As heart disease continues to be the leading cause of death for Americans, the need for healthcare providers to advise patients on lifestyle choices that can reduce the risk and complications for cardiovascular disease. One of these choices is to increase fiber consumption since Americans only consumer approximately half of the recommended daily intake of fiber while the benefits are well-established.
Fiber is a crucial component of a heart healthy diet. Fiber’s benefits range from aiding in weight loss to stabilizing blood sugar to reducing cholesterol. The health benefits conferred by ingested fiber result from the physical and chemical properties of each fiber type. The essential properties that differentiate fiber types and gastrointestinal impact are solubility, viscosity, and fermentability.
Solubility refers to the ability of fiber molecules to dissolve in water. The physiological benefits of insoluble fiber include increased satiety, decreased intestinal transit, and increased fecal bulking.
The effect of soluble fiber on human physiology and cardiovascular health can be profound. Heart healthy benefits associated with ingestion of soluble fiber are increased excretion of bile salts and decreased circulating cholesterol. Evidence suggests that soluble fiber hinders the reabsorption of bile salts in the small intestine into enterohepatic circulation. Bile recirculation is normally highly efficient but soluble fiber traps bile salts in the gut and inhibits reabsorption. Unabsorbed bile salts are excreted in greater quantities, creating a deficit in recycled bile acids in the liver. The body’s compensatory mechanism for this deficit is to increase the production of bile salts from circulating cholesterol, thus reducing total plasma cholesterol.
Fiber fermentability describes the mechanism of colonic bacteria metabolizing dietary fibers for fuel, resulting in the production of short chain fatty acids (SCFAs). Fermentability differs based on the individual physical and chemical properties of the fiber source. Fibers with low fermentability provide bulk to stool, which is associated with improved colonic health and ease of defecation. Fibers with high fermetability result in the production of SCFAs: acetate, butyrate, and proprionate. These SCFAs are the primary source of fuel for colonocytes in humans. Interestingly, priopionate in particular, is associated with inhibition of hepatic cholesterol synthesis.
Together, both insoluble and soluble fibers help to prevent or attenuate cardiovascular disease.
While many consumers are aware that fruits and vegetables contain fiber, they are likely less aware of the variety of foods that have been enriched with fiber. These foods can help consumers achieve the recommended daily intake of fiber.