Preliminary research from the Karolinska Institutet in Stockholm, Sweden, suggests that women who eat fish rich in omega-3 fatty acids have a lower risk of renal cell carcinoma (RCC), a common form of kidney cancer. The study was published in the Sept. 20 issue of the Journal of the American Medical Association.

RCC involving the renal parenchyma (the functional tissue of the kidney) accounts for more than 80% of all kidney cancers, and the rate has increased, especially among black women and men.

“We found that women who consumed one or more servings of fatty fish per week had a statistically significant 44% decreased risk of RCC compared with women who did not consume any fish,” the authors write. “Women who reported consistent long-term consumption of fatty fish…had a statistically significant 74% lower risk.”

The researchers believe an increased intake of fish rich in omega-3 fatty acids and vitamin D contributes to the lower cancer risk, but emphasize that additional studies are required to draw a firm conclusion. Fatty fish has 20 to 30 times more omega-3 polyunsaturated fatty acids than lean fish like cod, tuna, sweet water fish and seafood (shrimp, lobster, crayfish), as well as three to five times more vitamin D.

Please see our feature article, Which Fish Is Fit to Eat?, for information of making environmentally sound fish choices.
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Kidney stones develop when urine becomes too concentrated, causing minerals and other chemicals to bind together. Over time, these crystals combine and form a stone.

If you’ve ever suffered from painful kidney stones, your doctor has undoubtedly recommended dietary and lifestyle changes, including a prescription for potassium citrate, which makes urine less acidic. Some people, however, simply cannot tolerate the drug because of its gastrointestinal side effects, notes Clarita Odvina, MD, an assistant professor of internal medicine and the study’s lead author. In these cases, dietary sources of citrate, such as orange juice, may be an effective alternative to drugs.

All citrus juices contain citrate, a form of citric acid that gives citrus fruits their sour taste. But when researchers compared orange juice and lemonade, which have comparable citrate contents, they found orange juice boosted the levels of citrate in the urine and reduced the crystallization of uric acid and calcium oxalate (the “main ingredient” in kidney stones). Lemonade failed to increase levels of citrate—an important acid neutralizer and inhibitor of kidney stone formation.

If you’re a biochemistry geek, here’s how it works: The citrate in orange and grapefruit juice is accompanied by a potassium ion. The citrate in lemonade and cranberry juice is accompanied by a hydrogen ion. Hydrogen ions—but not potassium ions—counteract the beneficial effects of high citrate content.

So, the next time you head to your local natural and organic food store, grab a carton of freshly squeezed organic orange juice—or juice some organic oranges. Your kidneys will thank you!