Coronary heart disease (CHD) is the number one cause of death in the United States. Previous research has shown that eating a diet high in fiber may be one way to reduce your risk of developing CHD. There are several different ways that dietary fiber may reduce the risk of CHD, including: improving cholesterol profiles, lowering blood pressure , and improving insulin sensitivity .

Few studies, however, have looked more closely at the sources of dietary fiber (fruits, vegetables, or cereals) and risk of CHD. Additionally, only four studies on dietary fiber and heart disease have reported findings for women separately from men.

A new study in the February 23, 2004 issue of the Archives of Internal Medicine analyzed ten previously conducted studies to look at the type of fiber consumed and risk of CHD in women and men. Their findings show that consumption of dietary fiber from fruits and cereals reduces the risk of CHD in both men and women.

About the Study

This study included data from 245,186 women and 91,058 men who were all part of one of ten previously conducted studies. To be included in this analysis studies had to:

  • Follow a group of individuals over time
  • Report at least 150 incidents of CHD disease
  • Assess usual dietary intake through a validated method (such as a food frequency questionnaire or diet history)

The researchers looked at the participants’:

  • Total intake of dietary fiber
  • Intake of soluble fiber (i.e., found in oat bran, apples, citrus fruits) and insoluble fiber (i.e., found in whole grain products, wheat bran, vegetables)
  • Fiber intake from cereals (grains), fruits, and vegetables

They also looked at the total number of CHD events (non-fatal or fatal heart attack ) and the total number of deaths due to CHD over a 6 to 10 year period. The researchers then measured risk of CHD events and risk of death from CHD based on fiber intake.

The Findings

For every 10 gram per day increase in total dietary fiber, there was a 14% decreased risk of CHD events and a 27% decreased risk of dying from CHD. The study found that both soluble and insoluble fiber decreased risk of CHD, although the association was stronger for soluble fiber. Additionally, the more fruit or cereal fiber that was eaten, the lower one’s risk of a CHD event or death from CHD. Interestingly, no such relationship was observed with vegetable fiber.

Overall, the results were similar for men and women. The findings were also independent of other dietary factors, age, baseline body mass index, smoking, high blood pressure, diabetes, and high cholesterol.

Further research is needed to understand why vegetable fiber did not decrease risk of CHD. The authors noted that starchy vegetables (such as corn and peas), which tend to be low in nutrients and often heavily processed, contributed substantially to vegetable fiber in all studies. Thus it may have been that adverse effects associated with commonly consumed, highly processed vegetable products diminished any benefits that would otherwise have been seen from the vegetable fiber.

How Does This Affect You?

These findings reaffirm results from previous studies that show dietary fiber reduces the risk of CHD. In fact, the more fiber you eat, the lower your risk.

Although this study found that only fiber from fruit and cereals was associated with a decreased risk of CHD, it does not mean you should skimp on your vegetables. It does, however, highlight the benefit of consuming a variety of vegetables, including non-starchy ones.

The current dietary guidelines recommend that most adults get 25-30 grams of dietary fiber per day. Because fiber is found only in plants, this means that the majority of the food we eat should be plant-based high quality carbohydrates, such as fruits, vegetables, and grains.

These findings come at a time when many people are questioning the traditional high carbohydrate diet, based on grains, fruits, and vegetables. The message, of course, is that not all carbohydrates are created equal. The key is making sure that the foods you choose from these groups are indeed high in fiber and of high nutritional quality.