THE BASICS: Inadequate intake of dietary fiber contributes to the risk of developing obesity, type 2 diabetes, coronary artery disease, and colon cancer. For years, researchers focused on insoluble fiber, or roughage, but the bigger health benefits might actually come from soluble fiber. Soluble fiber helps reduce appetite, leading to less food consumption and then to weight loss. It can also relieve constipation, improve inflammatory (irritable) bowel disease, lower cholesterol and blood pressure, and enhance protection against cancer and infection.

ALIAS: The most common types of soluble fiber sold as dietary supplements include oat bran, flaxseed, glucomannan, beta-glucan, inulin,
and psyllium.

HOW SOLUBLE FIBER WORKS: Soluble fiber, sometimes called viscous fiber, expands and forms a gel when it encounters water in the digestive tract, creating a sense of fullness. Some types of soluble fiber reduce the absorption of cholesterol and enhance the growth of beneficial bacteria in the digestive tract. Although soluble fiber might actually slow the digestive process, its bulk promotes regular bowel movements and well-formed stools.

HEALTH BENEFITS: Different types of soluble fiber may have slightly different health benefits.

• Glucomannan. This type of plant fiber has several positive effects, according to a recent overview of the research in The American Journal of Clinical Nutrition. After daily consumption for several weeks, glucomannan can lead to a modest reduction of blood sugar levels. In a couple of studies, supplements promoted modest weight loss, which was enhanced when glucomannan was combined with a low-calorie diet. Other research has shown that glucomannan decreases total cholesterol, “bad” LDL cholesterol, triglyceride levels, and blood pressure.
• Beta-glucan. This type of soluble fiber enhances the immune system, and it may protect against cancer and infections, including fungal infections. Scientists recently discovered that macrophages, a type of white blood cell, ingest beta-glucan and then secrete a specific antitumor compound. Other researchers have reported that beta-glucan reduces LDL cholesterol and improves blood sugar control in people with type 2 diabetes.
• Inulin. Not to be confused with the hormone insulin, inulin is both a soluble fiber and a prebiotic, meaning that it is a food source for beneficial intestinal bacteria. Like other types of soluble fiber, inulin functions as a natural stool softener and can reduce constipation. A study in The Journal of Nutrition noted that it may reduce the severity of inflammatory bowel disease.
• Psyllium. Obtained from the seed husks of Plantago psyllium, psyllium helps normalize bowel movements, preventing both constipation and diarrhea. A study of 125 people with type 2 diabetes found that psyllium supplements led to significant reductions in blood sugar, total cholesterol, LDL cholesterol, and triglycerides. Other studies have yielded similar results. A recent article in the International Journal of Pharmaceutics noted that psyllium likely plays a role in preventing inflammatory bowel disease and ulcerative colitis.

BACKGROUND CHECK: Fruits and vegetables are rich sources of both soluble and insoluble fiber, so include a lot of them in your diet. Oats and seed husks are also excellent sources of soluble fiber.

HEADS UP: Taking large amounts of soluble fiber may result in constipation, flatulence, and bloating. Start with a small amount, such as one or two capsules, and increase the amount of fiber gradually along with your intake of fluids.

WHAT YOU SHOULD TAKE: Fiber supplements vary greatly, so follow directions on the label of the product you use. You should try to get 25 g of more fiber in your diet daily from food first, and supplements if needed. In general, take the supplements 15 to 30 minutes before eating, and do not take fiber with other supplements or medication; fiber absorbs them and keeps your body from absorbing them.

Product Examples

MegaFood, DailyFoods Organic Pure Food High Fiber Hemp Shake contains a fiber blend that helps you feel full longer, manage cravings, control blood sugar, and promotes heart health and healthy digestion.

Keep things running smoothly, and relieve gas and bloating, with Natural Factors PGX Ultra Matrix PLUS Smooth DigesT. Contains a unique and proprietary blend of highly purified fiber (including konjac root and alginate), plus fennel, anise, and caraway seed to ease digestive discomfort.

Hero Nutritionals Yummi Bears Fiber (for kids) is made from natural chicory root to prevent digestive problems and keep tummies healthy and happy.