Everything you need to know about Resistant Starch

Most of us are well aware of the benefits that probiotics (beneficial bacteria found in food and/or supplements) have on our gut health, but have you ever considered the importance of prebiotics (a form of dietary fibre that feeds bacteria in your gut) in the human diet to sustain a healthy gut microbiome and improve overall health? There are several forms of prebiotics (polyphenols, fibre and resistant starch). This article is going to look at the many benefits Resistant Starch (RS) has on our health. Resistant starch is a portion of food starch that remains intact through the stomach and small intestine, reaching the large intestine (colon) in its whole form.

Why is this important? When resistant starch reaches the colon, fermentation begins by resident microorganisms (gut microbiota) resulting in the formation of short-chain fatty acids (SCFAs) which promote a healthy colon. These SCFAs have multiple positive effects on the human body and have been shown to improve gut mobility and decrease the risk of leaky gut and inflammatory conditions of the bowel by promoting the maintenance of your intestinal lining(2). It also has a positive effect on blood sugar levels and insulin sensitivity due to the indigestible nature of RS.

There are four types of resistant starch:

· RS 1: physically inaccessible starch that is bound within cell walls - sources include partially milled or whole grains and legumes.

· RS 2: escapes digestion because of the intrinsic nature of the food (high amylose content) – sources include raw white potatoes and green bananas. This type can be found in powder forms, such as green banana starch or unrefined potato starch and is a great option to add to breakfast bowls/smoothies.

· RS 3: is produced when starchy foods are cooked and then cooled – sources include sweet potato, potato, white rice, and oatmeal. This way is cost-effective and a great way to introduce RS into your diet.

· RS 4: is a chemically modified starch and should be avoided.

When introducing RS to your diet, we encourage you to introduce it slowly to avoid gastrointestinal symptoms like bloating and gas. For example, start with half a teaspoon in powder form (RS Type 2) and increase as tolerated, aiming for 1-2 teaspoons per day. Alternatively, following a food first approach (Type 3), add ½ cup of cooked and cooled starchy food (e.g. white basmati rice, sweet potato, and potato) into a main meal 2-4 times per week and increase as necessary.

Note: Some Resistant starch food is low FODMAP friendly. Why? Because resistant starch is slowly fermented in the colon. It differs from FODMAPs due to this slow fermentation rate. FODMAPs are rapidly fermented and result in rapid increases in intestinal gas which, in IBS, can induce symptoms of pain, discomfort and bloating. The table above outlines high resistant starch foods with a green low FODMAP serve, so that you can include RS in your diet to improve bowel health while still following a low FODMAP diet.

The Hungry Microbiome provides a great overview if you are a visual learner.

If you are looking for further guidance and support with your gut health, please book a 15-minute complimentary appointment here.

References: 1. Bojarczuk A, Skąpska S, Mousavi Khaneghah A, Marszałek K. Health benefits of resistant starch: A review of the literature. Journal of Functional Foods. 2022;93:105094. doi: 10.1016/j.jff.2022.105094

2. Davani-Davari D, Negahdaripour M, Karimzadeh I, Seifan M, Mohkam M, Masoumi S et al. Prebiotics: Definition, Types, Sources, Mechanisms, and Clinical Applications. Foods. 2019;8(3):92. doi: 10.3390/foods8030092