Nutritional Impacts of Minimum Unit Pricing for Alcohol: Are there unintended diet consequences?

Background: In 2018, Scotland introduced a Minimum Unit Pricing (MUP) policy to remove very-low-cost alcoholic drinks from the market and reduce adverse social and health-related impacts of excessive alcohol consumption. Any increased spending on alcohol may reduce spending on food, and adversely impact diet quality. Objectives: To estimate the effect of MUP on dietary energy, nutrients and diet quality. Methods: Analyses were conducted on household level purchase data, collected by Kantar Worldpanel (KWP) over 53 weeks before and 54 weeks after the introduction of MUP, from 1987 households in Scotland and 6064 households in the north of England. Energy and food purchases were adjusted to per adult-equivalent values after accounting for estimated unavoidable food waste. Difference-in-differences analyses were conducted for energy, energy density, Diet Quality Index, and foods and nutrients that are relevant to the Scottish dietary goals. The Poisson pseudomaximum likelihood regression model with household fixed-effects was used, with estimates adjusted for age of main shopper, household composition, duration of KWP participation, total spending on non-food items, and month of the year. The effects of area level deprivation and levels of alcohol purchase were also explored. Results: The introduction of MUP in Scotland led to a 1.6% (95% Confidence Interval (CI) 0.02% - 3.16%) reduction in sugar purchase or 8 grams per adult-equivalent per week. This reduction was partly a result of a 16.6% (95% CI 7.15% - 25.96%) reduction in sugar from alcoholic drinks purchased. No significant associations were found between MUP and energy, energy density, other nutrients or diet quality. Households from more deprived areas, or with greater alcohol purchases, had greater levels of sugar reduction from alcohol. Conclusions: The introduction of MUP in Scotland was associated with small, but beneficial, statistically significant reductions in the purchase of sugar. There was no significant change in overall diet quality.