You’ve heard it before and now you’ll hear it again: Eat more fiber! At least that’s the conclusion of a study reported on by NutraIngredients-USA, which found an association between higher fiber intake, primarily insoluble fiber, and lower systolic blood pressure. Insoluble fiber is one of two types of fiber which serve different purposes in the body—insoluble fiber passes through your digestive system, adding bulk to wastes and promoting digestive motion, while soluble fiber binds to water and other compounds, keeping them in the digestive tract. The research, published in the British Journal of Nutrition, looked at data from 2,195 Americans ages 40 to 59 who participated in the International Study on Macro/micronutrients and Blood Pressure (INTERMAP). During four visits between 1996 and 1999, researchers measured the participants’ blood pressure, collected 24-hour urine samples, and administered 24-hour dietary surveys to evaluate fiber intake. After adjusting for lifestyle and dietary factors that could affect blood pressure, researchers found that:
Higher intake of insoluble fiber was associated with lower blood pressure. The researchers calculated that, for every 4.6 grams of insoluble fiber per 1,000 kilocalories consumed, systolic blood pressure was 1.81 mmHg lower. Soluble fiber intake was not associated with blood pressure.
Raw fruit was the main source of insoluble fiber in the participants’ diets, followed by whole grains and vegetables.
It’s important to note that more clinical research is needed to show whether increasing insoluble fiber intake can reduce blood pressure. However, fiber has previously been associated with decreased risk for diabetes and markers of cardiovascular disease, and increased weight loss, so this study may provide just one more reason to ensure you’re getting adequate amounts of fiber in your diet. Insoluble fiber, in particular, can be found in many delicious foods like wheat bran, wheat germ, whole wheat, popcorn, beans and lentils, veggies and their skins, fruits and their peels, and nuts and seeds.
Source: British Journal of Nutrition