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Recommendations Summary

PDM: Fiber and Prevention of Type 2 Diabetes 2014

Click here to see the explanation of recommendation ratings (Strong, Fair, Weak, Consensus, Insufficient Evidence) and labels (Imperative or Conditional). To see more detail on the evidence from which the following recommendations were drawn, use the hyperlinks in the Supporting Evidence Section below.


  • Recommendation(s)

    PDM: Fiber and Prevention of Type 2 Diabetes

    The registered dietitian nutritionist (RDN) should encourage individuals who are at high risk for type 2 diabetes to consume fiber at the level recommended by the USDA Dietary Guidelines (14g per 1, 000kcal). Limited research regarding fiber intake, independent of weight loss, reported no significant impact on outcomes in adults with metabolic syndrome or individuals with prediabetes. However, a high-fiber diet can help reduce body weight and therefore reduce the risk of type 2 diabetes.

     

    Rating: Fair
    Imperative

    • Risks/Harms of Implementing This Recommendation

      None.

    • Conditions of Application

      Research on synergistic effects of nutrients was not evaluated.

    • Potential Costs Associated with Application

      The costs of medical nutrition therapy (MNT).

    • Recommendation Narrative

      A total of four studies were included in the evidence analysis for this recommendation:

      • Two positive-quality randomized controlled trials (RCT) (Lindstrom et al, 2006; Lankinen et al, 2011)
      • One neutral-quality randomized controlled trial (RCT) (Wien et al, 2010)
      • One neutral-quality randomized crossover trial (RCT) (Pouteau et al, 2010).

      In Adults With Metabolic Syndrome

      • Glycemic-related outcomes (FBG, random BG, two-hour post-prandial BG, A1C):
        • Limited research reports that total fiber intake, independent of weight loss, has no significant impact on fasting blood glucose levels in adults with metabolic syndrome
        • Additional longer-term intervention studies are needed to ascertain an effect of total fiber intake on glycemic-related outcomes in adults with metabolic syndrome with or without meeting the metabolic syndrome criteria for impaired glucose tolerance and impaired fasting glucose
        • Evidence is based on the following: Pouteau et al, 2010.
      • Lipid outcomes (TG, HDL):
        • Limited research reports that total fiber intake, independent of weight loss, has no significant impact on triglycerides or HDL cholesterol levels in adults with metabolic syndrome
        • Additional longer-term intervention studies are needed to ascertain an effect of total fiber intake on lipid outcomes in adults with metabolic syndrome with or without meeting the metabolic syndrome criteria for lipid levels
        • Evidence is based on the following: Pouteau et al, 2010.
      • Anthropometric outcomes (WC, WHR):
        • There were no studies identified to evaluate the impact of total fiber intake, independent of weight loss, on anthropometric outcomes in adults with metabolic syndrome
        • Intervention studies are needed to ascertain an effect of total fiber intake on anthropometric outcomes in adults with metabolic syndrome with or without meeting the metabolic syndrome criteria for anthropometric measures.
      • Blood pressure outcomes:
        • There were no studies identified to evaluate the impact of total fiber intake, independent of weight loss, on blood pressure in adults with metabolic syndrome
        • Intervention studies are needed to ascertain the effect of total fiber intake on blood pressure in adults with metabolic syndrome with or without meeting the metabolic syndrome criteria for blood pressure.
      • Renal outcomes:
        • There were no studies identified to evaluate the impact of total fiber intake, independent of weight loss, on renal outcomes in adults with metabolic syndrome
        • Intervention studies are needed to ascertain an effect of total fiber intake on renal outcomes in adults with metabolic syndrome with or without meeting the metabolic syndrome criteria for renal measures.
      • Glycemic-related outcomes (FBG, random BG, two-hour post-prandial BG, A1C):
        • Limited research reports that type of fiber intake, independent of weight loss, has no significant impact on fasting blood glucose levels in adults with metabolic syndrome
        • Additional longer-term intervention studies are needed to ascertain an effect of type of fiber intake on glycemic-related outcomes in adults with metabolic syndrome with or without meeting the metabolic syndrome criteria for impaired glucose tolerance and impaired fasting glucose
        • Evidence is based on the following: Pouteau et al, 2010.
      • Lipid outcomes (TG, HDL):
        • Limited research reports that type of fiber intake, independent of weight loss, has no significant impact on triglycerides or HDL cholesterol levels in adults with metabolic syndrome
        • Additional longer-term intervention studies are needed to ascertain an effect of type of fiber intake on lipid outcomes in adults with metabolic syndrome with or without meeting the metabolic syndrome criteria for lipid levels
        • Evidence is based on the following: Pouteau et al, 2010.
      • Anthropometric outcomes (WC, WHR):
        • There were no studies identified to evaluate the impact of type of fiber intake, independent of weight loss, on anthropometric outcomes in adults with metabolic syndrome
        • Intervention studies are needed to ascertain an effect of type of fiber intake on anthropometric outcomes in adults with metabolic syndrome with or without meeting the metabolic syndrome criteria for anthropometric measures.
      • Blood pressure outcomes:
        • There were no studies identified to evaluate the impact of type of fiber intake, independent of weight loss, on blood pressure in adults with metabolic syndrome
        • Intervention studies are needed to ascertain the effect of type of fiber intake on blood pressure in adults with metabolic syndrome with or without meeting the metabolic syndrome criteria for blood pressure. 
      • Renal outcomes:
        • There were no studies identified to evaluate the impact of type of fiber intake, independent of weight loss, on renal outcomes in adults with metabolic syndrome
        • Intervention studies are needed to ascertain an effect of type of fiber intake on renal outcomes in adults with metabolic syndrome with or without meeting the metabolic syndrome criteria for renal measures. 

      In Individuals With Prediabetes

      • Glycemic-related outcomes (FBG, random BG, two-hour post-prandial BG, A1C):
        • Limited research reports no significant impact of total fiber intake, independent of weight loss, on fasting blood glucose, two-hour post-prandial blood glucose or A1C in individuals with prediabetes
        • Additional intervention studies are needed to ascertain the effect of total fiber intake on glycemic-related outcomes in individuals with prediabetes
        • Evidence is based on the following: Wien et al, 2010; Lankinen et al, 2011.
      • Lipid outcomes (TG, HDL):
        • Limited research reports no significant impact of total fiber intake, independent of weight loss, on triglycerides or HDL cholesterol in individuals with prediabetes
        • Additional intervention studies are needed to ascertain the effect of total fiber intake on lipid outcomes in individuals with prediabetes
        • Evidence is based on the following: Wien et al, 2010.
      • Anthropometric outcomes (WC, WHR):
        • Limited research reports mixed results regarding the impact of total fiber intake, independent of weight loss, on waist circumference in individuals with prediabetes
        • Additional longer-term intervention studies are needed to ascertain the effect of total fiber intake on anthropometric outcomes in individuals with prediabetes
        • Evidence is based on the following: Lindstrom et al, 2006; Wien et al, 2010.
      • Blood pressure outcomes:
        • Limited research reports no significant impact of total fiber intake, independent of weight loss, on systolic or diastolic blood pressure in individuals with prediabetes
        • Additional longer-term intervention studies are needed to ascertain the effect of total fiber intake on blood pressure in individuals with prediabetes
        • Evidence is based on the following: Wien et al, 2010.
      • Glycemic-related outcomes (FBG, random BG, two-hour post-prandial BG, A1C):
        • There were no studies identified to evaluate the impact of the type of fiber intake on glycemic-related outcomes in individuals with prediabetes
        • Intervention studies are needed to ascertain the effect of type of fiber intake on glycemic-related outcomes in individuals with prediabetes.
      • Lipid outcomes (TG, HDL):
        • There were no studies identified to evaluate the impact of the type of fiber intake on lipid outcomes in individuals with prediabetes
        • Intervention studies are needed to ascertain the effect of type of fiber intake on lipid outcomes in individuals with prediabetes.
      • Anthropometric outcomes (WC, WHR):
        • There were no studies identified to evaluate the impact of the type of fiber intake on anthropometric outcomes in individuals with prediabetes
        • Intervention studies are needed to ascertain the effect of type of fiber intake on anthropometric outcomes in individuals with prediabetes.
      • Blood pressure outcomes:
        • There were no studies identified to evaluate the impact of the type of fiber intake on blood pressure in individuals with prediabetes
        • Intervention studies are needed to ascertain the effect of type of fiber intake on blood pressure in individuals with prediabetes. 

      From Primary Prevention of Type 2 Diabetes Recommendations from the American Diabetes Association Standards of Medical Care, 2014

      Individuals at high risk for type 2 diabetes should be encouraged to achieve the U.S. Department of Agriculture (USDA) recommendation for dietary fiber (14g fiber per 1, 000kcal) and foods containing whole grains (one-half of grain intake) (Grade B).

      From Project IMAGE European Evidence-Based Guideline for the Prevention of Type 2 Diabetes, 2010

      • A diet with high fiber (more than 15g per 1, 000kcal), moderate fat (less than 35% of total energy), reduced saturated and trans fat (less than 10% of total energy) can lower body weight and reduce the risk of T2D and is therefore recommended (Grade B)
      • Comorbidities, particular MetS, should be monitored and taken into account when planning the diet (Grade C)
      • Currently there is no evidence from long-term prevention studies that reducing total dietary carbohydrate prevents T2D. Carbohydrate sources should mainly be whole-grain cereal, fruit, vegetables and legumes (Grade C).

    • Recommendation Strength Rationale

      For Adults with Metabolic Syndrome

      • Grade III evidence is available for the conclusion statements regarding the impact of total fiber intake, independent of weight loss, on the following outcomes:
        • Glycemic-related outcomes (such as fasting blood glucose, random blood glucose, two-hour post-prandial blood glucose, A1C)
        • Lipid (TG, HDL).
      • Grade III evidence is available for the conclusion statements regarding the impact of type of fiber intake, independent of weight loss, on the following outcomes:
        • Glycemic-related outcomes (such as fasting blood glucose, random blood glucose, two-hour post-prandial blood glucose, A1C)
        • Lipid (TG, HDL).
      • Grade V evidence is available for the conclusion statements regarding the impact of total fiber intake, independent of weight loss, on the following outcomes:
        • Anthropometric measures (WC, WHR)
        • Blood pressure
        • Renal measures.
      • Grade V evidence is available for the conclusion statements regarding the impact of type of fiber intake, independent of weight loss, on the following outcomes:
        • Anthropometric measures (WC, WHR)
        • Blood pressure
        • Renal measures.

      For Individuals with Prediabetes

      • Grade III evidence is available for the conclusion statements regarding the impact of total fiber intake, independent of weight loss, on the following outcomes:
        • Glycemic-related outcomes (such as fasting blood glucose, random blood glucose, two-hour post-prandial blood glucose, A1C)
        • Lipid (TG, HDL)
        • Anthropometric measures (WC, WHR)
        • Blood pressure.
      • Grade V evidence is available for the conclusion statements regarding the impact of type of fiber intake, independent of weight loss, on the following outcomes:
        • Glycemic-related outcomes (such as fasting blood glucose, random blood glucose, two-hour post-prandial blood glucose, A1C)
        • Lipid (TG, HDL)
        • Anthropometric measures (WC, WHR)
        • Blood pressure.

      From Primary Prevention of Type 2 Diabetes Recommendations from the American Diabetes Association Standards of Medical Care, 2014

      • The Academy of Nutrition and Dietetics Prevention of Type 2 Diabetes Work Group concurs with the references cited
      • Evidence in support of the recommendation was grade B.

      From Project IMAGE European Evidence-Based Guideline for the Prevention of Type 2 Diabetes, 2010

      • The Academy of Nutrition and Dietetics Prevention of Type 2 Diabetes Work Group concurs with the references cited
      • Evidence in support of the recommendation was grades B and C.

    • Minority Opinions

      Consensus reached.