Dietary garlic and onion reduce the incidence of atherogenic diet-induced cholesterol gallstones in experimental mice

Abstract

Mice fed with diet containing 0·5 % cholesterol for 10 weeks resulted in cholesterol supersaturation in gallbladder bile which promoted the formation of cholesterol gallstones (CGS). In this study, dietary hypocholesterolaemic spices, garlic and onion (both raw or heat-processed) were examined for their antilithogenic potential by including at 0·6 and 2·0 % level, respectively, along with lithogenic (LG) diet for 10 weeks. Dietary garlic and onion reduced the CGS incidence by 15-39 %, the effect being maximum in the heat-processed onion group. Dietary garlic and onion markedly reduced biliary cholesterol. The cholesterol:phospholipid ratio which was 1·58 in the LG diet group was reduced to 0·73 -0·96 in the garlic and onion groups. The biliary cholesterol saturation index was 0·92, 1·25, 1·09 and 0·86, respectively, in the heat-processed onion, raw garlic, heat-processed garlic and raw onion groups, while it was 1·9 in the LG group. The hydrophobicity index of bile was 20·08, 2 0·079, 2 0·032 and 20·073, respectively, in the heat-processed onion, raw garlic, heat-processed garlic and raw onion groups, while it was þ0·054 in the LG group. Hepatic hydroxymethyl glutaryl-CoA reductase activity was lowered in the LG diet-fed group, while dietary garlic or onion countered this alteration and also increased the activities of hepatic cholesterol 7a-hydroxylase and sterol 27-hydroxylase. Serum and liver cholesterol were decreased by feeding garlic or onion compared to the LG diet. Thus, dietary Allium spices exerted antilithogenic influence by decreasing the cholesterol hyper-secretion into bile and increasing the bile acid output thus decreasing the formation of lithogenic bile in experimental mice.

Diet and biliary tract cancer risk in Shanghai, China

“…Animal studies have shown dietary garlic and onions reduce diet-induced cholesterol gallstones [30], a well-established risk factor for gallbladder cancer [3, 31, 32, 33]. Evidence from our study supports this finding, as consumption of both garlic and onions was associated with a moderately decreased risk of gallbladder cancer.…”

“…Evidence from epidemiological studies shows a strong association between esophageal cancer and consumption of preserved and pickled vegetables [43]. A recent meta-analysis showed a 52% increase in gastric cancer risk from consumption of pickled vegetables [44]; an 86% increase in gastric cancer risk was seen in those from mainland China [30]. In a study of Japanese men and women, high intake of salted foods including salted fish, increased the risk of gastric cancer in men (RR Q5vs.Q1 : 2.23, p-value = 0.001); however, similar trends were not seen in women (RR Q5vs.Q1 :1.32, p-value = 0.48) [45].…”

Role and classification of cholesterol-lowering functional foods

“…Live lactobacilli and bifidonacteria cells can hydrolyze the conjugated bile acids, excrete them faster and reduce the extent to which they are reabsorbed (Kawase, Hashimoto, Hosoda, Morita, & Hosono, 2000). Dietary Allium spices (garlic and onion) exerts antilithogenic influence by decreasing the cholesterol hyper-secretion into bile and increasing the bile acid output, thus decreasing the formation of lithogenic bile in experimental mice (Vidyashankar, Sambaiah, & Srinivasan, 2009).…”

Allium sativum

“…Dietary garlic and onion reduced the cholesterol gallstone incidence by 15-39 % in mice, the effect being maximum in the heat-processed onion group (Vidyashankar et al 2009 ). Dietary garlic and onion markedly reduced biliary cholesterol.…”