Influence of PROP taster status and maternal variables on energy intake and body weight of pre-adolescents

Food bioactive peptides: functionality beyond bitterness

Bitter taste is an aversive taste because it is unconsciously associated with toxic compounds. However, a considerable variability in bitter sensitivity exists in those who have the genetic polymorphism for bitter taste receptors (TAS2Rs). Besides the oral cavity, TAS2Rs are present in many body tissues, including the gastrointestinal tract; therefore, they are crucial players both in the gustatory/hedonic system and in the homeostatic system, triggering numerous biological responses, including adipogenesis, carcinogenesis, or immunity. Bitter-tasting compounds are widely distributed in plant and animal foods and belong to many chemical classes. In this study, the evidence was reviewed on bitter peptides, considering the food sources, their formation in food under different processing and storage conditions and in the gastrointestinal tract during digestion, as well as their biological activities. Bitterness associated with peptides is due to the presence of hydrophobic amino acids in the C-terminus. The current literature mainly explores the enzymes and hydrolysis conditions, with the aim of reducing the formation of bitter peptides in hydrolysate preparation or food. Few studies highlight the bioactivity (namely, antihypertensive, antidiabetic, antioxidant, or immunity boosting), besides the bitterness. However, encapsulation of bitter peptides has been tentatively used to develop antihypertensive and antidiabetic supplements. In the era of personalized nutrition and precision medicine, the evidence available suggests the opportunity to use bitter bioactive peptides as functional ingredients in food. Such types of food may modulate a plethora of physiological mechanisms by targeting TAS2Rs in the gastrointestinal tract, thus modulating appetite sensations or gastrointestinal motility and discomfort according to individual nutritional needs and goals. More studies are needed to optimize the technological strategies to target TAS2Rs by bitter bioactive peptides, improve their stability in food, and validate the biological efficacy through well-designed in vivo studies.

Taste and oral somatosensation: Role of PTC bitter sensitivity, gender, and age

Sensitivity to the bitterness of phenylthiocarbamide (PTC) is considered to be linked to general taste perception, which is higher in women, and exhibits a slight decrease with age. Additionally, PTC sensitivity may contribute to somatosensory perception of spiciness and astringency. However, controversial data have been reported. This study investigates the relation between PTC perception, age, and gender on taste and somatosensory sensitivity using the Seven-iTT. A total of 200 healthy participants were classified based on their PTC perception, and subjects underwent an extended version of Seven-iTT to identify and rate the intensity of twelve stimuli. Results indicated that individuals classified as Tasters (T) exhibited higher taste scores compared to Non-Tasters (NT) for PTC, with age serving as a significant factor (p ≤ 0.009). Women outperformed men only among NT (p = 0.019). Older T demonstrated higher taste sensitivity than NT, suggesting that PTC status might act as a protective factor of gustatory function in aging. While PTC taster status significantly affected the intensity of sweet, salty, and bitter sensations (p ≤ 0.032), it had minimal impact on the intensity of somatosensory sensations (capsaicin and tannins). The combined use of Seven-iTT and the investigation of PTC status show promise for applications in research and clinical practice, offering a comprehensive approach to understanding taste perception and its implications for diet, nutrition, and aging.

Almli V. Basic taste sensitivity, eating behaviour, food propensity and BMI of preadolescent children: How are they related?

Background

Taste sensitivity has been reported to influence children's eating behaviour and contribute to their food preferences and intake. This study aimed to investigate the associations between taste sensitivity, eating behaviour, food frequency and BMI (Body Mass Index) in preadolescents.

Methods

Preadolescents' taste sensitivity was measured by detection threshold of sweetness (sucrose), sourness (citric acid), saltiness (sodium chloride), bitterness (caffeine, quinine), and umami (monosodium glutamate). In addition, the Child Eating Behaviour Questionnaire (CEBQ), the Food Propensity Questionnaire (FPQ) measuring food frequency, and the children's body weight and height were completed by the parents. A total of 69 child-parent dyads participated (preadolescents mean age =10.9 years).

Results

Taste sensitivity to caffeine bitterness was significantly associated with eating behaviour in food responsiveness, emotional overeating, and desire to drink. The preadolescents who were less sensitive to caffeine bitterness had higher food responsiveness scores. Those who were less sensitive to caffeine bitterness and to sweetness had higher emotional overeating scores. In addition, preadolescents who were less sensitive to sourness and bitterness of both caffeine and quinine demonstrated to have higher scores in desire to drink. There was no association between taste sensitivity and FPQ, but significant differences were observed across preadolescents' BMI for FPQ of dairy food items, indicating higher consumption of low-fat milk in the overweight/obese compared to the underweight/normal-weight subjects. There was no significant difference in taste sensitivity according to BMI. Preadolescents' eating behaviour differed across BMI, demonstrating a positive association between BMI and food approach, and a negative association between BMI and food avoidance.

Conclusions

This study contributes to the preliminary understanding of the relationships between taste sensitivity and eating behaviour in preadolescents. The results may be used to develop effective strategies to promote healthy eating practices by considering taste sensitivity in preadolescents.

A supervised learning regression method for the analysis of oral sensitivity of healthy individuals and patients with chemosensory loss

The gustatory, olfactory, and trigeminal systems are anatomically separated. However, they interact cognitively to give rise to oral perception, which can significantly affect health and quality of life. We built a Supervised Learning (SL) regression model that, exploiting participants' features, was capable of automatically analyzing with high precision the self-ratings of oral sensitivity of healthy participants and patients with chemosensory loss, determining the contribution of its components: gustatory, olfactory, and trigeminal. CatBoost regressor provided predicted values of the self-rated oral sensitivity close to experimental values. Patients showed lower predicted values of oral sensitivity, lower scores for measured taste, spiciness, astringency, and smell sensitivity, higher BMI, and lower levels of well-being. CatBoost regressor defined the impact of the single components of oral perception in the two groups. The trigeminal component was the most significant, though astringency and spiciness provided similar contributions in controls, while astringency was most important in patients. Taste was more important in controls while smell was the least important in both groups. Identifying the significance of the oral perception components and the differences between the two groups provide important information to allow for more targeted examinations supporting both patients and healthcare professionals in clinical practice.

CD36 genetic polymorphism and salivary cues are associated with oleic acid sensitivity and dietary fat intake

There is a lack of research on the combined effects of genetic variations (specifically CD36 SNPs-rs1761667 and rs1527483), dietary food habits (vegetarian or not), and the salivary environment on obesity and taste sensitivity, especially in the Indian population. The current study aims to better understand the relationship between impaired taste perception, fat consumption, higher BMI and obesity development by examining the combined association between CD36 SNPs, oleic acid (OA) detection threshold, and food habits among Indian participants. Furthermore, the relationship between oral fatty acid (FAs) sensitivity and taste physiology factors linked to inflammation and salivary proteins was considered. Participants with the minor allele (AA/AG) of CD36 (in both rs1527483 and rs1761667) consumed more fat, particularly saturated FAs (p = 0.0351). Salivary lipopolysaccharide, which causes inflammation, was significantly greater in non-vegetarians with a higher BMI (p < 0.05), and it exhibited a negative correlation (r = -0.232 and p < 0.05) with Ki67 gene expression, a marker for taste progenitor cells. A positive correlation (r = 0.474, p = 0.04) between TLR4 mRNA levels and the OA detection threshold was also observed. Participants with BMI > 25 kg/m2 had substantially higher TNF-α and IL-6 receptor mRNA expression levels, but there were no significant differences between the vegetarian and non-vegetarian groups. However, salivary CA-VI, which has a buffering capability on the oral environment, was lower in non-vegetarian adults with BMI >25. Thus, it was shown that non-vegetarians with overweight and obesity in India were in at-risk groups for the CD36 SNP (AA/AG at rs1761667 and rs1527483) and had higher levels of inflammatory markers, which exacerbated alterations in food behaviour and physiological changes, indicating their relevance in the development of obesity.

Automated identification of the genetic variants of TAS2R38 bitter taste receptor with supervised learning

Several studies were focused on the genetic ability to taste the bitter compound 6-n-propylthiouracil (PROP) to assess the inter-individual taste variability in humans, and its effect on food predilections, nutrition, and health. PROP taste sensitivity and that of other chemical molecules throughout the body are mediated by the bitter receptor TAS2R38, and their variability is significantly associated with TAS2R38 genetic variants. We recently automatically identified PROP phenotypes with high precision using Machine Learning (mL). Here we have used Supervised Learning (SL) algorithms to automatically identify TAS2R38 genotypes by using the biological features of eighty-four participants. The catBoost algorithm was the best-suited model for the automatic discrimination of the genotypes. It allowed us to automatically predict the identification of genotypes and precisely define the effectiveness and impact of each feature. The ratings of perceived intensity for PROP solutions (0.32 and 0.032 mM) and medium taster (MT) category were the most important features in training the model and understanding the difference between genotypes. Our findings suggest that SL may represent a trustworthy and objective tool for identifying TAS2R38 variants which, reducing the costs and times of molecular analysis, can find wide application in taste physiology and medicine studies.

Associations between Sweet Taste Sensitivity and Polymorphisms (SNPs) in the TAS1R2 and TAS1R3 Genes, Gender, PROP Taster Status, and Density of Fungiform Papillae in a Genetically Homogeneous Sardinian Cohort

Individual differences in sweet taste sensitivity can affect dietary preferences as well as nutritional status. Despite the lack of consensus, it is believed that sweet taste is impacted by genetic and environmental variables. Here we determined the effect of well-established factors influencing the general taste variability, such as gender and fungiform papillae density, specific genetic variants (SNPs of TAS1R2 and TAS1R3 receptors genes), and non-specific genetic factors (PROP phenotype and genotype), on the threshold and suprathreshold sweet taste sensitivity. Suprathreshold measurements showed that the sweet taste response increased in a dose-dependent manner, and this was related to PROP phenotype, gender, rs35874116 SNP in the TAS1R2 gene, and rs307355 SNP in the TAS1R3 gene. The threshold values and density of fungiform papillae exhibited a strong correlation, and both varied according to PROP phenotype. Our data confirm the role of PROP taste status in the sweet perception related to fungiform papilla density, show a higher sweet sensitivity in females who had lower BMI than males, and demonstrate for the first time the involvement of the rs35874116 SNP of TAS1R2 in the sweet taste sensitivity of normal weight subjects with body mass index (BMI) ranging from 20.2 to 24.8 kg/m2. These results may have an important impact on nutrition and health mostly in subjects with low taste ability for sweets and thus with high vulnerability to developing obesity or metabolic disease.

Bitter Taste Perception and Dental Biofilm Cariogenicity in Orthodontics

BACKGROUND

Bitter taste perception and sweetness preference have been associated with dental caries. Propylthiouracil (PROP) has been used to determine the genetic sensitivity to bitter taste in early childhood caries. However, the role of the bitter threshold in dental biofilm cariogenicity has not been reported. The purpose of this study was to investigate the role of individual taste sensitivity using PROP in dental biofilm cariogenicity in orthodontic patients.

METHODS

Forty orthodontic patients (12-42 years old) undergoing fixed appliance orthodontic treatment participated in this cross-sectional study. Their demographic, oral hygiene practice, and dietary habits data were obtained using a questionnaire. The patients' bitter taste threshold was measured using a PROP assay. The patients were subsequently classified as super-tasters (STs), medium-tasters (MTs), and non-tasters (NTs). Dental biofilm cariogenicity was determined using a 3-tone disclosing gel that becomes pink (new dental biofilm), purple (mature dental biofilm), and light blue (cariogenic dental biofilm) based on dental biofilm maturity.

RESULTS

The NT, MT, and ST groups comprised 10%, 27.5%, and 62.5% of the patients, respectively. Most of the STs (56%) and MTs (63.6%) were female, whereas no females were NTs. The dental biofilm cariogenicity was significantly different between the PROP bitterness groups (P < .05). The highest percentage of mature biofilm, followed by cariogenic and new biofilm, was found in the MT and ST groups. However, the cariogenic biofilm percentage was significantly higher compared with mature biofilm (P < .05) in the NT group. A low frequency (<1 time/d) of sugary and acidic food intake between meals was observed in the ST, MT, and NT groups with no significant difference amongst the groups (P > .05).

CONCLUSIONS

Cariogenic dental biofilm was highly present in orthodontic patients with the NT phenotype.

The Influence of Common Noncommunicable Diseases on Chemosensory Perception and Clinical Implications in Children and Adolescents

An increased incidence of noninfectious chronic diseases, such as obesity, diabetes, and allergies, has been noted in the last century, especially in the last 2 to 3 generations. Evidence suggested that the interrelation among these chronic conditions in pediatric age (e.g., children and adolescents aged 4-16 y) is complex and still unknown, reinforcing the interest of pediatricians in these diseases. Of interest is the need to better understand the link between these pathologies and sensory perception, since the chemical senses of taste and smell, together with chemesthesis, are reported to have a role in food choices and may provide a novel target for intervention in the treatment of these pathologies. This review aims to explore the current evidence on the link between these chronic conditions and chemosensory perception (i.e., taste and smell). In addition, the putative role that chemosensory perception may have on food choices and eating behavior of children and adolescents affected by these diseases are highlighted. Furthermore, the review addresses the unexplored issues that need to be investigated in this area. The literature data search suggested that no clear relation between taste and smell perception and the aforementioned diseases in young population yet exists. However, some possible trends have been highlighted in the adult population, in whom the duration of disease might have affected the relation. There is a need for further, high-quality, hypothesis-led research, with robust measures of taste and smell functions as the primary outcomes, to strengthen or deny this evidence.

Automated Classification of 6-n-Propylthiouracil Taster Status with Machine Learning

Several studies have used taste sensitivity to 6-n-propylthiouracil (PROP) to evaluate interindividual taste variability and its impact on food preferences, nutrition, and health. We used a supervised learning (SL) approach for the automatic identification of the PROP taster categories (super taster (ST); medium taster (MT); and non-taster (NT)) of 84 subjects (aged 18-40 years). Biological features determined from subjects were included for the training system. Results showed that SL enables the automatic identification of objective PROP taster status, with high precision (97%). The biological features were classified in order of importance in facilitating learning and as prediction factors. The ratings of perceived taste intensity for PROP paper disks (50 mM) and PROP solution (3.2 mM), along with fungiform papilla density, were the most important features, and high estimated values pushed toward ST prediction, while low values leaned toward NT prediction. Furthermore, TAS2R38 genotypes were significant features (AVI/AVI, PAV/PAV, and PAV/AVI to classify NTs, STs, and MTs, respectively). These results, in showing that the SL approach enables an automatic, immediate, scalable, and high-precision classification of PROP taster status, suggest that it may represent an objective and reliable tool in taste physiology studies, with applications ranging from basic science and medicine to food sciences.

Does Responsiveness to Basic Tastes Influence Preadolescents' Food Liking? Investigating Taste Responsiveness Segment on Bitter-Sour-Sweet and Salty-Umami Model Food Samples

The objective of this study was to investigate the relationships between taste responsiveness and food liking in preadolescents. Model food samples of grapefruit juice (GF) and vegetable broth (VB) modified with four additions of sucrose and sodium chloride, respectively, were employed. Intensity perception for sweetness, sourness, and bitterness were measured in GF while saltiness and umami were measured in VB. The children (N = 148) also completed food choice, familiarity, stated liking and neophobia questionnaires. The test was conducted at school, with instructions provided remotely via video call. Four segments were defined differing in basic taste responsiveness. Segments and sucrose concentrations significantly affected liking for GF, while no significant effect of segments and sodium chloride concentrations occurred on liking for VB. An increasing sucrose concentration was positively associated with liking for GF only in the segment with low responsiveness to bitter and sour tastes. No significant differences across segments were found for food choice, familiarity, stated liking, and neophobia. Conclusively, relationships between taste responsiveness and liking are product and basic taste-dependent in addition to being subject-dependent. Strategies to improve acceptance by using sucrose as a suppressor for warning sensations of bitterness and sourness can be more or less effective depending on individual responsiveness to the basic tastes.

Taste perception and expression in stomach of bitter taste receptor tas2r38 in obese and lean subjects

Differences in taste perception have been related to eating behavior, nutritional status, and diseases. Recently, taste receptors have been identified in several extra-oral tissues, such as the gastrointestinal tract, where they seem to influence processes like digestion, sense of satiety as well as energy balance and intraluminal changes occurring in obesity. Our study aims to analyze differences in taste perception among 42 obese patients (OB) and 41 normal-weight subjects (LEAN). Polymorphisms in the gene codifying for the bitter taste receptor TAS2R38 and its expression on the surface of the gastric mucosa were tested and compared among OB and LEAN. Taste intensity of PROP (6-n-propylthiouracil), quinine, sucrose, citric acid and NaCl were measured on a labeled magnitude scale. DNA from peripheral whole blood was extracted and three polymorphisms in the TAS2R38 gene (rs713598, rs1726866, rs10246939) analyzed. Gastric biopsies were collected during bariatric surgery in OB and during endoscopy in LEAN. RNA was extracted and TAS2R38 gene expression assessed by RT-Real-Time qPCR. Anamnestic and anthropometric data were recorded in all participants during baseline visits. Logistic regression analysis showed that OB perceives sweet (sucrose) and bitter (PROP or 6-n-propylthiouracil) taste more intensely than LEAN (p-value = 0.02 and p-value = 0.005, respectively). While polymorphisms in TAS2R38 gene did not differ among OB and LEAN, we observed a significant increase of TAS2R38 mRNA levels in the stomach of OB compared to LEAN (p = 0.01). Our results provide new evidence of a link between obesity and altered taste perception as well as TAS2R38 expression in the stomach.

Differences in Salivary Proteins as a Function of PROP Taster Status and Gender in Normal Weight and Obese Subjects

Taste plays an important role in processes such as food choices, nutrition status and health. Salivary proteins contribute to taste sensitivity. Taste reduction has been associated with obesity. Gender influences the obesity predisposition and the genetic ability to perceive the bitterness of 6-n-propylthiouracil (PROP), oral marker for food preferences and consumption. We investigated variations in the profile of salivary proteome, analyzed by HPLC-ESI-MS, between sixty-one normal weight subjects (NW) and fifty-seven subjects with obesity (OB), based on gender and PROP sensitivity. Results showed variations of taste-related salivary proteins between NW and OB, which were differently associated with gender and PROP sensitivity. High levels of Ps-1, II-2 and IB-1 proteins belonging to basic proline rich proteins (bPRPs) and PRP-1 protein belonging to acid proline rich proteins (aPRPs) were found in OB males, who showed a lower body mass index (BMI) than OB females. High levels of Ps-1 protein and Cystatin SN (Cyst SN) were found in OB non-tasters, who had lower BMI than OB super-tasters. These new insights on the role of salivary proteins as a factor driving the specific weight gain of OB females and super-tasters, suggest the use of specific proteins as a strategic tool modifying taste responses related to eating behavior.

Genetic Variation in the Bitter Receptors Responsible for Epicatechin Detection Are Associated with BMI in an Elderly Cohort

Globally, more than one-third of adults are overweight. Overweight and obesity are complex and multifaceted conditions, associated with an increased risk of chronic illness and early mortality. While there are known risk factors, these alone do not fully explain the varying outcomes between individuals. Recently, taste receptors have been proposed to have a role in the risk for obesity. These receptors are expressed throughout the gastrointestinal tract. In this system, they may be involved in modulating dietary intake and metabolic processes. The taste 2 family of receptors (T2Rs) detects bitter compounds. Receptors T2R4 and T2R5 detect (-)-epicatechin (epicatechin), an antioxidant polyphenol, which may have protective effects against obesity. However, the potential role for taste receptors in this association has not been explored. This study assessed whether polymorphisms in TAS2R4 (rs2233998 and rs2234001) and TAS2R5 (rs2227264) were associated with body mass index (BMI). Genotyping (Taqman qPCR assays) was performed on DNA extracted from blood samples (n = 563) from an elderly cohort. Homozygosity for the minor allele of all polymorphisms was significantly associated with a lower BMI in males. The TAS2R4-rs2233998 CC genotype, the TAS2R4-rs2234001 CC genotype and the TAS2R5-rs2227264 TT genotype were associated with lower BMI (2.1, 2.1 and 2.2 units; p = 0.002, 0.003 and 0.001, respectively). Epicatechin intake was not associated with BMI and genotype was not associated with epicatechin intake. This suggests that the association between TAS2R genotype and elevated BMI risk occurs through altered extra-oral responses and not directly via altered epicatechin intake.

Almli V. Investigating the Relationships between Basic Tastes Sensitivities, Fattiness Sensitivity, and Food Liking in 11-Year-Old Children

This study investigates the relationships between basic tastes and fattiness sensitivity and food liking in 11-year-old children. The basic taste sensitivity of 106 children was measured using different methods, namely detection (DT) and recognition (RT) thresholds, and taste responsiveness. Caffeine and quinine (bitter), sucrose (sweet), citric acid (sour), sodium chloride (salty), and monosodium glutamate (umami) were investigated for DT and RT at five concentrations in water solutions. In addition, taste responsiveness and liking were collected for the high-intensity concentrations. PROP (6-n-propylthiouracil) responsiveness was tested on paper strips. Fattiness sensitivity was measured by a paired comparison method using milk samples with varying fat content. Liking for 30 food items was recorded using a food-list questionnaire. The test was completed in a gamified “taste detective” approach. The results show that DT correlates with RT for all tastes while responsiveness to PROP correlates with overall taste responsiveness. Caffeine and quinine differ in bitterness responsiveness and liking. Girls have significantly lower DTs than boys for bitterness and sweetness. Food liking is driven by taste and fattiness properties, while fatty food liking is significantly influenced by fattiness sensitivity. These results contribute to a better holistic understanding of taste and fattiness sensitivity in connection to food liking in preadolescents.

Food Consumption Patterns and Body Composition in Children: Moderating Effects of Prop Taster Status

This cross-sectional study determined whether 6-n-propylthiouracil (PROP) taster status moderates the relationship between food consumption patterns and body composition in children. Children were recruited (n = 342, 50% female, 8-10 y) from across New Zealand. Using a food frequency questionnaire, these food consumption patterns were derived: Processed Foods, Fruit and Vegetables, and Breakfast Foods. Body composition variables included: body fat (%), fat mass (kg), fat mass index (FMI, kg/m²), body mass index (kg/m²) and waist to height ratio (W:Ht). Following adjustment for confounders, Processed Foods were positively associated with %fat (p = 0.015), fat mass (p = 0.004) and FMI (p = 0.016). Taste test strips determined PROP status. For Breakfast Foods, there were small negative associations with all body composition variables (p ≤ 0.001 to 0.037). The population sample was also stratified by PROP taster status. For the non-tasters, there were small to moderate negative associations between Breakfast Foods and each body composition variable (p = 0.003-0.045) except W:Ht (p = 0.112), and these relationships were stronger for girls compared to boys. For the tasters, there were small to moderate positive associations between Processed Foods with %fat (p = 0.030), fat mass (p ≤ 0.001) and FMI (p = 0.014). In conclusion, sensitivity to bitterness may moderate the relationship between food consumption patterns and body composition in children.

Human Tongue Electrophysiological Response to Oleic Acid and Its Associations with PROP Taster Status and the CD36 Polymorphism (rs1761667)

The perception of fat varies among individuals and has also been associated with CD36 rs1761667 polymorphism and genetic ability to perceive oral marker 6-n-propylthiouracil (PROP). Nevertheless, data in the literature are controversial. We present direct measures for the activation of the peripheral taste system in response to oleic acid by electrophysiological recordings from the tongue of 35 volunteers classified for PROP taster status and genotyped for CD36. The waveform of biopotentials was analyzed and values of amplitude and rate of potential variation were measured. Oleic acid stimulations evoked positive monophasic potentials, which represent the summated voltage change consequent to the response of the stimulated taste cells. Bio-electrical measurements were fully consistent with the perceived intensity during stimulation, which was verbally reported by the volunteers. ANOVA revealed that the amplitude of signals was directly associated, mostly in the last part of the response, with the CD36 genotypes and PROP taster status (which was directly associated with the density of papillae). The rate of potential variation was associated only with CD36, primarily in the first part of the response. In conclusion, our results provide direct evidence of the relationship between fat perception and rs1761667 polymorphism of the CD36 gene and PROP phenotype.

Investigation of the link between PROP taste perception and vegetables consumption using FAOSTAT data

In this work we investigated, in populations located in Central Asia, the relationship between PROP taste perception and vegetables liking and consumption using FAOSTAT dataset. Collected data were analysed using distance matrices, Mantel test and Pearson correlation. Populations showing similar ability in tasting PROP bitterness are more similar as respect to vegetable consumption (r = 0.63, p-value = .05). Moreover, a significant negative correlation was found between the percentage of Non Taster (NT) in different countries and the percentage of vegetable consumption (r = -0.87, p-value = .02), while a significant positive correlation emerged between the percentage of Super Taster (ST) and the percentage of vegetable liking (r = 0.87, p-value = .02). In our work we showed that differences in bitter perception among populations contributes to differences in vegetable liking and vegetable consumption. More in detail, populations with higher percentage of ST consume more vegetables than population where the majority of individuals are NT.

Factors Influencing the Phenotypic Characterization of the Oral Marker, PROP

In the last several decades, the genetic ability to taste the bitter compound, 6-n-propyltiouracil (PROP) has attracted considerable attention as a model for understanding individual differences in taste perception, and as an oral marker for food preferences and eating behavior that ultimately impacts nutritional status and health. However, some studies do not support this role. This review describes common factors that can influence the characterization of this phenotype including: (1) changes in taste sensitivity with increasing age; (2) gender differences in taste perception; and (3) effects of smoking and obesity. We suggest that attention to these factors during PROP screening could strengthen the associations between this phenotype and a variety of health outcomes ranging from variation in body composition to oral health and cancer risk.

Genetic variation in bitter taste receptor gene TAS2R38, PROP taster status and their association with body mass index and food preferences in Indian population

Polymorphisms in bitter taste receptor gene TAS2R38 alter the ability to sense the intensity of bitterness of phenylthiocarbamide (PTC) and 6-n-propylthiouracil (PROP). Genetic variation in sensitivity towards PTC and PROP may affect food preferences and susceptibility to certain diseases. This is the first study aimed at investigating frequency and distribution of TAS2R38 haplotypes in an Indian cohort. Additionally, we studied the association of TAS2R38 and PROP taster status with BMI and food preference. Three hundred and ninety three healthy adults who were 19-55years of age were selected as a convenience sample from 4 geographical regions of India. Single nucleotide polymorphisms (SNPs) of TAS2R38 (rs713598, s1726866 and rs10246939) were analyzed using polymerase chain reaction-restriction fragment length polymorphism. The prevalence of PAV/PAV diplotype was 9.9% and that of AVI/AVI diplotype was 43.76% among this Indian population. PROP status was determined on the basis of its threshold concentration of detecting bitterness, as evaluated by one-solution test. The PROP status revealed 25.95% supertasters, 32.06% medium tasters and 41.98% non-tasters (NT). BMI neither significantly (p>0.05) correlated with TAS2R38 genotypes nor with PROP taster status. Food preferences did not significantly (p>0.05) correlate with TAS2R38 diplotypes or PROP phenotypes.

Participants with Normal Weight or with Obesity Show Different Relationships of 6-n-Propylthiouracil (PROP) Taster Status with BMI and Plasma Endocannabinoids

Reduced taste sensitivity to 6-n-propylthiouracil (PROP), a genetic trait regarded as a general index for oral chemosensory perception, has been associated with a calorie-rich food preference and lower circulating endocannabinoid levels in participants with normal weight (NW), which suggests an adaptive mechanism to maintain a lean phenotype. In this study, we assessed whether participants with obesity (OB) show different patterns of plasma endocannabinoids and lipid metabolism biomarkers from those of NW, with further categorization based on their PROP sensitivity. NW and OB were classified by their PROP taster status as non-tasters (NT), medium-tasters (MT) and supertasters (ST). The blood samples were analysed for plasma endocannabinoids, nonesterified fatty acids (NEFA) and retinol, which have been associated to metabolic syndrome. In OB, we found a higher BMI and lower circulating endocannabinoids in ST vs. OB NT. However, OB ST showed lower circulating NEFA and retinol levels, which suggested a more favourable lipid metabolism and body fat distribution than those of OB NT. We confirmed lower plasma endocannabinoid levels in NW NT than in NW ST. These data suggest that PROP taste sensitivity determines metabolic changes and ultimately body mass composition differently in OB and NW.

Variation in the Ability to Taste Bitter Thiourea Compounds: Implications for Food Acceptance, Dietary Intake, and Obesity Risk in Children

The ability to taste bitter thiourea compounds, such as phenylthiocarbamide (PTC) and 6-n-propylthiouracil (PROP), is inherited. Polymorphisms in the bitter-taste receptor TAS2R38 explain the majority of phenotypic variation in the PROP phenotype. It has been hypothesized that the PROP phenotype is a marker for perception of a variety of chemosensory experiences. In this review, we discuss studies that have investigated the relationship between bitter-taste response and dietary behaviors and chronic health in children. Investigators have hypothesized that children who are PROP tasters have lower liking and consumption of bitter foods, such as cruciferous vegetables. Additionally, several studies suggest that children who are unable to taste PROP (i.e., nontasters) like and consume more dietary fat and are prone to obesity. The relationship between the PROP phenotype and obesity is influenced by multiple confounders, including sex, food access, ethnicity, and socioeconomic status. Future studies that adjust for these variables are needed.

Dose-Dependent Effects of L-Arginine on PROP Bitterness Intensity and Latency and Characteristics of the Chemical Interaction between PROP and L-Arginine

Genetic variation in the ability to taste the bitterness of 6-n-propylthiouracil (PROP) is a complex trait that has been used to predict food preferences and eating habits. PROP tasting is primarily controlled by polymorphisms in the TAS2R38 gene. However, a variety of factors are known to modify the phenotype. Principle among them is the salivary protein Ps-1 belonging to the basic proline-rich protein family (bPRP). Recently, we showed that oral supplementation with Ps-1 as well as its related free amino acids (L-Arg and L-Lys) enhances PROP bitterness perception, especially for PROP non-tasters who have low salivary levels of Ps-1. Here, we show that salivary L-Arg levels are higher in PROP super-tasters compared to medium tasters and non-tasters, and that oral supplementation with free L-Arg enhances PROP bitterness intensity as well as reduces bitterness latency in a dose-dependent manner, particularly in individuals with low salivary levels of both free L-Arg and Ps-1 protein. Supplementation with L-Arg also enhanced the bitterness of caffeine. We also used 1H-NMR spectroscopy and quantum-mechanical calculations carried out by Density Functional Theory (DFT) to characterize the chemical interaction between free L-Arg and the PROP molecule. Results showed that the -NH2 terminal group of the L-ArgH+ side chain interacts with the carbonyl or thiocarbonyl groups of PROP by forming two hydrogen bonds with the resulting charged adduct. The formation of this PROP•ArgH+ hydrogen-bonded adduct could enhance bitterness intensity by increasing the solubility of PROP in saliva and its availability to receptor sites. Our data suggest that L-Arg could act as a 'carrier' of various bitter molecules in saliva.

Consumption of a high-fat soup preload leads to differences in short-term energy and fat intake between PROP non-taster and super-taster women

Taste blindness to the bitterness of PROP (6-n-propylthiouracil) has been used as a genetic marker for food selection and adiposity. We have shown that PROP non-taster (NT) women have higher BMIs and habitually consume more fat and energy than either medium-taster (MT) or super-taster (ST) women. These data imply that differences in dietary selection underlie the body weight differences among PROP taster groups. However, no studies investigated energy compensation in women classified by PROP status. We investigated if NTs would compensate less accurately for the calories and fat in a high-fat soup preload in a subsequent test meal compared to MTs and STs. Energy intake from a buffet meal was measured in 75 healthy non-diet-restrained, lean women 30 min after the ingestion of a high-fat soup preload (0.8 kcal/g; 55% calories from fat), calculated to represent 10% of resting energy expenditure for each subject, or the same volume of water. Subjects (n = 20-28/taster group) ate a standard breakfast followed 3 hr later by an ad-libitum buffet lunch, on two occasions. There were no differences in energy intake or macronutrient selection across taster groups after water. After soup, NTs consumed more energy than STs. Fat intake (as %-energy) was higher in NTs (46.4% ± 2.4) compared to either MTs (36.1 ± 1.9%) or STs (38.1% ± 2.3; p < 0.05). NTs overate by 11% ± 5 after the soup compared to MTs and STs who underrate by 16% ± 6 and 26% ± 10, respectively (p < 0.01). These data suggest that small discrepancies in short-term energy compensation and selection of fat after a mixed-nutrient, high-fat preload may play a role in positive energy balance and increased adiposity in women with the PROP non-taster phenotype.

Examination of the perception of sweet- and bitter-like taste qualities in sucralose preferring and avoiding rats

Sucralose avoiding rats detect a bitter-like taste quality in concentrations of sucralose that are strongly preferred over water by sucralose preferring rats. Here, we investigated whether sucralose preferrers (SP) also detect a bitter-like quality in sucralose that may be masked by an increased perception of sucralose's sweet-like quality. A microstructural analysis of sucralose intake revealed that, at concentrations they avoided in preference tests, sucralose avoiders (SA) consumed smaller and fewer bouts of sucralose than SP. Interestingly, the concentration-dependent increase in sucralose preference in SP was not associated with larger bouts or increased lick rate, two measures that are expected to increase with increasing perceived sweetness. This suggests that SP can detect an aversive quality in sucralose, but this perception of a presumably bitter-like quality may be masked by increased salience of a sweet-like quality that sustains high levels of intake in SP. Further evidence for increased sweet-taste perception in SP, relative to SA, was obtained in a second study in which SP consumed more of a palatable sweet-milk diet than SA. These are the first data to suggest that SP are not blind to the bitter-like quality in sucralose, and that there may be differences in sweet-taste perception between SP and SA.

The gustin (CA6) gene polymorphism, rs2274333 (A/G), is associated with fungiform papilla density, whereas PROP bitterness is mostly due to TAS2R38 in an ethnically-mixed population

PROP responsiveness is associated with TAS2R38 haplotypes and fungiform papilla density. Recently, we showed that a polymorphism in the gene coding for the salivary trophic factor, gustin (CA6), affects PROP sensitivity by acting on cell growth and fungiform papillae maintenance, in a genetically homogeneous cohort. Since population homogeneity can lead to over estimation of gene effects, the primary aim of the present work was to confirm gustin's role in PROP bitterness intensity and fungiform papillae density in a genetically diverse population. Eighty subjects were genotyped for both genes by PCR techniques. PROP responsiveness was assessed by a filter paper method and fungiform papilla density was determined in each subject. As expected, PROP bitterness ratings were lower in individuals with the AVI/AVI diplotype of TAS2R38 than in individuals with PAV/PAV and PAV/AVI diplotypes. However, no differences in PROP bitterness among genotypes of the gustin gene, and no differences in the density of fungiform papillae related to TAS2R38 diplotype were found. In contrast, the density of fungiform papillae decreased as the number of minor (G) alleles at the gustin locus increased. In addition, the distribution of TAS2R38 genotypes within each gustin genotype group showed that the occurrence of recessive alleles at both loci was infrequent in the present sample compared to other populations. These findings confirm that papillae density is associated with gustin gene polymorphism, rs2274333 (A/G), in an ancestrally heterogeneous population, and suggest that variations in the frequency of allele combinations for these two genes could provide a salient explanation for discrepant findings for gustin gene effects across populations.

Genetic sensitivity to the bitter taste of 6-n-propylthiouracil (PROP) and its association with physiological mechanisms controlling body mass index (BMI)

Taste sensitivity to the bitter compound 6-n-propylthiouracil (PROP) is considered a marker for individual differences in taste perception that may influence food preferences and eating behavior, and thereby energy metabolism. This review describes genetic factors that may contribute to PROP sensitivity including: (1) the variants of the TAS2R38 bitter receptor with their different affinities for the stimulus; (2) the gene that controls the gustin protein that acts as a salivary trophic factor for fungiform taste papillae; and (3) other specific salivary proteins that could be involved in facilitating the binding of the PROP molecule with its receptor. In addition, we speculate on the influence of taste sensitivity on energy metabolism, possibly via modulation of the endocannabinoid system, and its possible role in regulating body composition homeostasis.

A population-based approach to study the impact of PROP perception on food liking in populations along the Silk Road

Taste is one of the main factors determining food choices. Differences in PROP bitter taste perception have been implicated in individual differences in food preferences and selection. The present study examined associations between, PROP phenotypes, self-reported food liking and TAS2R38 polymorphisms, the major gene implicated in PROP bitterness, in six different populations of the Caucasus and Central Asia, located along the ancient Silk Road. Differences in the distribution of PROP phenotypes across populations were detected, with a higher frequency of super tasters in Tajikistan (31.3%) and Armenia (39.0%) and a higher frequency of non tasters in Georgia (50.9%). While no relationships were observed between PROP phenotypes and food liking using standard statistical tests, we used an approach based on comparison of distance matrices derived from these data. The first matrix compared the food liking ratings of each population to all others pairwise using the Kruskal-Wallis test (at p<0.00063), and the second one compared the distribution of PROP phenotypes across all populations in a similar manner calculating the chi-square statistic as a distance measure. A strong correlation between the two matrices was found (Mantel test: r = 0.67, p-value = 0.03), suggesting that the pattern of food liking across populations was closely related to the distribution of PROP phenotypes. This same relationship was not observed when TAS2R38 genotypes were substituted for PROP phenotypes in this analysis. Our data suggest that a population-based approach utilizing distance matrices is a useful technique for detecting PROP-related differences in food liking and can be applied to other taste phenotypes.

Racial differences between African Americans and Asian Americans in the effect of 6-n-propylthiouracil taste intensity and food liking on body mass index

Taste intensity to 6-n-propylthiouracil (PROP) has been demonstrated to affect food acceptance and food intake. Because most PROP status research has been performed among predominantly white subjects, research is needed to test the effects of PROP taste intensity on food acceptance and body weight among racial minorities. This study was conducted to examine racial differences in the effect of PROP taste intensity and food liking on body mass index between African Americans and Asian Americans. A cross-sectional design with a sample of 50 African Americans (25 women, 25 men) and 50 Asian Americans (23 women, 27 men) in the New York City area aged 18 to 55 years was used in this study. Weight and height were measured and PROP intensity was assessed using PROP filter paper disks. Subjects rated the intensity of 171.15 g/L (0.5 mol/L) sucrose, 29.22 g/L (0.5 mol/L) sodium chloride, 4.8 g/L (0.025 mol/L) citric acid, and 0.127 g/L (3.2×10⁻⁴ mol/L) quinine solutions and completed a questionnaire to report their food liking/disliking for 19 food items. Characteristics were compared using analysis of variance or χ² test. A multiple linear regression model was fit with the covariates PROP mean, race, sex, age, fat-foods liking, and sweet-foods liking to predict body mass index score. The proportion of total nontasters was 22%. There were no significant differences in the PROP status distribution between African Americans and Asian Americans and in food likings between tasters and nontasters. Significant differences in fat foods, sugar, and black coffee liking were observed among the subracial groups (ie, African Caribbean, African black, East Asian, and South Asian). Race, sex, and age significantly contributed to predict body mass index score.

Pharmacogenetics of taste: turning bitter pills sweet?

Poor palatability of oral drug formulations used for young children negatively influences medication intake, resulting in suboptimal treatment. Some children are more sensitive to bitter tastes than others. Bitter tasting status is currently assessed by phenotyping with 6-n-propylthiouracil (PROP) as a bitter probe. Recent studies showed that interindividual differences in PROP sensitivity can be largely explained by three SNPs in TAS2R38, encoding a bitter taste receptor. Gustin, involved in the development of taste buds, and the sweet receptor genotype potentially explain remaining parts of PROP sensitivity variability. Other TAS2 receptor bitter receptor genes may also play a role in bitter aversions. Dependent on their genotype, children may have different medication formulation preferences. Taste genetics could improve drug acceptance by enabling better-informed choices on adapting oral formulations to children’s taste preferences. This paper presents an overview of recent findings concerning bitter taste genetics and discusses these in the context of pediatric drug formulation.

Energy intake and diet selection during buffet consumption in women classified by the 6-n-propylthiouracil bitter taste phenotype

BACKGROUND

Exposure to a variety of energy-dense foods promotes increased energy intake and adiposity. Taste blindness to the bitterness of 6-n-propylthiouracil (PROP) has been associated with increased adiposity in women and might be linked to an increased energy intake and greater selection of dietary fat.

OBJECTIVE

We investigated whether PROP nontaster (NT) women would consume more fat and energy in a buffet setting than medium taster (MT) or supertaster (ST) women.

DESIGN

Seventy-five non-diet-restrained, lean, young women [mean ± SEM BMI (in kg/m²): 21.5 ± 0.6; age: 26.1 ± 1.3 y) ate lunch and dinner in the laboratory for 3 consecutive days under the following 2 conditions: ad libitum control meals (CONTs) or high-variety buffet meals (BUFFs). A standard breakfast was consumed each day of the study (4 - d washout between conditions).

RESULTS

NTs and MTs consumed more energy and fat (as the percentage of energy) from BUFFs than did STs (P < 0.01), which contributed to higher daily energy intakes in these 2 groups of women during BUFFs (2149 ± 49 kcal/d for NTs and 2209 ± 48 kcal/d for MTs compared with 1933 ± 50 kcal/d for STs; P < 0.01). Together, NTs and MTs consumed an extra 246 kcal/d during BUFFs than during CONTs. In addition, compared with STs, NTs and MTs consumed more added fats and sweets (servings/d; P < 0.003) and more energy from snacks (P < 0.01) across all study days.

CONCLUSIONS

NT and MT women consume more daily energy than do ST women when eating in a buffet setting, which is a common type of dietary exposure. This increase in energy intake over time could contribute to a positive energy balance and increased adiposity previously reported in these women.

Facial affective reactions to bitter-tasting foods and body mass index in adults

Differences in food consumption among body-weight statuses (e.g., higher fruit intake linked with lower body mass index (BMI) and energy-dense products with higher BMI) has raised the question of why people who are overweight or are at risk of becoming overweight eat differently from thinner people. One explanation, in terms of sensitivity to affective properties of food, suggests that palatability-driven consumption is likely to be an important contributor to food intake, and therefore body weight. Extending this approach to unpalatable tastes, we examined the relationship between aversive reactions to foods and BMI. We hypothesized that people who have a high BMI will show more negative affective reactions to bitter-tasting stimuli, even after controlling for sensory perception differences. Given that hedonic reactions may influence consumption even without conscious feelings of pleasure/displeasure, the facial expressions were included in order to provide more direct access to affective systems than subjective reports. Forty adults (28 females, 12 males) participated voluntarily. Their ages ranged from 18 to 46 years (M=24.2, SD=5.8). On the basis of BMI, participants were classified as low BMI (BMI<20; n=20) and high BMI (BMI>23; n=20). The mean BMI was 19.1 for low BMI (SD=0.7) and 25.2 for high BMI participants (SD=1.8). Each subject tasted 5 mL of a grapefruit juice drink and a bitter chocolate drink. Subjects rated the drinks' hedonic and incentive value, familiarity and bitter intensity immediately after each stimulus presentation. The results indicated that high BMI participants reacted to bitter stimuli showing more profound changes from baseline in neutral and disgust facial expressions compared with low BMI. No differences between groups were detected for the subjective pleasantness and familiarity. The research here is the first to examine how affective facial reactions to bitter food, apart from taste responsiveness, can predict differences in BMI.

PTC bitter taste genetic polymorphism, food choices, physical growth in body height and body fat related traits among adolescent girls from Kangra Valley, Himachal Pradesh (India)

BACKGROUND

Bitter sensitivity among individuals and ethnic groups is partly due to polymorphic bitter taste receptor genes (TAS2Rs). PTC/PROP bitter taste responsiveness at locus TAS2R38 is a well-established index of individual variation in oral sensation that has been linked with predicting food liking and consumption. Previous studies suggest that the relationship between PTC/PROP and anthropometric traits remains controversial.

OBJECTIVES

To explore the role of TAS2R38 locus in taste choices, adolescent growth trend for body height, weight and fat patterning among girls and to evaluate their growth status.

MATERIALS AND METHODS

Cross-sectional data on 210 girls ranging in age from 11-18 years were collected from Palampur in the Kangra valley of Himachal Pradesh.

RESULTS

The proportion of PTC non-tasters was 19.52%. PTC tasters and non-tasters had some differences in their food choices and preferences. More sensitive PTC tasters had a low preference for raw cruciferous vegetables and bitter tasting foods (like bitter gourd) and beverages, while they had higher preference for sweet-tasting foods (p < 0.05). PTC tasters overtook their PTC non-taster counterparts from age 14 through 16 years in having higher mean average skinfold, percentage body fat, fat mass index and fat-free mass index. PTC non-tasters had higher mean stature than tasters through all age groups. PTC tasters had slightly higher mean body weight than tasters at age 11, but in later years the advantage was lost; the total gain among non-tasters through adolescence was higher (78.20%) than tasters (66.92%). PTC thresholds significantly and negatively correlated with body height.

CONCLUSIONS

TAS2R38 locus seems to have a role in food tastes, choices and preferences. Perceived bitterness of PTC/PROP thresholds were significantly and negatively correlated with body height and fat-free mass. These results, thus, tentatively suggest that the PTC non-taster gene may help in better absorption of calcium than its counter taster allele. Studies on differences in calcium metabolism between PTC tasters and non-tasters are needed to confirm these indications across cultures.

Influence of the PROP bitter taste phenotype and eating attitudes on energy intake and weight status in pre-adolescents: a 6-year follow-up study

The PROP bitter-taste phenotype is a marker for food preferences and eating behavior, and may associate with differences in body weight in children. Previous work has shown that PROP status in combination with eating attitudes are better predictors of weight status in preadolescents, than either factor alone. However, no studies have examined the role of PROP phenotypes in body weight change in children over time. The primary objective of this study was to investigate current weight status and change in weight status in children from preschool (baseline) to preadolescence as a function of eating attitudes and PROP phenotype. Other measures included self-reported food intakes and physical activity by activity monitor. Seventy-three lean (BMI percentile=57.7±3.2%) children with mean age=10.3±0.5yrs, participated in the follow up. There were no group differences in energy intake, current BMI-percentile or change in BMI percentile from baseline by PROP phenotype in either boys or girls. However, there was a trend for non-taster girls to show a downward shift in BMI-percentile at follow up. Hierarchical regression analysis revealed that baseline BMI percentile and physical activity energy expenditure were the strongest predictors of current weight (28.5% variance),followed by child restraint, the taster×gender interaction, and the maternal BMI×maternal emotional eating interaction, accounting for 7.1%, 6.0% and 4.8% of variance in the model, respectively. These findings suggest that PROP status and eating attitudes are modest predictors of weight status in preadolescent children.

Greater energy reduction in 6-n-propylthiouracil (PROP) super-tasters as compared to non-tasters during a lifestyle intervention

Little is known as to how 6-n-propylthiouracil (PROP) taster status may influence changes in dietary intake in adults participating in a lifestyle intervention to assist with reducing weight. This secondary data analysis examined changes in energy, percent energy from macronutrients, and food group intake; physical activity; and body mass index (BMI) in super-tasters and non-tasters participating in two randomized controlled trials implementing a lifestyle obesity intervention. One trial focused on lowering energy density of the diet and the other trial focused on changing eating frequency. Overweight and obese participants (n = 57) who completed measures of dietary intake, physical activity, and anthropometrics at 0 and 3 months were included in the analyses. Taster status was determined at baseline: 46 non-tasters and 11 super-tasters. After controlling for condition assignment and baseline values, results indicated that a significantly greater reduction in energy intake occurred for super-tasters as compared to non-tasters (-1149 ± 561 kcal/day vs. -902 ± 660 kcal/day, p < 0.05). No other significant differences in changes in dietary intake, physical activity, or BMI were found. These results suggest that in situations of reducing energy intake, overweight and obese super-tasters may be more successful than overweight and obese non-tasters. More research is needed to understand the influence of taster-status on dietary change during a lifestyle intervention and how this may impact weight loss.

Taste perception and food choices

OBJECTIVES

The extent to which variation in taste perception influences food preferences is, to date, controversial. Bitterness in food triggers an innate aversion that is responsible for dietary restriction in children. We investigated the association among genetic variations in bitter receptor TAS2R38 and food choices in healthy children in the Mediterranean area, to develop appropriate tools to evaluate the relation among genetic predisposition, dietary habits, and feeding disorders. The aims of the study were to get a first baseline picture of taste sensitivity in healthy adults and their children and to explore taste sensitivity in a preliminary sample of obese children and in samples affected by functional gastrointestinal diseases.

METHODS

Individuals (98 children, 87 parents, 120 adults) were recruited from the general population in southern Italy. Bitterness sensitivity was assessed by means of a suprathreshold method with 6-propyl-2-thiouracil. Genomic DNA from saliva was used to genotype individuals for 3 polymorphisms of TAS2R38 receptor, A49P, A262 V, and V296I. Food intake was assessed by a food frequency questionnaire.

RESULTS

Children's taste sensation differed from that of adults: we observed a higher frequency of supertasters among children even in the mother-child dyads with the same diplotypes. Among adults, supertaster status was related with proline-alanine-valine (taster allele) homozygous haplotype, whereas supertaster children were mainly heterozygous. Regarding the food choices, we found that a higher percentage of taster children avoided bitter vegetables or greens altogether compared with taster adults. Taster status was also associated with body mass index in boys.

CONCLUSIONS

Greater sensitivity to 6-propyl-2-thiouracil predicts lower preferences for vegetables in children, showing an appreciable effect of the genetic predisposition on food choices. None of the obese boys was a supertaster.

Children who are pressured to eat at home consume fewer high-fat foods in laboratory test meals

Parents use greater pressure to eat with children who weigh less, but the impact of this practice is unclear. The purpose of this cross-sectional study was to determine the association between parental reports of eating pressure and children's actual intake across four identical ad libitum meals. Sixty-eight ethnically diverse, 4- to 6-year-old children from New York, NY, participated in this study from 2005 to 2007. Eating pressure was measured by the Child Feeding Questionnaire. Height and weight were measured and converted to body mass index z scores. Meals consisted of macaroni and cheese, string beans, carrots, grapes, graham crackers, cheese sticks, milk, pudding, and a sugar-sweetened beverage. Multiple regressions were performed to determine the extent to which pressure to eat predicted food intake after adjusting for BMI z score and child weight concern. Pressure to eat was negatively associated with child BMI z score (r=-0.37; P<0.01), energy intake (β=-.30; P<0.05), and energy density (β=-.28; P<0.05). In addition, pressure was negatively associated with intake of macaroni and cheese (β=-.26; P<0.05), whole milk (β=-.27; P<0.05), and pudding (β=-.33; P<0.01), but positively associated with vegetable intake (β=.43; P<0.01). However, both vegetable and milk consumption were low, so results should be interpreted with caution. These findings suggest that greater pressure to eat is associated with lower intake of some high-fat foods in the laboratory, where no pressure is applied.

Mexican American mothers' eating and child feeding behaviors

OBJECTIVE

The purpose of this study of Mexican-American mothers of 2-6 year old children was to explore the relationships among maternal attitude, perceived behavioral controls, mother's intent, mother's regulation of her own Simple Carbohydrate Intake (SCI), and mother's child feeding behaviors. The overall objective was to increase understanding of the complex process of intention to eat healthy.

METHODS

A prospective exploratory design using a convenience sample of a cohort of 82 Mexican-American mothers was used in this study. Structured questionnaires were selected to measure cognitive restraint, disinhibition, hunger, intent to regulate SCI, and mothers' monitoring, restricting, and pressuring of children's diets. Descriptive statistics and correlations were analyzed for each relationship.

RESULTS

The relationships between disinhibition, hunger, cognitive restraint, and the intent variable were significant. More than half of these mothers reported limiting soda and candy for themselves. According to the Food Frequency Questionnaire, mothers were regulating only one-third of simple carbohydrate items they intended to regulate. Significant relationships were found between mothers' regulation of her specific SCI and her control of child feeding behaviors including pressuring, monitoring, and restricting.

CONCLUSION

The findings support the idea that mother's eating behaviors, attitudes, and intent may affect how they feed their pre-school children. Nurses need to develop and test interventions targeted at educating Mexican-American mothers about healthy food choices and healthy child feeding behaviors.

Caries experience in 15-year-old school children in Bangalore with inherited taste sensitivity levels to 6-n-propylthiouracil: an observational study

AIM

  The relationship between sugar consumption and caries has been researched extensively for many years. The individual drive for the consumption of sweet food is controlled by a variety of biologic, psychologic, and sociologic factors. Sweet preference has been linked to bitter taste sensitivity to 6-n-propylthiouracil, a heritable trait. The present study investigates the association between inherited taste sensitivity to 6-n-popylthiouracil and dental caries experience in 15-year-old school children.

METHODS

  Two hundred 15-year-old school children from randomly selected schools in Bangalore, India, participated in the study. Data were collected regarding demographic factors and socioeconomic status by personal interviews with the children. Sensitivity to 6-n-propylthiouracil was determined using Tepper filter paper method, and the responses were recorded on the labeled magnitude scale. Each child was examined thoroughly for oral hygiene status and caries experience. Appropriate statistical tests, such as chi-squared test, Fisher's exact test, and Kruskal-Wallis test, were used to analyze the data.

RESULTS

  Non-tasters were significantly associated with caries experience (P < 0.001). The decayed component in non-tasters (3.43 ± 2.18) was statistically significant when compared to tasters (2.86 ± 1.58 medium tasters, 1.50 ± 0.55 supertasters).

CONCLUSIONS

  After all associated factors were controlled, 6-n-propylthiouracil taste status was the only independent variable significantly related to overall caries experience.

Greater energy intake from a buffet meal in lean, young women is associated with the 6-n-propylthiouracil (PROP) non-taster phenotype

Taste blindness to 6-n-propylthiouracil (PROP) is a common phenotype that has been associated with increased adiposity in women, and might be linked to increased selection of dietary fats. Since exposure to a variety of high-fat/energy-dense foods is known to promote excess energy intake, we investigated if PROP non-taster women would consume more fat and/or energy in a buffet setting than super-taster women. Subjects were non-diet restrained, lean, young women; 14 were non-tasters and 18 were super-tasters. Subjects ate lunch in the laboratory on four separate days. On one day they consumed an ad libitum, fixed-item lunch (control). On the other three days they consumed different buffet lunches (pizza/tacos/sub sandwiches with salad bar and choice of beverage and dessert). Energy intake from the control lunch did not differ between groups. When intake was averaged across the buffet lunches, non-taster women consumed 357+64 kcal more energy than during the control lunch (88% more), whereas super-taster women consumed 198+71 kcal more energy than during the control lunch (38% more). Neither fat intake nor selection of high-fat foods differed between groups. These data suggest that non-taster women consume more energy from a buffet meal than super-taster women, but not more fat. Increased responsiveness to a variety of energy-dense foods could be one mechanism contributing to increased energy intake and greater adiposity in non-taster women.