Dietary Intervention on Atopy

This study evaluates whether a dietary pattern lower in saturated fats and higher in whole grains, fruits, and vegetables reduces AD severity in young Singaporean adults over a 2-month period, as measured by changes in Scoring Atopic Dermatitis (SCORAD) scores.

The SCORAD index is a validated measure of AD severity that integrates lesion extent, clinical signs (erythema, edema, oozing/crusting, excoriation, lichenification, dryness), and patient-reported symptoms. It quantifies affected body surface areas (e.g., head, limbs, trunk), enabling standardized baseline assessment and sensitive monitoring of changes over time.

This outcome evaluates changes in skin barrier function using objective bioengineering measurements, including skin hydration, transepidermal water loss (TEWL), pH, and sebum levels. These parameters capture key physiological aspects of atopic dermatitis (AD) beyond clinical severity.

Measurements will be obtained using standardized instruments: Tewameter® (TEWL; g/h/m²), Corneometer® (skin hydration via relative permittivity), Skin-pH-Meter PH® (surface pH), and Sebumeter® (sebum content; 0-350 scale). Assessments will be conducted at predefined anatomical sites corresponding to SCORAD evaluation areas.

Participants demonstrating improvement will be defined based on directional changes toward normalized values across these parameters, enabling an objective assessment of skin barrier recovery following the intervention.

This outcome assesses the impact of the dietary intervention on participants' quality of life using the Dermatology Life Quality Index (DLQI), a validated 10-item instrument measuring the effect of skin disease on daily functioning and psychosocial well-being.

DLQI scores range from 0 to 30, with higher scores indicating greater impairment. Changes in DLQI will be evaluated alongside clinical severity (SCORAD) to provide a more comprehensive assessment of intervention effects. A reduction of ≥4 points will be considered the minimal clinically important difference (MCID), consistent with established thresholds.

This outcome evaluates changes in the use of AD-related medications as an indicator of disease control and treatment burden. Medication use will be recorded for both maintenance therapies (e.g., moisturizers, topical preparations) and symptom-control treatments (e.g., topical/oral corticosteroids, antihistamines).

Frequency of use will be categorized as: never/rarely (<1 day/week), occasionally (1-2 days/week), or most/all days (≥3 days/week). An aggregate medication utilisation score, adapted from validated scoring systems in allergic disease research, will be computed to quantify overall treatment use.

Reductions in medication utilisation will be interpreted as supportive evidence of improved disease control in response to the dietary intervention.

Anthropometric outcomes will be assessed as separate measures. Height (cm): Height will be measured using a calibrated stadiometer and recorded in centimeters.

Weight (kg): Weight will be measured using a calibrated digital scale and recorded in kilograms.

Body Mass Index (BMI, kg/m²): BMI will be calculated as weight (kg) divided by height squared (m²) and classified according to Asian-specific criteria. Changes in BMI will be used as an aggregate indicator of overall anthropometric status.

This outcome assesses systolic blood pressure (mmHg) and diastolic blood pressure (mmHg). Measurements will be taken in duplicate using a validated automated sphygmomanometer under standardized conditions.

This outcome evaluates changes in fasting lipid parameters. Venous blood samples will be collected after a 10-12 hour fast and analyzed for serum total cholesterol, triglycerides, and HDL cholesterol (mmol/L) using enzymatic methods. LDL cholesterol will be estimated using the Friedewald equation. Together, these parameters characterize the lipid-lipoprotein profile.

This outcome evaluates changes in systemic immune function through circulating cytokine and chemokine levels. Fasting venous blood samples (15 mL) will be collected in EDTA tubes and processed by centrifugation to isolate plasma.

Plasma samples will be aliquoted and analyzed for a panel of inflammatory protein markers, including cytokines and chemokines relevant to atopic dermatitis and immune regulation. Changes in marker concentrations over time will be used to assess the immunomodulatory effects of the dietary intervention.

This outcome assesses changes in gut microbiota profiles in response to the dietary intervention. Stool samples (~10 mm³) will be collected at baseline, day 28, day 56, and day 84 using standardized procedures to preserve microbial integrity.

Microbial DNA will be extracted using validated commercial kits, and 16S rRNA gene sequencing will be performed to characterize bacterial taxa. Microbiota changes will be evaluated using:

Alpha diversity (within-sample diversity), reflecting richness and evenness of microbial communities Beta diversity (between-sample differences), reflecting shifts in overall community composition.

These measures will be used to examine whether dietary modification is associated with changes in gut microbial ecology, which may influence systemic inflammation and AD outcomes.