The question of what constitutes an “adequate” blood level of vitamin D is a “controversial topic,” according to Manson.
In the study, the team found that 2000 IU per day was “very safe,” without side effects or adverse events.
“Blood levels for deficiency and recommended blood levels vary across organizations, labs and countries, which is one of the reasons for doubt about the test’s usefulness,” Manson said.
The U.S. Preventive Services Task Force and most professional societies in the U.S. do not recommend universal screening for vitamin D blood levels or routine use of vitamin D supplements, the researcher pointed out.
“Vitamin D tamps down inflammation, a major cause of telomere shortening and chronic diseases of aging.”
“The National Academy of Medicine recommends 600 IU of vitamin D per day for adults up to age 70 and 800 IU above age 70, stating that these intakes will meet the requirements of the large majority of adults in the population,” she said.
“However, recent guidelines from the Endocrine Society suggest that vitamin D supplements may be helpful for adults aged 75 and older, infants and children, pregnant women, and those with a diagnosis of prediabetes, but they don’t specify a specific dose.”
For anyone who has concerns about getting adequate vitamin D from their diet and/or time outdoors, Manson said that supplementation with 1000 to 2000 IU/day of vitamin D would be “very reasonable.”
“In the U.S., foods such as dairy products, cereal and orange juice are often fortified with vitamin D, so checking nutrition labels can help you make better decisions about which foods to purchase,” she advised.
“Fatty fish, such as salmon, sardines and tuna, and wild mushrooms are other sources.”
Groups at high risk for vitamin D deficiency include those living in nursing homes, people with malabsorption conditions like Crohn’s or celiac disease, those being treated for osteoporosis or other bone health problems, and those with major dietary restrictions, such as severe lactose intolerance, according to Manson.
