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Helping Women's Health
CHORI Scientists Win Highly Competitive USDA Grant for First-Time Evaluation of Calcium and Vitamin D in Pregnant and Lactating Women

CHORI scientists Ellen Fung, PhD, and Janet King, PhD, have just garnered a highly competitive grant from the United States Department of Agriculture (USDA) to evaluate for the first time the calcium and vitamin D requirements of pregnant and lactating women.

Current prenatal recommendations for calcium and vitamin D are based on the requirements for healthy, non-pregnant women. No studies have ever been done to determine the adequacy of the current dietary calcium and vitamin D recommendations on maintaining bone health in women are during pregnancy and nursing.
"We need actual data collected from pregnant women with outcomes related to bone density specifically. We now have the technology that is both precise and safe to use during pregnancy and lactation."

Calcium and vitamin D have long been tied to overall bone health, and deficiencies are known to be associated with osteoporosis - weak and brittle bones resulting from low bone density.

"We know that calcium and vitamin D are absolutely critical to optimization of the skeleton. If you don't have enough of these two essential nutrients, you can't successfully mineralize bone," says Dr. Fung.

The existing data regarding bone loss collected from small numbers of women following pregnancy conflicts with epidemiological data collected in women who have had a large number of children, however.

As Dr. Fung explains, "There are a number of different studies that have shown that there is a huge calcium loss that occurs during gestation and an even greater loss during lactation. You look at how much women lose during these periods, and depending on how many children they have, they are at a major deficit."

Strangely, the smaller, intensive studies that demonstrate this don't match up with larger epidemiologic studies that suggest that women who have had many children, 6 or more, seem to have higher bone mass and fracture less than women with fewer children.

"We don't know why that is. Maybe they have higher estrogen levels, maybe these women have better balance and fall less therefore fracture less or maybe women who are able to have this many children simply have higher bone mass to begin with," says Dr. Fung.
"When you look at smaller, focused calcium studies, the results of the epidemiologic studies don't make sense, it would seem like you could never make back the amount of bone loss documented during gestation and lactation, and that's what makes our study so important."
Over the 3-year, $500 thousand grant, Drs. Fung and King will assess both white and black women because evidence also suggests the two groups of women metabolize calcium and vitamin D very differently. African American women tend to have much lower levels of vitamin D, which is known to be important to the skeleton, but somehow have a much higher bone mass. As a result, three groups of women, with subsets of both ethnicities, will be given either a regular prenatal supplement, a supplement with 1000 mg more calcium, or a supplement with 1000 mg more calcium plus 2000 more IU of vitamin D.

Calcium, vitamin D levels and bone density will all be measured throughout the second and third trimesters, and should provide the most conclusive evidence to date regarding bone health in pregnant women - as well as a significant key to helping with osteoporosis prevention.
"Although it can affect men, osteoporosis is primarily a disease in women. One in two women over the age of 60 fracture as a result of osteoporosis, a much higher occurrence rate than the more highly publicized breast cancer rates," says Dr. Fung.

"If we can find a way to lesson the potentially detrimental affects of pregnancy on the skeleton by increasing the requirements of calcium and vitamin D, then we hope to have a beneficial affect for women later in life."

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Tuesday, May 17, 2011 8:19 AM

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