Red meat, dairy, and insulin sensitivity: a randomized crossover intervention study.
Study Goal
The researchers aimed to compare the effects of a high-dairy diet versus a high-lean red meat diet on insulin sensitivity in overweight and obese individuals.
Results Summary
The study found that a high-dairy diet reduced insulin sensitivity compared to a high-lean red meat diet, particularly in women, with no significant difference in men. Fasting insulin levels were higher after the dairy diet, but fasting glucose remained unchanged.
Population
Overweight and obese men and women, some with impaired fasting glucose or impaired glucose tolerance.
Effective Dosage
Not specified (high consumption of primarily low-fat dairy from milk, yogurt, or custard).
Duration
4 weeks per dietary intervention.
Interactions
None mentioned.
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
diet high in primarily low-fat dairy (from milk, yogurt, or custard) with no red meat | increase | fasting insulin | 47 overweight and obese men and women | - | significantly higher | #1 |
diet high in primarily low-fat dairy (from milk, yogurt, or custard) with no red meat | no change | fasting glucose | 47 overweight and obese men and women | - | no change | #2 |
diet high in primarily low-fat dairy (from milk, yogurt, or custard) with no red meat | decrease | insulin sensitivity | 47 overweight and obese men and women | - | decrease | #3 |
diet high in primarily low-fat dairy (from milk, yogurt, or custard) with no red meat | decrease | insulin sensitivity | women | - | significantly lower | #4 |
diet high in lean red meat with minimal dairy | decrease | HOMA-IR | women | 1.33 ± 0.8 compared with 1.71 ± 0.8 | significantly lower | #5 |
diet high in primarily low-fat dairy (from milk, yogurt, or custard) with no red meat | decrease | insulin sensitivity | women | 14.7% | 14.7% lower | #6 |
diet high in primarily low-fat dairy (from milk, yogurt, or custard) with no red meat | no change | insulin sensitivity | men | - | no difference | #7 |
diet high in primarily low-fat dairy (from milk, yogurt, or custard) with no red meat | no change | C-peptide | 47 overweight and obese men and women | - | not different | #8 |
diet high in lean red meat with minimal dairy | no change | C-peptide | 47 overweight and obese men and women | - | not different | #9 |
control diet that contained neither red meat nor dairy | no change | C-peptide | 47 overweight and obese men and women | - | not different | #10 |
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 high-dairy 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 ± 0.8 compared with 1.71 ± 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.