It's never too early to start making fiber a big part of your daily diet. A new study shows that a high-fiber diet helps protect against heart disease later in life, especially for young and middle-aged adults.

Northwestern University researchers came to this conclusion after analyzing data from over 11,000 adults, and found that younger (20 to 39 years) and middle-aged (40 to 59 years) adults with the highest fiber intake had a significantly lower estimated lifetime risk for cardiovascular disease, compared to those with the lowest fiber intake.

The association isn't as strong in older adults, however. Lead author Hongyan Ning, M.D., believes it's likely that the heart-healthy benefits of dietary fiber requires a long time to take effect. Which is why young and middle-aged adults should start eating a diet rich in fiber, Ning urges.

Tips to up your fiber intake

A high-fiber diet falls into the American Heart Association's recommendation of 25 grams of dietary fiber or more a day. Good sources include fiber-rich fruits, vegetables, legumes and whole grains.

Do aim to get your daily fiber intake from whole foods, rather than processed fiber bars, supplements and drinks. "A processed food may be high in fiber, but it also tends to be pretty high in sodium and likely higher in calories than an apple, for example, which provides the same amount of fiber," advises Donald M. Lloyd-Jones, M.D., corresponding author of the study and a cardiologist at Northwestern Memorial Hospital.