Taste Thresholds and Food Dislikes

A possible genetic association between PROP-tasting and alcoholism

Fifty-five young adult subjects and their parents were classified as alcoholic or nonalcoholic based on a standardized questionnaire (the MAST) filled out by the subjects. Subjects' thresholds for detection of 6-n-propylthiouracil (PROP; a PTC-like compound) were determined with the experimenter blind to MAST responses. There was a significantly higher proportion of nontasters of PROP among children of alcoholics than among children of nonalcoholics. There was no relationship between the child's alcoholism status and ability to taste PROP. These results are inconsistent with the view that excessive use of alcohol causes the association between nontasting and alcoholism and are consistent with the view that there is a genetic association between PROP/PTC-tasting and alcoholism.

Learned food aversions: a family study

This study aimed to establish the reliability of prevalence estimates and various reported features of food aversions in the general population, explore relationships between aversions and selected individual characteristics, especially a familial association, and to assess the dietary implications of aversions. One hundred families comprised of 416 6-76 y/o individuals completed a questionnaire eliciting health, demographic and dietary information. A history of aversions was reported by 37.5% of subjects and 26.3% had current aversions. The prevalence was comparable in males and females through age 20 when the female:male ratio increased to about 2:1. A stable and higher level of aversions was observed in subjects 11-40 y/o compared to those younger or older. The mean onset of first aversions was about 16 years, and the mean duration was approximately 11 years. High protein foods were the most common target. The majority of aversive foods were rated as familiar and previously pleasant. Correlations were noted between aversions and medication use, food allergy and, in adults, BMI. The principal new finding was a significant familial association for aversions.

Use and perceived attributes of cruciferous vegetables in terms of genetically-mediated taste sensitivity

Bitter tasting compounds in cruciferous vegetables resemble chemically the compound phenylthiocarbamide (PTC). As sensitivity to PTC is genetically mediated, it was hypothesized that this characteristic would be linked to greater sensitivity of the bitter tasting components in cruciferous vegetables, and that PTC sensitivity would be reflected in less favourable sensory perceptions and lower use of the vegetables. PTC status was determined for healthy, racially and culturally similar women, alike in foodways and aged 18-46 years. The frequency of use and perceptions of sensory, post-ingestional and social attributes of 11 cruciferous and two non-cruciferous vegetables in both raw and cooked forms were compared between the PTC tasters and non-tasters. Minimal effects of PTC status on these factors were observed. Only two vegetables showed significant differences in use--PTC non-tasters used cooked turnip and raw watercress significantly more than did PTC tasters. Perceived bitter taste and aroma did not offer an explanation for the findings. Similarly, familiarity, early exposure, and tolerance did not account for any group differences. PTC status, especially in terms of non-tasting propensity, may have some sensory-specific effects which will impact on the use of cruciferous vegetables by young and mature women, but environmental factors may offset this effect and must be considered in studies of food behaviour.

Family environment, not heredity, accounts for family resemblances in food preferences and attitudes: a twin study

Monozygotic and same-sex dizygotic twin pairs reported on their food preferences, the variety of foods of the same general category (e.g. types of soup) in their diet, and their concern about contact of their food with disgusting or other unacceptable substances (contamination sensitivity). Although there was substantial resemblance between siblings for many of these items, there was no clear evidence for a heritable component on any item. The only case for which there was an interpretable and significantly greater resemblance among monozygotic than among dizygotic twins (out of 23 questions) was preferred degree of hotness resulting from chili pepper in foods. These results confirm the prediction that in omnivorous animals, such as humans, genetic predispositions will be minimal with respect to food. The modest sibling resemblances on a number of measures are primarily attributable to a shared environment.

Nutrients and behaviour: research strategies for the investigation of taste characteristics, food preferences, hunger sensations and eating patterns in man

Although, as described elsewhere in this report, the consumption of particular nutrients can modify behaviors that are not directly related to eating, it seems highly likely that the main function of nutrient-induced changes in neurotransmitter synthesis is to provide the brain with information about what has been eaten, which the brain can then utilize in deciding what to eat next. This chapter summarizes research strategies and techniques which have been used to assess the effects of drugs and diseases on appetite and food consumption, and which might also be useful in exploring the effects of particular nutrients. Crude measures of total food intake and of global hunger ratings are probably too insensitive to reveal the subtle effects of many nutrients. Some alternative procedures allow the assessment of particular aspects of feeding behaviour, (e.g. food or nutrient choice), and of the relationships between such behaviour and the individual's metabolic and physiological state, sensory functions, taste hedonics, and affective response to foods.