From boba tea to protein bars: Study names 8 foods harming your digestive health

A study conducted by Harvard-trained gastroenterologist, Dr Saurabh Sethi, reveals how some popular food items, eight of them to be precise, could be disrupting your gut microbiome when consumed daily.

While these foods are not inherently dangerous, he argues that their ingredients, sugar content or level of processing could contribute to bloating, digestive discomfort and metabolic issues in some people.

Why gut health matters more than ever

According to Harvard Health, the gut microbiota helps digest food, absorb nutrients, regulate appetite and support immune function. A healthy balance of beneficial bacteria is considered essential for overall wellbeing.

"The gut is home to trillions of microbes forming a complex community called the gut microbiota," Harvard Health explains. These microbes help keep harmful bacteria in check and support several important bodily functions.

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When that balance is disrupted - a condition often referred to as dysbiosis — digestive symptoms such as bloating, gas, irregular bowel movements and abdominal discomfort may become more common.

1. Boba tea: A sweet treat with hidden drawbacks

Bubble tea, also known as boba tea, has exploded in popularity worldwide. Typically made with tea, milk, flavoured syrups and chewy tapioca pearls, it is often viewed as a fun alternative to fizzy drinks.

However, Dr Sethi warns that many commercial bubble teas contain large amounts of added sugar and calories.

While the tea itself may provide antioxidants, the combination of sweet syrups and tapioca pearls can significantly increase sugar intake. Excessive consumption of sugary drinks has been linked to inflammation, metabolic problems and changes in the gut microbiome.

The tapioca pearls themselves are largely made from starch and provide little fibre, protein or micronutrient value.

Healthier alternative: Choose a reduced-sugar bubble tea, skip extra syrups and consider smaller serving sizes.

2. Sweetened oatmeal packets

Oatmeal has long been considered one of the healthiest breakfast options available. Whole oats are rich in fibre, particularly beta-glucan, which supports digestive and heart health.

The problem arises with heavily sweetened instant oatmeal packets.

Many flavoured varieties contain significant amounts of added sugar, artificial flavourings and preservatives. These additions can undermine some of the benefits associated with traditional oats.

Healthier alternative: Prepare plain rolled oats and add fresh berries, nuts, cinnamon or seeds for natural flavour and additional nutrients.

3. Energy drinks

Energy drinks are often marketed as performance enhancers, but their ingredient lists can tell a different story.

Many contain large quantities of caffeine, sugar and artificial additives. High caffeine intake may trigger digestive symptoms in some people, including acid reflux, stomach irritation and diarrhoea.

Excess sugar consumption may also negatively influence gut bacteria and contribute to inflammation.

Healthier alternative: Unsweetened tea, black coffee in moderation or simply staying well hydrated throughout the day.

4. Flavoured coffee creamers

Your morning coffee may not be the issue - what goes into it could be.

Many flavoured creamers contain added sugars, emulsifiers, artificial flavourings and highly processed oils. Some research suggests certain food additives and emulsifiers may affect the gut lining and alter the composition of gut bacteria.

While occasional use is unlikely to cause major problems, regular consumption may contribute to a less favourable dietary pattern overall.

Healthier alternative: A splash of milk, unsweetened plant-based milk or a sprinkle of cinnamon.

5. Fast-food milkshakes

Milkshakes are often perceived as indulgent desserts rather than health foods, but many consumers underestimate just how much sugar and saturated fat they contain.

Large servings can deliver hundreds of calories and substantial amounts of added sugar in a single drink.

For individuals sensitive to lactose, milkshakes may also trigger bloating, gas and digestive discomfort.

Healthier alternative: Homemade smoothies made with fruit, yoghurt and minimal added sugar.

6. High-sodium canned soups

Soup sounds healthy, but not all soups are created equal.

Many canned varieties contain surprisingly high levels of sodium. Excess sodium intake has been linked to elevated blood pressure, and some research suggests highly processed foods may also negatively affect gut health.

High sodium levels can contribute to water retention and feelings of bloating, which many people mistakenly attribute solely to digestive issues.

Healthier alternative: Look for low-sodium varieties or prepare homemade soups using fresh ingredients.

7. Ultra-processed protein bars

Protein bars are a staple among gym-goers and busy professionals, but not every bar deserves its health halo.

Some products contain sugar alcohols, emulsifiers, artificial sweeteners and highly processed ingredients designed to improve texture and shelf life.

According to digestive health experts, ingredients such as sorbitol and maltitol can trigger gas, bloating and diarrhoea in sensitive individuals.

Healthier alternative: Whole-food protein sources such as Greek yoghurt, eggs, nuts or fresh fruit paired with nut butter.

8. Sweetened rice cakes

Rice cakes are often marketed as a low-calorie snack, but flavoured versions can contain added sugars and refined ingredients.

Because they are typically low in fibre and protein, they may leave you feeling hungry shortly after eating.

Repeated blood sugar spikes from refined carbohydrate-heavy snacks can also contribute to increased cravings and poor appetite regulation.

Healthier alternative: Wholegrain crackers, nuts or fruit with protein-rich toppings.

Are these foods really harmful?

It is important to keep these warnings in perspective.

No single food is likely to "destroy" your gut health overnight. Digestive health is influenced by your overall dietary pattern, lifestyle, sleep quality, physical activity and genetics.

Most nutrition experts agree that the biggest concern is the regular consumption of highly processed foods rich in added sugars, artificial additives and refined ingredients.

The occasional bubble tea or protein bar is unlikely to cause serious harm for most healthy individuals. Problems tend to arise when these foods become everyday staples.