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While revising this Analysis article (BMJ 2019;366:l4137, doi:10.1136/bmj.l4137) the authors mistakenly included a section on the reanalysis of the Minnesota Coronary Experiment. The authors had originally agreed among themselves not to include the section in the final manuscript for two reasons. First, the key message of the article is to move from recommendations of single nutrients into food based recommendations because saturated fat is a heterogeneous group of fatty acids with divergent health effects, and the effect is furthermore dependent on the food matrix they exist in. For that reason, the authors felt the section was redundant. Second, for a discussion of the health effects of polyunsaturated fat, the authors did not feel that the section provided a balanced and complete analysis of the issue. Soon after publication the authors contacted The BMJ to notify the journal of the mistake and request correction of the article by removing the following paragraphs, which does not substantially change the message or argument of the Analysis: “Reanalysis of the Minnesota Coronary Experiment (a double blind randomised controlled trial that tested whether replacing saturated fat with polyunsaturated fat reduced coronary heart disease and death) also supports the claim that serum cholesterol is not a valid surrogate biomarker for cardiovascular disease risk when making dietary changes.10 Despite the finding that the polyunsaturated fat diet produced a 13% greater reduction in serum cholesterol than the saturated fat diet, there was no reduction in cardiovascular disease endpoints.10 “The reanalysis found a 22% higher mortality for each 0.78 mmol/L reduction in serum cholesterol caused by the polyunsaturated diet.10 A meta-analysis found that cholesterol lowering using polyunsaturated fat diets did not show any evidence of benefit on mortality from coronary heart disease (1.13, 0.83 to 1.54) or all cause mortality (1.07, 0.90 to 1.27).10” These paragraphs have been removed from the article online.

Sustainability standards are gaining in importance in global markets for high-value foods. While previous research has shown that participating farmers in developing countries may benefit through income gains, nutrition impacts have hardly been analysed. We use survey data from smallholder coffee farmers in Uganda – certified under Fairtrade, Organic, and UTZ – to analyse impacts on food security and dietary quality. Estimates of instrumental variable models and simultaneous equation systems show that certification increases calorie and micronutrient consumption, mainly through higher incomes and improved gender equity. In certified households, women have greater control of coffee production and monetary revenues from sales.

Many developing countries are experiencing a food system transformation with a rapid growth of supermarkets. Research has shown that smallholder farmers can benefit from supplying supermarkets in terms of higher productivity and income. Here, we analyze impacts on farm household nutrition. Building on data from vegetable farmers in Kenya, we show that participation in supermarket channels has sizeable positive effects: calorie, vitamin A, iron, and zinc consumption are all increased by 15% or more. We also analyze impact pathways, using simultaneous equation models. Supermarket-supplying households have higher incomes, a higher share of land under vegetables, and a higher likelihood of male control of revenues. Furthermore, income and the share of land under vegetables have positive impacts, while male control of revenues has negative impacts on dietary quality. The total nutrition effects of supermarket participation could be even more positive if women were able to keep their control over farm revenues in the process of commercialization. The methods developed and used may also be useful for other impact studies to better understand agriculture-nutrition linkages.

Many developing countries are experiencing a food system transformation with a rapid growth of supermarkets. Research has shown that smallholder farmers can benefit from supplying supermarkets in terms of higher productivity and income. Here, we analyze impacts on farm household nutrition. Building on data from vegetable farmers in Kenya, we show that participation in supermarket channels has sizeable positive effects: calorie, vitamin A, iron, and zinc consumption are all increased by 15% or more. We also analyze impact pathways, using simultaneous equation models. Supermarket-supplying households have higher incomes, a higher share of land under vegetables, and a higher likelihood of male control of revenues. Furthermore, income and the share of land under vegetables have positive impacts, while male control of revenues has negative impacts on dietary quality. The total nutrition effects of supermarket participation could be even more positive if women were able to keep their control over farm revenues in the process of commercialization. The methods developed and used may also be useful for other impact studies to better understand agriculture-nutrition linkages.

Many developing countries are experiencing a food system transformation, with a rapid growth of supermarkets. Research has shown that smallholder farmers can benefit from supplying supermarkets in terms of higher productivity and income. Here, we analyze impacts on farm household nutrition and show that participation in supermarket channels has sizeable positive effects: calorie, vitamin A, iron, and zinc consumption are all increased by 15% or more. We also analyze impact pathways, using simultaneous equation models. Supermarket-supplying households have higher incomes, a higher share of land under vegetables, and a higher likelihood of male control of revenues. Furthermore, income and the share of land under vegetables have positive impacts, while male control of revenues has negative impacts on dietary quality. The total nutrition effects of supermarket participation could be even more positive if women were able to keep their control over farm revenues in the process of commercialization. The methods developed and used may also be useful for other impact studies to better understand agriculture-nutrition linkages.