Researchers have discovered multiple health risks associated with vitamin D deficiency. Vitamin d deficiency is now believed to be a global health issue that can affect overall health and well-being and lead to a variety of health issues.
Investigators from the International Osteoporosis Foundation published findings that vitamin D deficiency has severe repercussions for increasing risk of fracture from poor bone health worldwide. The study, published in the scientific journal Osteoporosis International, suggested that vitamin D deficiency is a global problem, regardless of arguments about dosing guidelines. The highest rates of vitamin D deficiency were discovered in South Asia and the Middle East.
Vitamin D deficiency has been linked to inability to lose weight. Researchers from the University of Minnesota found a linear relationship between higher vitamin D levels and weight loss, combined with a low calorie diet. Shalamar Sibley, MD, MPH, an assistant professor of medicine at the University of Minnesota concluded from the study, "Our results suggest the possibility that the addition of vitamin D to a reduced-calorie diet will lead to better weight loss.", though more studies were suggested. The findings were presented at The Endocrine Society's 91st Annual Meeting in Washington, D.C. this year.
The Journal of Alzheimer's Disease (May 2009), linked Alzheimer’s disease to low levels of the vitamin. The article, "Does Vitamin D Reduce the Risk of Dementia?" by William B. Grant, PhD looked at previous studies showing that vitamin D can protect the brain from inflammation, an important contributor to Alzheimer’s disease. Alzheimer’s disease is also linked to tooth loss from lack of bone density. The study suggested more studies are needed to define the link between vitamin D deficiency and dementia.
The Moores Cancer Center at the University of California, San Diego explored the link between low levels of vitamin D and cancer. The study, published online May 22, 2009 in the Annals of Epidemiology, reported the link between cancer and vitamin D had been proven in over 200 epidemiological studies, with the physiologic basis confirmed in over 25000 lab studies.
Asthma severity was also linked to low levels of vitamin D in a study published May 2009 in the American Journal of Respiratory and Critical Care Medicine. It is difficult to know how much vitamin D to take. Graham Devereux, M.D., of the Department of Environmental and Occupational Medicine at the University of Aberdeen in the accompanying editorial in the same issue of the journal said, "Ultimately, it is only by investigating the effects of vitamin D in doses at, and above, those currently recommended that decisions can be made on the optimal intake of vitamin D and the possible prevention and treatment of asthma.” Research regarding optimal vitamin D levels is sorely needed.
In March, a study from the Mayo Clinic showed that chronic pain sufferers might benefit from higher levels of vitamin D. Michael Turner, M.D., a physical medicine and rehabilitation physician at Mayo Clinic and lead author of the study wrote, "Vitamin D is known to promote both bone and muscle strength. Conversely, deficiency is an under-recognized source of diffuse pain and impaired neuromuscular functioning. By recognizing it, physicians can significantly improve their patients' pain, function and quality of life."
Adolescents were found to suffer higher rates of obesity in association with lower vitamin D levels. Researchers from the Medical College of Georgia found that teens age 14 to 19 were slimmer when their vitamin D levels were higher. Dr. Yanbin Dong, a molecular geneticist and cardiologist at the MCG Gerogia Prevention Institute explained, "As humans, our largest source of vitamin D should be the sun. But we don't spend enough time outdoors to get enough sun exposure and when we do, we're often covered up and wearing sunscreen," she said. "We can get vitamin D from certain foods, like fatty fish and liver, but it's not in a lot of foods that we commonly consume. In this country, our milk is fortified with vitamin D. Unfortunately, teens just don't drink enough milk to get their daily requirements."
Colds and flu
Vitamin D deficiency was also found to be linked to increased chances of colds and flu – an important message for the impending threats each flui season. Investigators from the University of Colorado Denver (UC Denver) School of Medicine, Massachusetts General Hospital (MGH) and Children's Hospital Boston suggest that vitamin D plays an important role for boosting immunity. The report, published February 23 in the Archives of Internal Medicine, also showed that vitamin D can help prevent respiratory infection, again important for risk of developing flu complications, and for those with asthma and emphysema. Vitamin D levels of 40 or higher were associated with a forty-percent reduced risk of respiratory infection in an analysis of adult and adolescents chosen from the Third National Health and Nutrition Examination Survey (NHANES III).
Muscle power was found to be reduced in adolescent girls with lower vitamin D levels. The study showing that vitamin D is linked to increased strength appeared in the Journal of Clinical Endocrinology and Metabolism. Adolescent girls with the highest vitamin D levels outperformed those with lower levels in jump height, power, force and speed.
Increased fracture risk for elders
Findings published in the March 23 issue of Archives of Internal Medicine showed that low vitamin D levels are associated with increased risk of fracture among elders. The study did not suggest vitamin D therapy for elders, but the authors did say that higher doses of vitamin D should be further researched.
Lower birth weight
Low vitamin D levels during early pregnancy could also lead to lower birth weight, found in a January 2013 published study. Infants whose mother's had levels less than 0.015 parts per million were found to have infants weighing 1.6 pounds lower than normal.
Higher chance of cancer for smokers
A first of a kind study published March 14, 2013 in the journal Clinical Chemistry suggested low vitamin D could raise risk of tobacco related cancer for smokers.
“Our analyses show that the association between lower concentrations of plasma vitamin D and higher risk of cancer may be driven by tobacco-related cancer as a group, which has not been shown before,” stated author Børge G. Nordestgaard, MD, DMSc, in the paper. “This is important for future studies investigating the association between plasma vitamin D and risk of cancer.”
Research suggests vitamin D may have an anti-cancer effect, but smoking interferes with metabolism and function of the vitamin and may lead to decreased levels. Authors of the paper say a simple blood test could help improve health for smokers in the report, titled "Low Plasma 25-Hydroxyvitamin D and Risk of Tobacco-Related Cancer".
Can you get too much vitamin D?
There is now some research suggesting too much vitamin D during pregnancy might raise risk of food allergy for offspring during infancy and early childhood. Researchers from Leipzig Helmholtz Centre for Environmental Research – UFZ suggest vitamin D supplements should be avoided during pregnancy, based on study findings published February, 2013.
Women with high vitamin D levels during pregnancy were more likely to have babies with allergies to foods like egg white, milk protein, wheat flour, peanuts or soy beans in the analysis, published in the journal Allergy.
One study hints at the possibility that too much vitamin D could promote heart disease through inflammatory pathways. In a January 2012 study analysis, Johns Hopkins researchers found a possible, but not proven link between too much vitamin D and heart risks. The finding was published in the American Journal of Cardiology.
Researchers at the Intermountain Heart Center linked higher vitamin D levels to heart rhythm disturbance known as atrial fibrillation. In the study, people whose levels were 100 nanograms/100ml/dl were two and a half times more likely to have atrial fibrillation than patients whose level was normal, which is between 41 and 80 nanograms per 100ml
Evidence continues to mount that low vitamin D levels are linked to increased health risks. How much vitamin D is best for optimal health is still the subject of debate. Vitamin D levels can be measured by your physician with a simple blood test. If you feel you are deficient, ask your doctor for a test and recommendation for a vitamin D supplement that could improve overall health and well-being.
This page updated April 11, 2013
"Study links excess vitamin D levels with onset of atrial fibrillation"
The American Journal of Cardiology
“Relation Between Serum 25-Hydroxyvitamin D and C-Reactive Protein in Asymptomatic Adults (From the Continuous National Health and Nutrition Examination Survey 2001 to 2006)”
Muhammad Amer et al.
Published online October, 2011
European Journal of Allergy and Clinical Immunology
"Maternal and newborn vitamin D status and its impact on food allergy development in the German LINA cohort study"