Eating Healthily May Improve Kidney Health

Kidney decline slowed in kidney disease patients who reduced sodium intake and ate fresh foods

(RxWiki News) Healthy eating is tied to a wide range of health benefits, from heart health to a lowered risk for cancer. And new research suggests that eating less salt and more fresh foods may prevent kidney disease and benefit kidney disease patients.

For people who already have kidney health problems, reducing sodium intake may keep their disease from progressing to end-stage kidney disease, one new study found.

A second new study found that healthy diets low in sodium and high in potassium may prevent kidney disease.

In the first study, the authors studied patients who replaced salt (sodium) usually found on the kitchen table with a salt substitute. In the other study, the authors looked at different diets to see which one helped the kidneys function best.

The first study — by Meg J. Jardine, PhD, of the George Institute of International Health in Australia, and colleagues — involved 120 villages in China with 2,566 people. The authors wanted to see whether they could get people to eat less sodium, and if doing so meant people would have less protein in their urine. Protein in the urine can be a sign of kidney disease.

The researchers had some villages use a potassium substitute for salt. In other villages, the villagers did not change the way they ate. There were equal numbers of people in each group.

When the researchers checked the urine for protein, people who had used a salt substitute had less protein in their urine (0.82 grams per day less) than people who did not change their diet.

Patients in villages that ate less sodium had a 33 percent decreased chance of having protein in their urine than those in the villages who used as much sodium as they always had.

The second study was done by Andrew Smyth, MBBCh, of the National University of Ireland in Galway. He and colleagues studied 544,635 people from the National Institutes of Health-AARP Diet and Health Study who completed a food frequency survey used to assess diet quality.

Smyth and team found that patients who ate the least sodium and most potassium had lower rates of chronic kidney disease than those whose diets were high in sodium. Potassium is often found in fresh foods like leafy greens, squash and bananas. Smyth and team noted that patients with diets high in fresh foods — such as the Mediterranean diet — also had lower rates of kidney disease than those who didn't eat many fresh foods.

“Rather than focusing on the intake of specific healthy foods alone, our data suggest that the whole diet is important," Smyth told dailyRx News. "For example, consuming lots of healthy foods (such as fruits and vegetables) may be offset by the consumption of high amount of unhealthy foods (such as fats, sugars). A healthy diet should also contain higher potassium intake and not too much sodium. The majority of sodium consumed in the Western world is contained within food, rather than added during the table or when cooking."

Both studies were presented Nov. 15 at the American Society of Nephrology Kidney Week 2014 in Philadelphia.

The study by Dr. Jardine and team was funded by the National Institutes of Health, the United Health Group and a private foundation. The study by Smyth and team was funded by the Health Research Board of Ireland. The authors disclosed no conflicts of interest.

Review Date: 
November 13, 2014