Effect of the Molecular Weight of Oat β-glucan on Its Ability to Lower Serum Cholesterol
Condition: Hypercholesterolemia
MeSH terms: Hypercholesterolemia
Study type: Interventional
Phase: Phase 2

Summary: 
      The purposes of this study were:

        1. To determine if a breakfast cereal containing 3g of high molecular weight oat
           beta-glucan fiber would lower low-density lipoprotein (LDL) - cholesterol (the "bad"
           cholesterol) compared to a control cereal containing wheat fiber.

        2. To determine if the LDL-cholesterol-lowering effect of oat beta-glucan fiber was reduced
           when the molecular weight of the fiber was reduced.
    

Detailed description: 
      The FDA allows a health claim that oat products may reduce the risk of heart disease, based
      on meta-analyses showing a cholesterol-lowering effect of oat beta-glucan, if the product
      delivers at least a 3g daily dose of oat beta-glucan. However, not all studies have
      demonstrated a lowering of oat products. This may be due to variable bioactivity of the
      beta-glucan in the oat products. The bioactivity of oat beta-glucan is believed to depend
      upon its viscosity in the gut. Factors influencing viscosity include the molecular weight
      (MW) of the beta-glucan molecule and the amount of soluble beta-glucan in the product, which,
      in turn determines its concentration (C) in solution. In finished food products both MW and C
      can be modified by beta-glucanase enzymes present in other ingredients in the food (eg. wheat
      flour), processing (eg. extrusion) and storage (eg. freezing of moist products such as
      muffins). The effect of altering the MW and solubility of beta-glucan in foods on glycemic
      responses has been shown, but a role for MW and C in cholesterol lowering has not been
      established.

      To address this issue, this study was designed with 2 primary objectives:

        1. An extruded oat cereal containing 3g high-molecular weight oat β-glucan daily will
           reduce LDL cholesterol compared to a control wheat bran cereal.

        2. A significant correlation exists between LDL cholesterol and log(C×MW), where C is the
           amount of soluble β-glucan in the daily dose of cereal and MW is the molecular weight of
           the β-glucan in the cereal.
    

Intervention name(s): Wheat bran; 3g high MW; 4g medium MW; 3g medium MW; 4g low MW
Intervention type(s): Dietary Supplement; Dietary Supplement; Dietary Supplement; Dietary Supplement; Dietary Supplement
Intervention description(s): 21g per day of ready to eat breakfast cereal containing wheat bran with 8g of total dietary fiber and 0.5g beta-glucan.; 20.2 grams per day of ready to eat cereal containing 6g total dietary fiber and 3g oat beta glucan with high molecular weight; 28.5g ready to eat cereal containing 8g total dietary fiber and 4g oat beta glucan with medium molecular weight; 21.1g of ready to eat cereal containing 6g total fiber and 3g oat beta glucan with a medium molecular weight; 28.7g ready to eat cereal containing 8g total dietary fiber and 4g oat beta glucan with low molecular weight
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Treatment
Keywords: humans; randomized clinical trial; dietary fiber; nutrition; beta-glucan; oats; LDL cholesterol; coronary heart disease