04 October 2018
THURSDAY, Oct. 4, 2018 (HealthDay News) — Vitamin D supplements have long been touted as a way to improve bone health and possibly ward off the bone-thinning disease osteoporosis in older adults. But a new study contends that claims of benefits from supplements of the “sunshine vitamin” fall flat. A review of previously published studies found that taking either high or low doses of vitamin D supplements didn’t prevent fractures or falls, or improve bone density. Vitamin D is found in very few foods. One of the biggest sources of the vitamin is exposure to sunlight. “Vitamin D supplement use is common, particularly in North America,” where up to 40 percent of older people take them, said lead researcher Dr. Alison Avenell. She is clinical chair in health services research at the University of Aberdeen in Scotland. “Most adults don’t need to take vitamin D supplements, although they are unlikely to do harm if taken in low doses,” she added. Vitamin D supplements do prevent rare conditions, such as rickets in children and osteomalacia (softening of bones) in adults. People at risk of vitamin D deficiency include those with little or no sun exposure, such as nursing home residents who are indoors all the time, or those who always cover their skin when outside, Avenell said. There’s also existing evidence that vitamin D helps prevent cancer or heart disease, she added. “Preserving bone strength involves keeping active, not smoking, not being too thin, and taking medications for osteoporosis,” Avenell said. Based on the new findings, Avenell thinks guidelines that recommend vitamin D supplements for bone health should be changed. For the new report, Avenell and her colleagues reviewed 81 studies, most of which dealt with vitamin D alone, not in combination with the mineral calcium. “Calcium supplements on their own have minimal effect on bone mineral density and fracture, and may increase the risk of cardiovascular disease,” Avenell said. The only evidence that calcium and vitamin D together prevent fractures comes from a trial of older people with very low vitamin D levels in nursing homes. But calcium and vitamin D may also increase the risk of cardiovascular disease, Avenell said. In addition, most of the studies covered in the new review included women aged 65 and older who took more than 800 IUs (international units) of vitamin D daily. The new study found no meaningful effect of vitamin D supplementation when it came to reducing any fracture, hip fractures or falls. This type of study, called a meta-analysis, tries to find common elements among previously published studies. This kind or research, however, is limited by differences in the methods and conclusions of the different studies analyzed by researchers, so the findings may not be consistent across the board. Dr. Minisha Sood, an endocrinologist at Lenox Hill Hospital in New York City, said this new study should convince doctors that vitamin D supplements don’t have a role in maintaining healthy bones, but they do have other benefits. Previous research suggests that vitamin D, when taken in tandem with calcium, may help prevent certain cancers and protect against age-related declines in thinking and memory. “What is important to keep in mind is that those with low vitamin D were not represented in this meta-analysis, and vitamin D supplementation — repletion, actually — is still necessary for those with low vitamin D levels, regardless of age,” Sood said. The findings were published online Oct. 4 in The Lancet Diabetes and Endocrinology. More information For more on vitamin D, visit the U.S. National Institutes of Health.
15 March 2018
THURSDAY, March 15, 2018 (HealthDay News) — Your need for calcium gets a lot of attention, but your body can’t use it without its partner, vitamin D, according to the American Academy of Orthopaedic Surgeons. Most adults need 1,000 milligrams of calcium each day. Recommendations for vitamin D range from the current recommended daily allowance of 600 International Units (IUs), all the way up to 4,000 IUs to best support bone health. Adding key foods to your diet will help you get both these nutrients, which can take extra effort if you’re limiting calories to lose weight. Start with salmon, sardines and tuna, fatty types of fish that have both calcium and vitamin D. For other foods high in calcium, opt for more low-fat milk and yogurt, broccoli, kale, bok choy and other green leafy vegetables. Vitamin D is added to milk, but it isn’t found naturally in many foods other than egg yolks and shiitake mushrooms — a great vegetable for making low-cal dishes. Your body can make vitamin D from sun exposure, but that requires a careful approach to avoid increasing skin cancer risk. It’s also hard to get enough rays during winter months and in some parts of the country. Talk to your health care provider to find out what’s right for you. Many foods are now fortified with vitamin D, calcium or both. A great option is unsweetened almond milk. Some brands deliver half your daily calcium and a quarter of your vitamin D needs in a 30-calorie, 8-ounce glass. Always read nutrition labels because the amounts of these nutrients vary by product and by brand. The calcium content of a food must always be listed in the nutrient panel, but you’re likely to see the vitamin D content only on foods that are fortified with it. More information The American Academy of Orthopaedic Surgeons has more on daily requirements of calcium and vitamin D for different age groups and life stages.
09 January 2018
TUESDAY, Jan. 9, 2018 (HealthDay News) — High doses of vitamin D seem to keep arteries more flexible and pliable, potentially warding off future heart disease, heart attacks and strokes, preliminary research suggests. In just four months, vitamin D supplements reduced arterial stiffness in a group of 70 young black men and women, according to results from a small-scale clinical trial. The flexibility of participants’ arteries improved even more with higher doses of vitamin D, said senior researcher Dr. Yanbin Dong, a professor with the Medical College of Georgia at Augusta University, in Augusta. “Their arterial stiffness decreased, and the more vitamin D, the better,” Dong said. Vitamin D is known to be essential for bone health, but for the past couple of decades scientists have suspected it might be important in other ways, he said. “The vitamin D receptor is expressed everywhere in your body, in almost every single type of cell,” Dong said. “That’s why people think vitamin D might have something more to offer.” To see if the vitamin might improve the health of blood vessels, Dong and his colleagues recruited a group of overweight or obese black Americans who were deficient in vitamin D. Human skin naturally synthesizes vitamin D when exposed to bright sunshine. However, darker skin absorbs less sunlight, making black people more susceptible to vitamin deficiency, the researchers said. In addition, body fat tends to capture and hold vitamin D, also contributing to deficiency. The study participants were placed into four groups. Three groups took oral doses of vitamin D amounting to 600 international units (IU), 2,000 IU or 4,000 IU daily. The fourth group took inactive placebos. The National Academy of Medicine currently recommends that people get 600 IU of vitamin D daily, Dong said. The researchers chose 2,000 IU because they suspected that might be the best dose, and 4,000 IU because that’s the highest level before people start experiencing toxic effects. Also, previous studies have shown that, taken daily, 2,000 IU and 4,000 IU doses of vitamin D can bring a vitamin-deficient person’s levels of vitamin D back within a normal range, the study authors noted. Those in the study who took 4,000 IU daily — more than six times the currently recommended amount — experienced a 10.4 percent reduction in arterial stiffness within four months, the findings showed. Those who took 2,000 IU a day experienced a 2 percent decrease in arterial stiffness during the same timeframe. People who took the currently recommended dose of 600 IU had a slight increase in arterial stiffness — about 0.1 percent. Those who took the placebos had a 2.3 percent increase, according to the report. No toxic effects were observed among people who took the larger doses of the vitamin, Dong said. Vitamin D might help arterial health by blocking a hormone system that increases constriction of blood vessels, the researchers said. It also helps reduce inflammation, which has been linked to hardened arteries. Dong expects that some whites also would benefit from vitamin D supplementation. “We expect we would see similar effects in white people who have similar vitamin D deficiency and are overweight,” he said. However, taking handfuls of vitamin D will not excuse a person from eating right or exercising for their heart health, Dong added. “I don’t think vitamin D should be an alternative for any other lifestyle modifications,” Dong said. “We need to exercise, we need to eat sensibly. Vitamin D is just like anything else. It could be helpful on top of those things. It cannot replace.” These findings, however, present an opportunity to ward off heart disease in younger people at high risk, said Dr. Robert Eckel, director of the University of Colorado Hospital’s Lipid Clinic. Hardening of the arteries tends to be irreversible in older people who already have large amounts of arterial plaque as well as health problems such as diabetes and high cholesterol, Eckel said. This study, though, focused mainly on people in their 20s, he noted. “Looking at vitamin D earlier in life — before there’s a lot of cardiovascular disease on board — could be an encouraging improvement,” said Eckel, who was not involved with the new study. “We’re talking about primary prevention here.” The study participants should be tracked to see if their more flexible arteries translate to lower rates of heart disease and stroke later in life, Eckel said. Future trials should also examine the effects of vitamin D on other races and ethnic groups, he said. The study was published online recently in the journal PLOS One. More information The U.S. Office of Dietary Supplements has more on vitamin D.