Fiber from whole grain bread may be better for reducing heart disease risk than fruits and veggies, study suggests

• Fiber from foods like vegetables and grains is important for digestion, metabolism, and longevity.
• Whole grain fiber may have unique benefits over other foods for heart health, new research suggests.

Eating enough fiber is important for health, but some sources of fiber may be more heart-healthy than others, new research suggests.

Fiber from whole grains may reduce inflammation and lower risk of heart disease more than fiber from fruits and vegetables, according to a study published March 31 in JAMA Network Open.

Researchers from several universities, including the Harvard Chan School of Public Health and Columbia University, looked at data from 4,125 adults aged 65 and older over about 25 years of follow-up. The researchers compared fiber intake (calculated from food surveys) to markers of inflammation in their blood and the rate of heart disease cases in participants over time.

The researchers found that total fiber was associated with fewer markers of inflammation and lower risk of heart disease, which wasn't a surprise. Previous research has suggested that getting enough fiber improves your gut health, regulates blood sugar, and reduces the risk of chronic illnesses.

However, when separating the data by sources of fiber, researchers found one specific type was linked to lower heart disease risk and inflammation — fiber from whole grain foods like dark bread, high-fiber cereal (like oatmeal), and bran.

In contrast, fiber from fruits and vegetables — like apples, oranges, bananas, beans, broccoli, and peas — was not consistently linked with lower inflammation.

The difference was surprising, said Rupak Shivakoti, lead author of the study and assistant professor of epidemiology at Columbia Mailman School of Public Health.

"Fiber in general is thought to play a role in reducing inflammation but our study data suggests that fruit and vegetable fiber might have less of a role in inflammation levels compared to cereal fiber," Shivakoti told Insider.

The results suggest whole grains may be especially helpful in reducing inflammation and heart disease risk, but more research is needed to determine how best to reap benefits of different fiber sources for health.

Whole grains may have unique benefits for heart health

Initially, researchers theorized that whole grain fiber might reduce heart disease risk by lowering inflammation more than other types of fiber. While it was true that whole grains were linked to lower inflammation, it didn't fully explain the disparity.

Other nutrients in whole grain besides fiber may help account for the benefits, including protein, B vitamins, healthy fat, and minerals.

The study was limited in that it was observational, and so data couldn't directly show that whole grain fiber caused better health outcomes. It also focused on a specific population of older, predominantly white adults. As a result, more research is needed to see how whole grain fiber might lead to benefits, and for whom.

For now, the best advice is to follow current recommendations for total fiber intake, and don't skimp on fruits and veggies, since they're still a good source of nutrients, according to Shivakoti.

"There are still of course other well-known health benefits from consuming fruits and vegetables, and thus their sufficient consumption remains important," he said.

And if you're concerned about heart health or inflammation specifically, consider adding a few more servings of whole grains to your diet.