• 1.

    Carrero JJ, et al. Plant-based diets to manage the risks and complications of chronic kidney disease. Nat Rev Nephrol 2020; 16:525542. doi: 10.1038/s41581-020-0297-2

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 2.

    Makarem N, et al. Variability in daily eating patterns and eating jetlag are associated with worsened cardiometabolic risk profiles in the American Heart Association Go Red for Women Strategically Focused Research Network. J Am Heart Assoc 2021; 10:e022024. doi: 10.1161/JAHA.121.022024

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 3.

    Wilkinson MJ, et al. Ten-hour time-restricted eating reduces weight, blood pressure, and atherogenic lipids in patients with metabolic syndrome. Cell Metab 2020; 31:92104.e5. doi: 10.1016/j.cmet.2019.11.004

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 4.

    Tyson CC, et al. DASH diet and blood pressure among Black Americans with and without CKD: The Jackson Heart Study. Am J Hypertens 2019; 32:975982. doi: 10.1093/ajh/hpz090

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 5.

    Banerjee T, et al. Food insecurity, CKD, and subsequent ESRD in US adults. Am J Kidney Dis 2017; 70:3847 [erratum in Am J Kidney Dis 2017; 70:736]. doi: 10.1053/j.ajkd.2016.10.035

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 6.

    Belanger MJ, et al. Covid-19 and disparities in nutrition and obesity. N Engl J Med 2020; 383:e69. doi: 10.1056/NEJMp2021264

New Dietary Approaches to Managing Kidney Disease

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Kidney patients have long complained that the diet recommended for them is bland, tasteless, and hard to follow. But that old advice is being challenged by new research that may offer more palatable alternatives to old dietary approaches to managing kidney disease.

During the Diet and CKD [Chronic Kidney Disease]: What to Eat, When to Eat, How to Eat session at Kidney Week 2021, a panel of speakers highlighted evidence backing the health benefits of plant-based diets, time-restricted eating, and culturally sensitive dietary interventions for Black, Latinx, or Hispanic patients with kidney disease.

Rethinking diet dogma

Juan-Jesus Carrero, PhD Medicine,

Kidney patients have long complained that the diet recommended for them is bland, tasteless, and hard to follow. But that old advice is being challenged by new research that may offer more palatable alternatives to old dietary approaches to managing kidney disease.

During the Diet and CKD [Chronic Kidney Disease]: What to Eat, When to Eat, How to Eat session at Kidney Week 2021, a panel of speakers highlighted evidence backing the health benefits of plant-based diets, time-restricted eating, and culturally sensitive dietary interventions for Black, Latinx, or Hispanic patients with kidney disease.

Rethinking diet dogma

Juan-Jesus Carrero, PhD Medicine, PhD Pharm, MBA, MSc, professor of cardio-renal epidemiology in the Department of Medical Epidemiology and Biostatistics at the Karolinska Institute in Sweden, explained that the traditional kidney diet has emphasized avoiding plant foods because of concerns about electrolyte abnormalities, hyperphosphatemia, hyperkalemia, and protein malnutrition.

“Patients do not like these recommendations which are difficult to adhere to,” Carrero said. Patients report feeling deprived of healthy eating—lacking motivation to eat the recommended foods—and have difficulties eating away from home. “I would like us all to rethink these old dogmas and discuss whether plant-based diets can be of benefit for our patients,” he said.

Advice to restrict potassium-rich produce can inadvertently deprive patients of other nutrients that may be beneficial for patients with kidney disease, Carrero said. He noted that it may not account for hidden sources of dietary potassium from processed foods and that potassium content in foods may also vary by how much a person eats or how the food is cooked. For example, boiling food can reduce potassium levels by 75%, he said. Potassium absorption may also be affected by the combination of foods that patients eat.

“Dietary potassium restriction as a means to prevent hyperkalemia and CKD may have been well intended, but it is not supported by strong evidence,” he said.

In a recent review, Carrero and colleagues highlighted the benefits of plant-based diets for patients with CKD, such as increased fiber intake, beneficial effects on gut microbiota, heart health benefits of plant-based fats, reduced acidosis, and potentially better control of hyperphosphatemia because plant phosphorous may not be as bioavailable (1).

Carrero said slow and careful changes with close monitoring may enable patients to transition to more plant-based diets. Fresh produce prepared at home is best, he said. Distributing fruits and vegetables throughout the course of the day and controlling portions may minimize risks. He said more research is needed on plant-based diets in CKD.

On the clock

Meal timing may also be a useful intervention to improve patient health, said Michelle Gumz, PhD, associate professor in the Division of Nephrology, Hypertension, and Renal Transplantation, College of Medicine at the University of Florida, Gainesville. Gumz highlighted how disruption of the circadian clock that keeps the body entrained to the 24-hour light-dark cycle may contribute to an increased risk of CKD, hypertension, or cardiovascular disease.

We live in a 24-7 society in an environment that is not in sync with our internal [clock],” Gumz said. “These pathological states can further disrupt the clock, and this can lead to a vicious cycle.”

For example, shift work has been associated with a 2- to 3-fold increased risk of CKD, and individuals who do not have the typical nightly dip in blood pressure associated with normal circadian rhythms are at greater risk of cardiovascular and kidney events, she noted.

The body's circadian rhythms are controlled by a central clock in the brain that is entrained to both light and the timing of food intake, Gumz explained. Peripheral clocks in the organs and tissues of the body are entrained by foods. Both the central and peripheral clock are controlled by a cycle of gene expression that regulates the expression of 50% of the genes in the body, including many important for cardiovascular and kidney health, she noted.

“If your eating circadian rhythm is out of sync with the light-dark cycle, those eating patterns can entrain the peripheral clocks,” Gumz explained. “This will result in misalignment between the brain and the peripheral clocks. This can lead to metabolic dysfunction and is likely to increase cardio-metabolic risk factors.”

For example, a recent study showed that women who have inconsistent eating patterns have higher blood pressure, higher body mass index, and worse blood sugar control (2). But several ways to restore healthy circadian clock function have been studied, including time-restricted eating, noted Gumz. Another recent study showed that patients with metabolic syndrome who restricted their eating to a 10-hour window for 12 weeks lost weight, lowered their blood pressure, and improved their lipid profile (3).

“Timing of food intake can alter blood pressure and cardiovascular risks,” Gumz said. She said more study is needed to see if time-restricted eating helps restore a normal pattern of nighttime blood pressure dips in patients with kidney disease.

Addressing diet disparities

Diet is considered a modifiable factor in kidney disease, but dietary modifications are not easy, said Crystal Tyson, MD, assistant professor of medicine in the Division of Nephrology at Duke University Medical Center in Durham, NC. Socioeconomic, environmental, behavioral, and cultural, as well as the patient's kidney disease and co-morbid conditions all need to be factored into dietary interventions. Overall, she noted that Americans’ diets are poor and that Black, Hispanic, and Latinx individuals have a greater prevalence of poor dietary scores than their White and Asian counterparts.

“Improving diet in US racial and ethnic minorities may reduce disparities in kidney outcomes,” she said.

The DASH (Dietary Approaches to Stop Hypertension) diet is one of the most studied dietary patterns, particularly among people of Black race, Tyson said. A study by Tyson and her colleagues found that Black individuals with CKD who were more adherent to the diet had low blood pressure, but overall adherence was low (4). Focus groups conducted by the team at Duke with Black patients with CKD found the participants thought the DASH diet was culturally compatible, but they expressed some concern that it wasn't consistent with previous dietary advice they had received about eating fruits and vegetables, salt, or protein. Other barriers included inadequate cooking skills and concerns about how to buy or use unfamiliar foods.

“Interventions should include cost-effective and time-efficient strategies to follow a healthy diet and emphasize food sources that are convenient and accessible in the local environment,” Tyson said. They should also provide instructions on measuring serving sizes, cooking tips, and resources about new foods and address kidney-related diet concerns.

Nimrit Goraya, MD, a nephrologist at Baylor Scott & White Health in Temple, TX, also highlighted some barriers to healthy food access in racial and ethnic minority communities. Food insecurity, which has been linked (5) to a higher risk of CKD and progression to end-stage kidney disease, disproportionately (6) affects Black and Hispanic or Latinx households. The pandemic has increased food insecurity in the United States, particularly among these groups, she said.

Living in “food deserts” without easy access to supermarkets can also be a barrier to healthy eating. Goraya explained that individuals who live in areas with limited access to food resources may purchase energy-dense foods from gas stations or bodegas. This leads to individuals having a higher dietary acid load, which may contribute to higher acid excretion and CKD progression.

Making healthy foods easily available through vouchers or food banks can facilitate healthier eating, Goraya said. Family-based interventions that work to build trust in communities and engaging trusted community leaders can also help. For example, church-based programs have demonstrated success. Counseling on how to prepare healthy foods can also help, she said.

It is important to avoid stereotypes about what racial and ethnic minorities eat and to focus on individualized interventions. “Dietary patterns are diverse within cultures, and the breadth of that diversity should be recognized,” Tyson said. Because of this, it is important to address a patient's individual needs and preferences, she said.

References

  • 1.

    Carrero JJ, et al. Plant-based diets to manage the risks and complications of chronic kidney disease. Nat Rev Nephrol 2020; 16:525542. doi: 10.1038/s41581-020-0297-2

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 2.

    Makarem N, et al. Variability in daily eating patterns and eating jetlag are associated with worsened cardiometabolic risk profiles in the American Heart Association Go Red for Women Strategically Focused Research Network. J Am Heart Assoc 2021; 10:e022024. doi: 10.1161/JAHA.121.022024

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 3.

    Wilkinson MJ, et al. Ten-hour time-restricted eating reduces weight, blood pressure, and atherogenic lipids in patients with metabolic syndrome. Cell Metab 2020; 31:92104.e5. doi: 10.1016/j.cmet.2019.11.004

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 4.

    Tyson CC, et al. DASH diet and blood pressure among Black Americans with and without CKD: The Jackson Heart Study. Am J Hypertens 2019; 32:975982. doi: 10.1093/ajh/hpz090

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 5.

    Banerjee T, et al. Food insecurity, CKD, and subsequent ESRD in US adults. Am J Kidney Dis 2017; 70:3847 [erratum in Am J Kidney Dis 2017; 70:736]. doi: 10.1053/j.ajkd.2016.10.035

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 6.

    Belanger MJ, et al. Covid-19 and disparities in nutrition and obesity. N Engl J Med 2020; 383:e69. doi: 10.1056/NEJMp2021264

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