A kind of starch to reduce colon cancer risk from eating red meat?

4 Aug 2014

New research suggests that a specific kind of starch can reduce the risk for colorectal cancer that comes with the consumption of red meat (beef, pork & lamb).

 

Evidence suggests that red meat - beef, pork, lamb - can increase the risk of colorectal cancer if consumed in high enough proportions. A new study suggests, however that the consumption of resistant starch could potentially reduce this risk, making diets high in red meat safer to eat.

Red meat has been associated with increasing the risk of colorectal cancer more and more over the past 20 years. "Total meat consumption in the USA, European Union, and the developed world has continued to increase from the 1960s, and in some cases has nearly doubled," says Karen J. Humphreys, a research associate from Flinders University in Adelaide, Australia, who worked on the study.

The American Institute of Cancer Research state that red meat contains substances such as "heme iron" that have been linked to the development of colon cancer. Heme iron is the compound that gives red meat its color and can damage the lining of the colon.

Comparing two 4-week diets

The study, published in Cancer Prevention Research, involved 23 healthy volunteers (17 male and six female) aged 50-75 trialing two different diets for 4-week periods; one diet was high in red meat consumption and one was high in a kind of starch called "resistant starch".

Resistant starch differs from other starches in that it escapes digestion while passing through the stomach and small intestine. When it reaches the large intestine, it can produce beneficial molecules known as "short-chain fatty acids".

These short-chain fatty acids include "butyrate", which is known to inhibit tumor cells in the colon while promoting the growth of healthy ones. The alternative diet to the red meat diet within the study was high in butyrate resistant starch.

The participants would embark upon eating one of the diets for a 4-week period, and then after a 4-week washout period, they would commence following the other diet for another 4 weeks.

The researchers found that after eating 300 g of lean red meat per day for 4 weeks, nearly twice the daily amount recommended by the American Heart Association (AHA), participants had a 30% increase in levels of specific kind of molecules in their rectal tissue, that scientists believe promote cancer.

After consuming 40 g of butyrate resistant starch per day alongside red meat for 4 weeks, the participants' levels of these molecules were brought back down to baseline levels.

Sources of resistant starch

Humphreys identifies the following as good examples of natural sources of resistant starch:

Bananas (that are still slightly green) Beans Chickpeas Lentils Whole grains.

Although over 90% of colorectal cancer cases occur in people who are 50 years old or more, this study is limited by the size and variety of its participating group. Further research will certainly need to expand upon its scale, as well as look out for other variable factors that could impact on the results.

As ever, maintaining a balanced diet is recommended as the best way to stay healthy and reduce the risk of illness.

The AHA recommend limiting the amount of red meat that is consumed every day, as it generally contains more cholesterol and saturated fats than other types of meat and vegetables. If red meat is to be consumed, it is best not to consume more than 170 g per day.

 

Source: Medical News Today

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