Eating a diet rich in fiber has long been known to help keep your digestive tract working properly. It's also thought to lower the risk of heart disease, some cancers and diabetes. Now, a new study suggests it could reduce the risk of death from cardiovascular, infectious and respiratory diseases.

People who ate a high-fiber diet decreased their risk of dying over a nine year period compared to those who ate less fiber, according to a new study in the Archives of Internal Medicine.

The findings are based on a diet study from the National Institutes of Health and AARP, which included 219,123 men and 168,999 women ages 50 to 71 when the study began. Researchers from the National Cancer Institute examined food surveys completed by the participants in 1995 or 1996. After nine years about 11,000 people died and researchers used national records to determine the cause.

People who ate at least 26 grams per day were 22 percent less likely to die than those who consumed the least amount of fiber -- about 13 grams per day or less. Men and women who consumed diets higher in fiber also had a reduced risk of cardiovascular, infectious and respiratory diseases, the study found. Getting fiber from grains seemed to have the biggest impact, the authors write.

The study has some limitations -- mainly, people who ate high-fiber diets might also have been more likely to eat healthier diets overall, attributing to their longevity. Still, the study offers more evidence that fiber is certainly good for you.

Federal dietary guidelines recommend people consume at least 14 grams of fiber per 1,000 calories, so about 28 grams for an average 2,000 calorie-per-day diet. But many experts say Americans don't get enough.

So where can you find fiber? Food such as raspberries, lentils, peas and barley and oat bran are packed with fiber. Here are some good resources for including fiber in your diet.

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