E-Kidney | April 2012

A Weighty Matter: The Link between Obesity and CKD

Obesity can cause kidney disease both directly and indirectly, and therefore, the obesity epidemic in America is expected to increase rates of chronic kidney disease (CKD) in the U.S.

Obesity directly causes kidney disease, because the kidneys have to work harder to filter out toxins and to meet the metabolic demands of the increased body mass index (BMI) in obese individuals. This is called hyperfiltration and in the long term, it is associated with increased risk of developing CKD. As an indirect cause, obesity increases the major CKD risk factors, type-2 diabetes and high blood pressure.

Obese individuals should be screened for kidney disease on a regular basis. “Weight reduction can prevent, reduce risk and, in some cases, cure CKD, cardiovascular disease, high blood pressure, and diabetes,” says Dr. Joseph Vassalotti, National Kidney Foundation Chief Medical Officer, “and so losing weight is not about vanity. It is an important step to take to improve overall health.”

In order to treat obesity and CKD, people should focus on three areas: healthy diet, physical activity and adequate sleep.

1. In terms of diet, obese individuals should focus on eating smaller portions; drinking water rather than sugary drinks; consuming the recommended amount of protein (0.8 gm/kg/body weight) since excess protein increases the kidneys’ work load; and minimizing salt intake to 2,300 milligrams/day for healthy young people and 1,500 milligrams/day for all Americans over age 50, or for younger people with diabetes, high blood pressure or CKD. An example of a diet that is healthy and low-salt is the DASH diet. For more information about this diet, click here
2. Physical activity is essential for healthy weight reduction. Exercise increases energy expenditure, promotes weight loss and helps sustain a healthy weight. The goal to work towards is two hours and thirty minutes of moderate-intensity exercise a week. This is usually spread out over the week in intervals of, 20-30 minutes at a time, or even less.
3. Adequate sleep promotes maintenance of a healthy weight. Most people require about 7 hours of sleep each night. Many studies suggest that irregular sleep patterns, eating before going to sleep and short sleep duration are all linked to obesity.

Healthy lifestyle and an environment promoting healthy eating and physical activity will help in the prevention and treatment of obesity which in turn can reduce the risk of CKD as well as heart disease and diabetes.