Paging Dr. Frischer: Fiber

Allow me to start with my conclusion: Eat more fiber. You’ve heard this before. Why?

Dietary fiber, also known as roughage or bulk, is found (mainly) in fruits, vegetables, whole grains, seeds, nuts and legumes. It is famous for preventing constipation, but foods containing fiber can also provide so many other health benefits, like helping to maintain a healthy weight, and lowering the risk of diabetes, heart disease and even some cancers.

Other food components (like fats, proteins, and carbohydrates) are broken down, absorbed and digested. Fiber, however, is not digested. It passes, relatively intact, through the stomach, small intestines and colon, and out of the body.

It is either soluble, which dissolves in water, or insoluble, which doesn’t. Soluble fiber can help lower blood cholesterol and glucose levels. It is found in oats, peas, beans, apples, citrus fruits, carrots, barley and psyllium. Insoluble fiber promotes the movement of material through the digestive system and increases stool bulk, so it helps with constipation. Whole wheat flour, wheat bran, nuts, beans and vegetables such as cauliflower, green beans and potatoes are good sources of insoluble fiber.

What else does eating a wide variety of high-fiber foods help to do for us?

-Normalize bowel movements. Dietary fiber increases the weight and size of the stool and softens it, making it easier to pass. If the stool is watery or soft, eating fiber helps to solidify it.

-Maintain bowel health. A high fiber diet may help to lower the risk of developing hemorrhoids, diverticular disease, and colorectal cancer. In addition, the “good” bacteria that make up our gut’s microbiome feed on the fiber that has fermented in the GI tract. Fatty acids are produced that can lower systemic inflammation, which is linked to nearly every major chronic health problem.

-Lower cholesterol levels. Soluble fiber lowers blood cholesterol levels by reducing cholesterol absorption and lowering low-density lipoproteins (LDL).

-Control blood sugar levels. Soluble fiber can slow sugar absorption, which improves blood sugar levels. A diet high in fiber is associated with a lower risk of developing type 2 diabetes, and a diet which mixes soluble and insoluble fiber shows the most benefit.

-Achieve and maintain a healthy weight. High fiber foods tend to be more filling than low fiber foods, so we eat less and stay satisfied longer. High fiber foods take longer to eat and are less calorie dense.

-Reduce heart disease. Studies show a high correlation between high fiber intake (especially soluble fiber) and a reduced risk of cardiovascular disease and stroke.

-Reduce cancer risks. A number of studies point to a high fiber diet lowering the risk of colorectal and breast cancer. The studies looked at the soluble fiber found in fruit, but note that soluble fiber is also plentiful in other foods mentioned here.

-Increase longevity. People who eat more fiber, including soluble and insoluble, had a lower chance of dying from anything, including cardiovascular disease and cancer. This means even if you suffer from one of these diseases, consuming fiber may help protect you from dying from it.

-Detox the bowels. Without using special bowel cleansers, fiber naturally helps to eliminate toxins from the GI tract. Soluble fiber soaks up potentially harmful compounds, including excess estrogen and unhealthy fats. Fiber moves food through the bowels and gives the gut less time to absorb chemicals like BPA, mercury and pesticides.

-Maintain strong bones. Some types of soluble fiber act as prebiotics, which promote beneficial gut bacteria, which in turn increases the absorption and effect of minerals like calcium. Prebiotics are found in fruits, vegetables, nuts and whole grains.

-Prevent dementia. This is recent and very exciting news, coming out of studies from Japan. Soluble fiber consumption appears to be associated with a lower risk of developing dementia. This appears to apply to almost all types of dementia. Further studies are in progress.

I recommend that you take time to increase fiber consumption gradually, over a period of weeks. This allows the body’s natural bacteria to adjust, and will help to avoid intestinal gas, abdominal bloating and cramping. Drink more water when eating more fiber. What are some easy ways to include more fiber in your diet?

• Start the day with a high fiber breakfast cereal.

• Look for “whole grain” on labels, and choose products that list whole wheat or whole grain as the first ingredient. Use whole grain flour when baking.

• Add a few tablespoons of unprocessed wheat bran to your favorite recipes.

• Eat more legumes, like beans, peas, and lentils.

• Select snacks like fresh fruit, raw vegetables, low fat popcorn, whole grain crackers, nuts, seeds, and dried fruits.

Those who suffer from irritable bowel syndrome, chronic constipation, diverticulosis, and diarrhea can benefit from supplements like Metamucil, Citrucel, and FiberCon. For others, however, it is far better to get fiber from natural food sources. Supplements do add fiber to the diet, but lack the variety of fiber and the vitamins, minerals and other benefits that are found in real food and in a balanced diet.

Dr. Alan Frischer is former chief of staff and former chief of medicine at Downey Regional Medical Center. Write to him in care of this newspaper at 8301 E. Florence Ave., Suite 100, Downey, CA 90240.