Background: Higher protein diets, especially from animal sources, have seen a rise in popularity due to potential metabolic. This may have consequences for kidney function particularly in rising middle class populations who are allocating more income towards meat. The objective of this systematic review and meta-analysis was to evaluate the effects of higher versus lower protein intake on glomerular filtration rate (GFR) in adult populations without renal impairment.
Methods: Search strategies were developed and electronic databases searched: MEDLINE and EMBASE. Data were extracted up until June 3, 2015. The main outcome measure was GFR and a random effect model (Cochrane’s Review Manager Version 5.3) was used to pool mean differences in GFR values.
Results: Database searches yielded 25 trials from 1914 articles that were eligible for analysis based on inclusion/exclusion criteria. 12 studies were randomized controlled trials and 11 studies were crossover trials. As a result of data presented, 2 crossover studies were treated as 4 trials to result in 25 total trials. A total of 810 subjects from 25 trials were included in this systematic review and meta-analyses. The age of participants was 24-62 years and their BMI was 21-36 kg/m2. Higher protein compared to lower protein-containing diets were associated with increased GFR values [mean difference (MD): 8.33 ml/min (95% CI 4.87 to 11.79), P < 0.00001] but this was less pronounced when assessing change from baseline GFR values [MD: 4.71 ml/min (95% CI 0.06 to 9.36), P = 0.05]. Moreover, significant heterogeneity was present and funnel plot asymmetry indicated potential publication bias in both meta-analyses.
Conclusion: Higher protein diets were associated with increased GFR, however, these results were inconclusive due to significant heterogeneity and overestimation by random effect analyses. There is still no clear evidence that high protein diets negatively impact renal function in healthy populations. / Thesis / Master of Science (MSc) / Globally, the leading causes of mortality in industrialized countries are cardiovascular disease (CVD), stroke, and type 2 diabetes (T2D). Deaths from these chronic diseases now outpace deaths due to malnutrition. Being overweight and obese increases the risk of both morbidity and mortality from CVD, stroke, and T2D. Global rates of overweight and obesity have now reached ‘epidemic’ proportions and the World Health Organization has stated that, “… [a] global epidemic of overweight and obesity – ‘globesity’ – is taking over many parts of the world. If immediate action is not taken, millions will suffer from an array of serious health disorders.” Over the past 20-30 years, the popularity of higher protein energy restricted diets have grown due to the potential benefits regarding weight loss, appetite regulation, and maintenance of lean (muscle) mass. Additionally, the expansion of the global ‘middle-class’ has resulted in families allocating more income towards meat products as a primary protein source in their diet. A health concern is that higher protein intake may have an adverse effect on kidney function. In individuals with chronic kidney disease, higher protein diets have been shown to result in further renal impairment. However, the effects of increased protein intake in healthy populations are unclear. The aim of this systematic review and meta-analysis was to compare higher versus lower protein diets on kidney function in healthy populations based on the literature to date. This was accomplished by looking at changes in glomerular filtration rate (the rate at which kidneys filter blood), which is the ‘gold standard’ marker of kidney function.
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/18152 |
| Date | 11 1900 |
| Creators | SITHAMPARAPILLAI, ARJUN |
| Contributors | PHILLIPS, STUART, M., Global Health |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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