Augmenting one’s intake of particular vitamins has been a controversial subject in medicine for years. Remember Dr. Linus Pauling and vitamin C? He recommended huge doses of the vitamin as a general cure-all for many ailments, but others in medicine disagreed and pointed out the potential harm from such large doses. For several decades, there has also been controversy, albeit less vehement, regarding Vitamin D and health. This particular vitamin, sometimes called the “sunshine vitamin,” is produced in the skin in response to sunlight. So persons who are not exposed to sufficient sunlight, such as those living in less warm climates or who are seldom outdoors, may have insufficient levels of vitamin D.  

​An important function of vitamin D is to help the body absorb calcium and phosphorus, so adherents of supplementation of this vitamin contend this will prevent bone abnormalities such as osteoporosis and osteomalacia. This will help to avoid bone fractures when someone falls.

​Some physicians also contend that vitamin D can reduce the risk of multiple sclerosis and heart disease as well as depression. Vitamin D deficiency can lead to conditions such as fatigue, bone or muscle pain, and stress fractures. However, there is no firm consensus about how much vitamin D the normal body needs. 

​But if supplemental vitamin D can potentially achieve the benefits noted, why not take more of it? It turns out the too much vitamin D can be toxic, especially in those with pre-existing conditions such as granulomatous disorders, or certain lymphomas. To cause harm the vitamin D level would likely have to be much greater than would ordinarily be achieved even with the usual supplementation dosages.  

The greatest risk of excessive dosages of vitamin D is that it can lead to someone absorbing too much calcium from food. In fact, one of the arguments for vitamin D supplementation is to increase calcium levels to avoid the bone problems noted with osteoporosis. However, hypercalcemia (too much calcium) can cause digestive distress, fatigue and confusion, kidney stones, and high blood pressure and cardiac abnormalities.  

A study reported in Current Rheumatology in 2019, entitled “The vitamin D and calcium controversy: an update” concluded that the benefits of “holistic” vitamin D supplementation have not been shown: “The benefits of vitamin D and calcium supplements for holistic fall and fracture prevention remain uncertain.” It also concluded that recent evidence “supports the concept that high-dose vitamin D has adverse musculoskeletal effects.” A meta-data review of published literature also did not confirm that “high-dose supplements reduces the risk of cardiovascular events.’’

The general conclusion of those who study vitamin supplements is “don’t rely on advertisements or internet advice.” Find out whether your doctor thinks your level of a particular vitamin is low enough to be concerning, and rely on your doctor’s advice about supplementing that vitamin. Your doctor can take into account whether you have other medical factors that may predispose you to harm from an excess of that vitamin.