Wholemeal versus wholegrain breads: proportion of whole or cracked grain and the glycaemic response.
OBJECTIVE
To determine the effect on the glycaemic response to bread of the ratio of whole cereal grains to milled flour.


METHODS
Randomised assignment of groups of diabetic volunteers to test and control meals, taken after an overnight fast. Test foods were also analysed for in vitro digestion with human saliva.


METHODS
Tertiary care centre.


METHODS
Groups of six drawn from pool of 16 volunteers with diabetes mellitus (11 men, five women; mean age 64 (SE 3); 10 taking insulin, five taking oral agents, one controlled by diet; other characteristics comparable).


METHODS
All patients took standard white bread control meals on three occasions spanning the study and on different mornings took test meals containing varying ratios of whole cereal grains (barley or cracked wheat) to milled flour (75:25, 50:50, 0:100). All meals contained 50 g available carbohydrate and were eaten in 15 minutes. Capillary blood samples were taken for determination of glucose concentrations every 30 minutes for three hours.


METHODS
Glycaemic index of foods (= increase in area under blood glucose concentration curve for test food divided by increase in area under curve for white bread control X 100).


RESULTS
Significant trend to lower glycaemic index with increasing proportion of whole cereal grains in test bread (p less than 0.05) and lower in vitro digestibility (p less than 0.001). Breads containing up to 75% whole grain were considered palatable.


CONCLUSIONS
Breads containing a high proportion of whole cereal grains may be useful in reducing the postprandial blood glucose profile in diabetics because they are more slowly digested. These breads should be called "wholegrain" in distinction to "wholemeal" breads made from milled flour.
D001786:Blood Glucose / Q000378:metabolism*; D001939:Bread / Q000145:classification; D003920:Diabetes Mellitus / Q000097:blood*; D004032:Diet; D004063:Digestion; D002523:Edible Grain; D005260:Female; D005433:Flour; D006801:Humans; D008297:Male; D008875:Middle Aged; D011897:Random Allocation
D001786:Blood Glucose