FW: Cross Post: Diet Can Alter Risk of Kidney Stones

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Cross Post: Diet Can Alter Risk of Kidney Stones

By Serena Gordon

HealthDay Reporter

MONDAY, Nov. 17 (HealthDayNews) -- Belying the common belief that

calcium contributes to kidney stones, a new study of young women has

found eating foods rich in this mineral may actually reduce the risk

of getting the painful condition.

Dietary calcium, whole grains and vegetables all appear to lower the

chances you'll get kidney stones, while a high sugar intake may do

the opposite, the study finds.

Contrary to what was believed in the past, eating more protein

doesn't increase your risk of kidney stones either, the researchers

say. The study also found no additional risk from taking calcium

supplements.

" Dietary factors are important, " says study author Dr. Curhan,

an associate professor of medicine and a nephrologist at Brigham and

Women's Hospital in Boston. " Dietary modification may reduce an

individual's risk of kidney stones. Our findings challenge the

belief that calcium should be restricted. "

Curhan presented the findings Nov. 16 at the American Society of

Nephrology's annual meeting in San Diego.

Curhan and his colleagues gathered data from the large Nurses'

Health Study II, which includes more than 100,000 women. For this

study, the researchers focused on 96,000 women between the ages of

27 and 44 at the start of the study who had completed dietary

information surveys in 1991 and 1995.

At the start of the study, none of the women had kidney stones. At

the end of the eight-year study period, 1,223 women had developed

kidney stones.

Kidney stones form from substances in the urine. The most common

type of stone forms from calcium oxalate in the urine. Other

substances that contribute to stone formation include uric acid,

struvite and cystine, the researchers say.

Stones come in varying sizes -- from a grain of sand to the size of

a golf ball. Some stones pass through the urinary tract system on

their own, but some get stuck and block the flow of urine. When this

happens, medical intervention is necessary.

The researchers found women who had the highest dietary calcium

intake from foods such as milk, cheese and yogurt reduced their risk

of kidney stones by 27 percent. Consumption of phytate, a naturally

occurring substance found in whole grains and vegetables, lowered

the risk of kidney stones by 37 percent, and a higher fluid intake

also appeared to reduce the risk of kidney stones.

What did raise the risk of developing kidney stones was sugar. Sugar

increased kidney stone risk in young women by slightly more than 30

percent. Meat and calcium supplements didn't appear to significantly

increase or decrease the risk.

Dr. Khalid Zafar, a nephrologist at Beaumont Hospital in

Royal Oak, Mich, says, " The take-home message here is that people

with kidney stones should not decrease dietary calcium and they can

take supplements and eat meat. "

He says the finding that supplements don't increase the risk of

kidney stones in young women is especially important, because women

need calcium to prevent osteoporosis, and many don't get sufficient

amounts from their diet.