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According to the National University Hospital, 90 per cent of Singaporeans are lactose intolerant to varying degrees. But who knew it was possible to become lactose intolerant after a bad bout of food poisoning


The background

Sometime in August last year (2017), my colleagues and I went to a nearby mall for a quick lunch. We ate at a well-known – and often crowded – local eatery where I had my usual plate of nasi lemak and a cup of soya bean. We’d actually been to this exact outlet many times before with no issues. And all was fine, until maybe half an hour after lunch when I felt my stomach start to churn. It grew increasingly uncomfortable and I had to make a trip to the washroom. After clearing my bowels, I thought that was it and all was fine again. Until… it wasn’t.

We were driving out of the mall when I suddenly felt my stomach pull again. My gut was cramping and churning badly, but there were no washrooms in sight. Since it takes less than 10 minutes to reach the office, I thought I’d just hold it in. That was probably the longest 10 minutes of my life. I was shivering and breaking out in cold sweat in the car as my colleagues did their best to distract me from the discomfort. I actually needed the washroom so urgently that I half-considered asking my editor to pull over so that I could relieve myself behind some random trees. When we finally made it back, I ran straight to the first-floor washroom and cleared my bowels again though I was just passing out water. Later that afternoon, two of my colleagues who drank soya bean also had stomach cramps and the runs, so I think we found the culprit.


The aftermath

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Since then, my stomach has never been the same again. What started as food poisoning turned into a long-drawn battle with an incredibly weakened digestive system and, surprisingly, a severe case of secondary lactose intolerance. As a backgrounder, I’ve never had a problem with dairy before this. I used to drink a cup of milk every other day and I’m a huge cheese eater. But since the August incident, I’ve slowly come to accept that my stomach starts to churn and I’ll have the runs if I drink even the slightest hint of milk. Initially, I thought it was because I was still recovering from food poisoning. But after seeing three doctors over the span of six months and tracking my diet, I’ve realised that my biggest trigger for an upset stomach is dairy. The worst culprits so far are fresh milk, ice cream (the tragedy!) and yogurt.

So, just what happened to my gut health? I seriously never thought this could happen to me – or anyone, for that matter. I’ve never heard of anyone developing lactose intolerance from a bout of food poisoning before. Intrigued, I sussed out Dr Gwee Kok Ann, medical director and consultant gastroenterologist at Gleneagles Hospital, to find out more.

Is it possible to develop lactose intolerance after a bad bout of food poisoning?

Dr Gwee: Yes, it is possible. The enzyme responsible for digesting lactose, known as lactase, is situated on the tips of villi. Villi are finger-like projections on the internal intestinal lining. When there is an infection that involves the small intestine, the lactase enzyme on the tips of the villi are expected to be damaged, thus reducing one’s ability to digest and absorb lactose.

Sometimes, after an episode of food poisoning, certain functions of the intestine may also be changed. Intestinal movements may become faster and more sensitive to gas, and an imbalance of the naturally-occurring bacteria in the colon can also result in greater fermentation of lactose – which again leads to more gas.

This damage to the intestinal lining may take up to two months to recover.


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Is it possible to suddenly develop irritable bowel syndrome (IBS) after food poisoning?

Dr Gwee: An episode of severe food poisoning is a well-recognised cause of IBS. This is called post-infection IBS. Other common triggers of IBS include antibiotic treatment, majorly stressful life events and surgery to the gallbladder or pelvis.

Can someone who developed secondary lactose intolerance “train” their bodies to tolerate dairy again?

Dr Gwee: Most people with secondary lactose intolerance do not lose all their ability to tolerate lactose. There is usually some residual lactase enzyme on the intestinal lining that will allow for absorption of small quantities of lactose.

How well the intestine can handle the lactose load will also depend on the speed at which it moves through the intestine. The faster the intestinal movements, the worse the lactose intolerance. The trick is to avoid consuming dairy with substances that stimulate intestinal movements such as coffee and to eat some food before consuming dairy.

Consuming probiotics could also help by improving the balance of colonic bacteria in the gut so that there is less gaseous fermentation of lactose, and by reducing inflammation in the colon so that it is less sensitive to gas. It is also possible for some probiotics to promote some recovery of lactase enzymes and improve intestinal permeability.



The plan

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Dr Gwee’s explanation sheds light on why I’m the most intolerant to fresh milk, ice cream and yogurt since these are all pretty non-solid items (i.e. they pass through the intestinal tract very quickly).

Currently, I’m slowly rebuilding my gut health by taking probiotic tablets daily. I’m also heeding the advice of Winnie Ong, fermentation expert and co-founder of local kombucha and kefir makers Craft & Culture, to order a mix of probiotic-rich foods like miso or kimchi whenever I eat out. This introduces different strains of good bacteria to my system to strengthen it.

Since I got officially diagnosed as being lactose intolerant earlier in January, I’ve also been consciously avoiding dairy. So far, my efforts seem to be paying off. From needing to rush to the toilet up to five or six times a day, I now go just once in the mornings (my usual). My gut seems less reactive as well. I’m also supposed to lay off lactose totally for at least the next one or two months so that my intestinal lining has a chance to properly recover (I used to blindly take small amounts of dairy every week to strengthen my gut but the only thing I achieved was more toilet trips and an increasingly sensitive gut). So far so good, but I don’t know if I’ll ever be able to tolerate dairy again. The thought of never indulging in a scoop of creamy gelato definitely saddens me, but it’s a price I’m willing to pay if it finally means good gut health.

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