No Additional Benefits on Cardiometabolic Risk Parameters of Reduced Red Meat or Increased Fiber Intake in an Energy-restricted Diet

By Heather Nelson Cortes, PhD and Kevin C Maki, PhD

 

To date, results from epidemiological studies have suggested that a high intake of red meat is associated with a higher risk of developing type 2 diabetes (T2D) while high fiber intake is associated with a lower risk 1-5. Furthermore, high intakes of red meat have also been suggested to be linked to increased risks of cardiovascular disease (CVD) and mortality 6,7.  One of the main approaches for reducing risk of T2D and CVD is weight loss 8-10. Research findings have also suggested that cardiometabolic risk can be improved with dietary modification independent of weight loss 11,12.

 

Willman et al. completed a 6-month, randomized controlled dietary intervention trial to assess whether lower intake of meat or higher intake of dietary fiber would have additional benefits when incorporated into an energy-restricted diet 13.  Subjects were randomized to one of three groups with all groups being instructed to reduce their caloric intakes by 400 kcal/d below their weight-maintenance requirements and exercise 3 hours/week.  The control group just decreased their caloric intake.  The “no red meat” group avoided red meat, but was able to eat turkey, fish or chicken, and subjects in the “fiber” group increased their fiber intake to at least 40 g/day.  The researchers also analyzed 9-month follow-up data from the Tuebingen Lifestyle Intervention Program (TULIP) cohort, which included subjects (n = 229) at increased risk of diabetes 14.  The intervention in TULIP consisted of increased physical activity and decreased caloric intake.

 

All participants in the 6-month trial lost weight (mean 3.3 ± 0.5 kg, P < 0.0001). Glucose tolerance and insulin sensitivity improved (P < 0.001), and body and visceral fat mass decreased in all groups (P < 0.001), with no difference among the groups.  Similarly, liver fat content decreased (P < 0.001) with no differences among the groups.  The liver fat decrease correlated with the decrease in ferritin during intervention (r2 = 0.08, P = 0.0021). This association between ferritin and liver fat changes was confirmed in TULIP (P = 0.0084).

 

Comment.  Neither the absence of dietary red meat nor the increase in fiber intake had an additional effect beyond calorie restriction and exercise on risk markers for T2D or CVD.  These results confirm that weight loss can lead to improvement in glucose metabolism, body fat composition and liver fat content and do not indicate incremental benefits for restriction of red meat intake or increasing dietary fiber intake.  Additional research is needed to assess effects of these dietary factors during weight loss maintenance.

 

References

  1. The InterAct Consortium. Association between dietary meat consumption and incident type 2 diabetes: The EPIC-InterAct study. Diabetologia 2013;56:47–59.
  2. Fretts AM, Howard BV, McKnight B, et al. Associations of processed meat and unprocessed red meat intake with incident diabetes: The Strong Heart Family Study. Am J Clin Nutr 2012;95:752–8.
  3. Lajous M, Tondeur L, Fagherazzi G, et al. Processed and unprocessed red meat consumption and incident type 2 diabetes among French women. Diabetes Care 2012;35:128–30.
  4. 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;94:1088–96.
  5. Wittenbecher C, Mühlenbruch K, Kröger J, et al. Amino acids, lipid metabolites, and ferritin as potential mediators linking red meat consumption to type 2 diabetes. Am J Clin Nutr 2015;101:1241–50.
  6. Etemadi A, Sinha R, Ward MH, et al. Mortality from different causes associated with meat, heme iron, nitrates, and nitrites in the NIH-AARP Diet and Health Study: Population based cohort study. BMJ 2017;357:1957.
  7. Sun Q. Red meat consumption and mortality: Results from 2 prospective cohort studies. Arch Intern Med 2012;172:555.
  8. Tuomilehto J, Lindström J, Eriksson JG, et al. Prevention of type 2 diabetes mellitus by changes in lifestyle among subjects with impaired glucose tolerance. N Engl J Med 2001;344:1343–50. 

  9. Knowler WC, Barrett-Connor E, Fowler SE, et al. Reduction in the incidence of type 2 diabetes with lifestyle intervention or metformin. N Engl J Med 2002;346:393– 403. 

  10. Jensen MD, Ryan DH, Apovian CM, et al. 2013 AHA/ACC/TOS guideline for the management of overweight and obesity in adults: A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and The Obesity Society. J Am Coll Cardiol 2014;63:2985– 3023. 

  11. Estruch R, Ros E, Salas-Salvadó J, et al. Primary prevention of cardiovascular disease with a Mediterranean diet. N Engl J Med 2013;368:1279–90.
  12. Estruch R, Martínez-González MA, Corella D, et al. Effect of a high-fat Mediterranean diet on bodyweight and waist circumference: A prespecified secondary outcomes analysis of the PREDIMED randomised controlled trial. Lancet Diabetes Endocrinol 2016;4:666–76.
  13. Willmann C, Heni M, Linder K, et al. Potential effects of reduced red meat compared with increased fiber intake on glucose metabolism and liver fat content: a randomized and controlled dietary intervention study. Am J Clin Nutr. 2019;109:288–96.
  14. Schmid V, Wagner R, Sailer C, et al. Non-alcoholic fatty liver disease and impaired proinsulin conversion as newly identified predictors of the long-term non-response to a lifestyle intervention for diabetes prevention: Results from the TULIP study. Diabetologia 2017;60:2341– 51. 


 

Photo by Jez Timms

Leave a Comment