Dietary Flaxseed Slows Tumor Growth in Mouse Model

Results obtained from experiments with mice prone to development of intestinal tumors showed that a diet enriched with flaxseed meal or oil decreased the number and size of tumors as compared to animals whose diets were supplemented with corn meal or oil.

Flaxseed is the richest plant source of lignan precursors, which are important because the lignans that mammals produce from this food precursor have been shown to be protective against breast and colon cancer. Furthermore, flaxseed contains secoisolariciresinol diglucoside (SDG), a potent antioxidant and a known precursor of the mammalian lignans, enterolactone and enterodiol. These compounds have other pharmacological properties including phytoestrogen properties similar to isoflavones.

In the current study investigators at South Dakota State University (Brookings, USA) chose to investigate the possible chemopreventive effects of dietary flaxseed on the development of intestinal tumors in ApcMin mice, a strain that develops spontaneous intestinal tumors due to a mutation.

To this end they separated ApcMin mice into five different groups, which were fed with control (AIN-93M meal), corn meal, flaxseed meal, corn oil, or flaxseed oil supplemented diets.

Results published in the March 2, 2009, issue of the journal Nutrition and Cancer showed that dietary flaxseed significantly decreased the number and size of tumors in the small intestine and colon as compared to control, corn-treated groups. Intestine, colon, and serum samples of corn-treated groups showed higher levels of omega -6 fatty acids, whereas the flaxseed treated groups exhibited higher levels of omega -3 fatty acids. Lignans were detected in the serum, intestine, and colon samples from the flaxseed meal group. Colon samples from the flaxseed meal group showed significantly lower expression of the enzymes COX-1 and COX-2 as compared to similar samples from the corn meal group.

"Results indicated that mice on diets supplemented with flaxseed meal and flaxseed oil had, on average, 45% fewer tumors in the small intestine and the colon compared to the control group," said senior author Dr. Chandradhar Dwivedi, professor of pharmaceutical sciences at South Dakota State University. "Dietary flaxseed oil and meal are effective chemopreventive agents against colon and intestinal tumor development in experimental animal models. Further studies are needed to establish the optimal amount of flaxseed that should be incorporated into human diets to get an antitumor benefit and to explore the possible mechanism of action by which flaxseed can help prevent colon cancer."

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