Your Cart is Empty
Research shows that the effects of resistant starch can vary from person to person highlighting the need to capitalize on personalized nutrition recommendations according to the composition and diversity of an individual's gut microbiome.
Gut health is influenced by several different factors, including lifestyle, environment, and genetics, but one very important and essential factor is diet. There are so many different foods and food groups available, we must choose wisely which ones to indulge in. Amongst the many examples of healthy nutrients that offer unique benefits is resistant starch.
The production of biochemicals created during the fermentation of resistant starch goes on to produce a plethora of health benefits. However, although resistant starch has many purported benefits, its effect on the gut microbiome and its host varies between individuals.
So, in this article, we explore the latest research which looked to identify the predictors of the gut microbiota response to resistant starch. The results help to reinforce the need for a personalized nutrition approach to capitalize on the unique and individual benefits of dietary fiber, including resistant starch.
Starch is a product we get from foods such as potatoes, bread, rice, pasta, and cereal. In this form, starch contains some limited benefits like vitamins and minerals, and produces energy that can be easily used up[i].
Resistant starch, however, packs a greater nutritional punch because it acts similarly to insoluble fiber. For example, resistant starch increases fiber to that equivalent of brown rice, brown bread, or even wholemeal pasta, meaning it has a better impact on your health, including digestion[ii].
Resistant starches are types of carbohydrates that are not broken down into sugar and evade digestion in the small intestine. Hence the name “resistant”. Resistant starches lower the pH in the gut and help to increase the production of short-chain fatty acids (SCFAs), creating an optimal environment for health-promoting bacteria species to thrive[iii].
Resistant starch is a collective term for 5 different types:
|
Type
|
Examples |
|
RS1 |
Bound to the fibrous cell walls of grains, seeds, and legumes. |
|
RS2 |
Found in green bananas and raw potatoes |
|
RS3 |
Formed when starchy foods, particularly potatoes and pasta are cooked and cooled before eating. The cooling process converts the digestible starches into resistant starch through a process called retrogradation |
|
RS4 |
Man-made resistant starch, formed through chemical processes (chemically modified) |
|
RS5 |
Created by manufacturers by heating and cooling starchy foods with specific liquids, such as fats or waxes |
Resistant starch consumption usually has metabolic health benefits. For example, Li et al (2024) demonstrated that supplementation with resistant starch for 8 weeks in overweight or obese people induced an average weight loss of 2.8 kg and improved insulin resistance[iv].
However, several studies have shown that the response from the gut microbiota and host physiology can differ from person to person. So, Devarakonda and colleagues (2024) investigated the changes to the composition of the gut microbiota and SCFA concentrations following supplementation with two types of resistant starch (RS2 and RS4) using digestible corn starch as their control[v].
The purpose of the study was to identify predictors of the individual gut microbiota responses to RS supplementation.
In this study, 76 healthy adults started the 7-week crossover study, and 59 completed it.
Each participant was assigned a study ID number and was assigned to an RS group as follows:
The participants were then asked to consume crackers containing RS2, RS4, or the digestible control starch in their assigned treatment order. Each was consumed for 10 days alongside their usual diet. The treatment order is shown in Figure 1. and details a 5-day washout period between each treatment, where no crackers were eaten. The participants collected fecal samples before and after each treatment period.
Source: Devarakonda et al (2024)
Figure 1. Participants were assigned to groups A or B for a 7-week crossover dietary intervention study. They supplemented their diet with crackers containing one of three starches in a selected order as demonstrated above. Each treatment period lasted for 10 days followed by a 5-day washout period where no crackers were consumed. Fecal samples were collected at the start of the study, and the beginning and end of each treatment period. Food records and saliva samples were collected at baseline and during each treatment period.
One of the major findings from the study was the identification of the specific species that change in response to two different types of resistant starch, namely RS2 and RS4. The study found that individuals respond uniquely to resistant starch, meaning some people experience benefits while for others it may have little or even no effect.
This is important because increasing your intake of dietary fiber gets a lot of promotion, but in reality, if a specific type does not affect you as an individual, it would be better to prioritize the types that do. That’s where personalized nutrition comes in and where studies like this one can help. Some of the most important observations of the study are discussed below.
The order of treatment affected SCFA concentration changes. For example, the results showed that butyrate production significantly increased from beginning to end in Group B but reduced in Group A.
Similar observations were noted for propionate. The concentration of propionate increased from start to end in Group A but was reduced in Group B during treatment with RS2.
However, during RS4 treatment propionate concentration significantly decreased in Group A but increased in Group B. The researchers found that propionate concentration increased regardless of the type of RS consumed and went on to try to identify the specific variants that changed from the beginning to the end of the first treatment.
11 variants were found including members of Blautia and Coprococcus with most still being present at the beginning of the control treatment. Therefore, these microbes could have contributed to the increase in SCFA concentrations that were observed during the control treatment.
Further research is needed to understand whether the presence of specific taxa (Blautia, Coprococcus,Ruminococcus, Bacteroides,and so on) is important in influencing SCFA concentrations when resistant starch is present.
In general, the researchers discovered that both resistant starch types reduced the total concentrations of acetate, propionate, and butyrate, but that the digestible control increased all of them and the total SCFA concentration. The greatest effect the control had was on the concentration of propionate.
The study found that a lower alpha diversity before consuming RS2 was linked to increased acetate and butyrate responses. The researchers hypothesized that this relationship could be associated with the enhancement of microbes that break down RS2 or produce SCFAs at the expense of a reduction of several other bacterial species.
What is alpha diversity?
Alpha diversity refers to the richness or diversity within a particular ecosystem[vi]. It tells you how diverse a single sample is.
Overall, the study by Devarakonda et al (2024) identified several factors that may predict the differing individual responses to resistant starch, particularly RS2 and RS4. Of note, they identified that alpha diversity and the abundance of certain bacteria before resistant starch supplementation could predict changes in fecal SCFA concentrations after consuming RS.
The study suggests that people with an increased SCFA concentration in their feces as a result of consuming resistant starch are likely to observe improvement in the metabolism of sugar (glucose) and fats.
This is important because, despite common advice to increase our dietary fiber intake, it appears that the effects and benefits are not universal. Therefore, a more personalized approach to nutrition and indeed gut health is likely to be more effective. Yet, further work is required to ascertain if individuals who do not respond to resistant start are more likely to respond to other dietary fiber forms.
Despite this, there are proactive things you can do to promote the diversity of your gut microbiome. For example, our daily Akkermansia probiotic is coated in resistant starch to promote the survivability of the next-generation probiotic.
Our PureHMO® range including the 2’-Fucosyllactose Super Prebiotic Powder is known to feed 200 billion CFU of probiotics (good bacteria). The promotion of key bacterial species known to support health, like Bifidobacteria and Akkermansia,helps to diversify and balance the microbiota.
Overall, the study published in Gut Microbes and conducted by researchers at Cornell University demonstrates that the health effects of dietary fiber can differ between individuals. Therefore, this suggests that dietary recommendations should take a more tailored approach according to the composition and diversity of the individual’s gut microbiome.
Written by: Leanne Edermaniger, M.Sc. Leanne is a professional science writer who specializes in human health and enjoys writing about all things related to the gut microbiome.
[i] Starchy foods (carbohydrates) - nutritional information [Internet]. [cited 2024 Jul 29]. Available from: https://www.nutrition.org.uk/nutritional-information/starchy-foods/
[ii] Diabetes UK. Carbs and cooking [Internet]. Diabetes UK; [cited 2024 Jul 29]. Available from: https://www.diabetes.org.uk/guide-to-diabetes/enjoy-food/carbohydrates-and-diabetes/carbs-and-cooking#:~:text=An%20experiment%20on%20the%20BBC,rise%20of%20blood%20glucose%20levels.
[iii] Resistant starch [Internet]. 2020 [cited 2024 Jul 29]. Available from: https://badgut.org/information-centre/health-nutrition/resistant-starch/
[iv] Li, H., Zhang, L., Li, J. et al. Resistant starch intake facilitates weight loss in humans by reshaping the gut microbiota. Nat Metab 6, 578–597 (2024). https://doi.org/10.1038/s42255-024-00988-y
[v] Devarakonda SLS, Superdock DK, Ren J, Johnson LM, Loinard-González AAP, Poole AC. Gut microbial features and dietary fiber intake predict gut microbiota response to resistant starch supplementation. Gut Microbes. 2024 Jan-Dec;16(1):2367301. doi: 10.1080/19490976.2024.2367301. Epub 2024 Jun 24. PMID: 38913541; PMCID: PMC11197919.
[vi] Walters KE, Martiny JBH. Alpha-, beta-, and gamma-diversity of bacteria varies across habitats. PLoS One. 2020 Sep 23;15(9):e0233872. doi: 10.1371/journal.pone.0233872. PMID: 32966309; PMCID: PMC7510982.
Rhonda Jones
September 05, 2024
Very informative information….I’m grateful and appreciative of the time and concerns of health you put into your products.