Resistant Starch: Feeding Your Gut Microbiome From the Inside Out
Digestion and elimination can be considered to be the foundation of all health. When these systems are healthy and functioning well, all organs of the body benefit and many seemingly unrelated health conditions can be resolved.
Our gut microbiome plays a major role in the health of our digestive system. It should be an entire thriving community of bacteria, viruses, fungi and other beneficial microorganisms, that play an important role in our nutrient absorption, immune functions and protecting us against harmful pathogens. Instead, our microbiome is under constant pressure from modern diets, chemical overload and excessive antibiotic use.
When most of us think about gut health, we think of probiotics - kefir, sauerkraut and expensive supplements. But what if one of the most powerful ways to support your gut isn't adding more bacteria at all? What if it's feeding the beneficial bacteria that are already there?
This is where resistant starch comes in.
Over the past few months I've been diving deep into the research surrounding resistant starch and the gut microbiome, and I have read many fascinating scientific reviews exploring how resistant starch interacts with our gut microbes and the compounds they produce. What I like the most about all of this, is how simple this concept is. We're not talking about expensive supplements, we're talking about foods that many of us already eat. Potatoes, rice, legumes and green bananas. They are all foods that, when prepared in the right way, can become powerful fuel for the beneficial microbes living within us.
Most starches we eat are broken down and absorbed in the small intestine, When you eat freshly cooked rice, bread, pasta, or potatoes, digestive enzymes break those starches down into glucose, which is then absorbed into the bloodstream. Resistant starch does exactly what the name suggests, it resists digestion in the small intestine and passes undigested into the large intestine where it is fermented by our microbiota. You could say it acts like a fibre. Instead of feeding us, it feeds our microbiome.
Top dietary sources of resistant starch are: Beans, lentils, chickpeas and green peas. Oats, barley and wheat also contain large amounts when consumed in their unprocessed forms. Root vegetables such as potatoes, yams and kumera, especially when cooked then cooled. Green bananas and plantains are also a high food source. Pasta, when cooked and cooled is also a good source of resistant starch. Fermented rice and sourdough bread is also very high in resistant starch. Its not just about incorporating these foods into our diets though, its about combining them with other healthy foods. Variety is key. A healthy, varied microbiome thrives on a diet that contains a good balance of different foods and nutrients.
Our digestive tract is home to trillions of microorganisms collectively known as the gut microbiome. These microbes are essential to human health. They help us to digest food, produce essential vitamins, support immune functions, influence our inflammation processes, produce beneficial compounds and communicate with our nervous systems. Like every living thing, our resident bacteria need food, and resistant starch happens to be one of their favourite meals.
When resistant starch reaches our colons, the beneficial bacteria living there begin fermenting it. This fermentation is simply the process by which the microbes break down the compounds we cannot digest ourselves. During this process they produce a number of substances, the most notable being short-chain fatty acids (SCFAs). SCFAs are some of the most important compounds made inside our gut.
The three major SCFAs are:
🌿 Acetate. Acetate is the most abundant short-chain fatty acid. Once produced, it can travel throughout the body and be used as an energy source by various tissues.
Research suggests acetate may play roles in our energy production, metabolic regulation, appetite signalling and the communication between our gut and other organs. Additionally, studies have found that circulating acetate can cross the blood-brain barrier and influence brain functions, especially in regulating appetite, this is one of the reasons why we have the feeling of being full for so long after eating resistant starch. Honestly, I can eat resistant starch for breakfast around 6am and not get hungry again until 1 or 2 pm. Its really amazing. Acetate also has anti-inflammatory properties, and may modulate inflammatory responses and aid chronic inflammatory disorders. Think of acetate as the microbiomes most widely distributed messenger and fuel source for the body.
🌿 Propionate. Propionate is largely processed by the liver. Research suggests it may help support healthy blood sugar regulation as well as our metabolic balance and glucose metabolism. Propionate appears to help the body communicate more effectively about energy use and storage. Another intriguing aspect of propionate is its capacity to influence the gut-brain axis. Research suggests that it can signal the brain to produce appetite-regulating hormones, potentially influencing satiety and energy intake. This is why resistant starch plays such a big role in weight management. In terms of immune regulation, propionate also exerts anti-inflammatory effects in the body.
🌿 Butyrate. Butyrate is often considered the superstar of the microbiome world. Unlike acetate and propionate, butyrate is primarily used locally within the gut. The cells lining the colon rely heavily on butyrate as their preferred fuel source, and without adequate butyrate production, the intestinal lining may not function as effectively. The latest research suggests butyrate helps support: gut barrier integrity, digestive health, healthy immune regulation, balanced inflammatory responses and a healthy intestinal environment. Butyrates role in maintaining the gut barrier function is vital in preventing unwanted substances from entering the bloodstream, thereby averting potential inflammatory responses and allergic reactions that can be traced back to gut and microbiome dysfunction. Butyrate does much more than nourish the cells lining the colon. Research suggests it can influence how certain genes are switched on and off, helping regulate cell growth, repair, and normal cell life cycles. Butyrate has a potential role in supporting colon health and reducing the risk of abnormal cell growth, as it encourages damaged or abnormal colon cells to undergo normal programmed cell death (apoptosis). Butyrate also has powerful anti-inflammatory effects. It appears to help calm excessive immune responses and encourages the development of specialised immune cells that help maintain balance within the digestive tract. This is one reason butyrate is receiving significant attention in research into inflammatory bowel conditions and overall gut health.
SCFAs as a whole also modify gut pH and move it towards an environment that is favorable towards the growth of beneficial bacteria, but inhospitable to pathogenic strains.
🫐 My gluten and dairy free resistant starch breakfast 🫐
As I began exploring resistant starch, I noticed something. All the recipes I found online revolve around overnight oats. The problem? I don't eat gluten or dairy. While some people can eat oats and tolerate them perfectly well, they aren't the right option for me, if I eat any foods containing gluten and diary I get very bad flare ups of inflammation which leads to pain and mobility issues in my legs. All the recipes I found online also contained a gluten and diary free option. Swap the oats out for buckwheat goats or quinoa they said I'm not sure if the people who say these things have ever tried what they write, but let me tell you. Buckwheat groats or quinoa soaked overnight is not a nice thing. And they really doesn't soak up any of the liquid or soften that much. In one word.... yuck! I want my food to be good for me and taste good as well!
So I started experimenting. After quite a bit of trial and error, and many inedible dishes, I came up with a simple overnight rice recipe that combines several different microbiome-supporting foods in one bowl.
Gluten & Dairy Free Overnight Rice
Ingredients
• 1 cup cooked organic jasmine rice (starchy rice varieties work best. Basmati rice will not work in this recipe.)
• ½ cup kefir (dairy, water or coconut milk kefir, raglan makes a coconut kefir milk now which is delicious)
• ¼ tsp Ceylon cinnamon
• Pinch of salt
• 1 Tbsp chia seeds softened in 3 Tbsp water for 10 minutes (if you can tolerate chia, if not leave this step out.)
Mix together and leave in the fridge overnight or for at least 8 hours.
The following morning top with:
• Walnuts
• Hemp seeds
• Blueberries
Optional sweetener if you think you need it you can drizzle 1 tsp of either maple syrup, coconut sugar or honey on top.
This recipe supports the gut biome in the following ways:
The cooked and cooled rice provides the resistant starch. The kefir provides beneficial microorganisms (probiotics) and other fermentation products. The chia seeds provide soluble fibre and mucilage that help nourish microbes and also helps to repair our gut mucosa. The walnuts contain fibre and polyphenols that gut bacteria can utilise, hemp seeds provide healthy fats, minerals and additional fibre. The Blueberries.... well they are worth a mention all on their own, they provide anthocyanins and other polyphenols that may support beneficial microbes including Akkermansia. More about this below. In many ways this recipe combines four important microbiome-supporting categories:
✓ Resistant starch
✓ Fermented foods
✓ Soluble fibre
✓ Polyphenol-rich foods
Meet Akkermansia - one of the most interesting gut bacteria we have. Akkermansia muciniphila lives within the mucus layer lining our digestive tract. At first that sounds concerning because Akkermansia actually feeds on our mucin, the substance that forms our mucus layer. However, by doing so it appears to stimulate the body to produce fresh mucus. Think of it like pruning a fruit tree in your garden. A little removal encourages renewal.
Healthy populations of Akkermansia have been associated with: a stronger gut barrier function, improved metabolic health, better blood sugar regulation, reduced inflammatory markers and greater microbial diversity. And here is where the blueberries come in, blueberries are rich in compounds called polyphenols. More specifically, they contain anthocyanins, the pigments responsible for their deep blue-purple colour. Many of these compounds survive digestion and reach the colon where they interact with the microbiome. And these polyphenols are one of the favorite foods and may help encourage the growth of beneficial bacteria including Akkermansia. This is one reason blueberries are often highlighted in gut health research. They are not simply a source of antioxidants. They may also act as food for beneficial microbial communities.
‼️ An important note. Not everyone responds to resistant starch in the same way. People with IBS, small intestinal bacterial overgrowth (SIBO), sensitive digestion and existing bloating and gas issues may need to introduce resistant starch gradually and slowly. When beneficial bacteria suddenly receive more food, fermentation increases, for some people this can temporarily lead to an increase is gas, bloating, abdominal discomfort and changes in bowel habits. This doesn't necessarily mean resistant starch is unsuitable for you, It may simply mean the microbiome needs time to adapt. Research has shown that with persistance, the microbial environment will change for the better and the symptoms will ease. A gradual approach is often best. Start with small portions and observe how your body responds.
There is no universal response to dietary changes. Two people can eat the exact same food and experience completely different microbial changes. Why? Because each person's microbiome is unique. The bacteria living inside you today is different from those living inside someone else. This is why personalised nutrition is so important.
The more we learn about the gut microbiome, the clearer it becomes that health isn't simply about feeding ourselves. It's also about feeding the trillions of organisms that live alongside us.
Resistant starch provides a simple, affordable way to do exactly that. Whether it comes from cooled rice, potatoes, legumes, or green bananas, resistant starch can help nourish beneficial bacteria and support the production of compounds such as acetate, propionate and butyrate. And sometimes supporting your microbiome doesn't require another supplement. Sometimes it starts with yesterday's rice, a handful of blueberries, and understanding that the bacteria living inside you need feeding too.
Let your food be your medicine.
Kim x