Influence of income on diet quality and daily iron and zinc intake: analysis of the National Diet and Nutrition Survey of British females aged 11–14 and 15–18 years

Abstract

Abstract Purpose A negative socio-economic gradient exists for diet and health outcomes. Since cheaper diets are associated with increased energy and lower nutrient density, we investigated the influence of income on iron and zinc intakes and overall diet quality for adolescent (DQI-A) females aged 11–18 years. Methods National Diet and Nutrition Survey (NDNS years 7 and 8) data for iron and zinc intake and overall diet quality was assessed by household income quintile across females aged 11–18 years. Results Equivalised household income positively correlated with Diet quality index for adolescents (DQI-A) (P < 0.001) Females aged 15–18 years in income quintiles (IQs) I and 2, had a greater proportion of respondents with low to intermediate DQI-A score compared to higher IQs (P = 0.002). NDNS data showed intake was negatively influenced by income amongst females aged 11–14 years for iron (P = 0.009) and zinc (P = 0.001) with those from the lowest incomes consistently consuming significantly less than those from the highest. DQI-A was positively correlated with iron intakes for 11–14 (P = 0.001) and 15–18 years (P < 0.001). Forty-one percent of 15–18-year-olds plasma ferritin stores were below the 15 µg L−1 and 21% had some form of anaemia. Cereal and cereal products were the greatest contributors to iron in all groups. Conclusion Females in the lowest income groups are at greater risk of lower overall diet quality and inadequate iron and zinc intakes. Amongst older adolescents, there is evidence of iron stores being depleted and an increased prevalence of anaemia.