Educate Women about Current Goals, Role of Vitamin D

The present target level of calcium intake for most peri- and postmenopausal women is 1200 mg/day, reiterates a new position statement released by the North American Menopause Society (NAMS) (Menopause. 2006; 13:862-877). But many women do not reach that goal and are therefore at risk for a variety of adverse health consequences, including falls, fractures, and osteoporosis.

Adequate vitamin D status is required to properly metabolize calcium and achieve the nutritional benefits of this important mineral. The authors define adequate vitamin D status as a serum 25-hydroxyvitamin D level ≥30 ng/mL, which usually requires a daily oral intake of at least 400 to 600 IU of vitamin D, they note.

"Adequate calcium intake in the presence of adequate vitamin D status has been shown to reduce bone loss in peri and postmenopausal women, and reduce fractures in postmenopausal women older than age 60 with low calcium intakes," said Wulf Utian, MD, PhD, executive director of NAMS. "Adequate calcium intake is also considered a key component of any bone-protective therapeutic regimen."

The new position statement is an update of the NAMS consensus opinion published in 2001 and is based on the most recent published medical literature.

Calcium needs increase at the time of menopause, largely because of the greater bone resorption and estrogen-related shifts in calcium absorption and excretion. Calcium absorption during menopause may be limited by declining serum vitamin D levels because of age-related declines in intestinal responsiveness, cutaneous synthesis of the parent vitamin, and renal synthesis of the active form of the vitamin.

Postmenopausal women in the United States and Canada generally have low calcium intakes, with an approximate median of 600 mg/day. Factors associated with inadequate calcium intake in older women include lactose intolerance, consuming a pure vegetarian diet, and poor eating habits.

In the menopausal years, "calcium intake remains important," said Robert Heaney, MD, of Creighton University, Omaha, Neb, and chair of the position statement advisory board. "However, patient compliance tends to be poor. Average calcium consumption is far below the amount recommended for optimal bone health."

Dietary sources are the preferred means of obtaining adequate calcium levels (Table). Dairy products are considered the major source of calcium for most Americans, providing about 70% of the total calcium intake in postmenopausal women.

Alternative sources of dietary calcium include leafy green vegetables; canned salmon or sardines; and calcium-fortified fruit juice, cereal, and bread.

Calcium supplements are a useful option for those who do not consume enough calcium from their diet alone. Because supplements vary in calcium content, formulation, and absorbability, the authors recommend taking calcium supplements in divided doses throughout the day, with meals.

Women at increased risk for vitamin D deficiency include those who are older than 70, homebound, or obese; who have malabsorption syndromes, or liver or kidney disease; who have increased skin pigmentation; or who always wear sun protection when they are outdoors.

NAMS suggests that physicians should encourage patients to adhere to the calcium intake plan and educate their patients about proper calcium and vitamin D intake. Remember that taking too much calcium also carries adverse consequences. However, most people today achieve too low, not too high, levels.

Physicians should remind women of the importance of adequate vitamin D intake and of the relative paucity of food sources for this vitamin.