Effect of Resistant Starch on Blood and Liver Lipids in Hamsters

Cereal Chem. 73(2):176-178 Serum and liver lipid responses were studied in young hamsters fed CL as compared to those fed NS, or both. The lowering of CH resulted diets containing cholesterol (CH) and either no fiber or 20.5% fiber. from a reduction of both high-density lipoprotein (HDL) CH and nonFiber was provided as resistant starch (RS) or as cellulose (CL); the noHDL CH. Like serum CH, serum triglyceride levels were also lower in fiber diet was based on normal starch (NS). After four weeks, serum hamsters fed RS and CL-nearly 50% lower compared with those fed total CH in hamsters fed RS was 16.2% lower, and in those fed CL NS. Liver CH and lipid levels defied this trend in that CH levels were 13.1% lower, than in hamsters fed NS. This effect may be specific to RS higher in hamsters fed RS than in those fed NS or CL. and CL, may be the result of lower weight gains in hamsters fed RS and Resistant starch (RS) is defined as the sum of starch and starch degradation products that resist digestion in the small intestine (Asp 1992). RS occurs naturally in some prepared foods in small amounts (Englyst and Cummings 1985); however, high-amylose corn starch can be modified to contain significant levels of RS (Kevin 1995). Although RS is starch, it analyzes as fiber (Berry 1986) and functions as fiber (Ranhotra et al 1991, Van Munster et al 1994, Phillips et al 1995). RS is becoming a food ingredient of increasing interest. It does not hold much water and, thus, may be a preferred fiber source for use in low-moisture products such as cookies and crackers. RS is also free of gritty mouthfeel and, unlike traditional fiber sources, is reported not to alter flavor and textural properties of foods. These characteristics can improve the processing and quality of foods such as baked and extruded products where RS may be added. If RS can be shown to also favorably affect health parameters, this may further underscore the importance of this ingredient. A study with healthy young men recently showed RS caused a significant reduction in postprandial glycemia and insulinemia (Raben et al 1994), as compared to normal starch (NS). RS may also affect blood cholesterol (CH) and triglyceride (TG) levels favorably. This study was undertaken to examine this possibility using hamsters, a more suitable model for lipid studies than rats (Beher et al 1992), as the test model. MATERIALS AND METHODS Test Materials RS (CrystaLean) was obtained from Opta Food Ingredients, (Bedford, MA). It is prepared from high-amylose corn starch by subjecting corn starch to repeated heating and cooling cycles and other processing steps. NS, a pregelatinized corn starch, was obtained from American Maize-Products Co., Hammond, IN. Cellulose (CL, Solka-Floc) was obtained from FS & D Corp. (Urbana, OH). These materials were analyzed (Table I) and used to formulate test diets (Table II). Test Diets Diet NS (NS-based) contained virtually no fiber, while diet RS (RS-based) and diet CL (CL-based) contained 20.5% fiber each (Table II). All diets contained the same level of protein (15%) and lCorresponding author: American Institute of Baking, 1213 Bakers Way, Manhattan, KS 66502. Phone: 913/537-4750. Fax: 913/537-1493. Publication no. C-1996-0212-03R. i 1996 American Association of Cereal Chemists, Inc. 176 CEREAL CHEMISTRY fat (10%) and the sources differed minimally. All diets also contained 0.5% CH and were complete in nutrients required by weanling hamsters (NRC 1987).