In a previous post, we had a sneak preview about the two types of fiber and their indispensable role in the body. In this post, we will investigate the current evidence based research on the established health benefits, which are innumerable. Here are a few key benefits. Please bear in mind that this is by no means an all encompassing list:
LDL and HDL: There is strong evidence linking increased soluble fiber intake with lower LDL cholesterol without affecting the protective HDL cholesterol. (1). (Think “L”stands for “lousy”, artery clogging cholesterol, that should be kept “low” and “H”stands for “healthy”cholesterol, that should be kept “high”).
Soluble vs insoluble: While soluble fiber has been associated with a decrease in cardiovascular disease risk factors, it is the insoluble fiber that is ironically associated with lower incidence of cardiovascular disease.(2). However, as noted in the previous post, one needs to consume both types in ample quantities as each type offers many varying benefits.
Whole grains and heart disease: A recent study published in the March 2015 edition of JAMA, investigated women from the Nurses’ Health Study (1984-2010) and men from the Health Professionals Follow-Up Study (1986-2010), 2 large, prospective cohort studies and concluded that a higher whole grain consumption was associated with lower total and cardiovascular disease mortality in US men and women, independent of other dietary and lifestyle factors.(3).
Soluble fiber (prebiotics) serves as food for the bacteria in your colon. Short chain fatty acids called propionate produced from soluble fiber have been associated with decreased cholesterol synthesis. Although more human studies are required, some short chain fatty acids such as butyrate have been associated with decreased colon cancer risk.(4).
Fiber is King: Carbohydrates serve as fuel for your body, not unlike the gasoline we must pump into our cars every so often if we expect them to run. However, like gasoline the quality of the fuel matters. Emerging and compelling evidence links higher intake of whole grain foods and cereal fiber in particular, with decreased incidence of diabetes.(5),(6),(7),(8).
On the other hand, poor quality carbohydrates produced from the refining of whole grains can increase your risk of diabetes significantly. High fat, low fiber diets can increase insulin resistance, (the body is unable to utilize available insulin effectively), eventually leading to Type 2 diabetes. Substituting whole grains for refined grains can considerably reduce your risk.(5).
Not surprisingly, a 2014 meta-analyis showed that an increased glycemic index and glycemic load diet (the extent to which foods raise your blood sugar), is associated with an increased risk of Type 2 diabetes (9).
Delayed gastric emptying: Fiber’s ability to prolong digestion, thus slowing down the rate at which the stomach empties out (called delayed gastric emptying), allows food to linger in the stomach longer. This creates a sense of fullness and satiety following a meal that goes a long way in helping with weight management. This might explain why the bowl of bran with strawberries tends to be far more satisfying than a bowl of “refined” Rice Krispies. Because of the body’s inability to digest fiber, fiber contributes very little metabolizable energy. (Exception: soluble fibers are fermented by bacteria in your colon, thus contributing a small amount of energy).
Decreased caloric density: Moreover, foods that are high in fiber tend to be lower in total fat and “added sugars”. As a result, it is possible that this may contribute to weight loss by providing less caloric density (decreased calories or food energy per bite).
Shortfall nutrient: Despite all the accumulating evidence touting the benefits of fiber, it sadly remains a “shortfall” nutrient with most Americans consuming barely 15 grams per day.(10). Less than 5% of most age and gender subgroups have usual intakes of fiber that meet the adequate intake (AI) level of 25 to 38 grams/day identified by the Institute of Medicine (IOM). (11).
Reap what you sow: If readers will forgive the cliche, you reap what you sow (literally and otherwise), when it comes to whole grains. In order to reap the healing potential of food, we need to consume grains and legumes in their intact form, chock-full of fiber and nutrients. It is worth noting that the interactions between nutrients, referred to as food synergy that is found in fiber rich carbs such as fruits, vegetables, whole grains and legumes also contribute significantly towards optimal health.
Fibrilicious!: Refer to lentil and black bean soup, Indian style chickpeas, red rice, broccoli with garlic and carrot salad recipes for delicious ways of increasing your fiber intake. For simple tips on how you can increase your fiber intake on a daily basis, please refer to Whole grains and fiber: unravelling the puzzle.