Widespread vitamin D deficiency likely due to sunscreen use, increase of chronic diseases, review finds Date:By Guest Nicole
May 1, 2017
American Osteopathic Association
Results from a clinical review find nearly 1 billion people worldwide may have deficient or insufficient levels of vitamin D due to chronic disease and inadequate sun exposure related to sunscreen use.
Results from a clinical review published in The Journal of the American Osteopathic Association find nearly 1 billion people worldwide may have deficient or insufficient levels of vitamin D due to chronic disease and inadequate sun exposure related to sunscreen use.
The study also found that 95 percent of African American adults may have vitamin D deficiency or insufficiency. Vitamin D variations among races are attributed to differences in skin pigmentation.
"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," said Kim Pfotenhauer, DO, assistant professor at Touro University and a researcher on this study. "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 metabolize vitamin D from food sources.
Considered a hormone rather than a vitamin, vitamin D is produced when skin is exposed to sunlight. 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, if found to be low, discuss treatment options. However, universal screening is likely neither necessary nor prudent absent significant symptoms or chronic disease.
Increasing and maintaining healthy vitamin D levels can be as easy as spending 5-30 minutes in midday sun twice per week. The appropriate time depends on a person's geographic location and skin pigmentation -- lighter skin synthesizes more vitamin D than darker skin. It is important to forgo sunscreen during these sessions because SPF 15 or greater decreases vitamin D3 production by 99 percent.
"You don't need to go sunbathing at the beach to get the benefits," said Dr. Pfotenhauer. "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. Dr. Pfotenhauer said supplements are a good option, as they are effective and pose few risks, provided they are taken as directed and a physician is consulted beforehand.
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.
"Science has been trying to find a one-to-one correspondence between vitamin D levels and specific diseases," said Dr. Pfotenhauer. "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."
Currently, insufficiency is defined as between 21 and 30 ng/ml and deficiency is considered below 20ng/ml by the Endocrine Society.
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By Guest Nicole
Researchers at University of California, San Diego School of Medicine report that higher levels of vitamin D - specifically serum 25-hydroxyvitamin D - are associated with a correspondingly reduced risk of cancer. The findings are published in the April 6, online issue of PLOS ONE.
"We have quantitated the ability of adequate amounts of vitamin D to prevent all types of invasive cancer combined, which had been terra incognita until publication of this paper," said Cedric Garland, DrPH, adjunct professor in the UC San Diego School of Medicine Department of Family Medicine and Public Health and member of Moores Cancer Center at UC San Diego Health.
Garland and his late brother, Frank, made the first connection between vitamin D deficiency and some cancers in 1980 when they noted populations at higher latitudes (with less available sunlight) were more likely to be deficient in vitamin D, which is produced by the body through exposure to sunshine, and experience higher rates of colon cancer. Subsequent studies by the Garlands and others found vitamin D links to other cancers, such as breast, lung and bladder.
The new PLOS ONE study sought to determine what blood level of vitamin D was required to effectively reduce cancer risk. The marker of vitamin D was 25-hydroxyvitamin D, the main form in the blood. The researchers employed a non-traditional approach, pooling analyses of two previous studies of different types: a randomized clinical trial of 1,169 women and a prospective cohort study of 1,135 women. A clinical trial focuses upon whether a specific test or treatment is safe and effective. A prospective study looks for outcomes during the study period, in this case incidence of cancer among participants.
By combining the two studies, the researchers obtained a larger sample size and a greater range of blood serum levels of 25-hydroxyvitamin D or 25(OH)D.
The only accurate measure of vitamin D levels in a person is a blood test. In the Lappe trial cohort, the median blood serum level of 25(OH)D was 30 nanograms per milliliter. In the GrassrootsHealth prospective cohort, it was higher: 48 ng/ml.
The researchers found that the age-adjusted cancer incidence was 1,020 cases per 100,000 person-years in the Lappe cohort and 722 per 100,000 person-years in the GrassrootsHealth cohort. Cancer incidence declined with increased 25(OH)D. Women with 25(OH)D concentrations of 40 ng/ml or greater had a 67 percent lower risk of cancer than women with levels of 20 ng/ml or less.
Recommended blood serum levels of vitamin D have been a source of vigorous debate in recent years. In 2010, the Institute of Medicine (IOM) concluded that levels lower than 12 ng/ml represented a vitamin D deficiency and recommended a target of 20 ng/ml, which could be met in most healthy adults (ages 19 to 70) with the equivalent of 600 International Units of vitamin D each day.
Subsequently, other groups have argued for higher blood serum levels: 50 ng/ml or more. Above 125 ng/ml, there may be side effects. Many vitamin D supporters now advocate 800 to 1,000 IUs daily; more for persons older than 70 and pregnant or lactating women.
Garland does not identify a singular, optimum daily intake of vitamin D or the manner of intake, which may be sunlight exposure, diet and/or supplementation. He said the current study simply clarifies that reduced cancer risk becomes measurable at 40 ng/ml, with additional benefit at higher levels.
"These findings support an inverse association between 25(OH)D and risk of cancer," he said, "and highlight the importance for cancer prevention of achieving a vitamin D blood serum concentration above 20 ng/ml, the concentration recommended by the IOM for bone health."
Garland said a broad effort to increase 25(OH)D concentrations to a minimum of 40 ng/ml in the general population would likely and substantially reduce cancer incidence and associated mortality.
"Primary prevention of cancer, rather than expanding early detection or improving treatment, will be essential to reversing the current upward trend of cancer incidence worldwide," the researchers wrote. "This analysis suggests that improving vitamin D status is a key prevention tool."
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