The effects of
vitamin deficiency on
intestinal cancer are unclear, and even less is known about the consequences of excessive intake. We therefore investigated the actions of altered
vitamin content on
intestinal polyp development, cell proliferation and crypt fission in a mouse model of
neoplasia. Ninety multiple intestinal
neoplasia (ApcMin/+) mice and 90 wild-type littermates, 4 weeks old, were divided into six groups and fed either a control semi-synthetic diet, or the semi-synthetic diet with the
vitamin content lowered to a third of the RDA or the semi-synthetic diet with the
vitamin content increased 5-fold (except for
retinol and
folate, which were doubled). The number and size of
polyps in the small and large intestines were scored after 8 weeks on the diets, as was cell proliferation (native mitoses per crypt) and crypt fission. The small intestines of the low and high
vitamin groups were heavier than the controls. There were significantly more
polyps and the tumour burden was higher in both the low and the high
vitamin groups (P < 0.02). Proliferation was slightly reduced by the
vitamin alteration and crypt fission was significantly increased in the ApcMin/+ mice when compared with the wild-type (P < 0.001). Fission indices were decreased by
vitamin alteration in the small intestine, and increased in the colon, but only in the ApcMin/+ mice. The effects of
vitamin alteration on
polyp number were most pronounced in the proximal intestine, which is also the site of maximum crypt fission. Both
vitamin deficiency and over-supplementation can markedly enhance
polyp number and tumour burden.