Low-income purchase selections : what is the price of choosing healthier alternatives?



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The primary hypothesis of this study was that low-income individuals purchase more packaged foods of lower healthiness and lower price compared to similar packaged foods of higher healthiness and higher price. The Nutrition Metric was chosen as the system to measure the nutritional value of foods because it is in the public domain and uses nutrients common to the Nutrition Facts panel; however, prior to use, the validity of the Nutrition Metric needed to be tested. The convergent validation of the Nutrition Metric was tested with four systems (NuVal, Guiding Stars, WXYfm, Go-Slow-Whoa) that met the study criteria. A sample of 600 foods that were purchased over a 104 week period that ended in November 2009 by 34,407 low-income households was drawn to achieve at least 168 items having scores available for each system. The Nutrition Metric had a positive correlation with all scoring systems for the 174 foods (P<0.01) that verified its validity as a tool to assess food healthiness. The Nutrition Metric was used to measure the healthiness of packaged products from the list of low-income food purchases (n=316). Products had a negative mean healthiness score of -0.88 ± 1.72 and low levels (<5% Daily Value) of dietary fiber, vitamin A and C, iron, and cholesterol. The majority of the products (n=305) did not have a nutrient claim on product packaging. The Nutrition Metric was a successful tool that can be utilized to assess the healthiness differences between products with and without nutrient claims purchased by low-income shoppers with counterpart products at the supermarket. Food price and healthiness differences were evaluated for the list of packaged products (n=305 (minus 11 single ingredient cooking staples)) commonly purchased by low-income shoppers to counterpart products of the same brand and package size with or without nutrient claims. Products with nutrient claims (n=77), on average, had higher healthiness scores and prices than products without claims (n=77) (P<0.01). Research and education initiatives that promote the selection of products with claims instead of products without claims are potential options to improve the diets of low-income consumers.