RESUMEN
A fatty diet is regarded as one of the most important risk factors related to the etiology of colorectal cancer, and this effect is linked to the quantity and principal types of fatty acids consumed. In this study, the chemopreventive effects of different oils on rats were investigated. Forty Wistar rats received 1,2-dimetilhidrazine (DMH) and were divided into 4 groups fed normal lipid diets to which 4% olive, fish, flaxseed, or soybean oils (control) were added. The group fed with fish oil presented higher levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid in hepatic tissue and greater levels of linolenic acid and EPA in adipose tissue compared to the other treatments. In the proximal portion of the colon, lower levels of aberrant crypt foci were found in the fish and flaxseed oil groups; however, this behavior was not observed in the middle and distal regions. Via a benchmarking method, the fish oil group showed a greater transforming growth factor ß expression and lower interleukin-8 expression in relation to the other treatments. Fish oil in a normal lipid diet demonstrated a limited protective effect on the colonic precancerous mucosa in carcinogen-treated rodents, whereas it had a beneficial effect on inflammatory modulation.
Asunto(s)
Neoplasias del Colon/tratamiento farmacológico , Neoplasias del Colon/patología , Aceites de Pescado/farmacología , Interleucina-8/sangre , Interleucina-8/efectos de los fármacos , 1,2-Dimetilhidrazina/toxicidad , Animales , Carcinógenos/toxicidad , Colon/efectos de los fármacos , Colon/metabolismo , Colon/patología , Neoplasias del Colon/inducido químicamente , Ácidos Docosahexaenoicos/farmacología , Ácido Eicosapentaenoico/farmacología , Masculino , Ratas , Ratas Wistar , Ácido alfa-Linolénico/farmacologíaRESUMEN
OBJECTIVE: We evaluated the effects of peanut oil intake on appetite, energy expenditure, body composition, and lipid profile in lean and overweight adults. METHODS: In a parallel-arm, long-term feeding trial, lean and overweight participants received a daily peanut oil load in a milk shake equivalent to 30% of their resting energy expenditure for 8 wk. Forty-eight adults (24 lean and 24 overweight, 12 male and 12 female in each group) completed the protocol. Anthropometric indices, appetite, dietary intake, energy expenditure, and plasma lipids were monitored. RESULTS: Energy intake increased significantly in the overweight but not in the lean participants. A statistically significant body weight gain (median 2.35 kg) was also observed among the overweight subjects, although this corresponded to only 43% of the theoretical weight gain. Among overweight subjects, high-density lipoprotein cholesterol increased significantly and low-density lipoprotein cholesterol decreased at week 4, but neither concentration was significantly different from baseline at week 8. Similar, but less marked, changes were observed in lean subjects. Resting energy expenditure was 5% greater (P < 0.01) in the overweight group, but no significant difference was observed in the lean subjects. No marked differences of appetite were observed over time in either group or between overweight and lean participants. CONCLUSION: These data indicate that ingestion of peanut oil elicits a weaker compensatory dietary response among overweight compared with lean individuals. Body weight increased, albeit less than theoretically predicted. The weaker effect of whole nuts on body weight reported in previous studies suggests components other than oil may be responsible.