Higher levels of omega 3 polyunsaturated fatty acid (n-3 PUFA) derived from seafood contribute to a decreased risk of incident chronic kidney disease (CKD) and a slower decline in renal function, as shown in a study. However, such association does not exist with plant-derived n-3 PUFAs.
“Although the magnitude of these associations was modest, our findings suggest adequate consumption of seafood and oily fish should be part of healthy dietary patterns,” the researchers said.
This pooled analysis included 19 prospective studies from 12 countries identified up to May 2020. Studies measuring n-3 PUFA biomarker data and incident CKD based on estimated glomerular filtration rate (eGFR) were included in the analysis.
De novo analysis with prespecified and consistent exposures, outcomes, covariates, and models were performed by each participating cohort. Inverse variance weighted meta-analysis was used to pool results across cohorts.
Incident CKD, the primary outcome, was defined as new-onset eGFR <60 mL/min/1.73 m2. On sensitivity analysis, the primary outcome was defined as new-onset eGFR <60 mL/min/1.73 m2 and <75 percent of baseline rate.
A total of 25,570 participants were included in the primary outcome analysis. Of these, 4,944 (19.3 percent) developed incident CKD during a median follow-up of 11.3 years. [BMJ 2023;380:e072909]
Multivariable adjusted models demonstrated an association between higher levels of total seafood n-3 PUFAs and a lower incident CKD risk (relative risk [RR] per interquintile range, 0.92, 95 percent confidence interval [CI], 0.86‒0.98; p=0.009; I2, 9.9 percent). Categorical analyzes revealed that participants in the highest quintile had a 13-percent lower incident CKD risk than those in the lowest quintile (RR, 0.87, 95 percent CI, 0.80‒0.96; p=0.005; I20.0 percent).
In contrast, plant-derived α linolenic acid (ALA) levels were not associated with lower incident CKD risk (RR, 1.00, 95 percent CI, 0.94‒1.06; p=0.94; I25.8 percent).
Sensitivity analysis confirmed these results. In addition, the association seemed to persist across subgroups by age (≥60 vs <60 years), eGFR (60‒89 vs ≥90 mL/min/1.73 m2), hypertension, diabetes, and coronary heart disease at baseline.
“Although our findings do not prove a causal relationship between seafood n-3 PUFAs and CKD risk, they are supportive and consistent with current clinical guidelines that recommend adequate intake of seafood as part of healthy dietary patterns, especially when seafood replaces the intake of less healthy foods,” the researchers said.
[Circulation 2018;138:e35-47; 2015-2020 Dietary Guidelines for Americans. 8th ed. Washington, DC: US Government Printing Office; 2015]
In a recent systematic review of randomized controlled trials, n-3 PUFA supplementation was found to improve lipid profile and lower oxidative stress, but not blood pressure in CKD patients. Another systematic review showed that n-3 PUFA supplementation could reduce the progression to kidney failure in CKD patients who were not receiving renal replacement therapy. [BMC Nephrol 2021;22:160;
Clin Nutr 2020;39:358-368]
“Therefore, current clinical guidelines do not recommend the use of n-3 PUFA supplementation to prevent further decline in renal function for those with existing CKD, although using n-3 PUFA supplementation to treat hypertriglyceridemia is recommended,” the researchers said. [Am J Kidney Dis 2020;76(Suppl 1):S1-107]
“Our findings highlight the need for large randomized controlled trials to assess increased intake of seafood n-3 PUFAs for the primary prevention of CKD and decline in renal function,” they added.