Aidan:
Welcome to the Ideal Nutrition Podcast. My name is Aidan Muir, and I’m here with my co-host Torwen Eerkins. This is episode 261, where we’re talking about common foods linked with bloating and gut issues. As a bit of background, we’re probably talking about more general bloating and gut issues. So we’re not speaking about very specific gastrointestinal conditions. This won’t cover coeliac disease or inflammatory bowel disease, or anything like that. Obviously, we strongly encourage ruling those things out first in many cases. But we’ll be talking about more general stuff.
Torwen:
For sure. Bloating is probably one of the most common gastrointestinal complaints we hear about in clinic. Bloating is the feeling of fullness or pressure in the abdomen. And it is often caused by gas build-up, poor abdominal emptying, increased sensitivity, or abdominal volume. It can also come with discomfort.
Before we talk about food triggers, it is worth flagging something. For some people, chronic bloating is more than just gut issues and diet choices. It can actually be an underlying sign of a gastrointestinal condition, like Aidan just mentioned. So if you are experiencing bloating, it is important that you rule out conditions like coeliac disease and IBD. If it is persistent, severe, or worsening in symptoms, please go chat to your doctor before trying to self-manage.
Aidan:
So, going through foods and food components individually, the first one we’ll start with is lactose. This is in no particular order. Roughly 65 to 70% of the world’s population has some degree of lactose malabsorption after childhood. I really like that stat. If you asked a bunch of people, you would not get 65 to 70% reporting lactose intolerance. But that is a really high percentage of people that have some degree of this. That figure is obviously skewed by population groups. For example, in East Asian populations, it is as high as 90 to 95%.
Whereas in people of northern European descent, it is closer to five to fifteen percent. One reason I care about identifying lactose intolerance or lactose malabsorption specifically is dairy-related. A lot of people feel like they do not do well with dairy. They could be completely fine with dairy from other angles. It may specifically just be lactose that is the issue. There are many ways you can go about testing this. I think the simplest one is testing lactose-free milk and seeing if you get symptoms.
Then test regular milk and see if you get symptoms. You would have enough of it to cause symptoms. Repeat the test if you are unsure. That is more accurate than breath testing, which people previously used as a method. I would say even what I just said there is more accurate.
Torwen:
For sure. A bit of science behind why lactose can cause bloating is because it is not digested properly. People may lack the enzyme to break down the lactose. It reaches the large intestine, which means gut bacteria can ferment it. This produces gas, which causes bloating, cramping, and potentially sometimes diarrhoea.
Doing a test like Aidan mentioned is great. It is worth noting that lactose intolerance also exists on a bit of a spectrum. Lots of people can tolerate small amounts of things like milk in a coffee. Hard cheeses are naturally quite low in lactose. Some people may also tolerate fermented dairy without many symptoms. Full elimination is not always necessary.
Aidan:
And something that I am surprisingly passionate about is people being able to tolerate small amounts of it. For example, if a hard cheese has 0.1 gram of lactose. A number I use is three grams in a single sitting without symptoms. Almost every single person with lactose intolerance can tolerate that. That is a number I am very comfortable with.
There is even a paper dietitians always send me whenever I face content about lactose intolerance. It says that people can tolerate 12 grams, which is the equivalent of one cup of milk. I do not think most people who self-identify as having lactose intolerance will avoid symptoms from a cup of milk. There is more going on here. The reason I am passionate about those low amounts being clearly not an issue is the mechanism.
If it is going through undigested and causing fermentation, 0.1 grams can only ferment so much. Larger amounts can ferment far more. But it is not like coeliac disease, where your body is attacking itself. It is just going through undigested, and this fermentation process occurs. If somebody got symptoms from a very low amount of lactose, I would speculate that something else caused those symptoms.
Torwen:
For sure. Our next one on the list is more general gastro triggers. Some foods can irritate the gut, especially if there is inflammation in the stomach lining. So they may be worth exploring if you experience more upper stomach bloating. They may also be worth exploring if you experience bloating quite soon after eating.
Foods include fatty foods, which slow gastric emptying. If food sits in your stomach longer, it can lead to fullness, reflux, and bloating. Spicy foods can irritate the gut lining. Carbonated drinks introduce gas directly into the digestive tract, which is quite simple. But it can be overlooked if you consume them quite frequently. Alcohol and caffeine are two others to be mindful of as well.
Aidan
That is often frontline general bloating and IBS-style management stuff. One thing I found interesting is that I heard so many people say stuff like that. Then, after reading all this research on FODMAPs and other things, I saw a study. It put together a large group of people and told them to avoid these foods. There was a massive improvement in symptoms as well. It was almost to the same degree as some far more complicated approaches.
That said, in many cases, people will have difficulties with that. They may not want to say, “I am not going to drink forever.” Or they may not want to say, “I am not going to have caffeine forever.” There are other challenges that come alongside this as well. Another one we are going to talk about is sugar alcohols. We often find these in protein bars, chewing gum, and sugar-free lollies. They are also in a lot of low-carb, sweet alternative products in general.
Even within this category, there are different sections I would be aware of. Maltitol, sorbitol, and mannitol are common triggers of bloating. Whereas xylitol and erythritol are less likely to be issues. Once again, this is due to how much is needed to make things sweet. It is also due to how fermentable they are as well.
Torwen:
For sure. Same with the polyol. It is a sugar alcohol. If it does not get absorbed, it gets fermented by gut bacteria. This then produces gas. In large quantities, that causes bloating and pain. If you eat a lot of diet products or low-sugar products and experience bloating, this may be worth investigating. Gluten and wheat often get a lot of attention. And yes, that is for good reason, but it can be a bit misunderstood.
It is very important to separate coeliac disease from non-coeliac gluten sensitivity. With coeliac disease, even tiny amounts of gluten can trigger an immune-mediated response. We are not talking about that today. We are talking more about general bloating symptoms. So, for people without coeliac disease, symptoms can occur with gluten ingestion. Interestingly, a lot of research suggests it may be the fructan component of wheat.
Fructan is a FODMAP, and it may drive these symptoms. If this is something you want to trial, a really easy swap is spelt-based alternatives. If you are okay with that, it is more likely the fructan than the gluten in the food.
Aidan:
Garlic and onion is another common trigger here. I do not have too much to say on it beyond it being a really common one. If we went through a group of people with heaps of bloating, garlic and onion are common triggers. It is tricky because they are prebiotic-rich foods. So they are great for health overall, and even for other reasons too.
But they can be a common trigger. A lot of people can still have them in smaller amounts without it being a trigger. There is often a threshold as well. But it is another one to look out for. I have also come across a lot of people who only get symptoms when they eat out. It is because they do not add flavour when they are cooking at home. That is part of why.
Torwen:
I was going to say the tricky part with onion and garlic is that it is honestly everywhere. It is often there when you eat out, and it can be quite hidden. So exactly what Aidan said. If you are eating out and noticing symptoms, consider whether this is what is going on. The other thing is having a portion that you might be able to tolerate.
Do some trials. You might know that you can tolerate a quarter of an onion compared to more than that. It means you are not avoiding foods that are great for gut health for no reason.
Aidan:
Other FODMAPs. One we will go on is oligosaccharides. The simplest way I would look at this is legumes. Legumes are a big trigger for a lot of people. This is particularly true if you are not used to having them in your diet. It is also true if there is a quick increase. But they can be a trigger for people regardless. One little hack that can help is rinsing them. Cooking them well is another thing that can help too.
Torwen:
Mannitol is found in sweet potatoes, mushrooms, cauliflower, and that sort of thing. That can be an issue for some people too.
Aidan:
Then there are generally high or rapidly increased fibre diets. The far more common one is a quick increase in fibre. That can cause issues as well. It is something you want to start relatively low with. Then go slow with your increases. That can often allow your body time to adapt and offset this.
The other area is far rarer. But if people have a really high intake of fibre across the board, this could also be a thing. One thing that makes this tricky to interpret is the overlap. Most people who have a really high fibre intake also have a high intake of other triggers. Usually, this includes other FODMAP stuff alongside other food chemicals and things too.
Torwen:
For sure. Meal size is probably another one that is important to consider. Larger meals do stretch your stomach. They will slow gastric emptying. They increase the volume of food that needs to move through the digestive tract at one time. This can cause bloating, fullness, and discomfort. So it is important to think about whether you get bloated after super large meals. If you do, just split up your meals into smaller meals across the day.
Aidan:
Then we have another category where we have put a bunch of stuff in here. That includes food chemicals, histamines, and then SIBO is in here as well. With food chemicals, I will start with that one. We have salicylates, amines, glutamates, plus some food additives as well. These can be triggers too. Even salicylates are found in a lot of plant-based foods. So that is another thing that overlaps a fair bit with FODMAPs as well.
Torwen:
For sure. With histamines, it is foods that are high in histamines themselves. There are also histamine liberators, which cause your body to release more histamines. There are also DAO inhibitors, which can prevent the DAO enzyme from breaking down histamines.
I had two more things on that list in our other category. That includes delayed transit or gastroparesis. That can be a cause of bloating for some people. That is something you will most likely chat to a GP and gastroenterologist about. Then there is constipation. Just make sure that you keep your bowels moving. If you think about constipation in the gut, having volume there can then cause bloating as well.
Aidan:
Cool. Now practical. We have a few things that you could start with. One is a food and symptom diary. I love this recommendation. One caveat I have is that I do not think it is as perfect as people make it seem. Some of these things can cause issues as much as 24 hours later. Wheat is a great example of that. Lactose is much quicker. A food and symptom diary could work perfectly there.
You have lactose, and an hour later, or maybe slightly less, you have symptoms. Wheat is harder to pick up on a food and symptom diary. If you have wheat every day and symptoms every day, you cannot connect it that easily. The big thing with a food and symptom diary is timing.
Torwen:
If you are bringing it to a professional, make sure you are quite specific with timing. For that exact reason, it can be so hard to pick patterns without symptom timing. It is also hard if you are putting all your symptoms in there randomly. Also note things like your meal size, stress levels, and anything else that you think might be relevant.
Our other practical recommendation was making sure that you do get testing where appropriate. I think that makes a lot of sense. We said before, coeliac disease. Then whether or not you do other tests, stool samples, or that sort of thing. In terms of commercially sold food sensitivity tests, this is something we do not recommend. They often lead to unnecessarily overly restrictive diets. There is also not much research supporting them.
Aidan:
The last practical recommendation is for elimination and reintroduction-style work. We recommend chatting to a dietitian. Anyone who has listened to this for a long time knows I do not plug dietitians super often. Even though I would love to. But a line I have is that I have been a dietitian for almost 10 years. I have never had an exception to this so far. I am sure it exists. But I have never seen somebody do a low FODMAP diet well by themselves. That is crazy, because I have seen so many people do so many things well by themselves.
I have seen so many people do weight loss well by themselves, so many people manage diabetes well by themselves, and so on and so forth. But I have not seen that with the low FODMAP diet or any of these other elimination diets. I am sure it exists. I just have not seen it. Even if it is out there, which I am sure it is, it means something. Statistically, it is probably a lot more likely to go well with a dietitian. So I encourage that as well.
Torwen:
One hundred percent. I have never seen anyone that has done that. I am exactly in the same boat as you. The last little thing I had on there that might help is considering any others. That could be things like probiotics or antispasmodics. Specifically, peppermint oil is a muscle relaxant. This helps to relax, which allows trapped gas to pass through. That can help reduce IBS-style symptoms. The dose for that is 0.2ml to 0.4ml of peppermint oil three times a day.
That would be 30 to 60 minutes before eating. It is worth knowing about a few other strategies before going completely restrictive with your diet. We will wrap up here then. This has been episode 261 of the Ideal Nutrition Podcast. As always, if you enjoyed this episode, we would love if you could leave a positive review. Thank you.