Dietary intake of total, animal, and plant proteins and risk of all cause, cardiovascular, and cancer mortality: systematic review and dose-response meta-analysis of prospective cohort studies

Abstract

ObjectiveTo examine and quantify the potential dose-response relation between intake of total, animal, and plant protein and the risk of mortality from all causes, cardiovascular disease, and cancer.DesignSystematic review and meta-analysis of prospective cohort studies.Data sourcesPubMed, Scopus, and ISI Web of Science until December 2019, and references of retrieved relevant articles.Study selectionProspective cohort studies that reported the risk estimates for all cause, cardiovascular, and cancer mortality in adults aged 18 or older.Data synthesisRandom effects models were used to calculate pooled effect sizes and 95% confidence intervals for the highest versus lowest categories of protein intake and to incorporate variation between studies. Linear and non-linear dose-response analyses were done to evaluate the dose-response relations between protein intake and mortality.Results32 prospective cohort studies were included in the systematic review and 31 in the meta-analysis. During the follow-up period of 3.5 to 32 years, 113 039 deaths (16 429‬ from cardiovascular disease and 22 303‬ from cancer) occurred among 715 128 participants. Intake of total protein was associated with a lower risk of all cause mortality (pooled effect size 0.94, 95% confidence interval 0.89 to 0.99, I2=58.4%, P<0.001). Intake of plant protein was significantly associated with a lower risk of all cause mortality (pooled effect size 0.92, 95% confidence interval 0.87 to 0.97, I2=57.5%, P=0.003) and cardiovascular disease mortality (pooled hazard ratio 0.88, 95% confidence interval 0.80 to 0.96, I2=63.7%, P=0.001), but not with cancer mortality. Intake of total and animal protein was not significantly associated with risk of cardiovascular disease and cancer mortality. A dose-response analysis showed a significant inverse dose-response association between intake of plant protein and all cause mortality (P=0.05 for non-linearity). An additional 3% energy from plant proteins a day was associated with a 5% lower risk of death from all causes.ConclusionsHigher intake of total protein was associated with a lower risk of all cause mortality, and intake of plant protein was associated with a lower risk of all cause and cardiovascular disease mortality. Replacement of foods high in animal protein with plant protein sources could be associated with longevity.

Dose–response relationship between protein intake and muscle mass increase: a systematic review and meta-analysis of randomized controlled trials

“…High protein intake during pregnancy has been reported to increase the risk of small-for-gestational-age infants 32 and neonatal death. 33 While inconsistent results regarding renal function 34 and cancer mortality 35 have been reported, some studies report that high protein intake is associated with lower renal function in individuals with mild renal insufficiency 36 and that high consumption of animal proteins is associated with a higher risk of cancer mortality in middle-aged individuals. 37 Thus, consuming moderate amounts of protein to maintain overall nitrogen balance is important in these populations, particularly because of the risks associated with excessive protein intake.…”

B Vitamins and One-Carbon Metabolism: Implications in Human Health and Disease

“…This increase in cancer risk may be associated with increased folate-cycle driven metabolism, such as increasing nucleotide synthesis, to the benefit of rapidly dividing cancer cells. One could hypothesize a similar effect for methionine, but a recent meta-analysis comparing high plant protein intake to high animal protein intake found no change in cancer-associated mortality, though there was an increase in all-cause mortality with a high animal protein diet [147].…”

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“…However, there are still significant gaps at both the population and individual level concerning dietary guidelines to maintain health. Several reviews and investigations have focused on defining appropriate nutrient intakes for improved BC patient outcomes (100,166,(184)(185)(186)). Yet, changes in life-style and food choices represent a challenge for BC patients; for example, Shi et al found that newly diagnosed with BC consistently consume excessive fat and slightly increased consumption of fruits and vegetables following diagnosis (166).…”