A higher protein ketogenic (keto) diet can speed up kidney failure and cause other medical problems in patients with kidney disease, according to the most comprehensive review of these diets to date.
Keto diets are low-carb and high-fat, with disagreement as to whether the diet is high in protein, according to study co-author Shivam Joshi, MD, clinical assistant professor of medicine at NYU Grossman School of Medicine in New York, New York. The average keto diet consists of 1.2-2.0 g / kg / day of protein, said Dr. Joshi, adding that he and his colleagues technically view this as a high amount. However, proponents of keto diets consider this protein intake to be normal or average, possibly because the typical American diet is already 1.2-1.5 g / kg / day of protein, said Dr. Joshi.
The review, published in Frontiers in Nutrition, showed that the potential long-term risks of the keto diet include heart disease, cancer, diabetes, kidney stones, Alzheimer’s, and other diseases.
Keto diets, which can lead to ketosis, can be especially unsafe for women who are pregnant or who may become pregnant.
“Keto diets are, by definition, very high in fat and protein, and that poses a challenge to long-term kidney health,” said study co-author Neal Barnard, MD, associate professor of medicine at the George Washington University School of Medicine in Washington. DC and President of the Medical Committee for Responsible Medicine.
Stress diseased kidneys
In patients with impaired kidney function due to diabetes, high blood pressure, or infection, high protein intake accelerates the loss of kidney function, said Dr. Barnard. “A keto diet can really put a strain on a battered kidney,” he said.
The review confirmed that high animal fat consumption was linked to an increased risk of albuminuria and chronic kidney disease (CKD). “Nephrologists see many patients looking for ways to lose weight, and many also have diabetes, high blood pressure, and atherosclerosis. There is evidence that ketogenic diets can cause further harm and should not be recommended, ”said Dr. Barnard. “A healthy diet of vegetables, fruits, whole grains and legumes that is planned accordingly leads to healthier long-term weight control and helps to maintain kidney function as much as possible.”
Effects on metabolic acidosis
Dr. Joshi said the keto diet has the potential to worsen metabolic acidosis. A common treatment for metabolic acidosis is sodium bicarbonate, which can cause side effects such as worsening edema and increased blood pressure. By increasing the potential acidity of a keto diet, patients can make their acidosis worse and require more medication for treatment, said Dr. Joshi.
“Some diets have the potential to worsen underlying kidney disease or complications of kidney disease, while other diets can help alleviate kidney disease progression, kidney disease complications, and in some cases, the causes of kidney disease, such as diabetes and High blood pressure, “said Dr. Joshi.
Keto Diets and Type 1 Diabetes
Because keto diets contain concentrated fats, meat, poultry, fish, eggs, and cheese, they have been linked to an increased risk of diabetes. These foods are often high in saturated fat, cholesterol, chemical contaminants, and other potentially inflammatory compounds. When the researchers examined adults with type 1 diabetes, they found studies that suggested both favorable and unfavorable results. One small study suggested that the keto diet might improve blood sugar control in patients with type 1 diabetes, but it did trigger more frequent and extreme hypoglycemic episodes.
The researchers concluded that the only well-supported use of keto diets is to reduce seizure frequency in some people with drug-resistant epilepsy.
Harold A. Franch, MD, professor of medicine at Emory University School of Medicine in Atlanta, Georgia, said the new study results weren’t surprising given the known problems with excess protein and high net acidity in the diet. “1998 studies showed that Atkins diets, the predecessor to the keto diets, decreased kidney stones by increasing urinary calcium and lowering protective citrate. The effect of dietary proteins on individual nephron elevation [glomerular filtration rate], worsening proteinuria and promoting kidney progression are a long history for nephrologists, ”said Dr. Franch.
Ketosis and PKD
Nephrologist Kam Kalantar-Zadeh, MD, PhD, professor of medicine in the University of California’s Irvine School of Medicine and adjunct professor of epidemiology in Los Angeles’ UCLA Fielding School of Public Health, said that some keto diets are more vegetarian prevail, but there is little published research on their effects on kidney health.
In recent years, he said, studies have indicated that ketosis can improve kidney cyst growth in patients with polycystic kidney disease (PKD). To date, research has shown that some ketogenic diets can lead to rapid regression of renal cystic stress in mouse, rat, and cat models of PKD. “However, some people have said that keto diets are like drinking olive oil for lunch. We know ketone levels in the body and in your urine go up, and that will have some consequences, ”said Dr. Kalantar-Zadeh.
[Editor’s note: Dr. Kalantar-Zadeh serves as medical director for nephrology for Renal & Urology News.]
Crosby L., Davis B., Joshi S. et al. Ketogenic Diets and Chronic Illnesses: Weighing Benefits Against Risks. Front Nutr. Published online July 16, 2021. doi: 10.3389 / fnut.2021.702802
Torres JA, Kruger SL, Broderick C, et al. Ketosis improves kidney cyst growth in polycystic kidney disease. Cell metab. 2019; 30 (6): 1007-1023.e5. doi: 10.1016 / j.cmet.2019.09.012