Older Adults & Vitamin D Deficiency

Many people know that vitamin D deficiency can affect bone health and lead to osteoporosis and hip fractures in older adults. Research is also finding possible links between vitamin D deficiency and other health conditions that primarily affect older adults. These include heart disease, diabetes, cancer and cognitive impairment.

Definitions

Vitamin D deficiency is measured through blood serum values. A value of less than 25 nanomoles per liter, or nmol/L, is considered deficient. A value of 25 to 75 is considered insufficient, and 75 to 250 nmol/L is considered sufficient. A Vitamin D dosage is measured in terms of IU, or International Units.

The Food and Nutrition Board at the Institute of Medicine has set the daily Adequate Intake, AI, of vitamin D at 200 IU from birth through age 50. This increases to 400 IU for adults ages 51 to 70, and 600 IU for those 70 and over.

Causes

Older people tend to get less sunlight exposure, and their skin is less efficient at synthesizing vitamin D, explains David A. Mark, Ph.D., a nutrition researcher and consultant. A deficiency can also be caused by inadequate amounts of vitamin D in the diet, the kidneys' inability to convert vitamin D into its active hormone form, or when the digestive tract is unable to absorb vitamin D properly. According to Medline Plus, 40 percent of older people in Florida have a vitamin D deficiency, and rates are generally higher in colder climates

Correcting a Deficiency

An older adult with a diagnosis of vitamin D deficiency cannot recover
through food alone, according to Mark. "Depending on how severe the deficiency, their health care provider may prescribe an oral vitamin D product, typically at 50,000 IU once a week, for several months, or else recommend daily use of non-prescription dietary supplements, which are available at up to 5,000 IU per tablet or softgel," adds Mark.

Interactions with Medications

It's important to tell your health care provider if you are on any medications before starting vitamin D supplements. Vitamin D can have a negative impact when taken with some medications, including certain steroids, weight-loss drugs, cholesterol-lowering medications and anti-epileptic drugs.

Natural Sources

Exposing your arms and legs to the sun for five to 10 minutes three days a week, spring through fall, provides adequate exposure to vitamin D for many people, according to endocrinologist Michael F. Holick, M.D., at Boston University School of Medicine.

Fish is the best food source for vitamin D. A tablespoon of cod liver oil provides 1,360 IUs, and 3 ounces of cooked sockeye salmon contains 794 IUs. In comparison, one cup of vitamin D-fortified milk contains 115 to 124 IUs of vitamin D, according to the National Institutes of Health.