People with chronic kidney disease (CKD) are often advised to modify their diet, but is this practice supported by the available evidence? A study in the Cochrane Database of Systematic Reviews—performed by a team of researchers from Australia, New Zealand, Sweden, and Italy—reviewed the data on the potential benefits and risks of a strict diet among patients with various stages of CKD.*

What they did

• The review included 1,639 people with CKD across 17 studies.
• Participants were men and women with mostly moderate-to-severe CKD, including people with end-stage kidney disease (ESKD) receiving dialysis or with kidney transplantation.
• The authors combined the studies to look for any patterns or overall effects.

What they found

• Patients’ diets consisted of more fruits and vegetables, poultry and fish, nuts and olive oil, and cereals and legumes—with less red meat, sugar, and salt. 
• Participants’ diets were tracked for an average of one year.
• Overall, nutritional counseling, or healthier eating habits, were found to have indefinite effects on mortality and cardiovascular conditions, but improved blood pressure and serum cholesterol disease risk factors in six studies and quality of life in two studies.
• Dietary changes led to a higher estimated glomerular filtration rate (eGFR) in five studies. (eGFR describes the flow rate of filtered fluid through the kidney.)
• Dietary changes were also associated with a higher level of serum albumin in six studies. (Albumin is a protein that transports hormones, fatty acids, and other compounds in the blood).
• In one study, a Mediterranean diet reduced LDL cholesterol levels—a risk factor for atherosclerosis and heart disease.

An uncertain conclusion

The authors concluded that while dietary modification may improve quality of life and certain health factors in people with CKD (eGFR, serum albumin, cholesterol, and blood pressure), its effect on mortality, heart disease, and ESKD remains uncertain, as the studies weren’t designed for that determination. How these diet-related health improvements may affect the long-term well-being of people with CKD is still unknown.

“This means we still need large and good‐quality research studies to help understand the impact of diet on the health of people with kidney disease,” said the authors.

*Palmer, S.C.; Maggo, J.K.; Campbell, K.L.; et al. (2017, April 23). Dietary interventions for adults with chronic kidney disease. Cochrane Database of Systematic Reviews.