“Oatmeal is good for your heart.” You hear that a lot, and not just from oatmeal companies. Many cardiologists and other health professionals recommend starting the day with a bowl of oats. There’s a good reason: Oatmeal is one of many foods that contains soluble fiber, a substance that can help your heart by reducing the amount of LDL cholesterol (also know as “bad” cholesterol) in your blood (1). Research shows that a moderate increase in the amount of soluble fiber in a person’s diet is likely to lower his or her risk of developing heart disease. It can also slow the progression of heart disease once it has begun. That’s not all: Soluble fiber can help lower the risk of developing diabetes. And the benefits of a diet rich in soluble fiber apply to children as well as adults. A 2009 study showed that soluble fiber helps reduce a child’s risk for future chronic diseases including cancer, heart disease, and diabetes by helping to maintain normal blood sugar and blood pressure levels (2).
A Sponge for Cholesterol What exactly is soluble fiber, and how does it work its magic? Fiber is the part of a plant food that your body cannot digest. It travels intact through your stomach, intestines, and colon and exits from your body. There are two kinds of fiber, and both are good for you. Insoluble fiber, which does not dissolve in water, adds bulk to the material moving through your digestive system and is good at relieving constipation. It’s found in whole wheat, nuts, and many vegetables. Soluble fiber, as the name implies, dissolves in water, forming a gel-like substance. In addition to oats, soluble fiber can be found in beans, barley, flaxseed, and certain vegetables and fruits.
Scientists aren’t sure exactly how soluble fiber reduces the LDL or “bad” cholesterol in your blood, but they suspect it works like this: Soluble fiber acts like a cholesterol “sponge” by soaking up cholesterol-laden bile salts in the small intestine and eliminating these salts along with waste. That not only removes harmful cholesterol from your body, it also keeps bile acids from being “recycled” back to the liver. As a result, the liver must produce new bile acids, and to do that, it pulls LDL cholesterol out of the bloodstream (1). That reduces “bad” cholesterol levels even further, which is good news for your heart: If there’s less bad cholesterol floating around in your bloodstream, it means there’s less that can collect on the walls of the arteries, where it increases the risk of heart attack and stroke.
Other Health Benefits The benefit of soluble fiber doesn’t stop with cholesterol reduction. Soluble fiber can also lower triglycerides—fats in the blood that contribute to heart disease. According to a 2010 study, it may also help reduce blood pressure and that’s good for your heart health (3, 4). Soluble fiber can also benefit people at risk for diabetes by regulating blood sugar. It slows down the body’s absorption of sugar, reducing the risk of developing type 2 diabetes and helping to control existing cases of diabetes (4, 5). If that’s not impressive enough, emerging research shows that certain forms of soluble fiber may enhance the body’s immune function (2).
Foods With Fiber Does this make you want to eat more soluble fiber? It should. And if you’re like many Americans, you probably need to boost your intake of both kinds of fiber, soluble and insoluble. On average, children and adults in the U.S. consume less than half of the recommended amount of fiber. The USDA suggests that adult women get about 28 grams of total dietary fiber a day and adult men consume 36 grams a day. Children one year and older should consume 14 grams for every 1,000 calories in their diet (2).
At least 5 to 10 grams of your total daily fiber intake should consist of soluble fiber if you want to reap its cholesterol-lowering benefits, advises the Centers for Disease Control and Prevention (CDC) in its guidelines for a heart-healthy diet (6). That translates into about 1 ½ cups of cooked oatmeal (6 g of soluble fiber) plus a serving of fruit, such as apples or bananas (4 grams of soluble fiber). If you’re not a fan of oatmeal, there are lots of other tasty ways to get soluble fiber into your diet. Pears, citrus fruits, legumes such as kidney beans, peas, carrots, barley, and psyllium (seed husks) are all good sources (4, 5). Try to avoid processed foods like pulp-free juice and canned fruits and vegetables and substitute fresh high-fiber ones instead. While packaged fiber supplements are an option, it’s best to get your fiber fix from food sources, since you get the additional benefits of vitamins, minerals, and other nutrients. Whether you get your soluble fiber by starting the day with oat-based cereal, or munching on apples, beans, or barley as the day progresses, your body will thank you from the bottom of its heart.