Transcript: How May Plants Protect Against Diabetes?
Why is meat consumption a risk factor for diabetes? Why does there appear to be a stepwise reduction in diabetes rates as meat consumption drops? Rather than something they’re avoiding in meat, maybe it's something people are getting from plants. Free radicals may be the important trigger for insulin resistance; so, antioxidants in plant foods may help. Put people on a plant-based diet and their antioxidant enzymes shoot up. So not only do plants provide antioxidants, but also boost our endogenous antioxidant defenses—whereas, on the conventional diabetic diet, they get worse.
There are phytonutrients in plant foods that may help lower chronic disease prevalence by acting as antioxidants, anti-cancer agents, and by lowering cholesterol and blood sugar. Some, we’re now theorizing, may even be lipotropes, meaning having the capacity to hasten the removal of fat from our organs, like the liver, thereby counteracting the inflammatory cascade believed to be directly initiated by saturated fat-containing foods. Fat in the bloodstream, due to the fat we wear, or the fat we eat, not only causes insulin resistance, but also produces a low-grade inflammation that can contribute to heart disease and non-alcoholic fatty liver disease.
Fiber may also decrease insulin resistance. One of the ways it may do that is by helping to rid the body of excess estrogen.
There is strong evidence for a direct role of estrogens in the cause of diabetes, and it’s been demonstrated that certain gut bacteria can produce estrogens in our colon. High-fat, low-fiber diets appear to stimulate the metabolic activity of these estrogen-producing intestinal bacteria. This is a problem for men, too. Obesity is associated with low testosterone levels, marked elevations of estrogens, produced not only by fat cells, but also by some of the bacteria in our gut. Our intestinal bacteria may produce these so-called diabetogens—diabetes-causing compounds—from the fats that we eat. By eating lots of fiber, though, we can flush this excess estrogen out of our bodies.
Vegetarian women, for example, excrete two to three times more estrogens in their feces than omnivorous women, which may be why the omnivorous women had 50% higher estrogen blood levels. These differences in estrogen metabolism may help explain the lower incidence of diabetes in those eating more plant-based diets, as well as the lower incidence of breast cancer in vegetarian women, who get rid of twice as much estrogen because they get rid of twice as much daily waste in general.
Either way, meat consumption is consistently associated with diabetes risk. Dietary habits are readily modifiable—but, individuals and clinicians will consider dietary changes only if they are aware of the potential benefits of doing so. The identification of meat consumption as a risk factor for diabetes provides helpful guidance that can set the stage for beneficial behavioral changes. Meat consumption is something doctors can easily ask about. Once identified, at-risk individuals can then be encouraged to familiarize themselves with meatless options.
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 Katie Schloer.
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