(This Article appeared in the Oct-Dec 1997 Issue of
Researchers at the Children's Hopsital Medical Centre in Cincinnati, led by Ms Heidi Kalkwarf, conducted a study on calcium supplementation on lactating & non-lactating mothers. They found that increasing the calcium intake by about 1000mg per day in women with an average dietary intake of 720mg per day had no effect on the calcium concentration of breastmilk and did not alter the patterns of change in bone mineral density associated with lactation and weaning.
In an accompanying editorial by Ann Prentice, Phd., in The New England Journal of Medicine, she pointed to earlier studies of supplementation, which were initially greeted with skepticism, which also detected no effect of increased calcium intake in lactating women.
A calcium supplement (714 mg per day) consumed for 12 months by lactating Gambian women accustomed to a very low calcium intake (283 mg per day) had no observable effect on the calcium concentraion of breastmilk, the bone mineral density of the forearm, the efficiency of calcium absorption or biochemical markers of calcium and bone metabolism, although urinary calcium excretion increased. A similar study on American women with previously moderate to high calcium intake reached the same conclusion.
Decreases in bone mineral in lactating mothers have been well documented. Typically, during 3 to 6 months of lactation, bone mineral density is reduced by 3 to 5 percent at the spine and neck, and by 1 to 2 percent in the whole body. This bone mineral loss is similar or greater to women shortly after menopause. These losses are reversed in subsequent lactation and after the end of breastfeeding, possibly in connection with the return of menses. This kind of bone mineral loss occur even in women with a high calcium intake.
She concludes that lactation is associated possibly with an alteration
in calcium metabolism. This includes the temporary mobilization
and subsequent replacement of bone mineral. And this is independent
of dietary calcium intake and unresponsive to increases in calcium intake.
This does not mean that good nutrition, including maintaining adequate
calcium intake is not important during lactation. However, the
accumulating scientific data suggests that breastfeeding women need not
consume extra calcium.
(Adapted from the Editorial by Ann Prentice in The
New England Journal of Medicine, Aug 1997)
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