Ask The Expert: Can supplements or “clean eating” help prevent food allergies?

Food allergies appear to be on the rise, even among adults with no prior history. But this doesn’t necessarily mean more adults are developing them.

Prof Amelia Santosa, head and senior consultant at NUH’s Division of Rheumatology and Allergy, notes that the rise may be due to greater awareness, improved testing, and changing exposure patterns. Here, she explains how to spot the signs of food allergies and whether ‘clean eating’ or supplements can help prevent them in adults.

What are the signs of a food allergy?

Allergy symptoms usually appear within minutes of eating, and may include hives, flushing, itchy skin, or swelling of the lips, face or throat (angioedema). More severe reactions can involve breathing difficulties (throat tightness, wheezing, shortness of breath), gastrointestinal issues (severe vomiting or crampy abdominal pain), and dizziness or fainting – signs of a serious allergic reaction.

Do lifestyle factors like diet, gut health, stress, or even where you live affect your risk?

Yes – lifestyle and environment do play a role. Factors such as microbiome development, immune system shifts, pollutants, reduced microbial diversity, frequent antibiotic use, and even stress may all contribute. However, the exact causes – and how these can be translated into reliable prevention strategies for adults – remain unclear.

Are probiotics, supplements, or “clean eating” actually helpful in preventing allergies, or is that a myth?

There is currently no proven probiotic or supplement regimen that reliably prevents food allergies.

• PROBIOTICS: Some studies in infants and children suggest that certain strains given during pregnancy or early infancy may modestly reduce allergy risk. However, results vary by strain, timing and population, and the evidence remains inconclusive.

• SUPPLEMENTS: Research hints at possible benefits – for instance, maternal omega-3 supplementation may lower some risks – but findings are not yet strong enough to support routine use for allergy prevention.

• “CLEAN EATING” OR RESTRICTIVE DIETS: These are not evidence-based for allergy prevention in the general population, and may cause nutritional harm. In infants, early introduction of common allergens (rather than avoidance) appears to lower risk, but this does not apply to adult prevention.

Biggest misconceptions about food allergies?

“IF AN ALLERGY TEST (BLO OD OR SKIN) IS POSITIVE, I’M DEFINITELY ALLERGIC.”

False. A positive test alone doesn’t equal an allergy – it shows sensitisation, meaning your immune system has made antibodies, but you may never actually react to the food. True allergy requires both sensitisation and consistent symptoms (eg hives or swelling) after eating the food.

“ALLERGIES ALWAYS GET WORSE WITH EACH EXPOSURE.”

False. Reactions are unpredictable. Some people may have mild symptoms once and severe ones the next, while others remain mild for years. Severity depends on factors like the amount eaten, exercise, alcohol, infections or medications. Because of this unpredictability, every confirmed allergy should be taken seriously.

“IF I KEEP EATING THE FOOD, MY BODY WILL BECOME TOLERANT.”

False. This is dangerous. Continuing to eat an allergenic food can cause severe – even life-threatening – reactions. Tolerance can only be developed under strict medical supervision in specialised clinics (eg oral immunotherapy for certain allergens), not by self-experimentation.The safest approach is professional diagnosis and management with an allergy specialist.

Prof Amelia Santosa, rheumatologist at NUH, specialises in rheumatology and allergy, oversees clinical services, and is core faculty for the Internal Medicine Residency Programme.