A recent study has evaluated the association between dietary fibre intake and kidney function and the risk of chronic kidney disease.
Chronic kidney disease is a common and complex disease in which there is a decline in renal function. This disease is quickly becoming a serious public health issue as it often leads to early death or poor quality of life, and this directly places a burden on healthcare systems. The global occurrence of chronic kidney disease is rapidly increasing, and it currently affects approximately 10-15% of the population.
Many factors increase the risk of chronic kidney disease such as an aging population, high blood pressure, high cholesterol, smoking, and a poor diet. In addition to this, a high dietary intake of plant protein, vitamin C, magnesium, potassium, and fatty acids and a low dietary intake of animal protein and sodium are documented factors that may prevent chronic kidney disease. However, dietary guidelines have yet to be established for the preservation of healthy kidney function.
Researchers wanted to establish the relationship between dietary fibre intake from fruits, vegetables, legumes, or grains and kidney function, or the risk of chronic kidney disease. In a recent population-based prospective study carried out in Iran and published in The British Journal of Nutrition, researchers evaluated the association of total fibre intake with the risk of chronic kidney disease. This study followed 1,630 people without kidney disease for six years to determine the impact of diet on the risk of developing kidney disease.
High Fibre Led to Higher Kidney Function
The results of this study showed that a high-fibre intake was associated with a higher kidney function and a lower incidence of chronic kidney disease after approximately six years of follow-up. Those individuals who consumed more than 26g per day of fibre had a 50% decreased risk of chronic kidney disease compared to those who consumed less than 17.7g/day. The researchers also observed an 11% lower risk of chronic kidney disease if an individual was to increase their total fibre intake by 5g per day. This protective association was only observed for vegetable and legume fibre, no association was seen with regards to cereal or fruit fibre intake.
Interestingly, the results of this study regarding kidney function coincide with a recent meta-analysis that demonstrated that the risk of renal cell carcinoma was inversely associated with legume and vegetable fibre intake, but not with fruit or cereal fibre intake.
Researchers propose that the reason for this beneficial effect from dietary fibre intake may be due to the legumes decreasing the glycaemic index, meaning it decreases the level of sugars in your blood. Secondly, the researchers suggest this association may be due to the fact that these sources of fibre are rich in antioxidants and vitamins. Thirdly, vegetable and legume fibre intake are known to have a positive effect by decreasing known risk factors of chronic kidney disease such as diabetes, high blood pressure, and high blood lipids.
Despite the limitations of this study, which include a lack of repeating kidney function measurements and the lack of controlling for various confounders, the results do give an insight into the positive effects of nutrition on improving kidney function and preventing chronic kidney disease. Future population studies are warranted in order to confirm and support the findings of this study.
Written by Jade Marie Evans, MPharm, Medical Writer
Reference: Mirmiran.P et al. (2018). Dietary fibre intake in relation to the risk of incident chronic kidney disease. Available: https://www.cambridge.org/core/journals/british-journal-of-nutrition/article/dietary-fibre-intake-in-relation-to-the-risk-of-incident-chronic-kidney-disease/2E12BFE9C7F483AFB6921E568AF77E47. Last accessed 5th Feb 2018