Food for Kidneys: What's Good and Bad?

Kidney disease patients could benefit from pomegranate juice

(RxWiki News) With all the information out there these days, it can be hard to know which foods are good for you and which you should avoid. If you have kidney disease, your diet becomes even harder to manage.

Two new studies shed some light on what is good and bad for patients with kidney disease.

Pomegranate juice helps kidney disease patients manage their blood pressure. At the same time, many kidney disease patients are taking herbs and dietary supplements that could be harmful to their health.

"Watch what you eat if you have kidney disease."

For one study, Lilach Shema, Ph.D., of Western Galilee Medical Center in Israel, and colleagues looked at how drinking pomegranate juice affected the risk of heart disease in patients with kidney disease.

Pomegranate juice full of antioxidants - substances that protect your cells from molecules called free radicals. These molecules are made when the body breaks down food or when the body is exposed to harmful substances in the environment such as tobacco smoke and radiation. Free radicals can damage cells, and are thought to be involved in heart disease, cancer, and other conditions.

Through studying 101 dialysis patients, Dr. Shema and colleagues found that patients took 22 percent less blood pressure drugs after drinking three-and-a-half ounces of pomegranate juice three times a week for one year. In comparison, kidney patients who took a placebo instead of pomegranate juice had only a 7.7 percent reduction in the number of blood pressure drugs they took. About 12 percent of the pomegranate juice patients increased their intake of blood pressure drugs, while 34.6 percent in the placebo group increased their drug dosage.

The researchers also found that kidney patients who drank pomegranate juice had better blood pressure and cholesterol levels. Moreover, they had less plaque build-up in their arteries.

These findings suggest that drinking pomegranate juice could reduce the high rates of heart disease and death among people suffering from kidney disease.

In another study, Vanessa Grubbs, M.D., of the University of California, San Francisco, and colleagues wanted to see how the use of dietary supplements affected patients with chronic kidney disease.

It is known that a variety of herbs can be dangerous for kidney disease patients. In fact, the National Kidney Foundation names 39 different herbs that could harm kidney patients. Yet, there is not much information on how many patients take these potentially harmful herbs.

Dr. Grubbs and colleagues looked at data from more than 21,000 adults who reported their use of dietary supplements for the National Health and Nutrition Examination Survey.

More than half of the patients reported taking any dietary supplement within the past 30 days. The supplement was potentially dangerous in 15.3 percent of cases.

These results suggest that many patients with chronic kidney disease do not know that they are taking potentially harmful supplements. According to Dr. Grubbs, "Although people tend to think of dietary supplements as healthy, many contain ingredients that can actually be harmful to the kidneys." It is also possible that doctors and other healthcare providers do not know that some supplements are harmful. More research and more effort to educate patients and doctors is needed.

Both of these studies were presented at the American Society of Nephrology's Annual Kidney Week. As such, the findings still need to be reviewed by a panel of peers before they are validated and published in an academic journal.

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Review Date: 
November 11, 2011