Vitamin D and Bone Health

During the past few years, vitamin D and its role in bone health and immune function has been a hot topic in women’s health. Vitamin D is a crucial element involved in bone metabolism and calcium, phosphorous, and magnesium absorption.
Vitamin D deficiency can result in osteoporosis, postural instability leading to frequent falls, bone pain, abnormalities in immune function, and possibly may play a role in cardiovascular health and cancer prevention.
There are two forms of vitamin D that are important to humans: Vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). The latter form is obtained in human skin after exposure to UVB light. The active form of vitamin D is converted in the liver and kidney. In addition to sunlight, vitamin D can be obtained from certain foods. Since excessive sun exposure is not recommended secondary to fear of skin malignancy, women and men are encouraged to obtain extra fat soluble vitamin D from other sources such as cod liver oil, fish oil, eggs, fortified dairy products (milk, orange juice, and yogurt) and over the counter or prescribed supplements. Despite the opinions of many physicians who feel that most Americans do receive adequate vitamin D in the diet, there are still many females and males who have low vitamin D levels. Some elderly patients with sedentary lifestyle or individuals with certain medical conditions may be at risk for vitamin D deficiency.

These medical conditions may include:
a) Kidney disease
b) Intestinal condition (such as malabsorption, Inflammatory Bowel Disease, Celiac Disease)
c) Rheumatoid arthritis, Multiple sclerosis
d)Diseases requiring steroid use and seizure medications

A recent report released on December 6, 2010 from the Institute of Medicine focused on the recommended Vitamin D intake which is listed below:
a) 800 IU(international units)/d for women over the age of 71
b) 600 IU/d for females in other age groups, men and children

The IOM committee also recommends a serum level of at least 20 ng/ml to maintain adequate bone health for most individuals. This level is lower than the previously suggested value of 30 ng/ml.
Individuals at risk for falls and osteoporosis, especially the elderly or the specific groups mentioned previously in the article may develop severe vitamin D deficiency. These groups may require higher doses (1000 IU to 50,000 IU).
Every patient is different and may need more vitamin D supplementation according to his or her personal history.
Since vitamin D is crucial to calcium absorption, it is important to also review the IOM’s recommendation for calcium intake listed below:
a) 1200 mg/day for women over age 50 and males over age 71
b) 1000 mg/day for younger adult women (who are not breasting feeding or lactating) and adult men

Ask your physician to check a 25-hydroxy vitamin D level through a blood test and treat according to level and risk factors for osteoporosis. Repeat levels should be checked to avoid vitamin D toxicity, which can lead to high calcium levels in the blood and urine, kidney stones, muscle weakness, bone pain, confusion, and vomiting.

Magdalena Cadet, MD is the Director of Rheumatology and Osteoporosis Services New York Hospital Queens and Assistant Professor of Medicine at Weill Medical College of Cornell University