Recent research on the numerous benefits of Vitamin D
by Newsletter Editor
Vitamin D improves eye health
Doctors gave older mice vitamin D or a placebo for six weeks and found less inflammation, fewer protein deposits, and better retina function for vitamin D. Researchers also found fewer protein deposits in blood vessels, suggesting vitamin D may help prevent a range of age-related health issues.
Reference: Neurobiology of Aging; 2012, Vol. 33, No. 10, 2382-2389
Vitamin D reduces the risk of fibroids
Fibroids are non-cancerous tumors that form a mass in the uterus of premenopausal women. In this study, doctors measured vitamin D levels and sun exposure in 1,036 black and white women, aged 35 to 49, and used ultrasound to detect uterine fibroids. Half of the white women had sufficient levels of vitamin D, which doctors said was at least 20 nanograms per milliliter of blood, while 10 percent of black women had sufficient levels. Compared to those whose vitamin D levels were low, women with sufficient circulating vitamin D levels were 32 percent less likely to have a fibroid, regardless of race. In 2011, the U.S. increased its recommended dietary allowance for vitamin D to 600 IU per day for most people.
Reference: Epidemiology; 2013, Vol. 24, No. 3, 447-53
Low vitamin D levels linked to Alzheimer’s disease
In one study, doctors measured vitamin D in the diets of 498 women who were not taking vitamin D supplements and who did not have Alzheimer’s disease (AD) or other dementias at the start of the study. After seven years of follow-up, researchers divided the women into three groups; those who had developed AD, those who developed other dementias, and those who had not developed dementia.
Doctors found a direct link: as levels of vitamin D increased, chances of developing AD decreased. Women who got the most vitamin D—the top 20 percent—were 77 percent less likely to develop AD compared to all other women who got lower amounts of vitamin D.
Reference: The Journals of Gerontology Series A: Biological Sciences and Medical Sciences; 2012, Vol. 67, No. 11:1205-11
Vitamin D reduces cognitive decline
Doctors in a study measured vitamin D levels and cognitive performance in 6,257 older women still living independently in their communities. Women with the lowest levels of vitamin D—10 to 25 nanograms per milliliter of blood (ng/mL)—were much more likely to be cognitively impaired than women with more than 30 ng/mL of vitamin D. Four years later, doctors found that women with less than 20 ng/mL of vitamin D were much more likely to have experienced cognitive decline compared to the start of the study, while women with higher vitamin D levels were much more likely to have maintained cognitive function.
Reference: The Journals of Gerontology Series A: Biological Sciences and Medical Sciences; 2012, Vol. 67, No. 10, 1092-8
Vitamin D lowers chances of cardiovascular disease
Doctors said when vitamin D is deficient, chances for metabolic syndrome increase. Metabolic syndrome is a factor in cardiovascular disease (CVD). In one study, researchers measured vitamin D levels in 5,559 Korean men and women, aged at least 50, with CVD symptoms including chest pain, heart attack or stroke. Compared to those with the highest levels of vitamin D, those severely deficient in vitamin D—meaning 25 nanomoles per liter of blood (nmol/L) or less—were twice as likely to have CVD. This group also had other CVD factors including larger waist size, higher blood sugar levels, total circulating fats, and lower levels of HDL, the “good” cholesterol. Compared to those who were severely deficient, those with the highest levels of vitamin D—75 nmol/L or more—were half as likely to have CVD. According to doctors, Koreans have far less CVD than the older U.S. population.
Reference: Nutrition Research and Practice, 2012 Apr; 6(2), 162-8
Vitamin D reduced respiratory infections in kids by half
Recent evidence has shown that vitamin D is important not only for developing bones, but also for strengthening immune systems. Because the body produces vitamin D from the sun, it is particularly important to maintain good levels in winter months. This study took place in a northern climate, where vitamin D deficiency is common in winter. At the start of the study, all the 250 children who participated were very low in vitamin D. The children drank locally produced milk with or without 300 IU of added vitamin D per day. Over the course of the winter, parents of children in the vitamin D group reported about half the number of respiratory infections as parents of kids in the placebo group. In discussing their findings, doctors said the large benefit they saw was due to the very low levels of vitamin D at the start of the study, and suggest further study to determine the best level of vitamin D.
Reference: Pediatrics. 2012 Sep; 130 (3): e561-7
Overweight kids deficient in vitamin D
Doctors in one study compared vitamin D levels in 411 obese kids to 87 normal-weight kids, aged 6 to 16. Children told researchers about their daily diets including soda, juice, milk, fruit and vegetables, as well as how often they skipped breakfast. Half of the obese children were deficient in vitamin D compared to 22 percent for normal-weight kids, and 92 percent were low in vitamin D, compared to 68 percent for normal-weight kids. The more kids skipped breakfast, and drank soda and juice, the lower the levels of vitamin D. Obese kids were also more likely to show signs of insulin resistance, and doctors said that while this study does not prove a cause-and-effect relationship, they suspect low vitamin D levels may play a role in developing type 2 diabetes.
Reference: Journal of Clinical Endocrinology and Metabolism; 2012, Vol. 97, No. 1, 279-85