Dietary Supplements for the Prevention of Falls

Question

Several dietary supplements claim to prevent falls. Does the evidence support the use of them?

Response from Aleah M. Rodriguez, PharmD
Natural Medicines Research Fellow, Instructor of Pharmacy Practice, Creighton University, Omaha, Nebraska

Of adults aged 65 years or older, 9.6% have reported falling at least once in the past 3 months.^[1] Besides leading to significant costs owing to emergency room visits, falls can affect a person's quality of life because of fractures and other complications. Dietary supplements, especially vitamin D, creatine, and vitamin B₁₂, are used for fall prevention. Evidence to support the use of these supplements varies.

Vitamin D

Vitamin D receptors are found on muscle tissue. Muscle atrophy has been observed in severe vitamin D deficiency, and supplementation with vitamin D has been shown to increase type II fast-twitch muscle fibers in vitamin D–deficient patients. This type of muscle fiber is the first to be recruited when a quick response, such as fall prevention, is needed.

Vitamin D supplementation has been shown to improve strength, function, and balance in older adults.^[2] These findings have led researchers to investigate whether vitamin D supplementation could reduce fall risk. Studies have varied on the type of vitamin D used (ergocalciferol [D₂] vs cholecalciferol [D₃]), dose and dosing frequency, route of administration, calcium coadministration, and study population (age, sex, community-dwelling versus institutionalized). The majority of studies have addressed the use of vitamin D in older (≥ 65 years) female patients. The results of these studies have been mixed.

Several meta-analyses have attempted to address the heterogeneity among these studies and analyze the combined data. The body of evidence suggests that vitamin D supplementation may reduce the risk for falls by 13%-14% with a number needed to treat of 15.^[3,4,5,6,7] Subgroup analyses suggest that patients with vitamin D deficiency (serum concentration < 12 ng/mL or < 30 nmol/L) or vitamin D insufficiency (serum concentration < 30 ng/mL or 75 nmol/L) can expect a 30%-47% reduction in fall risk.^[4,7]

The reduction in fall risk also appears to be greater with concomitant calcium supplementation; vitamin D plus calcium reduced the risk for falls by 17%-21% in vitamin D–replete (serum concentration > 30 ng/mL or 75 nmol/L) patients.^[3,5,7] Daily doses of vitamin D and calcium used in the trials ranged from 400-800 IU vitamin D₃ plus 500-1000 mg calcium.^[3] Vitamin D doses of at least 700-1000 IU orally once daily without calcium also reduced the risk for falls by 18%-19%, while doses less than 700 IU per day did not appear effective.^[6]

Vitamin D supplementation in community-dwelling patients reduced the risk for falls by 20%-21%.^[5,7] Supplementation in institutionalized patients does not appear effective, but there has been less research on this population.

Subgroup analyses found a statistically significant difference in fall risk reduction only with vitamin D₃ and not with vitamin D₂, although there were fewer studies with vitamin D₂. On the basis of this limited evidence, vitamin D₃ should be recommended over vitamin D₂.^[5]

Some studies have used intermittent, high-dose vitamin D such as vitamin D₂ (300,000 IU orally or intramuscularly once, or oral vitamin D₃ 500,000 IU annually). A meta-analysis of these studies found that these intermittent high doses were not effective for fall prevention. Most patients in these studies had sufficient vitamin D levels, but until more is known, this dosing schedule should be avoided. There is some concern that excessive vitamin D levels may negatively affect muscle function and that intermittent dosing may not adequately maintain plasma concentrations over the long term.^[8]

On the basis of these findings and the relative safety of vitamin D, vitamin D₃ 700-1000 IU once daily (with or without calcium) is a reasonable intervention for older adults to reduce fall risk, especially in patients who are vitamin D deficient/insufficient.

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