EFFECTS OF DIETARY DIVERSITY ON FOOD ALLERGIES IN SOUTH AFRICA

Allergic diseases, including food allergies, are a growing public health concern in South Africa and globally. While traditionally rare among rural South Africans, rapid urbanisation and the adoption of ‘Westernised’ diets – high in ultra-processed foods (UPFs), sugar and saturated fats – have led to a ‘second-wave’ rise in the prevalence of allergies. Recent studies indicate a significant divergence between urban and rural areas, with challenge-proven food allergy rates reaching 2.5% in urban Cape Town compared to just 0.5% in rural areas. Dietary diversity, particularly in the first year of life, is a critical protective factor. Research suggests that for every additional food allergen introduced by 12 months, the risk of developing a food allergy is reduced by 33%. This diversity is thought to act through the gut microbiome to build immune tolerance. Conversely, restrictive diets and the heavy consumption of UPFs containing emulsifiers may increase intestinal permeability and allergy risk. However, maintaining dietary diversity faces significant economic hurdles. As at January 2026, the average monthly household food basket in South Africa cost R5 401.44, exceeding the national minimum wage of R5 239.46 per month since March 2026. High food inflation for nutritious staples such as vegetables (+8% to +16%) is forcing low-income families to substitute diverse nutrient-dense foods with cheaper high-calorie staples. To curb the rise in food allergies, prevention strategies should focus on the ‘biodiversity hypothesis’, which encourages the introduction of a wide variety of whole, fresh and fermented foods at about six months of age. Future efforts require collaborative research that includes immunology and nutrition to optimise the human microbiome for allergy prevention in the South African context.