A major drawback of taking individual vitamins is that you’ll need to plan your day and nutrition ritual to swallow more pills. This can take some real intention, especially if you’re frequently on the go. Not to mention, having multiple bottles in your medicine cabinet can create clutter, making it difficult to stay on top of your routine. Plus, it may become costly, albeit an investment in health and well-being.
Additionally, if you’re taking multiple supplements with the same vitamins and minerals, in limited cases, you may end up taking more than you need—which can introduce negative side effects or simply exceed your needs altogether. For example, a multivitamin with iron combined with a separate stand-alone high-dose iron. Granted, that very scenario may be warranted in certain situations under health care supervision (e.g., perinatal nutrition or addressing an iron deficiency). Nutrition is so very personalized.
In other cases, you are intentionally seeking additional amounts of nutrients in stand-alone formulas in order to bolster the baseline dose you receive in your multi. Vitamin D3 would be a prime example of that since science demonstrates that 5,000 IU or more is needed daily for adults to achieve and maintain sufficiency.
Many vitamins and minerals have a tolerable upper intake level (UL), or the max daily intake that has been demonstrated to be safe to take. Higher intake levels over prolonged periods of time may lead to side effects. This is often considered a greater concern with fat-soluble vitamins (A, D, E, and K), as they can accumulate in the body’s fat tissue—instead of being excreted in the urine like water-soluble vitamins—according to Whittington. For example, “too much vitamin K may interfere with blood clotting,” says Foley.
However, as Ferira once explained, making sweeping statements about the dangers of fat-soluble vitamins “lacks nuance and is an antiquated concept.” In fact, it’s quite difficult to reach toxic levels of fat-soluble vitamins, particularly vitamin D. She also says, “Every person is unique, so this is where consulting a health care provider makes a ton of sense.” For example, Ferira shares that “if you’re on medications related to blood clotting, then it’s important to keep your vitamin K intake constant and blood biomarkers monitored. It’s not about restriction but instead personalized approaches and monitoring.”
As far as minerals go: Taking too much iron may lead to GI issues related to things moving along (or not) and abdominal discomfort and could affect zinc absorption, notes Foley. And while taking a harmful amount of magnesium is incredibly rare, it can lead to digestive upset, depending on the form.
