Did you know that certain starchy foods like potatoes and pasta can be beneficial to your health by promoting weight loss, improving blood glucose control and lowering cholesterol? Yes, you read it right! But it’s not just any starchy foods, it’s specifically those that contain resistant starch.
Starch is a complex plant-derived sugar that forms the carbohydrate reserves of plants. It is a mixture of two polysaccharides, amylose, and amylopectin, whose proportions vary according to the type of food. Starches are found in starchy foods such as bread, pasta, rice, potatoes, legumes and also certain fruits. Depending on the rate of digestion, starch breaks down into three different types: fast-digesting starch, slow-digesting starch and resistant starch. Fast-digesting starch causes an immediate increase in blood sugar levels after its consumption, whereas slow-digesting starch is digested more slowly in the small intestine and therefore does not cause a spike in blood sugar levels. Resistant starch is not digested in the intestine. It is a type of dietary fiber that is soluble and highly fermentable. Thus, because resistant starch is not digested and absorbed into the small intestine, it is able to reach the colon, where it is fermented by intestinal bacteria, and produces short-chain fatty acids which can offer a range of health benefits. It can therefore be classified as a prebiotic. The ability of starch to resist digestion depends in part on its ratio of amylose and amylopectin, with amylose being digested more slowly. The resistant starch content in food is also strongly influenced by their preparation and processing techniques. Some resistant starch are naturally found in certain foods such as corn, some legumes, unground seeds, whole grains, uncooked oatmeal, green bananas, as well as potatoes, rice and pasta that has been cooked and then cooled. Other resistant starch are manufactured synthetically by industry and added to foods as an ingredient to lower their caloric intake and improve their textural and organoleptic characteristics while also increasing their dietary fiber content. It should be noted that although resistant starch is a type of dietary fiber, it is generally not listed on the nutritional labels of foods.
The consumption of resistant starch can have a positive impact on a variety of chronic diseases including intestinal and cardiovascular diseases, obesity and diabetes. When resistant starch is fermented by the bacteria in the colon, it produces butyrate, a short-chain fatty acid, which is partly responsible for its health benefits.
Butyrate that is produced by the fermentation of resistant starch promotes the absorption of water and sodium, which helps improve stool consistency. It can also increase blood flow to the colon, reduce inflammation, and promote the regeneration of the lining of the intestine. Butyrate is currently the subject of much research for its potential benefits in the prevention of colorectal cancer and for people with inflammatory bowel disease.
Resistant starch is a promising type of fiber for the prevention and treatment of type 2 diabetes and its complications. According to some meta-analyses, the consumption of resistant starch can help reduce fasting and postprandial blood sugar levels as well as improve insulin sensitivity, especially in people with diabetes who are overweight or obese.
Studies in rats and humans indicate that a chronic consumption of resistant starch can help lower cholesterol and triglycerides levels, thereby reducing the risk of cardiovascular disease.
Studies in rats suggest that consuming resistant starch may increase satiety, promote fat loss and prevent fat build-up. However, while the potential positive effects in humans are promising, they are not well-known. According to a recent meta-analysis including 11 studies, the effects of resistant starch consumption on obesity remains controversial and more long-term studies in humans are needed.
It should be noted that that consuming resistant starch may be more beneficial for some individuals than others. It has been suggested that differences in the microbiota of each individual could play an important role in determining the effects of the consumption of resistant starch on their health. In addition, there are different types of resistant starch, the effects of which may vary depending on the type.
Dietary fiber requirements vary between 25 and 40g depending on one’s age and gender. It is recommended that you consume a variety of different types of dietary fiber, including resistant starches. Unfortunately, the majority of people do not consume enough fiber and would greatly benefit from increasing their consumption.