Dietary Red and Processed Meat Intake and Markers of Adiposity and Inflammation: The Multiethnic Cohort Study

Abstract

Objective The potential influence of dietary factors on inflammation is important for cancer prevention. Utilizing data from control participants (312 men, 911 women) in two nested case-control studies of cancer within the Multiethnic Cohort, we examined the associations of red and processed meat intake with serum levels of leptin, adiponectin, C-reactive protein (CRP), tumor necrosis factor (TNF)-α, and interleukin (IL)-6 and the mediator effect of body mass index (BMI) on the above associations (if present). Methods Multivariable linear models were applied to assess the association between red and processed meat intake at cohort entry and serum biomarker levels measured 9.1 years later after adjusting for covariates and to determine the mediator effect of BMI. Results Overall red and processed meat intake was positively associated with serum leptin levels in men (β=0.180, P=0.0004) and women (β=0.167, P<0.0001). In women, higher red and processed meat consumption was significantly associated with higher CRP (β=0.069, P=0.03) and lower adiponectin levels (β=−0.082, P=0.005). In mediation analyses with red and processed meat intake and BMI as predictors, the associations of red and processed meat with biomarkers decreased substantially (as indicated by % change in effect: leptin in men, 13.4%; leptin in women, 13.7%; adiponectin in women, −4.7%; CRP in women, 7.4%) and were no longer significant (P>0.05), whereas BMI remained significantly associated with serum leptin (men: β=3.209, P<0.0001; women: β=2.891, P<0.0001), adiponectin (women: β= −1.085, P<0.0001) and CRP (women: β=1.581, P<0.0001). Conclusion The current data suggest that the amount of excess body weight or the degree of adiposity may mediate the relations between dietary red and processed meat intake and serum biomarkers associated with obesity and inflammation.

Unprocessed red meat intakes are associated with increased inflammation, triglycerides and HDL cholesterol in past smokers

“…We did not find any significant associations of unprocessed red meat with CRP, triglycerides, or HDL cholesterol in never smokers or current smokers. The null results among never smokers are partially supported by some previous studies, in which investigators demonstrated null associations between red meat and CRP after the adjustment of BMI 23,24 in the general healthy population; however, they did not conduct further stratified analyses based on smoking status. A recent meta-analysis indirectly supported our finding on lipids that the consumption of red meat did not change blood lipid levels in healthy individuals.…”

“…Previous studies examined whether red meat intake was associated with increased inflammation and disturbed blood lipids; however, the results were not consistent. Some studies found that the associations between red meat and C‐reactive protein (CRP), the most commonly used marker of inflammation, were largely attenuated and no longer significant after adjustment of the body mass index . A recent meta‐analysis summarising intervention studies showed that red meat intakes do not change blood lipid levels .…”

“…Some studies found that the associations between red meat and C-reactive protein (CRP), the most commonly used marker of inflammation, were largely attenuated and no longer significant after adjustment of the body mass index. 23,24 A recent meta-analysis summarising intervention studies showed that red meat intakes do not change blood lipid levels. 9 However, these previous studies did not stratify on smoking status 9,[23][24][25][26] or separate processed and unprocessed red meat.…”

“…23,24 A recent meta-analysis summarising intervention studies showed that red meat intakes do not change blood lipid levels. 9 However, these previous studies did not stratify on smoking status 9,[23][24][25][26] or separate processed and unprocessed red meat. [23][24][25][26] Therefore, more studies are warranted for investigating whether the associations between unprocessed red meat and CRP and blood lipids depend on smoking status, especially among past smokers.…”

Moderate Consumption of Red Meat, Compared to Soy or Non-Soy Legume, Has No Adverse Effect on Cardio-Metabolic Factors in Patients with Type 2 Diabetes

“…On the other hand, animal proteins, especially red meat are introduced as risk factors of diabetes progression [10,11]. Although underlying mechanisms which associate red meat consumption with its progressive metabolic abnormalities are not well defined, it is suggested that obesity-related inflammation and insulin resistance may be involved to some extent [12,13] Also red meat contains high saturated fat which could be related to hyperinsulinemia and risk of type 2 diabetes [14]. Based on previous clinical trials, the effect of red meat and plantbased proteins on diabetes outcomes is still controversial [15][16][17][18][19].…”