Feb. 23, 2007 -- Vitamin D, taken in a high dose, may help prevent falls in the elderly.
That finding comes from a study of 124 residents of a Boston nursing home.
The study shows that residents who took a daily dose of 800 international units (IU) of vitamin D for five months were less likely to fall than those who took either lower doses or no vitamin D.
"Ensuring that nursing home residents are receiving adequate daily supplemental vitamin D may reduce the number of falls in elderly nursing home residents and could potentially reduce the risk of fracture in this high-risk group," write the researchers.
They included Kerry Broe, MPH, of the Institute for Aging Research at Hebrew SeniorLife in Massachusetts. Hebrew SeniorLife operates senior health care, housing, research, and education in the Boston area.
The study appears in the Journal of the American Geriatrics Society.
About Vitamin D
Vitamin D acts in the body as a hormone. Its tasks include keeping bones strong by boosting their calcium absorption.
Vitamin D may also help muscle function, Broe's team notes.
The body makes vitamin D when exposed to sunlight. But that ability fades with age, leaving older adults at risk of vitamin D deficiency.
Vitamin D is also found in some foods, including milk fortified with vitamin D, cod liver oil, salmon, tuna, and eggs.
Participants in Broe's study were 89 years old, on average. Most were white women. All lived at a long-term care facility run by Hebrew SeniorLife.
Sixty-two percent of the group had fallen in the year before the study.
When the study started, 63% of participants were taking a multivitamin. But 57% of the entire group -- and 54% of those taking a multivitamin -- had low blood levels of vitamin D.
Vitamin D Supplements
Participants were randomly assigned to take vitamin D or an empty pill (placebo) for five months.
Those taking vitamin D were given one of four daily doses: 200 international units (IU), 400 IU, 600 IU, or 800 IU.
No one knew what dose they were taking, or whether they were taking the placebo.
Participants were allowed to keep taking multivitamins during the study, if they wanted to, but the researchers didn't supply anyone with multivitamins.
Currently, the Institute of Medicine says 600 IU of vitamin D per day is "adequate" for men and women 71 or older.
The nursing home was required to keep records of residents' falls. During the five-month study, 61 participants (59%) suffered falls.
The group taking 800 IU of vitamin D daily was the only one to show a reduced fall risk. They were 72% less likely to fall during the study period than those taking the placebo.
None of the other vitamin D doses were associated with reduced falls.
These results held when the researchers took age, BMI (body mass index), and other factors into account.
People can fall for many reasons; and it's not certain vitamin D was the sole reason for the drop in falls for residents taking 800 IU of vitamin D daily.
While the data doesn't show how much vitamin D participants got from their diet or sunshine, intake from those sources was probably "minimal," write the researchers.
Too Much of a Good Thing?
Vitamin D is one vitamin you shouldn't overdo. The body stores vitamin D in fat, and it can be unhealthy to let too much of the vitamin build up in the body.
The tolerable upper limit for daily vitamin D intake is 2,000 IU for adults 19 and older, according to Institute of Medicine standards.
Sunshine and diet are much less likely to cause excessive vitamin D levels than supplements, unless you're consuming lots of cod liver oil, according to the Office of Dietary Supplements, part of the National Institutes of Health.
None of the nursing home residents had excessive vitamin D levels during the study.