These are plant produced carbohydrates that the human gut cannot digest that are somewhat different than other forms of fiber. Resistant starches often have a starchy or even sweet taste and they are neither totally insoluble nor prone to forming gels. The main difference however is that resistant starches are not calorie-free. Generally, they provide us about 2 calories per gram of resistant starch. How is this possible given that I just stated that resistant starches are indigestible? The answer is that resistant starches are indigestible using human gut enzymes, but, not indegistible to many of the bacteria that inhabit the human colon. Thus, resistant starches pass totally unscathed all the way through the small intestine, but once they enter the colon they are digested but bacteria. However, the bacteria do not totally digest resistant starches; they turn some of them into fatty acids that the bacteria then secrete and which we then absorb as nutrient. This is why resistant starches provide a small amount of calories. More importantly, resistant starches appear to selectively nourish the "good" kinds of bacteria in the gut and therebye promote regularity and reduce risk for cancer. Because of their ability to promote beneficial bacteria, resistant starches are also called "pre-biotic" nutrients. Resistant starches are often found in roots of plants, but not all roots. A weird sunflower-like plant called a jerusalem artichoke has roots that are loaded with a resistant starch called "inulin" (NOT "insulin"). Regular artichokes also have a fair amount of inulin. A sweetener that has long been popular in Mexico is now being sold in the US and it is made from the root of the "blue agave" cactus which is also inulin-rich. |