Vitamin D variations among races are attributed to differences in skin pigmentation, but those with darker skin are far more likely to not have enough levels of vitamin D in the body.
The study also found that 95 percent of African American adults may have vitamin D deficiency or insufficiency.
Assistant professor Dr Kim Pfotenhauer, from Touro University, California, said: “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.
“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.”
Dr Pfotenhauer also said chronic diseases like Type 2 Diabetes and those related to malabsorption, including kidney disease, Crohn’s and celiac disease greatly inhibit the body’s ability to metabolise vitamin D from foods.
Considered a hormone rather than a vitamin, vitamin D is produced when skin is exposed to sunlight, and vitamin D receptors are found in virtually every cell in the human body.
As a result, it plays a wide role in the body’s functions, including cell growth modulation, neuromuscular and immune function and inflammation reduction.
Symptoms for insufficient or deficient vitamin D include muscle weakness and bone fractures.
People exhibiting these symptoms or who have chronic diseases known to decrease vitamin D, should have their levels checked and be treated if levels are too low.
Increasing and maintaining healthy vitamin D levels can be as easy as spending 5-30 minutes in midday sun twice per week.
Lighter skin synthesises more vitamin D than darker skin, and it is important to forgo sunscreen during these sessions because SPF 15 or greater decreases vitamin D3 production by 99 percent.
Dr Pfotenhauer added: “You don’t need to go sunbathing at the beach to get the benefits.
“A simple walk with arms and legs exposed is enough for most people.”
Food sources such as milk, breakfast cereals, and Portobello mushrooms are also fortified with vitamin D.
Research is ongoing to determine whether vitamin D deficiency has a role in multiple sclerosis, autoimmune disorders, infections, respiratory disease, cardiometabolic disease, cancer, and fracture risk.
Dr Pfotenhaur added: “Science has been trying to find a one-to-one correspondence between vitamin D levels and specific diseases.
“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 recognise those patients that need to be tested and treat them accordingly.”
The research was published in the Journal of the American Osteopathic Association today (Tues).