Long-time attributed benefits of vitamin D facing more doubts

A recent study has cast doubt on some of the benefits of vitamin D, but it is still recommended for some older adults.
A recent study has cast doubt on some of the benefits of vitamin D, but it is still recommended for some older adults.

By David Wilkening
Contributing Writer

REGION – The “sunshine” vitamin’s bright reputation as a long-standing panacea for various health issues has been further dimmed by a nationally recognized study by Brigham and Women’s Hospital.

The results raised the question reinforced recently by other studies: Is vitamin D overrated?

It was the first large, randomized study in the US, funded by the federal government. Researchers found that vitamin D pills taken with or without calcium had no effect on bone fracture rates. It also found the same results for people with osteoporosis and even those whose blood tests deemed them vitamin D deficient.   

That was a major finding of the study published in the New England Journal of Medicine. There remain various benefits from vitamin D, however.

No support for many vitamin D benefits

But the study results also found no support for other conclusions for a long list of purported benefits of vitamin D supplements. This was reported to be a surprise not only for the study researchers but also for long-time advocates of the sunshine vitamin. 

Noted benefit exceptions included patients with conditions like celiac or Crohn’s Disease who need vitamin D supplements. Also, those who live in conditions where they are deprived of sunshine and may not eat enough foods routinely supplemented with vitamin D.

An editorial published with the report urged millions of Americans taking vitamin D supplements to stop. Doctors also often check for vitamin D levels as part of routine blood tests.

“Providers should stop screening for 25 hydroxyvitamin D levels or recommending vitamin D supplements in order to prevent major diseases or extend life,” wrote Dr. Clifford Rosen, an editor at the New England Journal of Medicine and Steven R. Cummings, a research  scientist at the California Pacific Medical Center Research Institute. 

The research shows that the study is taking a “strong stand” by “taking on vitamin sellers, testing labs and advocates who have claimed that taking vitamin D, often in large amounts, can cure or prevent a wide variety of ailments and even help people live longer,” wrote medical reporter Gina Kolata in The New York Times.

Study involved large group of healthy people

The new research was a study called VITAL. It involved 25,781 generally healthy participants―both men and women, aged 50 and over. They were assigned to take 2,000 international units of vitamin D daily or a placebo.

The benefits of vitamin D have been a popular subject of medical experts for years. One major media outlet wrote as recently as 2008 that it welcomed warmer summer weather because more people will get their vitamin D from the sun, which could help “ward off a number of serious diseases.” 

“Our skin uses the sun’s rays to make vitamin D. Without it, the body can’t absorb dietary calcium, so it steals calcium from bones, increasing the risk of osteoporosis and fractures,” wrote the Harvard Women’s HealthWatch.

“Researchers have found that it’s active in many other issues outside of bone health, including its helping to control many other tissues and cells and controls many genes, including some associated with cancer, autoimmune disease and infection….“Hardly a month goes by without news about the risks of too little vitamin D or about a potential role in warding off diseases, including breast cancer, multiple sclerosis, and even schizophrenia,” said HealthWatch.

The site said, “evidence is so compelling that some experts already recommend at least 800 to 1,000 IU of vitamin D per day for adults.”

Still recommended for some older adults

Dr. JoAnn Manson, the principal investigator for the VITAL study who heads the preventative health department at Brigham, said other studies are underway to determine healthy amounts of vitamin D and other issues associated with its use.

She also recommends older adults with osteoporosis, prior fracture, or other bone health problems, as well as those unable to spend time outdoors or to have adequate vitamin D intake from food, should seriously consider a supplement of at least 1000-2000 IU daily. 

“Some older adults have restricted diets and low food intake,” said Manson. “They may also have a problem with absorption of some vitamins and minerals, which can be a problem not only for vitamin D but also for calcium, B12, and other micronutrients. People who are lactose intolerant and don’t eat dairy products or other foods fortified with vitamin D will also benefit from supplements,” she explained. “Although we generally recommend that people try to obtain these nutrients from foods, many older adults may be unable to reach target vitamin D levels from foods alone, especially if they spend little time outdoors, and will benefit from taking vitamin D supplements.”

Regarding screening for vitamin D deficiency, it should not be done routinely in the generally healthy population, but those with bone health problems and those with low dietary intake of vitamin D and limited time outdoors, will benefit from the screening, Manson said.

During the pandemic, she generally recommends continued use of Vitamin D supplements of at least 1000-2000 IUs daily, “especially for older adults.”

Possible COVID benefit

“Some evidence suggests that vitamin D may boost immune function and tamp down excess inflammation, both of which may be important to avoiding more severe illness from COVID-19,” Manson explained.  “We and others are doing randomized clinical trials testing vitamin D in COVID.” She said there is so far no conclusive evidence available for its benefits for COVID. She said vitamin D is safe at those levels and acts a form of insurance during the pandemic.

One recent report found that an estimated one billion people worldwide had vitamin D deficiencies. The National Institutes of Health (NIH) recommends healthy adults take in 600 units a day. Foods rich in vitamin D include salmon, tuna, mackerel and milk. And also sunlight.

Medical experts suggest checking with a physician to determine whether you need supplements in addition to diet and exposure to the sun. 



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