Beans May Lower Breast Cancer Risk - Color Doesn't Matter

Meat (red and processed) was just found to be associated with increased mortality - from cancer, heart disease, and other causes - in the largest prospective study (over half a million participants) investigating this link to date.

So, what may decrease mortality?

Beans. At least mortality due to breast cancer. So suggest the findings of this study that has also been making headlines:

Chemical Composition And Mammary Cancer Inhibitory Activity Of Dry Bean, Crop Science, Jan-Feb 2009

Researchers fed beans to rats. The number of rats that developed breast cancer (after being injected with a carcinogen) was 95% in the non-bean control group, and only 67% in the bean group. That's impressive.

Not only did beans reduce the incidence of cancer (how many rats developed tumors at all), but it also reduced the number of tumors in a rat that did get cancer - from 3.23 tumors down to 1.46. That's impressive.

Six types of beans were tested (2 crop years for each - 2004 and 2005):

Race Nueva Granada from Andean heritage:
White kidney beans
Dark red kidney beans

Race Durango from Middle American heritage:
Great northern beans
Small red beans

Race Mesoamerica also from Middle American heritage:
Navy beans
Black beans

Notice that in each of those three groupings (races), one bean was white or pale, the other was dark or colored. The researchers were trying to determine if there was something about dark-colored beans that gave them an edge over light-colored beans, since dark beans are known to be higher in antioxidants.

In fact, all three of the dark beans above were found by these researchers to be orders of magnitude higher in total phenolics and flavonoid content - both indicators of antioxidant content. The dark beans also displayed more antioxidant activity, as measured by an ORAC assay (Oxygen Radical Absorbance Capacity).

So, you'd think the dark beans would be better at inhibiting breast cancer? I thought that. They weren't. In this study, it mattered more what the heritage of the bean was (from where it was domesticated), than what color its seed coat was or what its antioxidant capacity was.

Although all beans reduced the cancer response, those from Andean heritage (white kidney and red kidney) performed better than the others (great northern, small red, navy, black). The improved performance of Andean beans was statistically significant.

Not only was the color of the bean not associated with anticancer activity, there was also no link found for protein content, fat, fiber, ash, or nitrogen-free extract.

The researchers were at a loss to describe just what it was about beans that gave them a strong anticancer effect.

I should note - the levels of antioxidants in cooked beans were markedly lower than in uncooked beans, to the point of being undetectable. This is because many antioxidant compounds are water soluble, leach into cooking liquid, and in this case were drained away. That didn't matter --> the cooked, drained, dried bean powder (with almost undetectable antioxidants) used in the study still had potent anticancer activity.

So, what do you think it is? What is it about beans? (I have a few ideas.)
________Note: Beans are not compatible with a number of diets, notably Low-carb diets (Atkins, Bernstein, Protein Power, and others) because of beans' carbohydrate content; Paleolithic or Caveman diets (Loren Cordain) because beans were not available in quantity during hunter-gatherer periods; Raw Food diets since sprouting alone doesn't improve digestibility enough to consume them in quantity; Locavore diets unless the beans were grown locally; and Breatharian diets whose followers claim food is not necessary.

Photo: That's a photo of some beans I had in my kitchen. The white are Great Northern Beans, the red are Dark Red Kidney Beans, the black are also known as Turtle Beans.