Prospective association between cancer risk and an individual dietary index based on the British Food Standards Agency Nutrient Profiling System.

Population-based, double-blind, placebo-controlled, randomized; 13,017 adults enrolled 1994–1995; mean baseline age 49.2 years; 42.4% male; cancer-free at baseline; 6435 normo-energy reporters included in analyses; median follow-up 12.6 years; dietary data collected via repeated 24 h records during the first 2 years.

Daily antioxidant vitamin and mineral supplements at nutritional doses, taken orally for 8 years.

FSA-NPS DI (higher scores = lower diet quality) is directly associated with overall cancer risk. A 1-point increase in FSA-NPS DI corresponds to an 8% higher risk of cancer (HR 1.08; 95% CI 1.01–1.15; P = 0.02); top vs bottom quintile (Q5 vs Q1) HR = 1.34 (95% CI 1.00–1.81; P = 0.03). The association is stronger in energy intake ≤ median (HR 1.10 per 1-point increment; 95% CI 1.01–1.20; P = 0.03) and not significant at higher energy intake. No significant associations for breast or prostate cancer. Findings support front-of-pack labeling based on this index to promote healthier food choices and potentially reduce cancer risk.

Generalizability limited due to volunteer, health-conscious sample; residual confounding cannot be ruled out; limited power for site-specific cancers beyond breast and prostate; reliance on self-reported 24 h dietary records with potential measurement error; long latency for some cancers may require longer follow-up.