Dietary fat and fatty acids modulate cholesterol cholelithiasis in the hamster

Abstract

We tested two hypotheses, i) whether the type and the amount of fat in the diet will affect the formation of cholesterol gallstones in the hamsters, and ii) whether palmitic acid, a major fatty acid component of butterfat, can act as a potentiator of cholesterol cholelithiasis in the hamster. Young, male golden Syrian hamsters (Sasco) were fed a semipurified diet containing casein, corn starch, cellulose and cholesterol (0.3%) to which various types and amounts of fat (butterfat, olive oil, menhaden oil, corn oil) were added. All diets contained 2% corn oil to supply essential fatty acids to the growing hamsters. No deaths or illness occurred during the experiment. Animals fed the semipurified diet plus 4% butterfat (group 1) had a gallstone incidence of 63%. Replacement of butterfat with either olive oil, corn oil or menhaden oil prevented the formation of cholesterol gallstones entirely (groups 2–4). When total butterfat was increased from 4% to 8% (group 8), the incidence of cholesterol gallstones increased to 80%. Substitution of 4% olive oil (group 5), corn oil (group 6), or menhaden oil (group 7) for the additional 4% butterfat significantly reduced gallstones to 35%, 45% and 30%, respectively. The replacement of 4% butterfat with 1.2% palmitic acid gave the highest incidence of cholesterol gallstones (95%). These results suggest that butterfat (and one of its components, palmitic acid) intensifies gallstone formation in this model whereas mono‐ and polyunsaturated fats act as inhibitors of cholesterol cholelithiasis. A fatty acid, possibly palmitic acid, appears to act as lithogen in our model.

Effect of Dietary Consumption, Advanced Age and Overweight on the Physical Characteristics of Cholesterol Gallstones and Biliary Lipid Composition in West Algerian Women

“…However, it is not clear which component of the diet plays the major role. An excessive intake of total energy [24], cholesterol [3], or fat Lamri-Senhadji/Mekki/El Kebir/ Bachir-Bouiadjra/Bouchenak/Belleville [25], has all been blamed. Even the type of fats (polyunsaturated) [26] and the type of sugar (refined) [26] ingested have been suspected as being responsible for producing gallstones in humans.…”

The Experimental Use of Syrian Hamsters

“…In earlier studies, gallstones were induced in Syrian hamsters by feeding a fat-free glucose-rich diet (Dam, 1971). Diet models have evolved to include elevated levels of butterfat (Cohen et al, 1992;Hayes et al, 1992;Holzbach, 1984). In hamsters, the butterfat-diet induces a high cholesterol/phospholipid ratio in bile which promotes cholesterol cholelithiasis.…”

The incorporation of fatty acids of different chain length into liver and biliary lipids in the perfused rat liver

“…The specific radioactivity of biliary choles-terol (as compared to liver cholesterol) was 12 times higher for C 2 and five times higher for MCFA. LCFA did not lead to 14 C-cholesterol synthesis.…”

“…A similar abnormality was induced in rats by a high legume diet (11). Dietary supplementation of fish oil in contrast to more saturated triacylglycerols (TAG) markedly increased the percentage of 20:5 and 22:6 in biliary PC, reducing the lithogenicity and incidence of cholesterol precipitates in rats (12), African green monkeys (13), and hamsters (14)(15)(16). Likewise, addition of fish oil to the diet of gallstone patients induced an increase in 20:5 and 22:6 in biliary PC with a concomitant reduction in 18:2 concentration (17).…”