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What Is Amylose? Top 9 Benefits + Side Effects of This Resistant Starch
December 29, 2017
Starchy foods often have a bad reputation, but are you aware that there are different kinds of starch in food? One in particular, amylose, can actually help your body to maintain a healthy gut and possibly even address the root biological causes of psychological problems.
Amylose is a resistant starch found in a large variety of foods. On average, Americans on the standard American diet absorb about three to eight grams of resistant starch (amylose) each day. (1)
Research about the benefits of resistant starch varies in regard to recommended daily intake, some suggesting at least 15–20 grams while others adhere to a “45 grams a day or less” philosophy.
Whatever the case, it’s likely that you can benefit from understanding the way that this starch operates in your digestive system and the benefits it could provide. However, there are some cautions for people with certain conditions when it comes to amylose, and I’ll touch on those a little later.
What Is Amylose?
Amylose is the name of a particular type of compound classified as a polysaccharide. Polysaccharides are strings of carbohydrate molecules strung together. Starch contains two of these strings: amylose and amylopectin. The latter makes up about 70 percent to 80 percent of the starch compound, while amylose accounts for the other 20 perc
ent to 30 percent.
Why is amylose such an important molecule to understand? It’s because amylose is a resistant starch (a type of insoluble fiber), meaning it is not digested but fermented in the gut by some strains of healthy bacteria. (2)
Since amylose is shaped as a straight chain, it positions itself into the harder-to-access portions of starch compounds to avoid digestion. This shape also makes it harder to gelatinize, an important part of the digestive process.
Not all amylose chains are the same, though. The types are broken down into four basic categories, labeled as RS1, RS2 and so on. “RS” stands for resistant starch, the term used interchangeably to refer to amylose.
RS1 is “physically unavailable starch.” The gut is unable to break down these molecules because it doesn’t have the necessary enzymes. This type is commonly in seeds, legumes and grain foods.
RS2 refers to high-amylose foods with indigestible starch in the raw state of the food. It’s found in unripe potatoes, bananas and plantains. If these items are cooked, the starch changes form and becomes digestible.
RS3, or “retrograde RS,” is the state of starch after cooking foods with types RS1 or RS2 and then allowing them to cool. You can reheat these foods at temperatures below 130 degrees without reconverting the starch to a digestible compound.
RS4 is a synthetic variety, such as “hi-maize resistant starch,” not recommended by most natural health advocates because it does not absorb in the same way as amylose from organic, whole foods.
Your health benefits exponentially from maintaining a diverse gut microbiome. To achieve this diversity, it’s important to eat a variety of life-giving foods that contain various nutrients vital to the digestion process, including prebiotics like amylose.
A gut environment that contains the right elements can support your health in a variety of ways, such as: (4)
- Protecting you from bad bacteria colonization that leads to infection, such as C. diff
- Producing biotin, folate and vitamin K, which cannot be achieved anywhere else in the body
- Breaking down toxins and carcinogens
- Maintaining a healthy metabolism and immune system (5)
- Reducing insulin resistance and risk of obesity (6)
- Encouraging production of butyrate, which decreases your risk of digestive cancers and inflammatory bowel disease (7)
Amylose is known as the “starchy, non-sticky starch” in cooking. It does not dissolve in water, and high levels of amylose help grains, like rice, maintain their shape. In food manufacturing, some companies use amylose as a stabilizer and thickener.
- Functions as a useful prebiotic
- Boosts immunity
- May reduce weight and help prevent obesity
- Could decrease heart disease risk factors
- Might alleviate diabetes symptoms
- Potentially lowers risk of colon cancer
- May lower risk of tooth decay
- Could improve neurological symptoms
- Part of a healing diet for leaky gut
1. Functions as a Useful Prebiotic
A particularly significant benefit of amylose is the way it functions as a prebiotic. These non-digestible compounds reach the colon without being digested, where they are fermented by gut microflora. (9) While most prebiotics are fibrous and classified chemically as oligosaccharides, amylose is one of the non-fiber types of prebiotics.
Remember, though, that not all amylose is the same. In lab tests, the amylose in lotus seed and purple potatoes outperforms that found in high-amylose maize starch (RS4) by producing healthy gut bacteria more efficiently. (10, 11)
Prebiotics contribute to good gut microflora, which in turn affect every internal body system. It’s the feature that makes them so effective for boosting health in such a large number of ways.
2. Boosts Immunity
One such benefit of good gut bacteria is a boosted immune response. In general, prebiotic foods cause the “prebiotic effect,” referring to a decreased concentration of cancer-promoting enzymes and bacterial metabolites in the gut that can cause illness. (12)
An animal study in 2016 found that supplementation with resistant starch may potentially improve intestinal bacteria and improved immune status, specifically in the bone marrow. (13)
3. May Reduce Weight and Help Prevent Obesity
The weight-loss properties of amylose are often debated, but there is some initial evidence that high-amylose foods can potentially help fight obesity. Two animal studies showed a significant reduction in fat tissue and an avoidance of weight gain when amylose was given to promote gut health. (14, 15)
Research from the Italy Department of Public Health found that, in a small test, people who ate large amounts of “fermentable carbohydrates” (amylose-rich foods) found an improvement in glucose tolerance for the current and following meal. This is known as the “second-meal effect” and speaks to the potential long-term benefits of resistant starch intake on weight. (16)
4. Could Decrease Heart Disease Risk Factors
The heart-healthy impact of resistant starch is also in the stages of early research. However, lab, animal and at least two human studies found that amylose has the ability to reduce cholesterol levels as well as high triglycerides. (17, 18, 19, 20)
More evidence is needed to definitively qualify heart disease risk reduction as a clear benefit of amylose, but the results are promising so far.
5. Might Alleviate Diabetes Symptoms
Each person’s body functions somewhat uniquely, but there is suggestive research that high-amylose foods could potentially help patients to reverse diabetes naturally. For one, foods with high amylose concentrations are usually low on the glycemic index, meaning they won’t spike insulin levels.
A key factor in the chronic nature of diabetes is insulin resistance, or the body’s ability to process glucose efficiently. Eating resistant starch may improve glucose tolerance, provide satiety (the feeling of being full), reduce weight in some cases and lower inflammation associated with diabetes. (21, 22)
Our current understanding of the way amylose operates implies that the best results to alleviate diabetes symptoms is to eat a combination of insoluble fibers like amylose and soluble fiber over a long period of time. (23, 24)
Although this is encouraging, it’s worth noting that one cohort study of 49 participants compared a low-carb ketogenic diet with a diet low on the glycemic index (which includes a good amount of resistant starch) and found that, while both groups saw an improvement in glycemic control, the ketogenic diet subjects had more pronounced results.
In fact, in this study, over 95 percent of the individuals on the keto diet reduced or eliminated their diabetes medications entirely, as opposed to 62 percent of the other group. (25)
6. Potentially Lowers Risk of Colon Cancer
A commonly sought-after benefit of prebiotics and resistant starch, in particular, is a potential reduction in colon cancer risk.
In Advances in Nutrition, a review was completed by a number scientists discussing the potential for resistant starch in helping to prevent and control chronic diseases in humans, including obesity, diabetes and colon cancer. They stated that animal intervention studies had provided promising results and that introductory human research has also stayed along those lines in the mechanisms of resistant starch to prevent colon cancer. (26)
Another review of resistant starch focused on its role in weight loss and maintenance also mentioned a correlation between amylose and decreased risk of colon cancer, although the animal studies imply that the results may not be the same for obese humans as for people already at a healthy weight. (27)
One possible reason resistant starch might play a role in the development of colon cancer is the association of low levels of resistant starch and the production of carcinogenic bile acids, such as deoxycholate. (27, 28)
Examining a large variety of people from 12 different cultures, research from the Dunn Clinical Nutrition Center in the U.K. recognized a connection between intake of resistant starch in combination with non-starch polysaccharides, such as cellulose and pectins, finding that a combination of both compounds seemed to decrease cancer risk by the largest margin. (29)
Again, multiple factors are at play in the development of cancer. An observational study published in 2012 was able to detect no difference in colon cancer risk when examining the results of people who were carriers of hereditary colon cancer. (30)
7. May Lower Risk of Tooth Decay
At least one article in Current Issues in Intestinal Microbiology recognizes a potential for amylose-rich foods to prevent tooth decay. This is probably because it does not gelatinize like other starches. (31)
8. Could Improve Neurological Symptoms
Have you heard of the gut-brain axis? This term refers to the interaction of the gut with the central nervous system.
Bacteria in the gastrointestinal (GI) tract can activate pathways involved in brain/nervous system signaling. Understanding this connection has been a focus in recent years to help scientists develop new approaches to prevent and treat mental illness. (32)
For example, it seems that healthy gut microbiota may be connected with instances of many neurological issues, including depression, dementia, anxiety, schizophrenia, Parkinson’s and bipolar disorder. (33, 34, 35)
Perhaps most notably is the discussion on the potential for resistant starch to improve gut health and prevent or alleviate the symptoms of autism. Research suggests that healthy digestive bacteria is strongly correlated with a lowered risk of autism. (36) In addition, researchers suggest autism-related neurobehavioral issues could be alleviated by adjusting gut microbiota. (37)
This is a likely reason that the Tufts University School of Medicine recommends introducing measures to maintain proper gut health earlier in life in order to help manage or prevent autism. (38)
9. Part of a Healing Diet for Leaky Gut
It’s probably obvious by now that high-amylose foods positively impact your digestive system. That’s probably why resistant starch can help treat leaky gut, an issue with the permeability of the gut that leads to a number of symptoms, including thyroid conditions, headaches, bloating, food sensitivities and more.
One way it can accomplish this is by increasing the concentration of butyrate, a fatty acid heavily involved in gut health. By increasing the butyrate in the gut, resistant starch decreases inflammation and improves the intestinal barrier responsible for the symptoms of leaky gut. (39, 40)
Potential Amylose Risks and Side Effects
- Might aggravate digestive problems
- Can increase side effects from certain medications or supplements
- Probably not recommended for cystic fibrosis patients
- Not suggested for people with mold exposure
- Could worsen certain inflammatory diseases
- Might contribute to gluten intolerance
1. Might Aggravate Digestive Problems
It might seem a little counterintuitive, but resistant starch does have the potential to cause gastrointestinal issues for certain people. Specifically, this affects people suffering from SIBO, or “small intestinal bacterial overgrowth.” This refers to an overgrowth of bacteria in the small intestine, instead of the colon.
Illnesses in the digestive tract, such as IBS, GERD and celiac disease, are related to SIBO. Because of the inability of the small intestine to pass resistant starch before it gets to the large intestine, people with these disorders most likely should minimize their overall starch intake.
2. Can Increase Side Effects from Certain Medications or Supplements
Certain medications, such as drugs for diabetes (arcabose), and weight loss supplements known as starch blockers likely interact poorly with resistant starch intake.
This is because they inhibit enzymes that aid in digestion. Consuming large amounts of amylose in combination with either of these can increase side effects like abdominal pain, diarrhea, flatulence and other GI problems. (41)
3. Probably Not Recommended for Cystic Fibrosis Patients
Closely related, patients with cystic fibrosis (CF) probably will not benefit from high levels of resistant starch in their diets. CF patients have well-documented deficiencies in digestive enzymes, including the ones that ferment starch, that often lead to heartburn and other GI complications. Those with CF are at a risk for SIBO about three times higher than people without the disease.
4. Not Suggested for People with Mold Exposure
People who have been exposed to mold or other fungal toxins have an elevated level of MMP9, a zinc-dependent enzyme that can cause damage if produced in too-large quantities in the body.
Some sources suggest that following a no amylose diet is one way to reduce MMP9 levels, so if you have been exposed to mold or toxins, it’s wise to consult with your health practitioner about dietary practices that will improve or worsen your condition.
5. Could Worsen Certain Inflammatory Diseases
While amylose-rich foods can help lower inflammation in some cases, there is at least one exception. Inflammatory conditions under the group “spondyloarthropathies” are probably caused by a specific pathogen, Klebsiella pneumoniae, that is sensitive to starches. (42)
Two such diseases are Crohn’s Disease and ankylosing spondylitis (a type of arthritis affecting the spinal joints). If you have or are at increased risk of these diseases, you would probably benefit more from a low-starch or no-starch diet, such as the keto diet.
6. Might Contribute to Gluten Intolerance
An intolerance to gluten products, without celiac disease, has been found in many healthy people. This is most likely due to the inflammation caused by gluten, but other factors may influence your body’s tolerance for foods containing gluten. (43)
Some experts suggest that gluten intolerance may be aggravated or worsened by high-starch diets.
Amylose in Food
Some foods high in amylose include: (44)
- Seeds, nuts and legumes (soak before cooking to remove harmful antinutrients like lectin)
- Some bread products (stick to sprouted or whole grain options)
- Corn products (be careful to only eat only organic, non-GMO corn)
- Oats and barley
- Bananas and plantains (unripe and cooked varieties have the most amylose)
- Raw starches and flours (try healthy varieties, such as arrowroot)
- Rice (especially cooked, then cooled rice)
- Most root vegetables and tubers, like cassava, lesser yam, boiled and cooled potatoes, and tapioca pearls
- Raw unmodified potato starch
There are a number of resources that recommend raw unmodified potato starch as an add-in to your food products to up your resistant starch intake, as it has the highest amount of amylose in any one food product per serving. For example, it would be an easy addition to a morning smoothie bowl or an evening soup.
Because foods high in amylose rank low on the glycemic index, that’s one way to start in recognizing foods low in amylose — look for high-GI foods. Low-amylose options include:
- Fruits (except bananas/plantains)
- Above-ground vegetables
- Meat, fish and poultry
- Sugar-laden treats and snacks (steer clear of these!)
- Processed bread/tortillas (also foods you should never eat)
Amylose vs. Amylopectin
The other compound found in starch, amylopectin, has a much different physical shape and behaves differently in food and the body. Here are the major variations between amylose and amylopectin. (45)
- Amylose constitutes 20 percent to 30 percent of starch compounds, while amylopectin makes up the remaining 70 percent to 80 percent.
- Amylose is a “straight chain polymer,” meaning it has a straight shape chemically. Amylopectin is a “branched chain polymer,” giving it a more complex chemical shape.
- Amylose is soluble in hot water and will not swell or turn to gel. Amylopectin is not as hot water-soluble and tends to thicken and gel.
- Amylose is not cold water-soluble. Amylopectin can be dissolved in cold water.
- Amylose is resistant starch, while amylopectin is more easily digested as it easily breaks down to glucose.
- Both amylose and amylopectin are unique to plants.
- High-amylose rice is firm and easily separated; high-amylopectin rice is sticky and soft.
- Amylose stores a large amount of energy, while amylopectin does not store as much per gram.
- Amylose and amylopectin make up starch, which is the polysaccharide that plants use to store energy.
- Amylose is one of two components that make up starch, the method by which plants store energy.
- Amylose constitutes about 20 percent to 30 percent of the starch molecule, while amylopectin makes up the remaining 70 percent to 80 percent.
- Because it is a resistant starch, amylose is not digestible and instead is fermented by healthy bacteria in the gut. This means it functions as a prebiotic in the digestive process.
- There are four varieties of amylose. RS1, RS2 and RS3 are naturally occurring, while RS4 is a manufactured version of the compound found in genetically modified foods.
- Due to its prebiotic impact in the body, amylose can help to maintain healthy digestion in many people as well as boost the immune system, encourage weight loss, curb diabetes symptoms and reduce risks of heart disease.
- Two other major benefits of amylose that have been studied at length are the ways it may help prevent colon cancer and offer neurological healing and stability for a variety of issues, including autism.
- There are people who probably will not benefit from amylose-rich diets, including those with certain bowel diseases connected to SIBO, cystic fibrosis, mold illness, spondyloarthropathies (a class of inflammatory diseases) or gluten intolerance.