Why high intake of red meat is unhealthy

World meat consumption has increased during the last decades, and evidence is mounting that high consumption of red and mainly processed meat is unhealthy to humans and is related to chronic diseases such as cancer, type 2 diabetes, and cardiovascular disease. A new study published in the Journal of Hepatology adds non-alcoholic fatty liver disease (NAFLD) to the list.

“NAFLD is considered as the hepatic component of the metabolic syndrome, with insulin resistance and inflammation as key factors in its pathophysiology,” explained lead investigator Professor Shira Zelber-Sagi, RD, PhD, from the School of Public Health, Faculty of Social Welfare and Health Sciences, University of Haifa, Israel.

“Unhealthy Western lifestyle plays a major role in the development and progression of NAFLD, namely, lack of physical activity and high consumption of fructose and saturated fat.

“Our study looked at other common foods in the Western diet, namely red and processed meats, to determine whether they increase the risk for NAFLD.”

In order to test the association of type of meat and cooking method with NAFLD and insulin resistance, investigators undertook a cross-sectional study among individuals 40 and 70 years old who underwent screening colonoscopy at the Department of Gastroenterology and Hepatology in the Tel Aviv Medical Centre, and who agreed to participate in a metabolic and hepatic screening study between 2013 and 2015.

After excluding some of the participants due to factors such as viral liver disease and alcohol abuse, close to 800 subjects were included in the main analysis, of whom a sub-sample of 357 subjects completed the meat questionnaire.

The results showed that high consumption of red and processed meat is independently associated with NAFLD and insulin resistance regardless of saturated fat and cholesterol intake and other risk factors such as BMI.

In addition, individuals who consumed large quantities of meat cooked using unhealthy methods and those already diagnosed with NAFLD who consumed high HCAs had a higher chance of having insulin resistance.

Although the association between high red and processed meat consumption and NAFLD remains to be confirmed by prospective studies, Prof. Zelber-Sagi, recommends limiting red and processed meat consumption in preference for healthier “white meat,” such as chicken or turkey, including fish in the diet, and steaming or boiling food instead of grilling or frying meat at a high temperature until it is very well done.

“NAFLD is primarily a lifestyle-oriented disease. With sound medical and nutritional guidance from their clinicians, patients are better informed and equipped to implement the lifestyle changes needed to help reverse this disease,” remarked Prof. Zelber-Sagi.