Transcript: Phytates for the Prevention of Cancer
Cancer prevention strongly acknowledges the importance of diet, as dietary factors are the most important environmental risk factors for cancer. Within recent years, a large number of naturally occurring health-enhancing substances of plant origin have been recognized to have beneficial effects on cancers, known as phytochemicals. Yes, beans, chickpeas, split peas and lentils are packed with all sorts of nutrients we need, but the reason they may protect against several degenerative diseases may be due to non-nutritive compounds in plants, or even so-called antinutrient compounds like phytates. The reputation of phytate has had a roller coaster ride ever since its discovery; it has undergone alternate eminence and infamy. What everyone can agree on though is that phytates, also known as phytic acid, are one of the most fascinating bioactive food compounds and are widely distributed in plant foods.
In the U.S. colon cancer is the second leading cause of cancer death, but in some parts of the world, they’ve had just a tiny fraction of our rates, with the highest rates reported in Connecticut, and the lowest in Kampala, Uganda. The famous surgeon Dr. Burkitt spent 24 years in Uganda and most of the hospitals in Uganda he contacted had never even seen a case of colon cancer. Noting they live off diets centered on whole plant foods, he figured that maybe it was the fiber that was so protective.
Studies like this, though, called that interpretation into question. Danes appear to have more colon cancer than Finns, yet Danes consume almost twice the dietary fiber. What else, then, could explain the low cancer rates among plant-based populations? Well fiber isn’t the only thing found in whole plant foods, missing from processed and animal foods. Maybe it’s the phytate.
Dietary phytate, rather than fiber per se, might be the most important variable governing the frequency of colon cancer, as we know phytate is a powerful inhibitor of the iron-mediated production of hydroxyl radicals, a particularly dangerous type of free radical. So the standard American diet may be a double whammy, the heme iron in muscle meat plus the lack of phytate in refined plant foods to extinguish the iron radicals.
This may account for what they found in the Adventist study. They found excess risk of cancer for higher intakes of both red meat and white meat, suggesting all meats contribute to colon cancer formation. About twice the risk for red meat eaters, and three times the risk for those eating chicken and fish, but those eating meat could reduce their risk in two ways, by cutting down on meat or by eating more beans, an excellent source of phytates.
So it’s not just how much meat we eat, but our meat to vegetables ratio. Between the two extremes (high-vegetable and low-meat diets versus high-meat and low-vegetable diets) a risk ratio of about 8 appears to exist, sufficient to explain a substantial part of the international variation in the incidence of colorectal cancer. Those with the worst of both worlds, high meat and low vegetable, were at 8 times the risk.
To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video. This is just an approximation of the audio contributed by Ariel Levitsky.
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