Studies show vitamin D fights these 3 diseases

By Alistair Gardiner
Published November 25, 2020

Key Takeaways

How often do you get out and enjoy the sunshine? If the answer is not much, you may want to start thinking about other ways to get a regular dose of vitamin D.

According to estimates, vitamin D deficiency affects roughly 1 billion people worldwide—and almost half the global population has at least some level of vitamin D insufficiency. Some studies indicated that not getting enough of the stuff may be a risk factor for all-cause mortality, and numerous researchers have concluded that we should all probably be getting a little more of it.

Vitamin D is a nutrient that’s naturally present in a few foods, but it’s also a hormone that our bodies produce. It helps us absorb and store calcium and phosphorus, both of which help to maintain healthy bones. The recommended daily amount of vitamin D is 600-800 IU. Besides getting out in the sun, some foods that are a source of the vitamin include fatty fish (like salmon, swordfish, sardines, and tuna), egg yolks, certain mushrooms, and vitamin D-fortified products like orange juice and milk.

There are numerous organs and tissues that have vitamin D receptors, which suggests that the vitamin plays several other roles in the body beyond keeping bones healthy. While clinical trials remain generally inconclusive, some studies have begun to shed light on vitamin D’s other benefits, which may include reducing cancer cell growth, reducing inflammation, and helping to control infections. Observational studies have demonstrated connections between lower rates of some diseases or conditions in populations that generally see more sun—a potential benefit of vitamin D.

According to the available research, here are three diseases that vitamin D may help you combat.


The results of studies on whether a vitamin D deficiency is associated with an increased risk of Alzheimer disease and dementia have been somewhat mixed. But the evidence is growing to support the hypothesis that getting more of this essential vitamin could help fight cognitive decline.

A study published recently in Alzheimer’s & Dementia looked at almost 1,800 over-65-year-olds, none of whom had dementia. Over the next 6 years, 329 of the participants developed some kind of dementia, and researchers found that those who had the highest vitamin D intake from food sources had the lowest risk of cognitive decline.

Another study had a similar aim and scope. Researchers monitored roughly 1,650 elderly adults free from dementia over the course of more than 5 years. Results of the observational study showed that those who were severely vitamin D deficient were at the highest risk of developing dementia and Alzheimer disease. Even so, the researchers acknowledged the possibility that this apparent association could be a result of the progression of the disease, rather than being causal.

Not all studies on vitamin D levels as a risk factor come to the same conclusion and further research is required in this area. However, it’s hard to ignore the mounting evidence supporting the supposition that vitamin D gives our brains a boost. A meta-analysis of 16 studies, published last year in BMC Neurology, found that vitamin D deficiency was associated with a 32% greater risk of dementia. The analysis further suggested that a severe vitamin D deficiency increased that risk by 48%, compared with a moderate deficiency.

Heart disease and hypertension

A growing body of evidence suggests that vitamin D deficiency may adversely affect the cardiovascular system, although further research is required to bolster this hypothesis.

Some studies have indicated that vitamin D causes this via its effect on the renin-angiotensin hormone system, which regulates blood pressure and fluid and electrolyte balance. Research suggests this function of the vitamin could work through the suppression of inflammation, or directly on the cells of the heart and blood-vessel walls.

One study, published in Circulation, followed more than 1,700 individuals without cardiovascular disease for more than 5 years. Researchers found a significant association between vitamin D deficiency and the development of cardiovascular disease. They noted that further work needed to be conducted to determine whether intervention with vitamin D could help to prevent the disease.

Various other studies have also come to the conclusion that vitamin D insufficiency appears to correlate with an increased risk of coronary artery or heart diseases.

In a similar vein, there is growing evidence that not getting enough vitamin D is associated with increased risks of hypertension.

According to one review on the subject, the results of clinical studies largely support the hypothesis that vitamin D sufficiency promotes lowering of arterial blood pressure. Again, further research is required, but in general, the science points to the fact that healthy levels of vitamin D are good for a healthy heart.


Yes, some research indicates that getting a regular dose of vitamin D may well be among measures to help protect against diabetes.

According to some studies, supplemental vitamin D may help reduce the impacts of age-related increases in glycemia and insulin resistance in healthy adults. One study, derived from the Nurses’ Health Study, even found that daily supplementation of calcium and vitamin D was associated with a 33% lower risk of developing type 2 diabetes.

Likewise, studies conducted with children as participants have indicated a link between living in a region with low levels of sunlight and higher rates of type 1 childhood diabetes. One study concluded that taking daily doses of vitamin D early in life reduced the risk of developing type 1 diabetes by as much as 80% over the following 30 years of life.

So, don’t hold back—go soak up some rays (responsibly, of course) and think about adding a regular portion of salmon to your diet. Your brain, heart, and various other parts of your body will thank you later.

Share with emailShare to FacebookShare to LinkedInShare to Twitter