Meat Consumption and Diabetes: The Facts
Meats do not contain carbohydrates and do not have a glycemic index, therefore, they do not raise blood glucose levels so they are thought to be healthy for diabetics. However, research is showing that this is not necessarily the case.
Recent statistics combining results from different studies have identified positive associations between red meat consumption and an elevated risk of Type 2 diabetes mellitus. (1, 2)
In another study, researchers looked at long-term health data of twenty years of follow-up from three Harvard University cohorts that included:
- Over 26,300 men participating in one Health Professionals Follow-Up Study.
- More than 48,700 women in a Nurses Health Study.
- Slightly over 74,000 women from a different Nurses Health Study.
Those who added more than half a serving of red meat per day from the time the study started showed a 48% greater risk of Type 2 diabetes at the next four-year checkup compared with participants who did not increase intake during that time. On the other hand, people who lowered their red meat consumption by more half a serving each day from the start of the study, enjoyed a 14% lower risk of having Type 2 diabetes over the course of the entire study compared with those who didn't change how much red meat they ate. Rates of diabetes were higher among people who consumed mostly processed meats such as salami and hot dogs compared with those who ate unprocessed red meat. (4)
But the question is why does increased consumption of red meat lead to higher risk for suffering from type-2 diabetes?
There are 3 main reasons that diabetes risk increases with red meat consumption:
- The high levels of salt in processed meat is well-known to increase blood pressure, but another less known effect is that it also causes insulin resistance.
- The high levels of nitrites and nitrates in processed meat have also been shown to increase insulin resistance but they also impair the function of the pancreatic beta-cells that produce insulin.
- The high levels of iron in animal meat, although an essential mineral, can cause pancreatic beta-cell damage leading to diabetes in individuals with hereditary haemochromatosis (a disorder in which the gastrointestinal tract absorbs too much iron). Heme iron, the readily absorbable type found in meat at high levels, leads to oxidative stress and cellular damage. Pancreatic islets have an extreme susceptibility to oxidative damage, due to low expression of the antioxidant defence system. Recent research shows that oxidative stress and cellular damage leads to an increased incidence of type 2 diabetes irrespective of the cause or the gene involved. (5)
References:
- Aune D, Ursin G, Veierød MB. Meat consumption and the risk of type 2 diabetes: a systematic review and meta-analysis of cohort studies. Diabetologia; 2009;52(11):2277-2287.
- Pan A, Sun Q, Bernstein AM, et al. Red meat consumption and risk of type 2 diabetes: 3 cohorts of US adults and an updated meta-analysis. Am J Clin Nutr; 2011;94(4):1088-1096. PubMed
- Pan A, Sun Q, Bernstein AM, Manson JE, Willett WC, Hu FB. Changes in Red Meat Consumption and Subsequent Risk of Type 2 Diabetes Mellitus: Three Cohorts of US Men and Women. JAMA Intern Med; 2013;173(14):1328-1335. doi:10.1001/jamainternmed.2013.6633.
- Driver, Jane A., Ashley Smith, Julie E. Buring, J. Michael Gaziano, Tobias Kurth, and Giancarlo Logroscino. Prospective cohort study of type 2 diabetes and the risk of Parkinson's disease 2003-2005. Diabetes Care; 2008; 31,10.
- Sundararaman Swaminathan, Vivian A. Fonseca, Muhammad G. Alam, Sudhir V. Shah. The Role of Iron in Diabetes and Its Complications. Diabetes Care; 2007; 30 (7) 1926-1933 doi: 10.2337/dc06-2625
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