In addition to potatoes, several other familiar plant products contain the same beneficial nutrient, namely resistant starch. The most familiar sources are vegetables, seeds, and grains, as well as potatoes, rice, and corn that have been cooled after cooking. Green bananas also contain it.
In recent years, potatoes had a bit of a bad reputation. They were seen as just starch, or fattening carbohydrates, with no nutritional value. The tone has since changed. Potatoes are now recommended as a healthy food that also provides vitamins B and C as well as many trace elements.
The latest plus is resistant starch, but only in potatoes that have been cooled after cooking. A carefully conducted study on the health benefits and weight-loss properties of resistant starch has just been published.
Starch is a carbohydrate that is broken down into sugars by the digestive enzymes amylases. Amylase cannot break down resistant starch, so it passes undigested to the delight of the microbes in the colon. Thus, it resembles fibers.
A Chinese research team conducted a thorough, double-blind, placebo-controlled study to monitor the effectiveness of resistant starch in weight loss and its impact on sugar metabolism.
Overweight or obese participants were given 40 grams of resistant starch mixed with water daily for eight weeks, alongside strictly standardized meals.
The resistant starch reduced the weight of the participants in the study group by nearly three kilograms. Laboratory tests measuring sugar metabolism also showed improved insulin sensitivity. The effects were mediated through the gut microbiome. A key player was a bacterium named Bifidobacterium adolescentis.
This and other beneficial bacteria altered the composition of bile acids and reduced inflammation by tightening the intestinal cell wall. Fat absorption also decreased.
