High dietary fiber intake may help prevent strokes. The belief that dietary fiber intake is protectively associated with certain diseases was postulated 40 years ago and then enormously fueled and kept alive by a great body of science since. Today it is generally believed that eating lots of fiber-rich foods helps prevent obesity, diabetes, and cardiovascular diseases such as stroke.
Strokes are the second most common cause of death worldwide. Moreover, stroke is a leading cause of disability, and so preventing strokes in the first place—what’s called primary prevention—should therefore, be a key public health priority.
The best observational studies to date found that fiber appears to significantly protect against the risk of stroke. Different strokes for different folks, depending, evidently, on how much fiber they ate. Notably, increasing fiber just seven grams a day was associated with a 7% reduction in stroke risk. And seven grams is easy, that’s like a serving of whole grain pasta with tomato sauce and an apple.
What’s the mechanism? Maybe it’s that fiber helps lower cholesterol and blood sugar levels. Or it could just be that those eating more fiber are just eating more vegetables, or fewer calories, or less meat and fat, or improving digestion, all of which may slim us down and lower our blood pressure and the amount of inflammation in our bodies. Does it really matter, though? As Dr. Burkitt commented on the biblical passage, “A man scatters seed on the land—the seed sprouts and opens—how, he does not know,” the farmer doesn’t wait to find out. Had the farmer postponed his sowing until he understood seed germination, he would not have lasted very long. So yes, let’s keep trying to figure out why fiber is protective, but in the meanwhile, we should be increasing our intake of fiber, which is to say increasing our intake of whole plant foods.
It’s never too early to start eating healthier. Strokes are one of many complications of arterial stiffness. Though our first stroke might not happen until our 50’s, our arteries may have been stiffening for decades leading up to it. Hundreds of kids were followed for 24 years, from age 13 in through 36 and researchers found that lower intake of fiber during a young age was associated with stiffening of the arteries leading up to the brain. Even by age 13, they could see differences in arterial stiffness depending on diet. Fiber intake is important at any age.