research poster

1. Abstract
Scientists have discovered that many cases of colon cancer are
greatly influenced by a person’s diet, and less impacted by genetic
background. Eating plenty of resistant starches (able to be fermented in
the large intestine as they escape digestion in the small intestine) could
to inhibit colon cancer through preventing the formation preneoplastic
lesions like aberrant crypt foci (ACF) in our bodies. Studies have
shown that those mice injected with cancer starters, such as
azoxymethane (AOM) contain higher amounts of ACF than those mice
that are not injected with cancer starters and are instead injected with a
saline control. 60 male A/J mice were divided into 4 equal groups and
placed on one of 4 diets (Control Starch, OSA, HA7, and RS5) each
with a varying resistant content. There were 10 AOM injected mice
and 5 saline injected mice per group. After euthanization of the mice
by carbon dioxide (CO2), the colons were extracted and stained to find
the amounts of ACF in the colons. The HA7 diet was the most
protective against colon cancer because the AOM injected mice that
consumed this diet contained the least amount of ACF in their colons
(the average was 0.6 ACF/mouse). On the other hand, the control diet
was the least protective against colon cancer because the diet contained
no resistant content. Thus we hypothesize that resistant starch fed in a
diet will be able to maintain near normal numbers of ACF and help to
inhibit the initiation and progression of colorectal cancer.
Intro
•Lots of ACF present in colon when one has colon cancer.
•Inhibiting colon cancer using resistant starches stabilizes the normal
amounts of ACF in our bodies.
•50, 830 people die from colon cancer every year.
•More African Americans than any other race are diagnosed with colon
cancer and more men than women are diagnosed with colon cancer.
•Resistant starches are thought to inhibit colon cancer through preventing
the formation of ACF in our bodies. Resistant starches are able to be
fermented in the large intestine and colon as they escape digestion in the
small intestine, which helps maintain normal healthy colonic tissue and
decreases the amount of precancerous lesions.
•Preneoplastic lesions, such as Aberrant Crypt Foci (ACF), are present in
high amounts in the colon when one has cancer.
Materials and Methods
•5 week old A/J mice
•The mice acclimated for 2 weeks on the control diet, and then remained
on the diet while receiving 4 weekly injections of AOM or Saline and
then they started on their test diets for 10 weeks.
•The mice were divided into 4 equal diet groups (OSA, HA7, RS5, and
Control Starch) with 10 AOM injected mice and 5 saline injected mice
per group. There were 15 mice per diet.
•We observed and recorded the changes in mice while they were on
their diets.
•The mice were euthanized by Carbon Dioxide and their colons were
extracted for analyses.
•The colons were stained with Alcian Blue and a counter stain to
observe and record the number of any ACF’s present.
Discussion
•The HA7 diet could prevent colon cancer more than any of the
other four diets.
•The HA7 diet would be the diet to choose if someone was trying to
inhibit colon cancer.
•All in all, in terms of which diet prevents colon cancer the most,
HA7 is the best, then the Control Starch, then OSA, and finally RS5.
Results
•All saline groups contained close to zero ACFs.
•CS/AOM=1.2 ACFs, HA7/AOM=0.6 ACFs, OSA/AOM=1.3 ACFs,
RS5/AOM=1.7 ACFs.
•HA7 is the most resistant and RS5 is the least resistant.
•RS5 and OSA’s resistant components were too high that they made
the effects of the AOM worse.
•The HA7 diet is able to effectively combat the effects of the AOM
and inhibit progression of this preneoplastic lesion and thus colorectal
cancer.
References
1. Angelle, Amber. "Colon Cancer: Causes, Symptoms and Treatments."
LiveScience.com. TechMedia Network, 2013. Web. 16 July 2013.
2. "What Are the Key Statistics about Colorectal Cancer?" What Are the
Key Statistics about Colorectal Cancer? American Cancer Society, 17
Jan. 2013. Web. 16 July 2013.
3. Staff, Mayo Clinic. "Definition." Mayo Clinic. Mayo Foundation for
Medical Education and Research, 13 Aug. 2011. Web. 16 July 2013.
Figure 1: Average ACFs in Each Diet
Picture 1: Colon with many ACFs
Marissa Jackson and Jadyn Johnson, Food Science and Human Nutrition, Iowa State University
Using Resistant Starch to Inhibit Preneoplastic Lesions