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Recommendations Summary

DM: Fiber and Diabetes 2008

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)

    DM: Fiber Intake and Glycemia

    Recommendations for fiber intake for people with diabetes are similar to the recommendations for the general public (DRI: 14 grams per 1000 kcal). While diets containing 44 to 50 grams of fiber daily are reported to improve glycemia; more usual fiber intakes (up to 24 grams daily) have not shown beneficial effects on glycemia. It is unknown if free-living individuals can daily consume the amount of fiber needed to improve glycemia.

    Rating: Strong
    Imperative

    DM: Fiber Intake and Cholesterol

    Include foods containing 25-30 grams of fiber per day, with special emphasis on soluble fiber sources (7-13 grams).  Diets high in total and soluble fiber, as part of cardioprotective nutrition therapy, can further reduce total cholesterol by 2-3% and LDL cholesterol up to 7%.

    Rating: Strong
    Imperative

    • Risks/Harms of Implementing This Recommendation

      • Excessive fiber intake can potentially have undesirable gastrointestinal side effects.

    • Conditions of Application

      None.

    • Potential Costs Associated with Application

      • Although costs of MNT sessions and reimbursement vary, medical nutrition therapy sessions are essential for improved outcomes.

    • Recommendation Narrative

      • There is inconclusive evidence that increasing dietary fiber will influence glycemic outcome in people with diabetes.   
      • Two studies with higher fiber and lower fiber diets both containing similar macronutrient percents of energy (Hagander et al, 1998; Chandalia et al, 2000) showed no significant difference between diets for A1C, and one study (Giacco et al, 2000) showed a 2% reduction in A1C only in subjects compliant with the 50 gram fiber diet. 
      • Three studies (Chandalia et al, 2000; Giacco et al, 2000; Kinmonth et al, 1982) found 24-hr glycemic profiles significantly lower on the higher fiber diet vs the lower fiber diet and one study (Del Toma et al, 1998) showed significantly lower postprandial glucose levels on the higher fiber vs the lower fiber diet. 
      • Two studies with higher fiber and lower fiber diets having different macronutrient percents of energy (Anderson et al, 1991; Milne et al, 1994) showed no change in A1C between diets; however, two studies (McCulloch et al, 1985; Stevens et al, 1985) showed significant improvement in A1C with the higher fiber diet vs the lower fiber diet. 
      • Three studies (Lindsay et al, 1984; Riccardi et al, 1984; Story et al, 1985) found no change in fasting blood glucose between diets, and one study (Simpson et al, 1988) found significant improvement in FBG for the higher fiber vs the lower fiber diet. 
      • One cross-sectional study (Buyken et al, 1998) found that fiber intake was inversely related to A1C and the other (Shimakawa et al,  1993) showed no relationship.  
      • When the above studies are divided according to environment (controlled or free living), type of diabetes, or “good” or “poor” control, they showed the same  results.  
      • There appears to be conclusive evidence that higher fiber diets will lower total cholesterol significantly vs lower fiber diets. In eight studies lipids were a measured outcome.   Seven studies (Riccardi et al, 1984; Stevens et al, 1985; Story et al, 1985; Hagander et al, 1988; Simpson et al, 1988; Anderson et al, 1991; Chandalia et al, 2000) showed a significant decrease in total cholesterol in the higher fiber group compared to the lower fiber group and one (Milne et al, 1994) showed no change. Three of the eight studies reported significantly reduced HDL-cholesterol (Riccardi et al, 1984; Simpson et al, 1988; Anderson  et al, 1991). 

      • Consuming diets high in total dietary fiber (greater than 25 grams per day) is associated with decreased risk for CHD and CVD (Van Horn, 1997; Liu et al, 1999; Wolk et al, 1999; Liu et al, 2002; Bazzano et al, 2003; Merchant et al, 2003; Pereira et al, 2004).  
      • Consuming diets high in total fiber (17-30 g/day) and soluble fiber (7-13 g/day) as part of a diet low in saturated fat and cholesterol can further reduce total cholesterol by 2-3% and LDL up to 7% (Brown et al, 1999; Ludwig et al, 1999; Saltzman et al, 2001; Van Horn et al, 2001; Davy et al, 2002; Jenkins et al, 2002).
      • Limited research indicates that other risk factors for CHD may be modified by a diet low in saturated fat and cholesterol and high in total and soluble fiber.  These risk factors include blood pressure, lipoprotein subclasses and particle sizes, and fasting and post-prandial insulin (Brown et al, 1999; Ludwig et al, 1999; Saltzman et al, 2001; Van Horn et al, 2001; Davy et al, 2002; Jenkins et al, 2002).
      • American Diabetes Association Recommendation:  As for the general population, people with diabetes are encouraged to consume a variety of fiber-containing foods.  However, evidence is lacking to recommend a higher fiber intake for people with diabetes than for the population as a whole (Grade B). 

    • Recommendation Strength Rationale

      • Conclusion Statement for Fiber and Diabetes given Grade I
      • Conclusion Statements for Fiber and CHD given Grades I, II and III    

    • Minority Opinions

      Consensus reached.