Processed Wheat Bran As a Food That Decreases Food Intake Daniel Gallaher, Dept

2 0 1 2 R E S E A R C H R E P O R T S

Processed Wheat Bran as a Food that Decreases Food Intake Daniel Gallaher, Dept. of Food Science and Nutrition, U of M, St. Paul

Research Questions Application/Use

Control of eating is clearly a very complex phenomenon. Wheat bran processed in such a way as to release bound However, a number of hormones have been identified that phenolics, which are predominantly ferulic acid, could be play important roles in both the desire to begin eating and used as a food ingredient for cereal-based foods such as the signal to stop eating. These are referred to as satiety- bread, pastries, ready-to-eat cereals, and pasta. Doing so related hormones. may well impart a significant health benefit by increasing satiety, as well as other health benefits identified in the Wheat bran is a rich source of phenolic compounds that, USDA study (improved glucose control, cholesterol lower- if absorbed, are thought to have highly beneficial health ef- ing). fects. Unfortunately, these phenolic compounds are nor- mally bound in such a way that they remain almost entirely Materials and Methods unavailable for absorption. As part of a recently completed USDA grant, we have conducted a study in obese, diabetic Plasma obtained from rats fed the diets contain unpro- rats (Zucker Diabetic Fatty rats) in which we fed wheat bran cessed and processed wheat bran were analyzed for that was chemically treated and subjected to high pressure satiety-related hormones by radioimmunoassay (RIA) or homogenization to release the phenolic compounds, there- ELISA. by making the phenolic compounds present in the wheat bran available for intestinal absorption. Rats consuming Economic Benefit to a Typical the processed wheat bran tended to weigh less and tended to consume less diet that rats consuming normal wheat 500 Acre Wheat Enterprise bran. Most importantly, the rats consuming the processed wheat bran diet clearly had less body fat, indicating that the Wheat bran is currently a byproduct of wheat milling with processed wheat bran was in some way reducing the ac- low economic value. Processing the wheat bran to release cumulation of body fat. bound phenolics would create a product with potentially much higher economic value. Creation of such a product We hypothesized that consumption of the processed may increase the value of wheat overall, thus providing wheat bran may have changed the concentration of these economic benefit to the wheat growers. satiety-related hormones in such a way as to decrease food intake in our animals compared to rats eating normal, un- Related Research processed wheat bran. Studies are currently underway examining the health ben- Results efits of whole wheat flour and its various fractions (refined wheat flour, wheat bran, and wheat germ) in Zucker Dia- betic Fatty rats. Parameters being examined include large The Zucker Diabetic Fatty (ZDF) rat is a model for intestinal fermentation, liver cholesterol, fatty liver, glucose the human condition referred to as metabolic disease. control, bile acid excretion, and plasma adipokine profiles. Metabolic disease is a risk factor for diabetes and car- These studies are intended to attempt to define which diovascular disease. Rats fed processed wheat bran had fraction(s) of wheat are most important in providing health reductions in the factors that define metabolic disease, benefits. An abstract of our results to date has been sub- such as high cholesterol, high fasting glucose, insulin mitted for the Experimental Biology 2013 meetings in April. resistance, and excess body fat. These rats also ate less diet. Although the hormone results were complex and the interpretation challenging, overall, the changes in the Recommended Future Research

satiety-related hormones were in the direction that would suggest that the processed wheat bran increased satiety Further work exploring more commercially feasible meth- and therefore may explain, in part, the decrease in food ods of processing wheat bran in such a way as to release intake. phenolics is clearly warranted. Additionally, studies on the mechanism of action of the released phenolics in producing the health benefits defined so far (e.g. cholesterol lowering, improved glucose control, reduced body fat) would be use-

Page 36 2 0 1 2 R E S E A R C H R E P O R T S ful in gaining acceptance of such a product. Finally, studies Publications on the benefits of the processed wheat bran in other animal models, such as a model of insulin resistance, or even hu- Youn, Moonyeon. The Effect of Intake of Whole Grains mans would be most beneficial for promoting wheat bran or Whole Grain Components on Type 2 Diabetes in Rats. processed to liberate phenolics as a commercial product. University of Minnesota. Ph.D. thesis. January 2012.

Other Sources of Funding for this Project

USDA NIFA/2009-55200-05011

Appendix

Basal-Lean Basal-Obese Plasma Ghrelin Wheat bran-Obese 3000 Optimized-Obese Soluble-Obese a Insoluble-Obese a 2500 LV_HPMC-Obese ab ab b bc abc b b bc b 2000 bc c c 1500

1000 Ghrelin (pg/ml)Ghrelin

500

0 Fasted Fed

Bars represent the means + SEM, n=12. Bars within a feeding state (fasted vs. fed) with different letters are significantly different (p<0.05).

Greater plasma concentrations of ghrelin are associated with great hunger. Thus, lower ghrelin concentrations suggest great satiety.

Page 37 2 0 1 2 R E S E A R C H R E P O R T S

Appendix continued:

Basal-Lean Plasma Amylin Basal-Obese Wheat bran-Obese 70 Optimized-Obese Soluble-Obese Insoluble-Obese a 60 LV_HPMC-Obese a

50 a a b a a 40 a c c c 30 c

Amylin (pg/ml) 20 d

0 Fasted Fed

High plasma concentrations of amylin are thought to increase satiety and decrease food intake. However, recent evidence suggests that amylin concentrations may also reflect the total amount of body fat.

Basal-Lean Plasma PYY Basal-Obese 80 Wheat bran-Obese Optimized-Obese a Soluble-Obese Insoluble-Obese a LV_HPMC-Obese a 60 a ab a a ab a 40 a a a PYY (pg/mL)

20 b

0 Fasted Fed

PYY is produced in the lower part of the small intestine and the colon, and high concentrations in the plasma have been found to lower food intake. That is, high PYY concentrations are thought to increase satiety.

Page 38