Eating enough seafood or oily Fish high in omega-3 fatty acids is linked with a modestly lower risk of developing kidney problems, a new study suggests.

Researchers also found that consuming omega-3-rich seafood was linked to a slowed decrease in renal function whereas no link was found with eating enough plant-derived omega-3 fatty acids.

Although the researchers note that this link was modest, their findings support clinical guidelines encouraging sufficient consumption of seafood and oily fish as part of healthy dietary patterns, particularly when seafood is being substituted for unhealthy foods.

The new study published in the The BMJ journal adds to the mixed bag of research suggesting increasing seafood consumption could play a beneficial role in the primary prevention of chronic kidney disease. 

It’s estimated that about 700 million people are affected by chronic kidney disease (CKD). For one, patients affected by chronic kidney disease have a heightened risk of heart disease and death. This is because it could eventually advance to kidney failure which has a negative impact on health and quality of life. 

Hence the need for factors that might prevent the onset and progression of chronic kidney disease to be singled out.

Animal studies suggest that consuming omega-3 polyunsaturated fatty acids (n-3 PUFAs) rewards kidney function. However, studies on humans are somewhat limited and most rely mainly on self-reported data which could be subject to error or inaccuracy. 

To fill this knowledge gap, the researchers combined findings from 19 cohort studies across over 12 countries identified up to May 2020 that examined the link between n-3 PUFA biomarkers and the development of kidney problems. 

Each cohort had measurements of the 4 biomarkers which included eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), docosapentaenoic acid (DPA), and alpha-linolenic acid (ALA). EPA, DHA, and DPA are derived from seafood. On the other hand, APA is mostly derived from plants. E.g. nuts, leafy green vegetables, etc.

The onset of chronic kidney disease was defined as an estimated glomerular filtration rate (eGFR) of less than 60mL/min/1.73m². 

It’s worth noting that eGFR indicates how well the kidneys are working (i.e. eliminating waste and excess fluid from the blood). Generally, normal values range from 90 to 120 mL/min/1.73 m2.

In total, the study involved 25,570 participants who were free from chronic kidney disease. All participants had an average age range of 49 to 77 years with an average eGFR at baseline ranging from 76.1 to 99.8mL/min/1.73m². 

During an average follow-up period of 11 years, the research team found that a total of 4,944 (19.3 percent) participants developed chronic kidney disease. 

Upon adjusting for a range of factors including age, gender, body mass index, race, smoking, alcohol consumption, heart disease, exercise, and diabetes, the team found that increased levels of total seafood derived n-3 PUFA were tied to an 8 percent reduced risk of chronic kidney disease onset.

Current dietary guidelines typically recommend eating at least two servings of oily fish per week to supply around 250 mg/day of long-chain n-3 PUFAs for the general population.

The study authors concluded with the need for large randomized controlled trials to be conducted to further assess the favorable role of seafood n-3 PUFAs in hindering and managing chronic kidney disease. 

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