Certain foods naturally contain more acid than others. There's been much debate about how those acids affect some bodily functions, such as the kidneys' job of getting rid of toxins and helping balance chemicals the body makes naturally.
Diets high in acidic foods worsened the chronic kidney disease of low-income blacks more than they worsened chronic kidney disease in low-income whites, according to a new study.
This study concluded that those acids led to some patients developing end-stage renal (kidney) failure faster and needing to undergo dialysis or a kidney transplant.
Fruits and vegetables contain the least acids. Meats, flour-based foods and other high-protein foods contain the most acids.
Deidra Crews, MD, FASN, of Johns Hopkins University School of Medicine, was this study's lead researcher.
She and her research team aimed to find out whether and at what speed high-acid foods pushed those with chronic kidney disease toward end-stage renal disease (ESRD). ESRD is when the kidneys permanently stop working on their own. Before ESRD, a patient suffers from chronic kidney disease (CKD), which typically results from such disorders as diabetes, high blood pressure, lupus and cysts that are hereditary.
The symptoms of chronic kidney disease include excessive urination or no urination, incontinence, bone pain, excessive fatigue, unusually bad breath, dry and itchy skin, a metallic taste in the mouth, headaches and insomnia.
The researchers analyzed health records of 159 non-Hispanic blacks and 760 non-Hispanic whites who had chronic kidney disease and whose yearly income fell below the federal poverty level. They also were listed in the yearly National Health and Nutrition Examination Survey from 1999 through 2004. All study participants were at least 20 years old.
Overall, 94 (12.4 percent) of the patients developed end-stage renal disease during the more than six years that the researchers tracked their medical condition.
Of those 94 people, 58 were black and 36 were white. That meant that blacks were at three times the risk of developing kidney failure that led to the need for dialysis or a kidney transplant, the researchers added.
The researchers wrote that, "Among [poor] adults with CKD, the detrimental effect of high dietary acid load on progression to ESRD appears to be greater for [blacks] than for [whites] and is worthy of further investigation in other populations."
They also wrote that black study participants were more likely to have a protein called albumin in their urine or to have diabetes.