Vitamin D: Bone Builder,
But Are There More Benefits?

Vitamin D has long been known as a vital element for bone health. Evidence for its role alongside calcium in supporting bone density and decreasing falls and fractures in the elderly has widespread acceptance while additional benefits remain controversial.

First, the benefit on which nearly all experts agree is its role as a key partner with calcium in bone metabolism. From the American Geriatrics Society comes a practice guideline sponsored by a multisociety panel for use of vitamin D.1

Key Areas of Guidance

Recommend an average daily intake from all sources of 4,000 IU of vitamin D3 for all older adults. This level of vitamin D intake should result in approximately 92% of older adults in the United States achieving target 25 hydroxyvitamin D, or 25(OH)D, levels regardless of skin pigmentation, obesity, or sun exposure.

According to the guidelines, clinicians are strongly advised to recommend vitamin D supplementation of at least 1,000 IU per day, as well as calcium supplementation, to community-dwelling older adults aged 65 and older to reduce the risk of fractures and falls. (Supplemental calcium doses in most studies range between 500 and 1,200 mg daily.)

Clinicians should review older adults’ vitamin D intake from all sources, including diet, supplements, and sunlight, and discuss strategies to achieve a total vitamin D input associated with fall and fracture prevention. Dietary sources such as salmon, tuna, mackerel, sardines, and shiitake mushrooms provide about 200 IU per serving. Milk products and fortified yogurts provide about 100 IU per 8-oz (240-cc) serving.

Routine laboratory testing for 25(OH)D serum concentrations before beginning supplementation is not necessary, according to the guidelines.

It is likewise unnecessary for clinicians to routinely monitor 25(OH)D for safety or efficacy when supplementation is within the recommended limits.

For high-risk patients, a serum 25(OH)D concentration of 30 ng/mL (75 nmol/L) should be a minimum goal for older adults, particularly for frail adults, who are at higher risk for falls, injuries, and fractures.

Special populations requiring dose increase and/or monitoring dose according to serum 25(OH)D include the following:

• those with dark skin pigmentation;
• those taking specific medications;
• those taking agents that bind vitamin D in the gut (eg, cholestyramine);
• those taking agents that accelerate the breakdown of vitamin D (eg, inducers of the cytochrome P450 pathway such as phenytoin and phenobarbital); and
• those with malabsorption syndromes.

More recently, it seems there are claims that vitamin D does far more than merely keep bones strong. Vitamin D supplementation has been suggested to affect everything from depression to cancer and dementia. For these conditions, most of the claims are based on observational studies rather than controlled trials. So more research is needed to reach firm conclusions. However, keep in mind that there is little risk of harm from taking the recommended doses of vitamin D discussed here.

— Rosemary Laird, MD, MHSA, AGSF, is a geriatrician, executive medical director of senior services for Florida Hospital at Winter Park, and past president of the Florida Geriatrics Society. She is a coauthor of Take Your Oxygen First: Protecting Your Health and Happiness While Caring for a Loved One With Memory Loss.

Reference

1. American Geriatrics Society Workgroup on Vitamin D Supplementation for Older Adults. Recommendations abstracted from the American Geriatrics Society Consensus Statement on Vitamin D for Prevention of Falls and Their Consequences. J Am Geriatr Soc. 2014;62(1):147-152.