Cardiovascular disease (CVD) is the leading cause of death in the United States. Fiber consumption in the diet alters insulin secretion, insulin blood levels and may alter CVD risk. Fiber with a meal reduces the insulin by slowing the rate of absorption of nutrients. The present study was done to further investigate fiber intake, insulin production, weight gain and other CVD risk factors.
The Coronary Artery Risk Development in Young Adults (CARDIA) study was done with 2909 patients between 18 and 30 years of age. This was a long-term observational study of dietary habits with blood testing of insulin levels and other blood levels.
One study discussed by Ludwig showed that people with high fasting insulin levels (which are associated with low fiber diets) have a 5.5 times the chance of developing heart disease as those with normal insulin levels. Obesity, smoking, age and physical inactivity are said to account for 50% of hyperinsulinemia.
Ludwig, et al, found that people with high fiber consumption diets showed correspondingly low insulin levels, low weight gain and low CVD risk levels. The authors speculated that this could have been due to fiber’s effect of lowering insulin levels. Insulin resistance results in high insulin levels (hyperinsulinemia), an important risk factor for CVD.
Low fiber diets stimulate more insulin production because of the high glycemic index. The high glycemic index diet results in hormonal changes, which result in overeating.
In this study, people who ate the most fiber gained the least weight and there is evidence that fiber may play a greater role in CVD risk than total fat or saturated fat intake. The different types of fiber were not researched in this study. Fat, protein and carbohydrate consumption did not reduce CVD risk as dietary fiber did.
CONCLUSION: Dietary fiber intake showed clear correlation with body weight, waist-to-hip ratio, fasting insulin levels and two hour insulin levels following a glucose test. There was a lower level association between fiber intakes and blood pressure, levels of triglyceride, high HDL cholesterol, low LDL cholesterol and fibrinogen. Fat, carbohydrate and protein intakes had poor correlation with CVD risk as compared to fiber intakes.
“High fiber diets may protect against obesity and CVD by lowering insulin levels.”
NOTE: Summary 28 reports a study that showed reduced risk of ovarian cancer in people who ate more dietary fiber. Large amounts of fiber can reduce copper blood levels according to Summary 32. Summary 87 reports that soluble fiber reduces blood cholesterol. Soluble fibers include guar gum, psyllium, pectin, and oat fiber. Read more about the importance of fiber.
To read the author’s abstract click on the link to the author’s title of the article above.