Q&A: Why do FODMAPs make you bloated? Is apple cider vinegar good for you?

Welcome back to our weekly Q&A Wednesday.

The first question (why do FODMAPs make you bloated?) is available to all subscribers. There is a further question behind the paywall (about apple cider vinegar).

If you have any questions that you would like to be answered in future weeks, please do submit them here.

Medical Disclaimer. Although I’m a doctor, I can’t replace your registered doctor. As such, the information in this newsletter is for information purposes only. It is not intended to be a substitute for medical advice, diagnosis or treatment. Always seek the advice of your qualified healthcare provider for any medical conditions, and never disregard professional medical advice because of information you have found in this newsletter. The publisher and authors of this newsletter assume no responsibility for any adverse effects that may result from the use of the information contained herein.

With many thanks to Gilly Brunton, leading nutritionist, for providing the answers this week.

Q. Why do FODMAP foods make you bloated?

• John

A. For many years dieticians and nutritionists have used the low FODMAP dietary approach when working with Irritable Bowel Syndrome clients. IBS is a digestive disorder where up to 90% of sufferers report bloating, and the low FODMAPs diet successfully reduces symptoms for many.

In short, the bloating is caused by excess gas, created in our intestines. FODMAP foods are rapidly fermented by our colonic microflora and this is where the increase in gas stems from. This increase in gas distends the bowel which can cause the sensation of bloating and abdominal pain or discomfort and may affect how the muscles in the wall of the bowel contract.

FODMAP stands for fermentable oligosaccharides (chains of sugar molecules), disaccharides (double sugar molecules), monosaccharides (single sugar molecules) and polyols (sugar alcohols) and are found in many foods. Some foods contain just one type, while others have several. When these sugars, starches, and fibres are consumed, they can aggravate gut symptoms in varying degrees from embarrassing flatulence to severe abdominal pain or chronic diarrhoea. Here’s a link to a list of low and high FODMAP foods.

It’s very important to state that this is not an immune condition or a food allergy (the immune system is not activated), but an intolerance to certain foods (or a mix of foods together which I like to refer to as a ‘bad disco’)!

Our Food’s Journey:

When we consume a meal, after chewing and swallowing, the foods begin their journey through the  gastrointestinal system and make an early pit-stop in our small intestine to drop off important nutrients. Our carbohydrates (sugars) are broken down here to simple sugars which can be absorbed and which are our primary energy source. BUT some people are less able to break down and absorb certain carbohydrates (the FODMAP carbohydrates) in their small intestine, hence creating a digestive problem.

The bugs in our colon:

Next, our large intestine (also called the colon) has the job of eliminating waste AND absorbing other nutrients and water. For many people, most of the nutrients have already been absorbed in the small bowel so the colon has very little to do (except to reabsorb water). In those people where the FODMAP foods reach the colon (because the small bowel hasn’t been able to absorb them), several things happen. The bacteria in our colon ARE able to break down these molecules, which is great because it means that we still get the nutrients and energy. But the downside is that this fermentation releases a lot of gas. Which can cause bloating and distension. The arrival of FODMAPs in the colon can also mess around with water levels in the bowel, and some people will suffer with diarrhoea or constipation as a result.

Consider the nerves: 

For those sensitive to FODMAPs, when consuming these foods the gut stretches and the nerves in that area react, leading to further discomfort and pain. People suffering from too much stress or anxiety, or low mood may have nerves in the gut that are “extra sensitive” - If these nerves ‘overreact’ to being stretched, the level of discomfort increases significantly.

Worth mentioning:

Those experiencing symptoms when consuming FODMAPs may also experience fatigue, low mood, and anxiety. The exact reason for this is unclear, but what is clear is that much more research is needed on this topic. We’ll be doing a full feature length newsletter soon covering the whole of the FODMAPs topic.