Almost 1 billion people worldwide may have deficient or insufficient levels of vitamin D, due to chronic disease, use of sunscreen, inadequate dietary sources, and malabsorption, according to an evidence-based clinical review published in the Journal of the American Osteopathic Association.
Pfotenhauer, DO, and Jay Shubrook, DO, Touro University, California College of Osteopathic Medicine, Vallejo, California, reported that the vitamin D deficiency among blacks may be more than 95% and that vitamin D variations among races are attributable to differences in skin pigmentation.
Researchers noted that breastfed infants are at a higher risk of vitamin D deficiency because breast milk contains little to no vitamin D, and a diet low in foods rich in vitamin D may also lead to deficiency.
The Endocrine Society currently defines insufficiency as between 21 ng/mL and 30 ng/ml; deficiency is considered less than 20 ng/ml, according to a press release.
“People are spending less time outside and, when they do go out, they're typically wearing sunscreen, which essentially nullifies the body's ability to produce vitamin D,” Pfotenhauer said in the release. “While we want people to protect themselves against skin cancer, there are healthy, moderate levels of unprotected sun exposure that can be very helpful in boosting vitamin D.”
Pfotenhauer also noted that chronic diseases such as type 2 diabetes and those related to malabsorption, including kidney disease, Crohn’s and celiac disease greatly inhibit the body's ability to metabolize vitamin D from food sources.
Other important points that the researchers noted in their evidence-based clinical review include:
•routine screening should be done only for patients at risk for vitamin D deficiency;
•patients with vitamin D deficiency should take vitamin D supplements to maintain bone health;
•vitamin D3 may be preferred over vitamin D2; and
•replacement dose for adults should be 50,000 IU/per week or 6,000 IU/per day.
“There may be additional benefits of vitamin D supplementation, but further evidence is needed to support recommendations,” Pfotenhauer and Shubrook wrote.
The researchers noted that whether vitamin D deficiency has a role in multiple sclerosis, autoimmune disorders, infections, respiratory disease, cardiometabolic disease, cancer, and risk for fracture is still being studied, and that there is no current consensus as to which form of supplemental vitamin D is superior.
“Science has been trying to find a one-to-one correspondence between vitamin D levels and specific diseases,” Pfotenhauer said in the release. “Given vitamin D’s ubiquitous role in the body, I believe sufficient vitamin D is more about overall health. Our job as osteopathic physicians is to recognize those patients that need to be tested and treat them accordingly.”
The release indicated increasing and maintaining healthy vitamin D levels can be done by spending 5 to 30 minutes in midday sun twice per week.
Healio Family Medicine recently compiled other recent research on vitamin D, including data that supplementation can reduce the risk for severe asthma attacks, and that low vitamin D levels may contribute to depression in psychotic disorders. – by Janel Miller
Shubrook reports serving as a consultant for AstraZeneca, GlaxoSmithKline, Lilly and NovoNordisk, and also receiving research support from Sanofi. Pfotenhauer reports no relevant financial disclosures.