December 9, 2010
Fruits and vegetables help delay kidney disease progression in early stages
Your mom said it, the health experts say it and now there’s reason for people with early kidney disease to do it. Eat your vegetables—and fruit every day. The health benefits of fruits and veggies for a general diet are well known. Now a study on patients with hypertension-related kidney disease gives people with early chronic kidney disease a reason to eat fruits and vegetables daily.
Participants in the study at Texas A&M College of Medicine, in Temple, included 40 patients with macroalbuminuric hypertension and estimated glomerular filtration rate (eGFR) levels of 60 to 90 mL/minute. They were given a diet that included fruits and vegetables such as apples, grapes, potatoes and other foods while avoiding some of the higher potassium fruits and vegetables. At the end of the 30-day period, all patients showed reduced excretion of 3 key indicators of kidney injury: albumin, transforming growth factor β, and N-acetyl-β-D-glucosaminidase. In other words, the participants had a reduction in kidney injury after simply adding fruits and vegetables to their daily intake over a 30 day period. This translate into a delay in progression of kidney failure.
According to lead researcher Nimirit Goraya, MD, patients with kidney disease are known to have acid retention, which is often treated with sodium bicarbonate to help slow the decline of kidney function. Some fruits and vegetables can help reduce the acid load.
How does this work? One job of the kidneys is to keep blood pH normal by excreting excess substances that can make the blood more acid or alkaline. The foods you eat can influence the acid load that is regulated by the kidneys. Foods containing chloride, sulfur and phosphorus contribute more acid and foods containing potassium, calcium and magnesium contribute more alkaline.
Acid contributing foods include meat, poultry, fish, eggs, cheese, peanut butter, breads, cereals, cakes, cookies, corn and lentils. Certain fruits–prunes, plums and cranberries also contribute to acidity.
Most other fruits and vegetables are alkaline contributing foods. Greens like Swiss chard, mustard and turnip greens, kale, spinach, beet and dandelion greens tend to be especially high in alkaline production.
Usually in early stage kidney disease, potassium is not restricted, so including more fruits and vegetables is not a concern. For patients who are experiencing high potassium levels it is wise to exclude higher potassium fruits and vegetables. Instead, include several daily servings of the lower potassium fruits and vegetables.
Future long-term, larger studies are needed to investigate if the results of this study were actually due to the reduction in acid production, or due to other components of the added fruits and vegetables.
In the mean time…eat your fruits and veggies everyday!
Try these kidney-friendly DaVita.com recipes to incorporate more fruits and vegetables in your diet:
Beet and Cucumber Salad
Carrot and Apple Casserole
Fruit Salad Slaw
Green Beans with Turnips