Over the last decade, numerous studies have shown that many Americans have low vitamin D levels and as a result, vitamin D supplement use has climbed in recent years. Vitamin D has been shown to boost bone health and it may play a role in preventing diabetes, cancer, cardiovascular disease and other illnesses. In light of the increased use of vitamin D supplements, Mayo Clinic researchers set out to learn more about the health of those with high vitamin D levels. They found that toxic levels are actually rare. Their study appears in the May issue of Mayo Clinic Proceedings. A vitamin D level greater than 50 nanograms per milliliter is considered high. Vitamin D levels are determined by a blood test called a serum 25-hydroxyvitamin D blood test. A normal level is 20-50 ng/mL, and deficiency is considered anything less than 20 ng/mL, according the Institute of Medicine (IOM). The researchers analyzed data collected between 2002 and 2011 from patients in the Rochester Epidemiology Project, a National Institutes of Health-funded medical records pool that makes Olmsted County, Minn., the home of Mayo Clinic, one of the few places worldwide where scientists can study virtually an entire geographic population to identify health trends.
Of 20,308 measurements, 8 percent of the people who had their vitamin D measured had levels greater than 50 ng/mL, and less than 1 percent had levels over 100 ng/mL. "We found that even in those with high levels of vitamin D over 50 ng/mL, there was not an increased risk of hypercalcemia, or elevated serum calcium, with increasing levels of vitamin D," says study co-author Thomas D. Thacher, M.D., a family medicine expert at Mayo Clinic. Hypercalcemia, or high blood calcium, can occur when there are very high levels of vitamin D in the blood. Too much calcium in the blood can cause weakness, lead to kidney stones, and interfere with the heart and brain, and even be life threatening. The Mayo researchers also found that women over age 65 were at the highest risk of having vitamin D levels above 50 ng/mL. The result was not surprising because that's a group that often takes vitamin D supplements, Dr. Thacher says. Another notable outcome: The occurrence of high vitamin D levels over 50 ng/mL increased during the 10-year period of the study, from nine per 100,000 people at the start of the study up to 233 per 100,000 by the end.
"We were surprised by that degree of dramatic increase in vitamin D levels," Dr. Thacher says. Only one case over the 10-year study period was identified as true acute vitamin D toxicity; the person's vitamin D level was 364 ng/mL. The individual had been taking 50,000 international units (IU) of vitamin D supplements every day for more than three months, as well as calcium supplements. The IOM-recommended upper limit of vitamin D supplementation for people with low or deficient levels is 4,000 IU a day. It's important for doctors to ask their patients about the doses of vitamin D supplements that they are using, Dr. Thacher says, because even capsules containing as much as 50,000 IU of vitamin D are available without prescription. If taken on a daily basis, that amount could lead to toxicity. Some natural sources of vitamin D include oily fish such as mackerel and salmon, fortified milk, and sunlight. "Our bodies will naturally produce vitamin D when our skin is exposed to sunlight, however, we don't recommend excessive exposure to sun due to the risk of skin cancer," Dr. Thacher added.
In an accompanying editorial in Mayo Clinic Proceedings, Dr. Michael F. Hollick, Ph.D., M.D., describes vitamin D's dramatic medical history, the need for judicious dosing, but the importance of vitamin D supplementation in those with low or deficient levels. "The evidence is clear that vitamin D toxicity is one of the rarest medical conditions and is typically due to intentional or inadvertent intake of extremely high doses," writes Hollick, a professor of medicine, physiology and biophysics at Boston University School of Medicine. More than one-third of Division I college athletes may have low vitamin D levelsGetting enough vitamin D each day could prevent some men from suffering from erectile dysfunction (ED), a new study suggests. Researchers at Johns Hopkins University analysed data from 3,400 men aged 20 and older who took part in the national Health and Nutrition Examination Survey. They found that men were more likely to suffer from ED if they suffered from vitamin D deficiency when compared to men who got the recommended amount of the "sunshine vitamin" each day.
"Checking vitamin D levels may turn out to be a useful tool to gauge ED risk," lead investigator Erin Michos commented on the study. The study found that vitamin D deficiency - defined as vitamin D levels below 20 nanograms per millilitre of blood - was present in 35% of men with ED, compared with 29% of men without ED. After the researchers took other factors known to lead to impotence into account - including certain medications, alcohol use, smoking, diabetes, inflammation and high blood pressure - they estimated that men who suffer from vitamin D deficiency are 32% more likely to have ED than men with adequate vitamin D levels. According to the Johns Hopkins University report, risk factors for vitamin D deficiency include being obese or overweight, undergoing limited outdoor activity, having darker skin and suffering from certain from inflammatory conditions, such as diabetes and inflammatory bowel disease. The good news is that ED can be fairly simple to treat if vitamin D deficiency is the root cause.
The study reads: "Vitamin D deficiency is easy to screen for and simple to correct with lifestyle changes that include exercise, dietary changes, vitamin supplementation and modest sunlight exposure." It's worth noting though that vitamin D deficiency may not be the only thing causing your ED. Other underlying causes can include hormonal problems, high cholesterol, diabetes, relationship problems, anxiety and depression, so it's important to visit your GP if you're suffering.More than 18 million men suffer from erectile dysfunction (ED), affecting more than 40 percent of men over the age of 40. Causes of ED are often related to vascular disorders, which are increased among men who have cardiovascular disease, diabetes, or are overweight or obese. Some men are affected by ED due to hormone imbalances, emotional distress, or nutrient deficiencies. New research is finding that low levels of vitamin D may contribute to erectile dysfunction. Researchers analyzed data from more than 3,000 men aged 20 years or older, who had not been diagnosed with heart disease.
Vitamin D deficiency was observed in 35 percent of the men with erectile dysfunction compared to 29 percent of men without ED. The researchers concluded that men with ED were 32 percent more likely to have low vitamin D even after accounting for other factors that affect impotence, such as alcohol consumption, smoking, diabetes, hypertension, inflammation, and medications. While the study is considered preliminary, it comes as good news to many men who suffer from ED for reasons that have been difficult to identify. Vitamin D levels are easy to assess and restore. Vitamin D status may be improved with exposure to natural sunlight, a more balanced diet, and vitamin D supplements. Vitamin D may also just be one among many factors contributing to erectile dysfunction such as insufficient levels of arginine or low testosterone. L-arginine is an amino acid produced by the body that is essential to the production of nitric oxide (NO). NO is vital to arterial blood flow, helping the blood vessels relax so that more oxygen-rich blood can circulate through the arteries.
Healthy blood flow is a major factor in the achievement and maintenance of an erection. Supplementing L-arginine can help maintain adequate levels and keep production of NO up, as well as incorporating arginine-rich foods like pork loin, turkey, pumpkin seeds, and chickpeas. Testosterone plays a role in modulating male sexual function, including regulation of an erection. Low testosterone have can have a substantial negative impact on the structure of penile tissues and the nerves necessary for an erection to occur. Testosterone levels may be restored safely and effectively with bioidentical hormone replacement therapy. It is rare that ED is linked to a single factor. The most important first step to developing an effective treatment for erectile dysfunction is finding the root cause of the issue. For some men that may be vascular issues related to other diseases or conditions, like high blood pressure, heart disease, diabetes, or obesity. For some men, it may be a nutritional deficiency, such as low vitamin D or L-arginine.