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1. Why do I feel unwell after eating foods I used to enjoy?

Food-related symptoms in older adults can have various causes. For some, underlying conditions like irritable bowel syndrome may make the gut more sensitive to certain triggers. Ageing may also bring changes in digestion — slower movement of food through the gut, reduced saliva or stomach acid, and shifts in gut bacteria can all contribute to bloating, discomfort or irregular bowel movements. In some cases, medications such as NSAIDs, antacids or antibiotics may also interfere with digestion.

2. What’s the difference between food intolerance, food sensitivity and allergy — and how can I tell which one I have?to

The term “food intolerance” is best applied to well-defined conditions like lactose intolerance, where the body lacks the enzyme needed to digest lactose in dairy. This often causes bloating, gas or diarrhoea after consuming milk-based products.

In contrast, a food allergy involves an immune response that typically causes immediate symptoms such as hives, swelling or breathing difficulty, sometimes life-threatening. Common allergens include peanuts, shellfish and eggs.

“Food sensitivity” is less well defined and not officially recognised in most clinical guidelines. It’s sometimes used to describe delayed symptoms that occur after eating certain foods, but the mechanisms causing these symptoms are not yet well understood.

If you consistently feel unwell after eating certain foods, take note of them and speak to a doctor or dietitian. They can help identify the cause and guide appropriate testing or dietary adjustments.

3. Are some foods more likely to trigger symptoms as we age?

Among all food-related conditions, lactose intolerance is by far the most common, especially in Asian populations. It occurs when the body lacks the ability to produce sufficient lactase, which is needed to digest lactose, a type of sugar found in milk and dairy products. Symptoms typically include bloating, gas and diarrhoea after consuming foods like fresh milk, creamy desserts or foods rich in butter such as kaya toast.

Other than lactose, some may notice discomfort after eating fatty, spicy or fried foods, such as sambal dishes, fried bee hoon or laksa, or after drinking carbonated or caffeinated drinks. It should be noted, however, these foods may be more likely to act as triggers in those with underlying GI sensitivity, rather than reflecting an actual food intolerance.

4. How do I know if my symptoms are due to something I ate?

If you notice symptoms that consistently follow certain foods, it may be worth exploring a food-related trigger. Keeping a simple food and symptom diary, where you note what was eaten and any symptoms that follow, can be a helpful first step in pinpointing triggers and patterns. If discomfort persists or worsens, consult a doctor or dietitian to identify the cause accurately.

5. Should I avoid problem foods completely, or can I still have small amounts?

In many cases, small portions are tolerable. For example, someone who has lactose intolerance may still enjoy cheese in kaya toast, or occasional pizza, without symptoms. Start with smaller portions and monitor your body’s response. Those with lactose intolerance may also be able to enjoy aged cheeses, yoghurt or lactose-free dairy.

It’s also important not to eliminate nutrient-rich foods unnecessarily, as this may lead to nutrient imbalances. If certain foods must be limited, finding appropriate substitutes is key to maintaining a well-balanced diet. Simple habits like eating smaller meals, avoiding heavy suppers and staying upright or taking a short walk after meals can help reduce symptoms, especially for those with reflux or indigestions.

6. Can these food-related symptoms be managed, or even reversed?

Reversing food intolerance is unlikely, especially if it has a genetic basis, such as in lactose intolerance. However, when symptoms stem from temporary issues, such as damage to the digestive system, improvement may be possible over time.

Management remains key. Using a food diary, individuals can identify trigger foods, observe tolerable portion sizes and adjust their intake to reduce discomfort. For example, people with lactose intolerance may still tolerate small amounts of dairy without symptoms.

Emerging research suggests that a fibre-rich diet, limited intake of ultra-processed foods and the judicious use of probiotics or prebiotics may support better gut health. A structured exclusion and reintroduction approach, guided by a dietitian or healthcare professional, is recommended for personalised and sustainable symptom management.