What are high GOS foods? And how does this prebiotic affect people with IBS?
Are you feeling overwhelmed by the complexities of managing your Irritable Bowel Syndrome (IBS) through diet? If so, you’re not alone. In this blog post, I’ll explain this type of carbohydrate and how it affects people with IBS.
If you don’t know what the low FODMAP diet is – take a look at my beginners guide to the low FODMAP diet first.
How do galacto-oligosaccharides (GOS) impact IBS?
If you have irritable bowel syndrome (IBS), understanding how different types of FODMAPs, like galacto-oligosaccharides (GOS), affect your gut is key to managing your symptoms.
GOS are a type of carbohydrate that doesn’t get digested in the small intestine. Instead, they travel to the large intestine, where your gut bacteria ferment them.
This process can lead to uncomfortable IBS symptoms like bloating, gas, and stomach pain.
What exactly are GOS?
GOS are chains of sugars found in foods like beans, lentils, and certain nuts. That’s why these foods are often known to cause a lot of gas!
The two main types you might have heard of are raffinose and stachyose.
Unfortunately, our bodies don’t produce the enzymes needed to break down these sugars, which is why they often cause trouble for those with IBS.
Why do some people tolerate GOS better than others?
Everyone’s tolerance to FODMAPs varies. While some people with IBS can handle small amounts of GOS, others may find them more triggering.
For instance, studies have shown that consuming less than 12g of GOS per day is often well-tolerated, but 15g or more can cause increased gas and bloating in people with IBS.
This happens because, as GOS are fermented in your large intestine, your friendly gut bacteria produce gas as a by-product.
In healthy individuals, this might lead to a normal amount of gas. A bit of extra wind, but nothing to worry about.
But if you have IBS, your gut may be more sensitive, leading to excessive gas, particularly smelly gas or increased pain and discomfort.
Why bacterial fermentation matters for your gut health
When your gut bacteria ferment GOS, they produce short-chain fatty acids (SCFAs), which are really good for your gut health. SCFAs help lower the pH of your colon, creating an environment that promotes the growth of friendly bacteria like lactobacilli and bifidobacteria. These good bacteria help balance your gut microbiome, and can crowd out harmful bacteria.
This is why we don’t want to cut out GOS-containing foods completely for too long.
Including small amounts of GOS containing foods can actually help maintain a healthy gut environment in the long term.
Want to eat a better diet for IBS?
Be mindful of FODMAP stacking
When managing your GOS intake, it’s important to avoid “FODMAP stacking.”
This means eating too many moderate-to-high FODMAP foods in one meal, which can tip you into a high FODMAP zone.
For example, having 40g of black beans alongside a handful of almonds could result in GOS consumption that might be triggering for your IBS symptoms.
How to reintroduce GOS into your diet
There’s no need to avoid GOS foods forever. The goal is to slowly retrain your gut to handle them. Start with small portions—like adding just 2 tablespoons of lentils to your curry. This can help your gut microbes adapt to GOS over time.
Reintroducing these foods gradually could help improve your tolerance and support a healthier gut.
Foods turn to moderate or high FODMAP at these levels:
- Almonds – 10 nuts
- Hazelnuts – 24 nuts
- Flax seeds 15g (1 tbsp)
- Cassava – 180g
Beans
- Pinto beans <28g (1.5 tbsp)
- Adzuki beans <40g (¼ cup)
- Black beans <45g (¼ cup)
- butter beans <60g
- borlotti beans <45g
- chickpeas, tinned, rinsed <80g (when these are dried, & boiled you can only eat <33g)
- cannellini beans <89g
- Lentils tinned, rinsed <65g (brown)
- Lentils (puy) 30g is low, 90g is high
- Lentils (red) 23g is low 46g is moderate
If you need to stay at low levels of GOS in your diet all portions of the above food should be smaller than the portions listed above.
In summary
FODMAPs can be tricky to understand, but it’s easier when you have meal plans, recipes, clear instructions on how to reintroduce and symptom trackers. Sounds good?
I specialise in working with people who have IBS, and I’m here to support you to find the best diet you can, with the most diverse foods you can tolerate.
If you want help figuring out your IBS triggers, start your Gut Reset with me over 3 months to find a diet that works for you. Just set up a free call to discuss what you need some help with. Email info@goodnessme-nutrition.com
IBS Nutritionist
Hi, I'm Anna Mapson, registered Nutritional Therapist.
I help people with IBS and SIBO get control of unpredictable gut symptoms to find long term relief from painful and embarrassing IBS without restrictive dieting.
I can help you to:
- understand your digestion better, so you recognise your triggers
- eat a well balanced diet, with tasty meals that are simple to prepare
- reintroduce your trigger foods so you can get back to enjoying food again
Find more about my 3 month 1:1 Gut Reset programme.
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