What's New in Vitamin D Research? A HealthCentral Explainer

Vitamin D is essential for calcium absorption, bone growth, bone remodeling and preventing osteoporosis. It also plays an important role in modulating cell growth, reducing inflammation and aids the immune system. All of these functions are well known to scientists, but, new research suggests vitamin D may play an even bigger role in our body.

How does vitamin D affect sleepiness?

Lower levels of vitamin D are correlated with more daytime sleepiness, but only among black people, according to a recent study published in the Journal of Clinical Sleep Medicine. Researchers looked at a series of 81 sleep clinic patients who had sleep issues and nonspecific pain. Most patients were eventually diagnosed with obstructive sleep apnea. Their vitamin D levels were measured by blood sampling and sleepiness was measured based on the Epworth Sleepiness Scale.

They found that in patients with normal vitamin D levels, progressively higher levels of daytime sleepiness were correlated inversely with progressively lower levels of vitamin D. Researchers noted that it is logical for race to play a role, as darker skin is an established risk factor for low vitamin D levels.

[SLIDESHOW: 8 Facts About Vitamin D and Rheumatoid Arthritis]** Can it prevent respiratory infections?**

Recent research has found that patients prone to infection that are given high doses of Vitamin D for a year significantly reduce their risk of developing respiratory tract infections, compared to their counterparts who did not receive the vitamin. The study, published in BMJ Open, was a double-blind randomized controlled trial with 140 volunteers who had respiratory infections for at least six weeks before the study began.

The volunteers were split into two groups – one group received 4000 IU daily of vitamin D3, the other group did not. They volunteers who received the vitamin had a 25 percent drop in respiratory tract infections. Researchers noted that fewer respiratory tract infections also meant fewer courses of antibiotics were needed for these patients.

Can vitamin D help osteoarthritis?

As much as helpful vitamin D can be, some things are just out of its reach. According to a recent study, taking vitamin D supplements will not improve pain relief or cartilage loss due to osteoarthritis in the knees. The study, published this month in JAMA, looked at 146 patients with osteoarthritis of the knee and split them into two groups.

One group received 2,000 IU a day of oral cholecalciferol, while the other group took a placebo. Researchers checked cartilage volume loss by magnetic resonance imaging (MRI) and a pain scale to track pain. They found that though vitamin D levels rose in the group receiving treatment, it did not correlate with any better outcomes. Cartilage in both groups was reduced by about 4 percent by the end of the study.

Does vitamin D have an impact on multiple sclerosis?

A November 2012 study found that high levels of vitamin D could prevent multiple sclerosis (MS) in pregnant mothers, but not their babies. The study, published in the journal Neurology, analyzed data of 291,599 blood samples from 164,000 people in Sweden. Researchers found that women with high levels of vitamin D in their blood had reduced their risk for MS by 61 percent, compared to those who had low levels of vitamin D in their blood. However, there was no link found between the mother’s vitamin D level and her child developing MS.

[SLIDESHOW: Vitamin D: What does it do and how to get it]** Can it prevent heart disease in diabetics?**

Another recent study published in the Journal of Biological Chemistry, found that diabetics with low levels of vitamin D are more likely to develop clogged arteries, which can lead to heart disease. For the study, researchers looked at vitamin D levels of 43 patients with type 2 diabetes. They compared these results to vitamin D levels of 25 non-diabetics of the same sex, body type and age. They found that in diabetics with low levels of vitamin D, or less than 30 nanograms per milliliter of blood, the macrophages were more prone to stick to the blood vessel walls. Eventually, this leads to cholesterol build-up, hardening of the arteries and obstructed blood movement.

Researchers say they took every factor into account, including blood pressure, cholesterol, diabetes control, body weight and race, and only vitamin D levels correlated to whether the macrophages stuck to the blood vessel wall. The researchers are conducting further research to see if giving vitamin D to diabetics can reduce the chance of getting clogged arteries.


n.p. (2011, June 24). “Dietary Supplement Fact Sheet: Vitamin D”. Office of Dietary Supplements – National Institutes of Health. Retrieved from http://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/

n.p. (2012, December 20). "Race May Play Important Role In The Complex Relationship Between Daytime Sleepiness And Vitamin D Levels." Medical News Today. Retrieved from http://www.medicalnewstoday.com/releases/254123.php

n.p. (2012, December 20). "High Vitamin D Doses Reduce Respiratory Tract Infection Risk." Medical News Today. Retrieved from http://www.medicalnewstoday.com/articles/254300.php

n.p. (2013, January 9). "Vitamin D No Help For Arthritis In The Knee." Medical News Today. Retrieved from http://www.medicalnewstoday.com/articles/254754.php

n.p. (2012, November 21). "Elevated Levels Of Vitamin D During Pregnancy May Prevent Multiple Sclerosis In Mothers." Medical News Today. Retrieved from http://www.medicalnewstoday.com/articles/253047.php

n.p. (2012, November 14). "Vitamin D Deficiency For Diabetics Can Lead To Clogged Arteries." Medical News Today. Retrieved from http://www.medicalnewstoday.com/articles/252821.php

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The HealthCentral Editorial Team

HealthCentral's team of editors based in New York City and Arlington, VA, collaborates with patient advocates, medical professionals, and health journalists worldwide to bring you medically vetted information and personal stories from people living with chronic conditions to help you navigate the best path forward with your health—no matter your starting point.