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Study under review: Positive effects of resistant starch supplementation on bowel function in healthy adults: a systematic review and meta-analysis of randomized controlled trials
Introduction
Resistant starch has become a popular topic over the last decade for its proposed health benefits as a fiber and for its potential as a functional food ingredient. As the name alludes, resistant starch is defined as a portion of starch that cannot be digested by human enzymes (it resists digestion), instead entering the large intestine to feed the microbiome.
There are currently five known types of resistant starch (shown in Table 1), which are briefly summarized in the table below and addressed in more detail in the FAQ section. All resistant starches act as a prebiotic fiber (which feeds the microbiome) and have been shown to facilitate a diverse and healthy microbiome. Additionally, resistant starch has been shown to increase the production of short-chain fatty acids within the colon, which may have anti-cancer effects and promote the growth of healthy colon tissue.
Designation | Description | Example |
---|---|---|
Resistant starch type-I | Physically inaccessible starch | Coarsely ground or whole-kernel cereal grains |
Resistant starch type-II | Native (uncooked) amylose starch | Raw potatoes or green bananas |
Resistant starch type-III | Retrograde starch | Cooked and cooled starchy foods such as potatoes or rice |
Resistant starch type-IV | Chemically modified starch | Various synthetic starches; not found in nature |
Resistant starch type-V | Amylose-lipid complex | High-amylose starches cooked in the presence of fat, such as stir-fried rice |
Composition, consistency, frequency, and weight of bowel movements have been proposed as key indicators of bowel function and digestive health. Despite a logical basis to suggest that consuming resistant starch would benefit bowel function, data from healthy humans is scarce and conflicting. For instance, two studies[1] have shown that resistant starch supplementation significantly increases fecal weight while another[2] reported a non-significant decrease.
To consolidate the currently available evidence, the current study performed a meta-analysis investigating how resistant starch supplementation affects bowel function in healthy adults.
Resistant starch is a type of fiber that has been suggested to have numerous health benefits for the gut and systemically. The current study was a meta-analysis of human trials investigating how resistant starch supplementation impacted bowel function.
Who and what was studied?
What were the findings?
What does the study really tell us?
The big picture
Frequently Asked Questions
What should I know?
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