Feeding habit that will help a kidney patient

New York, NY (April 17, 2013) – Poor eating habits, smoking and obesity are associated with increased risk for kidney disease, according to new research published today online in the National Kidney Foundation's American Journal of Kidney Disease.

Researchers led by Alex Chang, MD, MS of Johns Hopkins University found that people with normal kidney function whose diet quality was poor—high in red and processed meats, sugar-sweetened beverages and sodium, and low in fruit, legumes, nuts, whole grains and low-fat dairy—were more likely to develop kidney disease. Only 1% of individuals with no unhealthy lifestyle-related factors developed protein in their urine, an early indicator of kidney damage. That is compared with 13% of participants with three unhealthy lifestyle factors such as obesity, poor diet and smoking.

Obese people - those with body mass index (BMI) over 30 -- were twice as likely to develop kidney disease. An unhealthy diet independently impacted risk for chronic kidney disease even after adjusting for weight and other lifestyle-related factors.

Researchers also noted an association between those who currently smoke and the development of chronic kidney disease. Those who smoked were about 60% more likely to develop kidney disease.

In the first study to examine kidney disease risk factors in healthy young people, researchers used longitudinal data spanning 15 years on over 2,300 black and white adults, aged 28-40 from the Coronary Artery Risk Development in Young Adults (CARDIA) Study.

"Unlike family history of kidney disease, diet, smoking, and obesity are modifiable lifestyle factors that we can all control. By eating well, quitting smoking, and maintaining a normal weight, people can protect their kidneys and prevent future damage," says Dr. Chang.

Overall, those who developed kidney disease were more likely to be African American, living with diabetes or high blood pressure, have a family history of kidney disease, and consumed more soft drinks, red meat, and fast food than those who did not develop kidney disease.

"In the United States, 26 million adults are living with chronic kidney disease. We need to shift the focus from managing chronic kidney disease to preventing it in the first place. Using this study as evidence, we can encourage changes in individual lifestyle choices and behaviors, and ultimately prevent people from developing kidney disease," says Dr. Beth Piraino, National Kidney Foundation President.

Risk Reduction Tips from the National Kidney Foundation:

• Cut the sodium: Americans today consume 50% more than the recommended daily quantity of sodium -- 2,300 mg of sodium, about one teaspoon of salt, should be the daily limit.
• Reduce red meat: High protein diets, especially those containing large quantities of animal protein, may harm the kidneys. Red meat is also high in saturated fat—another no-no.
• Stop the soda: Sugar-sweetened beverages, such as sodas are high calorie and contain no nutritious value. Colas also have phosphorus additives which can harm the kidneys.
• Pass on processed foods: Crackers, potato chips, deli meats, cheese spreads, and instant potato mix are all examples of processed foods that are high in sodium and phosphorus additives - both which can have negative effects on the kidneys.
• Slow down with sugar: An overdose of sugar can lead to diabetes and obesity, which are linked to kidney disease.

Curl from national kidney foundation

How to Prevent Kidney Disease

By Robert C. Stanton, M.D.
Chief, Nephrology Section, Joslin Clinic

Diabetes, particularly type 2 diabetes, has become so common that diabetic kidney disease (nephropathy) has leaped ahead of high blood pressure as the leading cause of kidney failure in much of the world.

Kidney failure is a serious matter: The kidneys’ job is to filter waste products and excess fluids from the blood circulating through our bodies. If the kidneys fail, survival depends on either dialysis (being hooked up to a machine to do the kidneys’ blood-filtering) or a kidney transplant.

High blood glucose levels can damage blood vessels all over the body, including the tiny blood vessels that do the kidneys’ filtering. When those tiny vessels are damaged, they can’t do the job correctly. High blood pressure can result and make the problem worse, damaging more blood vessels and speeding up the progression of kidney disease. Both kidneys are affected.

Though 20-40 percent of those with diabetes develop kidney disease, it can be slowed significantly if diagnosed early and treated.

Prescription for Kidney Health

Five principles should be followed by everyone with diabetes to help prevent and treat kidney problems:

• Tight control of blood glucose levels (A1C less than 7 percent)
• Tight control of blood pressure: aim for lower than 130/80
• Control of lipids: LDL (“bad”) cholesterol should be less than 100 mg/dl, HDL (“good”) cholesterol should be above 50 mg/dl and triglycerides should be less than 150 mg/dl
• No cigarette smoking
• Blood pressure-lowering drugs, such as ACE inhibitors or angiotensin receptor blockers (ARBs), are effective in protecting the kidney from damage if you have signs of diabetic kidney disease

The Earlier You Know, the Better

There are no symptoms in the early stages of diabetic kidney disease. Symptoms of kidney failure—fatigue, nausea and fluid retention—usually don’t occur until the late stages of kidney disease because the kidney can still adequately filter the blood even after extensive damage.

Usually the first sign that the kidneys’ filtration system is damaged is an excess amount of protein in the urine, known as microalbuminuria. This is not just an early sign of kidney disease, but a well-established risk factor for cardiovascular disease, such as heart attack and stroke.

Two tests—one using urine and the other blood—must be performed annually for early detection. The urine sample is used to screen for microalbuminuria. The standard urine dipstick used in doctors’ offices does not measure this—a special machine is required instead.

The blood sample is used to measure the level of creatinine, a substance normally present in the blood, which increases if your kidneys are not functioning properly. The blood sample results are then plugged into a formula that estimates your kidneys’ filtering capacity. The most commonly used formula is called the MDRD equation.

One cannot overemphasize how important it is to measure your blood creatinine and to use the MDRD equation to estimate total kidney filtering. The creatinine value alone can be misleading, as it must be interpreted within the context of age and gender. Patients often have more advanced kidney disease than their blood creatinine value alone suggests.

For this reason, the National Kidney Foundation strongly urges all physicians to use the MDRD equation; however, not all (besides kidney specialists) routinely use it. An accurate estimate of your kidney function is essential for your doctor to decide what, if anything, needs to be done.

With aggressive treatment and yearly testing, we can greatly slow the decline in kidney function and reduce the number of people developing kidney failure. 

This article appeared in the Special Diabetes Insert in the  November 21, 2005 issue of TIME Magazine.