Colon cancer promotion, insulin resistance and metabolic measures, the role of dietary calcium, vitamin D and fat

Abstract

McKeown-Eyssen and Giovannucci suggested that hyperinsulinemia and/or energy availability may be important in both insulin resistance (IR) and colorectal cancer (CRC). In this thesis, it was hypothesized, first, that dietary calcium effects measures of CRC, IR and energy availability to the same extent. Results demonstrated that vitamin D had no effect on these measures and that elevated calcium was related to reduced CRC promotion and weight gain and increased fecal loss. Secondly, it was hypothesized that metabolic measures associated with IR may be important in carcinogenesis. It was shown that there are considerable diurnal variations and that a high fat diet (HFD) increased non-esterified fatty acids, triglycerides and insulin. This effect was more pronounced postprandially. Also, this HFD resulted in elevations in intracellular lipids of colon epithelial cells, spleen, muscle and liver. It was concluded that energy availability may be important in tissue defects associated with CRC and IR.