection has stayed with me, but I always wondered if there was any evidence to back up what they said that day. Do our bodies actually need these supplements?
It turns out that everyone’s needs are quite unique, and we should probably avoid sweeping generalizations when it comes to multivitamin/mineral (MVM) supplements. Vitamins are organic compounds derived from plants and animals, and minerals are inorganic compounds which come from the earth. Both are classified as micronutrients required for a broad range of our bodily functions.
Everyone has a unique diet with a unique intake of these micronutrients. Some people may require MVM supplements due to absorption problems, for example, those with chronic diseases like cystic fibrosis or celiac disease. If you follow a more restricted diet, such as a vegan diet, MVM supplementation may be advantageous. As we get older, our ability to absorb vitamins and minerals goes downhill and pregnant individuals may also need help filling in nutrient gaps — they are growing another human, after all.
Due to Canada’s high latitude, Canadians may also need extra help getting enough Vitamin D, called the sunshine vitamin. To target your specific needs, you have the option to take an individual vitamin supplement instead of an MVM.
If you are a young adult with no underlying health issues and opt for a varied diet that checks off every shelf of the food pyramid, you probably don’t need an MVM supplement. If you are concerned, it’s definitely best to talk with your doctor or a healthcare professional. The choice of whether or not to take a daily MVM is a personal one. Each individual should conduct their own risk-benefit analysis. But what are the pros and cons of MVM supplements?
On the bright side of things, MVM supplements have been shown to increase immunity for healthy older adults. A study recruited 42 healthy individuals in the 55 to 75-year age bracket. Half of these individuals received a placebo and the other half received an MVM supplement for 12 weeks. The researchers from Oregon State University found an inverse relationship between the severity of illness and zinc levels. By bridging nutrition gaps, MVMs can also help prevent anemia, birth defects of the brain and spinal cord and bone disease. A recent clinical trial has demonstrated that MVM supplementation may even stave off memory loss in older adults.
On the gloomy side, in a clinical trial with over 20,000 adults, MVM supplements have not been shown to significantly reduce mortality, cancer or cardiovascular disease. A longitudinal study with 8,000 participants provided evidence for an increased risk of asthma in Black infants who had a history of vitamin use within the first six months of life. The authors stated that this racial difference requires further exploration as it is unknown if it is due to a physiological difference, detected confounding or bias. This study also highlighted that bottle-fed children with early vitamin use had a higher risk for food allergies.
If you are taking any medications alongside MVM supplements, it is critical to discuss this with your doctor. MVM supplements can lower the effectiveness of medications, for example, Vitamin K — which is important for blood clotting — decreases the efficacy of blood thinners. You might have to push pause on your MVM supplements when on antibiotics as minerals such as Calcium, reduce the level of these drugs in the body, making them ineffective. Take extra care if you have kidney or liver disease and consult with your doctor before taking MVM supplements.
So, no — you should not automatically take an MVM supplement without a reason. MVM supplements should only be used to fill a nutritional gap and are not meant to replace a healthy diet. In Canada, you can be confident that MVM supplements are safe, effective and of high quality as they are regulated by Health Canada as non-prescription drugs. You can now take this information to conduct your own risk-cost analysis for taking MVM supplements, but make sure to consult with your doctor if you decide to start or stop taking MVM supplements.