Red meat, dairy, and insulin sensitivity: a randomized crossover intervention study

Abstract

Background: Epidemiologic studies have linked high consumption of red and processed meat with risk of developing type 2 diabetes, whereas high dairy consumption has been associated with decreased risk, but interventions have been limited. Objective: We compared the effects on insulin sensitivity of consuming a diet high in lean red meat with minimal dairy, a diet high in primarily low-fat dairy (from milk, yogurt, or custard) with no red meat, and a control diet that contained neither red meat nor dairy. Design: A randomized crossover study was undertaken with 47 overweight and obese men and women divided into 2 groups as follows: those with normal glucose tolerance and those with impaired fasting glucose or impaired glucose tolerance. Participants followed the 3 weight-stable dietary interventions for 4 wk with glucose, insulin, and C-peptide measured by using oral-glucose-tolerance tests at the end of each diet. Results: Fasting insulin was significantly higher after the dairy diet than after the red meat diet (P , 0.01) with no change in fasting glucose resulting in a decrease in insulin sensitivity after the highdairy diet (P , 0.05) as assessed by homeostasis model assessment of insulin resistance (HOMA-IR). A significant interaction between diet and sex was observed such that, in women alone, HOMA-IR was significantly lower after the red meat diet than after the dairy diet (1.33 6 0.8 compared with 1.71 6 0.8, respectively; P , 0.01). Insulin sensitivity calculated by using the Matsuda method was 14.7% lower in women after the dairy diet than after the red meat diet (P , 0.01) with no difference between diets in men. C-peptide was not different between diets. Conclusion: In contrast to some epidemiologic findings, these results suggest that high consumption of dairy reduces insulin sensitivity compared with a diet high in lean red meat in overweight and obese subjects, some of whom had glucose intolerance. This trial was registered at the Australian New Zealand Clinical Trials Registry as ACTRN12613000441718.

Acute effect of red meat and dairy on glucose and insulin: a randomized crossover study

“…The higher glucose response 30 min after consumption of the red meat meal may have been be attributable to a small difference in the glycemic load between the orange juice and the milk and yogurt or the type of sugar. An insulinotropic effect of dairy was not observed and could not account for the reduction in insulin sensitivity that we observed in our chronic feeding study (18). FIGURE 2 Mean 6 SEM postprandial glucose, insulin, and triglyceride concentrations after 2 isocaloric meals containing red meat (triangles) or dairy (circles) (n = 43).…”

“…Fasting glucose and insulin concentrations did not change in a comparison of two 5-wk weight-loss diets, one of which was high in lean red meat and one of which high in soy protein (16), whereas oily fish intake was shown to improve insulin sensitivity compared with the effect of red meat intake in an 8-wk crossover intervention (17). In contrast to epidemiologic evidence, our previous research showed that a 4-wk diet that was high in primarily low-fat dairy reduced insulin sensitivity compared with the effect of a diet high in lean red meat or no dairy (18).…”

Differential Effects of Red Meat/Refined Grain Diet and Dairy/Chicken/Nuts/Whole Grain Diet on Glucose, Insulin and Triglyceride in a Randomized Crossover Study

“…It appears that 2.8 g whey in milk and yogurt of our dairy/chicken/nuts/wholegrain meal has no effect on postprandial glycemia and insulin secretion and that meat and dairy protein probably have equivalent effects on insulin release. As there are inconsistent effects of dairy consumption on insulin sensitivity [37,38] and few dairy interventions examining acute effects on glucose and insulin [34] exist, the possible explanation for overall effects observed in the dairy/chicken/nuts/wholegrain meal of this present study are not due to dairy but other meal components. Alteration in gut microbiota may play a role in the beneficial effects seen with the dairy/chicken/nuts/wholegrain diet [39].…”

Short term elevation in dietary protein intake does not worsen insulin resistance or lipids in older adults with metabolic syndrome: a randomized-controlled trial

“…We have illustrated that elevation of dietary protein intake using dairy products does not have a negative influence on insulin sensitivity. While some studies have linked increased consumption of red meat to the development of insulin resistance [42], recent data from longitudinal feeding studies dispute this assertion [43]. These findings indicate that reasonable elevations in protein intake do not alter glucose kinetics in subjects with metabolic syndrome, and also highlight the empirical nature of nature of epidemiological research [44].…”