ORLANDO, Fla. — Vitamin D deficiency is likely the most common medical condition worldwide, and treatment requires a combination of proper diet, supplementation and “sensible” sun exposure, according to a speaker here.
Speaking at the AACE Annual Scientific and Clinical Congress, Michael F. Holick, PhD, MD, professor of medicine, physiology and biophysics and director of the general clinical research unit and the Bone Health Care Clinic at Boston University Medical Center, outlined the many “myths” surrounding vitamin D, including a commonly held belief that high levels of vitamin D supplementation can cause toxicity, leading to hypercalcemia.
Michael F. Holick
In fact, it is very difficult to become vitamin D intoxicated, and most infants, children and adults fall far short of where their 25-hydroxyvitamin D levels should be, Holick said. The health risks of vitamin D deficiency are far greater than many realize.
Vitamin D does not affect only bone health, Holick said.
“Rickets is the tip of the iceberg,” Holick said during his presentation. “Osteomalacia, diabetes, multiple sclerosis, rheumatoid arthritis, infectious diseases, hypertension, heart disease, common cancers, have all been associated with vitamin D deficiency.”
Deficiency in vitamin D has been associated with other conditions as well, Holick said, including dementia, schizophrenia, and pregnancy complications ranging from low birth weight to preeclampsia. Proper supplementation has been shown in studies to improve bone health, muscle strength and even physical performance, he said.
Holick recommended that most adults get between 2,000 and 3,000 IU vitamin D daily from a combination of dietary sources, sensible sun exposure and supplementation; children should receive 1,000 IU daily.
For infants, human breast milk, does not provide an adequate amount of vitamin D.
“If you give an infant human breast milk as their sole source of nutrition, that infant will be vitamin D deficient for that period of time,” Holick said.
The assay for 25-(OH)D is one of the most ordered assays by clinicians in the U.S., Holick said; however, not everyone needs to be screened for deficiency.
“We do not recommend that we screen everybody for 25-(OH)D, but only those who are at risk,” Holick said. “We should be improving their vitamin D status with supplementation.”
Sensible sun exposure — along with sunscreen — is a key component of proper vitamin D supplementation, Holick said, and noted that vitamin D from sun exposure lasts two times longer than that from supplements.
“The skin has a huge capacity to make vitamin D,” Holick said. “In 15 to 20 minutes, you can raise blood levels of 25-(OH)D.”
Food, Holick said, can be a rare source for vitamin D, though certain fish, such as wild caught (not farmed) salmon, do contain vitamin D.
Obesity, too, can lead to vitamin D deficiency, he said.
“The higher your BMI, the lower your 25-(OH)D,” Holick said. “Obese people need 2 to 3 times more [vitamin D] to satisfy that vitamin D requirement.”
The goal for most adults should be at least 30 ng/mL, although between 40 ng/mL and 60 ng/mL is preferred, according to Holick, who said he takes between 3,000 and 4,000 IU daily, and his level is about 55 ng/mL.
“Vitamin D deficiency is critically important from birth until death,” Holick said. “Vitamin D is a disease of the blood. There is a mountain of evidence linking it to these chronic illnesses.”
“We need sensible sun [exposure] and vitamin D supplementation,” Holick said. “It is not a hypothesis.” – by Regina Schaffer
Holick, M. The D-Lightful Vitamin D for Health: Truths and Myths. Presented at: The American Association for Clinical Endocrinologists Annual Scientific & Clinical Congress; May 25-29, 2016; Orlando, Fla.
Disclosure: Holick reports consulting for Quest Diagnostics and Ontometrics, Inc.