Do Brussels sprouts really make you gassier? Can a Christmas selection box do anything for your gut bugs? And will dining with your in-laws shift your microbiome?! We asked Dietitian Laura Tilt for the science.
1. Brussels sprouts make you fart
Fact - but it’s a side effect of feeding your microbes. If you have a sensitive gut, stick with a smaller portion.
A quick reminder before we get into it: farting is a normal, healthy part of digestion. Most people pass gas around 14-25 times a day. But it’s true that some foods create more gas than others, and sprouts are one of them. They contain a fermentable carbohydrate called raffinose, which humans can’t digest. Instead, it travels to the large intestine where gut bacteria break it down and use it for energy. When your gut bacteria ferment raffinose, they produce helpful compounds that support gut health as well as… Yes, gas.
For most people, the extra gas from a side of sprouts isn’t uncomfortable. But if you have a sensitive gut, or irritable bowel syndrome, that added gas can genuinely be painful. This doesn’t mean you need to banish sprouts from your plate. A smaller portion can make all the difference.
What about their reputation for being, well, a bit stinky? Like other brassica vegetables (cauliflower, cabbage and broccoli), sprouts contain sulphur-containing compounds called glucosinolates (glo-co-SIN-oh-lates). These are part of the plant’s defence system. When they reach the large intestine, your gut bacteria transform them into gases such as hydrogen sulphide and methyl mercaptan, both known for their strong sulphur smell. Hence the whiff.
Still, there are plenty of good reasons to enjoy these mini green powerhouses. They’re rich in vitamin C and folate, and higher intakes of glucosinolate-rich vegetables have been linked with a lower risk of colon cancer.
If you find sprouts do make you extra gassy, you don’t have to avoid them completely. Keeping to a smaller serving can help. According to Monash University (the creators of the low FODMAP diet), a portion of around 75 g - about four medium sprouts - is usually well tolerated by people with IBS.
2. Chocolate can feed your gut bugs
Fact - but go for a chocolate with a high percentage of cocoa to get the benefits.
The ingredient in chocolate that nourishes your gut microbes is cocoa. Cocoa is rich in polyphenols, clever plant compounds with antioxidant and anti-inflammatory effects. They’re not easily absorbed by your gut, but they can be broken down by your gut microbes, and this is where the magic happens. Cocoa polyphenols have been shown to encourage the growth of beneficial gut bacteria. Cocoa is also high in fibre, which provides an extra fuel source for your microbes.
Since it’s the cocoa doing the gut-friendly work, it makes sense to choose chocolate with a higher cocoa content. In the UK, milk chocolate has to contain 25% cocoa solids, while dark chocolate must contain 35% or more (but typically contains 50–90%).
If dark chocolate isn’t usually your thing, try pairing it with dried fruit like some raisins or dried cherries, or use it to make a hot chocolate, or grate into porridge. A 30g serving of dark chocolate provides around 3g of fibre - about ten percent of the recommended daily target.
3. You can eat your way out of a hangover
Fiction - The only real cure is prevention.
The idea that a cooked breakfast can fix a hangover is comforting, but sadly not supported by science. The misery you feel after drinking is thought to be partly down to the toxic byproducts of alcohol breakdown. Add in dehydration, disrupted sleep and the inflammatory response triggered by alcohol, and you’ve got the classic hangover cocktail.
Plenty of hangover “cures” claim to speed up alcohol metabolism or neutralise toxic byproducts - everything from B vitamins to Korean pear juice and the amino acid cysteine - but there’s no convincing evidence they make a meaningful difference, with the studies that do exist being low quality. Experts agree you can’t ‘cure’ a hangover, only manage the symptoms while your body does the work.
The best strategy is prevention. Have a plan for drinking before you begin, drink mindfully, alternate alcoholic drinks with water and avoid drinking on an empty stomach, as this speeds alcohol absorption and can lead to poorer choices.
If you still wake up feeling less than brilliant, focus on the basics:
- Hydrate (electrolyte drinks may be useful)
- Eat some carbohydrates to bring up your blood sugar
- Try gentle movement like a walk or get some fresh air if you’re able to
- Rest and catch up on sleep
4. Eating Christmas dinner with your in-laws can change your gut microbiome
Fact - potentially yes.
Plenty of things can nudge your gut microbiome over Christmas: richer food, less fibre, more alcohol and later nights. But could dinner with your in-laws play a part too?
One small study suggests it might. Researchers collected faecal samples from 28 healthy adults before and after Christmas, comparing those who spent the holidays with their own family versus those who visited their in-laws. After analysing the samples, they spotted two distinct patterns. In the in-law group, levels of certain Ruminococcus species fell - a change previously linked with stress. Stress levels weren’t measured in the study, but the authors hypothesised that visiting in-laws could have been stressful.
Meanwhile, those spending Christmas with their own family showed greater shifts in microbial diversity, which the researchers suggested could be due to more physical contact. For example, we know that our microbiomes are shaped by those we live with.
Naturally, this finding comes with a big pinch of Christmas sparkle. It’s one small study, and a faecal sample is only ever a snapshot of what’s going on in your gut. But it does highlight a useful reminder: Christmas can be stressful, whoever you’re with. So remember to build in small breathers - a walk outside or a few long, slow exhales - to support calm during the chaos.
5. Heartburn is inevitable at Christmas
Fiction - It’s more common, but it’s not a guarantee.
Heartburn - that burning, uncomfortable feeling in the middle of your chest - does spike over Christmas. In fact, the NHS heartburn and acid reflux page becomes the most-viewed health page of the festive period, with a visit once every 13 seconds. But that doesn’t mean a dose of Christmas heartburn is unavoidable.
Heartburn is caused when stomach acid escapes from your stomach up into the foodpipe. Normally a ring of muscle called the ‘lower oesophageal sphincter keeps this from happening. But certain things can relax this muscle or put pressure on it, making reflux more likely. Big meals followed by collapsing on the sofa? Tight waistbands? Extra alcohol? Very festive, but also a recipe for heartburn.
The good news is that small tweaks can make a big difference. Here’s how to support your digestion and keep heartburn at bay:
- Wear comfortable clothing and avoid tight waistbands
- Give yourself a few hours between eating and going to bed
- Take a gentle walk after meals
- Enjoy richer, high-fat foods in smaller portions, as they take longer to empty from the stomach
- Avoid eating to the point of discomfort - save leftovers for later, they’ll be just as delicious
- Go steady with alcohol
- Try a few minutes of slow, deep breathing to trigger the body’s “rest and digest” response
How to best support your gut microbiome over Christmas
Sources
Gas and bloating. Pub Med. (2006). Link.
Cruciferous vegetables intake and risk of colon cancer: a dose–response meta-analysis. Springer Nature. (2025). Link.
Identification of the 100 richest dietary sources of polyphenols: an application of the Phenol-Explorer database. PubMed. (2010). Link.
Cocoa Polyphenols and Gut Microbiota Interplay: Bioavailability, Prebiotic Effect, and Impact on Human Health. PubMed. (2020). Link.
No convincing scientific evidence that hangover cures work, according to new research. SSA. (2022). Link.
The effect of having Christmas dinner with in-laws on gut microbiota composition. ResearchGate. (2019). Link.
