Why the DASH and Mediterranean diets do not work for patients on dialysis

Issue: December 2018

ByPeggy Harum, RD, LD

Patients on hemodialysis experience a high mortality risk of 10% to 20%. This is at least 10-times higher than in the general population. There have been decades of research, but no high-quality evidence that specific treatments or preventative strategies can reduce mortality in this setting.^1-4

There are multitudes of weight loss diets and programs emerging all the time. On Jan. 3, 2018, the dietary approaches to stop hypertension, or DASH diet, was ranked the best diet for the eighth year in a row by U.S. News & World Report. It looks easy to follow. It is designed to lower blood pressure, promotes weight loss, lowers cholesterol and helps manage and/or prevent diabetes. However, is it a good diet for patients on dialysis?

NKF endorsement

Interestingly, the National Kidney Foundation tells us that the DASH diet is a recognized treatment for hypertension, heart disease and kidney disease. It can slow the progression of both heart disease and kidney disease. However, the NKF warns the DASH diet should not be used by people on dialysis because individuals on dialysis have special dietary needs that should be discussed with a registered dietitian (preferably a renal dietitian).⁵

There are lifestyle modifications, like healthy diets and exercise, that have beneficial effects on cardiovascular risk factors. Hypertension, insulin resistance and dyslipidemia could be improved in the general population with these changes. Recommended diets, including the Mediterranean and DASH diets, which emphasize the intake of fruits, vegetables, fish and low-fat dairy items, along with reduced intake of meat, refined sugars, salt and saturated fat, are associated with a 10% to 30% lower risk of cardiovascular disease and mortality in the general population.

A recent article in the Journal of the American Society of Nephrology discussed the association of Mediterranean and DASH diets with mortality in adults on hemodialysis.6 This study looked at 9,757 adult patients on hemodialysis. Cardiovascular disease accounted for about 40% of the deaths. In this study, the follow-up involved 8,110 patients on hemodialysis with 2,087 deaths (829 cardiovascular related) followed for a median period of almost 3 years. The Mediterranean and DASH diet scores were generally low and consistent across a range of European countries. There was no evidence that higher Mediterranean or DASH diet scores were associated with lower risk of cardiovascular or all-cause mortality. This study concluded that the Mediterranean and the DASH diets did not associate with cardiovascular or total mortality in hemodialysis. Dietary patterns that are protective in the general population do not predict better clinical outcomes in patients on hemodialysis.

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Here is a brief overview of the “diet” a person needs to follow if they choose to go on hemodialysis. There is a different more liberal diet if peritoneal dialysis, nocturnal hemodialysis or short daily home hemodialysis is selected.

Diet for hemodialysis

High protein: Eggs or egg whites, lean meats/poultry without skin/fish;

Reduced fluid: Restricted to 1 L to 1.5 L per day (patients usually stop urinating);

Sodium/salt: Restricted to 1.5 g to 2 g per day;

Potassium: Restricted to 2 g to 4 g per day (limit on fresh fruits and vegetables);

Phosphorus: Restricted to 800 mg to 1,000 mg per day (dairy products are limited to about a half cup a day);

Sugar: Some sweets may not be limited unless patient is overweight or diabetic;

Whole grains, beans and nuts: High in phosphorus. Fortunately, new research tells us that the phosphorus in nuts, beans and whole grains is not absorbed well, so small portions are acceptable; and

High blood pressure: Limit salt and salty foods. People on the DASH diet are also encouraged to do the same.

Foods with heart healthy fats like olive oil are recommended, while foods that have additives and/or preservatives (not recommended on the DASH diet) are to be avoided by patients on hemodialysis.

Conclusion

Although the DASH diet or the Mediterranean diet may be good for weight loss and healthy eating, it is not a good idea for a person on hemodialysis. Patients on dialysis are not on a diet to lose weight but rather to be healthy by eating enough protein, control blood pressure and blood sugar, limit fluid buildup and control electrolytes. My philosophy for patients with kidney disease who want to lose weight is eat less and do more.

References:
Chertow GM, et al. N Engl J Med. 2012;doi:10.1056/NEJMoa1205624.
Cooper BA, et al. N Engl J Med. 2010;doi:10.1056/NEJMoa1000552.
Eknoyan G, et al. N Eng J Med. 2002;doi:10.1056/NEJMoa021583.
Palmer SC, et al. Ann Intern Med. 2012;doi:10.7326/ 0003-4819-157-4-201208210-0000.
www.kidney.org/atoz/content/Dash_Diet.
Logan AG, et al. J Am Soc Nephrol. 2018;doi.org/10.1681/ASN.2018050459.

For more information:
Peggy Harum, RD, LD, is a dietitian with DaVita Kidney Care in Fort Worth, Texas. She is also a member of the Nephrology News & Issues Editorial Advisory Board. Disclosure: Harum reports no relevant financial disclosures.