Total, red and processed meat consumption and human health: an umbrella review of observational studies.

Meat consumption has represented an important evolutionary step for humans. However, modern patterns of consumption, including excess intake, type of meat and cooking method have been the focus of attention as a potential cause of rise in non-communicable diseases. The aim of this study was to investigate the association between total, red and processed meat with health outcomes and to assess the level of evidence by performing a systematic search of meta-analyses of prospective cohort studies. Convincing evidence of the association between increased risk of (i) colorectal adenoma, lung cancer, CHD and stroke, (ii) colorectal adenoma, ovarian, prostate, renal and stomach cancers, CHD and stroke and (iii) colon and bladder cancer was found for excess intake of total, red and processed meat, respectively. Possible negative associations with other health outcomes have been reported. Excess meat consumption may be detrimental to health, with a major impact on cardiometabolic and cancer risk.

Association between pre-pregnancy consumption of meat, iron intake, and the risk of gestational diabetes: the SUN project.

PURPOSE: We assessed the association of total meat, processed, and unprocessed red meat and iron intake with the risk of developing gestational diabetes mellitus (GDM) in pregnant women. METHODS: We conducted a prospective study among 3298 disease-free Spanish women participants of the SUN cohort who reported at least one pregnancy between December 1999 and March 2012. Meat consumption and iron intake were assessed at baseline through a validated, 136-item semi-quantitative, food frequency questionnaire. We categorized total, red, and processed meat consumption and iron intake into quartiles. Logistic regression models were used to adjust for potential confounders. RESULTS: We identified 172 incident cases of GDM. In the fully adjusted analysis, total meat consumption was significantly associated with a higher risk of GDM [OR = 1.67 (95% CI 1.06-2.63, p-trend 0.010)] for the highest versus the lowest quartile of consumption. The observed associations were particularly strong for red meat consumption [OR = 2.37 (95% CI 1.49-3.78, p-trend < 0.001)] and processed meat consumption [OR = 2.01 (95% CI 1.26-3.21, p-trend 0.003)]. Heme iron intake was also directly associated with GDM [OR = 2.21 (95% CI 1.37-3.58, p-trend 0.003)], although the association was attenuated and lost its statistical significance when we adjusted for red meat consumption [OR = 1.57 (95% CI 0.91-2.70, p-trend 0.213)]. No association was observed for non-heme and total iron intake, including supplements. CONCLUSIONS: Our overall findings suggest that higher pre-pregnancy consumption of total meat, especially red and processed meat, and heme iron intake, are significantly associated with an increased GDM risk in a Mediterranean cohort of university graduates.

Total meat (flesh) supply may be a significant risk factor for cardiovascular diseases worldwide.

Consumption of red meat instead of white meat has typically been associated with cardiovascular diseases (CVDs). Reflecting actual diet patterns, this study explored the role of total meat (red + white) in predicting CVD incidence. Data from 217 countries were extracted from United Nations agencies for the analyses in five steps. Bivariate correlations were applied to examine the relationship between total meat and CVD incidence globally and regionally. Partial correlation was applied to identify that total meat was an independent predictor of CVD incidence while socioeconomic status, obesity, and urbanization were statistically constant. Stepwise linear regression was conducted for selecting the significant predictor of CVD incidence. SPSS 28 and Microsoft Excel were used for correlation analyses. Globally, total meat correlated to CVD incidence strongly and significantly in bivariate correlation models. This relationship remained significant in partial correlation when socioeconomic status, obesity, and urbanization were statistically kept constant. Stepwise multiple regression identified that, second to socioeconomic status, total meat was a significant predictor of CVD incidence. Total meat correlated to CVD incidence in different country groupings. However, the correlations between total meat and CVD incidence were significantly stronger in developing countries than in developed countries. Worldwide, total meat (flesh) consumption correlated to CVD incidence independently, but significantly stronger in developing countries than in developed countries. This correlation is worth exploring further in longitudinal cohort studies.

Association Between Red and Processed Meat Consumption and Risk of Prostate Cancer: A Systematic Review and Meta-Analysis.

BACKGROUND: Debate on the potential carcinogenic effects of meat intake is open and the relationship between meat consumption and risk of prostate cancer remains uncertain. This meta-analysis was conducted to summarize earlier prospective studies on the association of meat consumption with risk of prostate cancer. METHODS: Relevant studies were identified by exploring PubMed/Medline, Scopus, Web of Science, EMBASE, and Google Scholar databases up to December 2020. Fixed-effects and random-effects meta-analyses were used for pooling the relative risks (RRs). Heterogeneity across studies was evaluated using the Q-statistic and I-square (I 2). A funnel plot and Egger's test was used to detect publication bias. Linear and non-linear dose-response analyses were performed to estimate the dose-response relations between meat intake and risk of prostate cancer. RESULTS: Twenty-five prospective studies were included in this meta-analysis. Totally, 1,900,910 participants with 35,326 incident cases of prostate cancer were investigated. Pooling the eligible effect sizes, we observed that high consumption of processed meat might be associated with an increased risk of "total prostate cancer" (RR: 1.06; 95% CI: 1.01, 1.10; I 2 = 1.5%, P = 0.43) and "advanced prostate cancer" (1.17; 1.09, 1.26; I 2 = 58.8%, P = 0.01). However, the association between processed meat and "advanced prostate cancer" was not significant in the random-effects model: 1.12 (95% CI: 0.98, 1.29). A linear dose-response analysis indicated that an increment of 50 grams per day of processed meat intake might be related to a 4% greater risk of "total prostate cancer" (1.04; 1.00, 1.08; I 2 = 0.0%, P = 0.51). "Total meat intake" was marginally associated with all outcomes of prostate cancer risk (1.04; 1.01, 1.07; I 2 = 58.4%, P < 0.001). CONCLUSIONS: This systematic review and meta-analysis of prospective studies indicated that increased consumption of "total meat" and "processed meat" might be associated with a higher risk of prostate cancer. SYSTEMATIC REVIEW REGISTRATION: https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=230824, identifier: CRD42021230824.

Should we recommend reductions in saturated fat intake or in red/processed meat consumption? The SUN prospective cohort study.

BACKGROUND & AIMS: While most studies have shown increased mortality associated with excessive red/processed meat consumption, the association of saturated fatty acids (SFA) intake with mortality is less homogeneous. We aimed to prospectively assess the association of both, meat consumption (red, processed, red + processed, and total) and SFA intake, with the risk of all-cause death. METHODS: We assessed 18,540 participants of the SUN (Seguimiento Universidad de Navarra) cohort, followed-up for a mean of 9.5 years. A validated 136-item FFQ was administered at baseline. We used Cox models adjusted for potential confounders. RESULTS: We observed 255 deaths during 176,916 person-years of follow-up. Age modified the association between meat consumption and all-cause mortality (p for interaction = 0.027, 0.075, and 0.013, for red, total, and processed meat, respectively). Among participants aged >45 years the fully-adjusted HRs (95% CIs) for one additional serving/d of red, total, and red + processed meat consumption were 1.47 (1.06, 2.04), 1.23 (1.05, 1.45), and 1.32 (1.05, 1.65), respectively, with significant linear trends (P for trend 0.022, 0.012, and 0.018, respectively). In these participants, SFA intake was non-significantly associated with mortality. However, isocaloric replacement of monounsaturated fat or carbohydrates by SFA resulted in significantly higher mortality risk. Likewise, replacing 100 g of vegetables, fruits & nuts or cereals by 100 g of red meat resulted in higher mortality risk. No association of meat consumption or SFA with all-cause mortality was observed in participants younger than 46 years. CONCLUSIONS: Among highly educated persons, aged >45 years, a high consumption of red, total, and red + processed meat was related to increased all-cause mortality, compared with those with low consumption, whereas no significant associations were found for SFA intake. Dietary guidelines should specifically limit meat consumption and not relying only in limiting SFA intake.

Prostate Cancer Incidence is Correlated to Total Meat Intake­ a Cross-National Ecologic Analysis of 172 Countries

Objective: To examine the association of total meat (animal flesh) consumption to prostate cancer incidence (PC61) at population level. Subjects and Methods: Data from 172 countries were extracted for analysis. Associations between country specific per capita total meat intake and PC61 incidence at country level were examined using Pearson's r and Spearman rho, partial correlation, stepwise multiple linear regression analyses with ageing, GDP, Is (index of magnitude of prostate cancer gene accumulation at population level), obesity prevalence and urbanization included as the confounding factors. Countries were also grouped for regional association analysis. The data were log-transformed for analysis in SPSS. Microsoft Excel, and ANOVA Post hoc Scheffe tests were applied to calculate and compare mean differences between country groupings. Results: Worldwide, total meat intake was strongly and positively associated with PC61 incidence in Pearson's r (r= 0.595, p<0.001) and Spearman rho (r= 0.637, p<0.001) analyses. This relationship remained significant in partial correlation (r= 0.295, p<0.001) when ageing, GDP, Is, obesity prevalence and urbanization were kept statistically constant. GDP was weakly and insignificantly associated with PC61 when total meat intake was kept statistically constant. Stepwise multiple linear regression identified that total meat was a significant predictor of PC61 with total meat intake and all the five confounders included as the independent variables (R2=0.417). Post hoc Scheffe tests revealed nine significant mean differences of PC61 between the six WHO regions, but all disappeared when the contributing effect of total meat on PC61 incidence rate was removed. GDP was not identified as the statistically significant predictor of PC61 in either of the models including or excluding total meat as the independent variable. Conclusions: Total meat intake is an independent predictor of PC61 worldwide, and the determinant of regional variation of PC61. The longitudinal cohort studies are proposed to explore the association further.

Replacing red meat and processed red meat for white meat, fish, legumes or eggs is associated with lower risk of incidence of metabolic syndrome.

BACKGROUND & AIMS: Few studies have assessed the association between consumption of red meat (RM) and processed red meats (PRM) and the incidence of metabolic syndrome (MetS) and results have been inconsistent. We investigated associations between total consumption of meat and its subtypes and incident MetS and estimated the effect of substituting RM or PRM for alternative protein-rich foods. METHODS: We analyzed 1868 participants (55-80 years-old) recruited into the PREDIMED study who had no MetS at baseline and were followed for a median of 3.2 years. MetS was defined using updated harmonized criteria. Anthropometric variables, dietary habits, and blood biochemistry were determined at baseline and yearly thereafter. Multivariable-adjusted hazard ratios (HRs) of MetS were estimated for the two upper tertiles (versus the lowest one) of mean consumption of meat and its subtypes during the follow-up as exposure. RESULTS: Comparing the highest vs the lowest tertile of consumption, we observed an increased risk of MetS incidence, with HRs of 1.23 (95% confidence interval [CI]: 1.03-1.45) and 1.46 (CI: 1.22-1.74) for total meat and pooled RM and PRM, respectively. Compared with participants in the lowest tertile, those in the highest tertile of poultry and rabbit consumption had a lower risk of MetS incidence. The risk of MetS was lower when one-serving/day of RM or PRM was replaced by legumes, poultry and rabbit, fish or eggs. CONCLUSION: RM and PRM consumption was associated with higher risk of MetS. Replacing RM or PRM with other protein-rich foods related to a lower risk of MetS and should, therefore, be encouraged. This trial was registered at controlled-trials.com as ISRCTN35739639.

Identification of Rosmarinic Acid-Adducted Sites in Meat Proteins in a Gel Model under Oxidative Stress by Triple TOF MS/MS.

Triple TOF MS/MS was used to identify adducts between rosmarinic acid (RosA)-derived quinones and meat proteins in a gel model under oxidative stress. Seventy-five RosA-modified peptides responded to 67 proteins with adduction of RosA. RosA conjugated with different amino acids in proteins, and His, Arg, and Lys adducts with RosA were identified for the first time in meat. A total of 8 peptides containing Cys, 14 peptides containing His, 48 peptides containing Arg, 64 peptides containing Lys, and 5 peptides containing N-termini that which participated in adduction reaction with RosA were identified, respectively. Seventy-seven adduction sites were subdivided into all adducted proteins including 2 N-terminal adduction sites, 3 Cys adduction sites, 4 His adduction sites, 29 Arg adduction sites, and 39 Lys adduction sites. Site occupancy analyses showed that approximately 80.597% of the proteins carried a single RosA-modified site, 14.925% retained two sites, 1.492% contained three sites, and the rest 2.985% had four or more sites. Large-scale triple TOF MS/MS mapping of RosA-adducted sites reveals the adduction regulations of quinone and different amino acids as well as the adduction ratios, which clarify phenol-protein adductions and pave the way for industrial meat processing and preservation.