A Mendelian trait for olfactory sensitivity affects odor experience and food selection.

Humans vary in acuity to many odors [1-4], with variation within olfactory receptor (OR) genes contributing to these differences [5-9]. How such variation also affects odor experience and food selection remains uncertain [10], given that such effects occur for taste [11-15]. Here we investigate ß-ionone, which shows extreme sensitivity differences [4, 16, 17]. ß-ionone is a key aroma in foods and beverages [18-21] and is added to products in order to give a pleasant floral note [22, 23]. Genome-wide and in vitro assays demonstrate rs6591536 as the causal variant for ß-ionone odor sensitivity. rs6591536 encodes a N183D substitution in the second extracellular loop of OR5A1 and explains >96% of the observed phenotypic variation, resembling a monogenic Mendelian trait. Individuals carrying genotypes for ß-ionone sensitivity can more easily differentiate between food and beverage stimuli with and without added ß-ionone. Sensitive individuals typically describe ß-ionone in foods and beverages as "fragrant" and "floral," whereas less-sensitive individuals describe these stimuli differently. rs6591536 genotype also influences emotional associations and explains differences in food and product choices. These studies demonstrate that an OR variant that influences olfactory sensitivity can affect how people experience and respond to foods, beverages, and other products.

Identification of regions associated with variation in sensitivity to food-related odors in the human genome.

Humans vary in their ability to smell numerous odors [1-3], including those associated with food [4-6]. Odor sensitivity is heritable [7-11], with examples linking genetic variation for sensitivity to specific odors typically located near olfactory receptor (OR) genes [12-16]. However, with thousands of aromas and few deorphaned ORs [17, 18], there has been little progress toward linking variation at OR loci to odor sensitivity [19, 20]. We hypothesized that OR genes contain the variation that explains much of the differences in sensitivity for odors, paralleling the genetics of taste [21, 22], which affect the flavor experience of foods [23-25]. We employed a genome-wide association approach for ten food-related odors and identified genetic associations to sensitivity for 2-heptanone (p = 5.1 × 10(-8)), isobutyraldehyde (p = 6.4 × 10(-10)), ß-damascenone (p = 1.6 × 10(-7)), and ß-ionone (p = 1.4 × 10(-31)). Each locus is located in/near distinct clusters of OR genes. These findings increase the number of olfactory sensitivity loci to nine and demonstrate the importance of OR-associated variation in sensory acuity for food-related odors. Analysis of genotype frequencies across human populations implies that variation in sensitivity for these odors is widespread. Furthermore, each participant possessed one of many possible combinations of sensitivities for these odors, supporting the notion that everyone experiences their own unique "flavor world."

The food choice kaleidoscope. A framework for structured description of product, place and person as sources of variation in food choices.

Despite a wide range of research approaches already being used to study eating and drinking, this complex aspect of human activity lacks conceptualisation and methodology for structured description of food choices. This paper introduces a metaphoric framework--the food choice kaleidoscope--as an approach to such inquiry. It conceptualises individual food choice events (or eating occasions) as being shaped by three main factors--product, person and place--and provides a descriptive approach through which patterns and variability in food choice events can be observed. The factors can be studied separately or in combination to reveal the joint influence of product, place and/or person factors. The approach is 'data hungry' and requires information about large numbers of eating occasions obtained for a variety of foods/beverage in a variety of situations. Using information about ∼5800 eating occasions obtained from 25 New Zealand women who self-completed 24-h recall diaries, the kaleidoscopic approach is illustrated. The data are analysed in relation to 30 food/beverage categories and 37 contextual (or 'place') variables, and at the level of individual participants. Results are presented that document: product-to-product variability in who eats/drinks what and where/how it is consumed; place-to-place variation in what is consumed and by whom; and person-to-person variability in what is consumed and where/how it is consumed. The most significant insight to emerge is the considerable heterogeneity that is hidden beneath the average patterns, and that average values may be inappropriate/irrelevant for this type of data.

Fruit consumption among people living in a high deprivation New Zealand neighbourhood.

OBJECTIVE: To investigate fruit consumption in a high deprivation population in New Zealand. METHOD: In 2007, 99 door-to-door interviews were conducted in a high deprivation neighbourhood in Auckland with a focus on measuring self-reported fruit consumption. RESULTS: On average, participants reported eating a serving of fresh fruit five to six times per week. At the time of the interview, more than a third of participants (38%) did not have any fresh fruit in the house and 60% of respondents reported that in the past month they had thrown out fruit between one to four times per week because it was considered to be past its best in terms of eating quality. Fruit juice was consumed on average one to two times per week. Self-efficacy for fruit consumption was positively associated with consumption. Relative to participants with lower levels of self-efficacy for fruit consumption, those with higher levels of self-efficacy were more likely to achieve the target of consuming two or more servings of fruit daily. CONCLUSION: Strategies that aim to increase self-efficacy beliefs for fruit consumption may contribute to improving compliance with the recommended two or more servings daily. Together with strategies that give consideration to the social and cultural context and community level interventions (involving schools, churches and local community groups) they represent a holistic approach that is likely to be necessary for improving fruit consumption in high deprivation populations.

Constraints upon food provisioning practices in 'busy' women's lives: trade-offs which demand convenience.

The present research explores food provisioning practices within women's lives. By drawing upon French social scientist Pierre Bourdieu's notions of habitus, cultural capital and field, a conceptual framework of the complex process leading to food provisioning practices is developed and investigated. To this end, repeated semi-structured interviews, participant observation, diaries and media analyses were conducted over a 3-month period with 11 women residing in Auckland (New Zealand), who were largely responsible for household food provisioning. The findings set the scene for challenging the notion of free choice. We argue that food provisioning practices are shaped by a process of trade-off between preferred practices and the constraints operating at a given point of time, resulting in practices which demand convenience in food provisioning to minimize time and cognitive effort.