Transcript: Plant-Based Diets & Artery Function
Endothelial dysfunction is the initial step in the development of peripheral artery disease, heart disease, and stroke. The remarkable finding that progressive endothelial dysfunction, the decline in the functioning of our arteries, is not an inevitable consequence of aging, that we can retain the arterial function we had in our 20’s into our 60’s, like the elderly Chinese, may, in part, be due to green tea, but other important dietary differences, including increased consumption of vegetables and fishes with lower consumption of other meat and dairy in the traditional Chinese diet, may be contributing to the protection observed in older Chinese arteries.
It’s probably not the fish. Pooling all the best double-blind, placebo-controlled studies found that fish oil supplementation has no significant effect on endothelial function. In, by far, the largest study done to date, comparing doses of fish oil equivalent to 1, 2, or 4 servings of fish per week, no effects of these long-chain omega 3 fats were found. This is consistent with studies that have looked at whole fish consumption as well.
Overall, there was no significant association between fish intake and endothelial function. In fact, in women, those eating the most fish had the worst arterial function. Women who ate fish more than twice a week had significantly impaired endothelial function compared to those who never or only rarely ate fish.
So, if it’s not the fish, maybe it’s the plants. Vegetarian diets appear to have a directly beneficial effect on endothelial function. Vegetarian arteries dilate four times better than omnivore arteries. Maybe it’s just because vegetarians tend to smoke less? Within five minutes of smoking a single cigarette, our endothelium is brought to its knees, completely clamped down, and this happens if you’re a smoker or simply breathing in second-hand smoke. But this study excluded smokers completely. The beneficial effects were independent of non-dietary risk factors. In fact, a healthy diet may even trump smoking. The preservation of endothelial function in older Chinese may help explain why they have such low heart attack rates, despite their high prevalence of cigarette smoking. And the improved arterial function was well correlated with the duration of eating vegetarian, the longer they ate healthy, the better their endothelial function appeared to be.
This was a cross-sectional study, though, a snapshot in time, so you can’t prove cause and effect. What we need is an interventional trial. Put people on a plant-based diet and see if their arterial function improves, which is exactly what Dr. Dean Ornish did, showing a significant boost in arterial function compared to control.
Is this just some intangible risk factor test result, though, or does it actually have real world implications? Are their arteries naturally dilating so much better that their chest pain actually improves?
Ornish showed that on his plant-based diet and lifestyle program, cardiac patients had a 91% reduction in angina attacks. In contrast, control group patients, who were instead told to follow the advice of their personal physicians for diet and lifestyle advice, had a 186% increase in reported angina attacks. This marked reduction in frequency, severity, and duration of angina chest pain was sustained five years later; a long-term reduction in angina is comparable to that of surgery, but without the knife.
But this was back in the 90’s, when Ornish was only studying a few dozen patients at a time. How about a thousand patients put on a whole-food, plant-based diet. Within three months, 74% of angina patients becoming angina free.
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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