A Brief Review of Genetic Approaches to the Study of Food Preferences: Current Knowledge and Future Directions

Multi-omic applications for understanding and enhancing tropical fruit flavour

Consumer trends towards nutrient-rich foods are contributing to global increasing demand for tropical fruit. However, commercial cultivars in the breeding pipeline that are tailored to meet market demand are at risk of possessing reduced fruit flavour qualities. This stems from recurrent prioritised selection for superior agronomic traits and not fruit flavour, which may in turn reduce consumer satisfaction. There is realisation that fruit quality traits, inclusive of flavour, must be equally selected for; but currently, there are limited tools and resources available to select for fruit flavour traits, particularly in tropical fruit species. Although sugars, acids, and volatile organic compounds are known to define fruit flavour, the specific combinations of these, that result in defined consumer preferences, remain unknown for many tropical fruit species. To define and include fruit flavour preferences in selective breeding, it is vital to determine the metabolites that underpin them. Then, objective quantitative analysis may be implemented instead of solely relying on human sensory panels. This may lead to the development of selective genetic markers through integrated omics approaches that target biosynthetic pathways of flavour active compounds. In this review, we explore progress in the development of tools to be able to strategically define and select for consumer-preferred flavour profiles in the breeding of new cultivars of tropical fruit species.

Impact of polygenic score for BMI on weight loss effectiveness and genome-wide association analysis

BACKGROUND

While environmental factors play an important role in weight loss effectiveness, genetics may also influence its success. We examined whether a genome-wide polygenic score for BMI was associated with weight loss effectiveness and aimed to identify common genetic variants associated with weight loss.

METHODS

Participants in the ONTIME study (n = 1210) followed a uniform, multimodal behavioral weight-loss intervention. We first tested associations between a genome-wide polygenic score for higher BMI and weight loss effectiveness (total weight loss, rate of weight loss, and attrition). We then conducted a genome-wide association study (GWAS) for weight loss in the ONTIME study and performed the largest weight loss meta-analysis with earlier studies (n = 3056). Lastly, we ran exploratory GWAS in the ONTIME study for other weight loss outcomes and related factors.

RESULTS

We found that each standard deviation increment in the polygenic score was associated with a decrease in the rate of weight loss (Beta (95% CI) = -0.04 kg per week (-0.06, -0.01); P = 3.7 × 10-03) and with higher attrition after adjusting by treatment duration. No associations reached genome-wide significance in meta-analysis with previous GWAS studies for weight loss. However, associations in the ONTIME study showed effects consistent with published studies for rs545936 (MIR486/NKX6.3/ANK1), a previously noted weight loss locus. In the meta-analysis, each copy of the minor A allele was associated with 0.12 (0.03) kg/m2 higher BMI at week five of treatment (P = 3.9 × 10-06). In the ONTIME study, we also identified two genome-wide significant (P < 5×10-08) loci for the rate of weight loss near genes implicated in lipolysis, body weight, and metabolic regulation: rs146905606 near NFIP1/SPRY4/FGF1; and rs151313458 near LSAMP.

CONCLUSION

Our findings are expected to help in developing personalized weight loss approaches based on genetics.

CLINICAL TRIAL REGISTRATION

Obesity, Nutrigenetics, Timing, and Mediterranean (ONTIME; clinicaltrials.gov: NCT02829619) study.

Exploring the potential causal effects of food preferences on irritable bowel syndrome risk: A two-sample Mendelian randomization study

OBJECTIVES

Irritable bowel syndrome (IBS) is a common disorder in gut-brain interaction. Diet plays an important role in the pathophysiology of IBS. Therefore, we aimed to explore the potential causal effects of food-liking on IBS to provide better diet advice for patients.

METHODS

Single-nucleotide polymorphisms associated with food-liking were selected as instrumental variables, which were obtained from the latest genome-wide association study (GWAS) conducted on 161 625 participants. The summary data of genetic associations with IBS were obtained from a recent GWAS with 433 201 European controls and 53 400 cases. We used inverse variance weighting as the main analysis. Sensitivity analyses were conducted to detect horizontal pleiotropy and heterogeneity.

RESULTS

Significant evidence revealed the protective effects of a vegetarian diet-liking on IBS, including asparagus, avocadoes, globe artichoke, aubergine, and black olives, while onion-liking showed potential deleterious effects. For meat and fish, preference for sardines and fried fish was marginally associated with IBS risk, but salami and salmon were potential protective factors. In terms of desserts and dairy products, preferences for cake icing, ketchup, and cheesecake were suggestively associated with higher IBS risk, while goat cheese-liking was marginally correlated with lower IBS risk. Additionally and suggestively, significant causal effects of IBS on increased preferences for globe artichoke and salami were also found in a reverse Mendelian randomization (MR) study.

CONCLUSION

Our study revealed potential causal associations between food preference and IBS from a genetic perspective, which provides a dietary reference for such patients.

Regulator of G-Protein Signalling 9: A New Candidate Gene for Sweet Food Liking?

Genetics plays an important role in individual differences in food liking, which influences food choices and health. Sweet food liking is a complex trait and has been associated with increased body mass index (BMI) and related comorbidities. This genome-wide association study (GWAS) aimed to investigate the genetics of sweet food liking using two adult discovery cohorts (n = 1109, n = 373) and an independent replication cohort (n = 1073). In addition, we tested the association of our strongest result on parameters related to behaviour (food adventurousness (FA) and reward dependence (RD) and health status (BMI and blood glucose). The results demonstrate a novel strong association between the Regulator of G-Protein Signalling 9 (RGS9I) gene, strongest single nucleotide polymorphism (SNP) rs58931966 (p-value 7.05 × 10^-9 in the combined sample of discovery and replication), and sweet food liking, with the minor allele (A) being associated with a decreased sweet food liking. We also found that the A allele of the rs58931966 SNP was associated with decreased FA and RD, and increased BMI and blood glucose (p-values < 0.05). Differences were highlighted in sex-specific analysis on BMI and glucose. Our results highlight a novel genetic association with food liking and are indicative of genetic variation influencing the psychological-biological drivers of food preference. If confirmed in other studies, such genetic associations could allow a greater understanding of chronic disease management from both a habitual dietary intake and reward-related perspective.

Genetic variation in sweet taste receptors and a mechanistic perspective on sweet and fat taste sensation in the context of obesity

Taste sensation enables humans to make nutritionally important decisions such as food preference and consumption. It functions as deterministic factors for unpropitious eating behavior, leading to overweight and obesity. The hedonistic feeling on consumption of fat and sugar-rich meals, in particular, has a negative influence on health. In addition, impairment in the taste receptors alters the downstream signaling of taste transduction pathway. Hence, genetic polymorphism in typical taste receptors is a predictor of taste sensitivity variance across individuals. The present review summarizes the effect of a single nucleotide polymorphism (SNP) in sweet taste receptors (T1R2/T1R3) on taste perception among individuals of various body mass index (BMI). Furthermore, in the context of obesity, we discussed the possibility of crosstalk between fat and sweet receptors as well as taste dysfunction in diseased individuals. In overall, a greater understanding of the physiological relationship between taste receptors, altered taste sensitivity, and genetic polymorphisms should lead to more effective obesity prevention approaches.

The rs35874116 single nucleotide polymorphism increases sweet intake and the risk of severe early childhood caries: a case–control study

Background

Dental caries is one of the most prevalent chronic diseases worldwide among children. The rs35874116 single nucleotide polymorphism (SNP) in the sweet receptor gene TAS1R2 has been associated with dental caries at a high risk in permanent teeth among school children and adults. To date, little is known about the association of this SNP with sweet intake and caries risk in the primary school children.

Methods

Total of 236 children were included, namely 118 subjects in the non-caries (NC) group and severe early childhood caries (S-ECC) group, respectively. Oral mucosa cells were collected from all the selected children, and the full length of exon 3 in TAS1R2 was sequenced to analyse rs35874116 polymorphism. A questionnaire was used to collect information about socio-demographic information, frequency of sweet intake and oral hygiene habits. Multiple logistic regression models were applied to assess the relationship of rs35874116 polymorphism with frequency of sweet intake and S-ECC among the five-year-old children.

Results

Children with the TT genotype of rs35874116 had a higher frequency of sweet intake than CT/CC carriers (51.3% vs. 32.7%; x2 = 5.436, p = 0.020), and S-ECC individuals were more likely to be TT genotype carriers than NC individuals (53.5% vs. 46.5%; x2 = 4.353, p = 0.037). Multiple logistic regression analyses showed that the TT genotype of rs35874116 was not only significantly related to the frequency of sweet intake (OR = 2.25, 95% CI = 1.14–4.44) but also significantly associated with S-ECC (OR = 2.11, 95% CI = 1.01 ~ 4.42).

Conclusions

The rs35874116 polymorphism might increase sweet intake and the risk of S-ECC among five-year-old children in Nanning, China.

Large-scale GWAS of food liking reveals genetic determinants and genetic correlations with distinct neurophysiological traits

We present the results of a GWAS of food liking conducted on 161,625 participants from the UK-Biobank. Liking was assessed over 139 specific foods using a 9-point scale. Genetic correlations coupled with structural equation modelling identified a multi-level hierarchical map of food-liking with three main dimensions: "Highly-palatable", "Acquired" and "Low-caloric". The Highly-palatable dimension is genetically uncorrelated from the other two, suggesting that independent processes underlie liking high reward foods. This is confirmed by genetic correlations with MRI brain traits which show with distinct associations. Comparison with the corresponding food consumption traits shows a high genetic correlation, while liking exhibits twice the heritability. GWAS analysis identified 1,401 significant food-liking associations which showed substantial agreement in the direction of effects with 11 independent cohorts. In conclusion, we created a comprehensive map of the genetic determinants and associated neurophysiological factors of food-liking.

Nutrigenomics reveals potential genetic underpinning of diverse taste preference of Chinese men

BACKGROUND

Taste preference varies geographically in China. However, studies on Chinese people's taste preference in different regions of China are limited, and are lack of research on the mechanism of differences in taste preference, especially in genetics.

OBJECTIVE

This study aims to investigate the characteristics of taste preference of Chinese men, and estimate whether diverse taste preference in Chinese have genetic underpinning.

METHODS

We conducted a questionnaire survey on taste preferences on 1076 males from 10 regions of China, and collected another 1427 males from the same regions which genotyped by microarray. We compared the correlation between different taste preference, and evaluated the correlation between the mutation frequency of inhouse database and different taste preference. The putative taste-preference-related genes were further utilized to estimate the candidate relationship on gene and gene network in different taste preference.

RESULTS

There was a correlation between different taste preferences in Chinese men. We found 31 SNPs associated with 6 kind of taste preferences. These SNPs located within or nearby 36 genes, and the tastes associated with 4 of these genes (TRPV1, AGT, ASIC2 and GLP1R) are consistent with the previous studies. Moreover, in different tastes which were suggested to be associated with each other, some putative related genes were the same or in the same gene network, such as pathways related with blood pressure, response to stimulus and nervous system.

CONCLUSIONS

This study indicates that the diverse taste preference of Chinese men may have genetic underpinning.

A Dual-Pathway Perspective on Food Choices in Adolescents: The Role of Loss of Control Over Eating

Introduction

One in three adolescents frequently consume unhealthy snacks, which is associated with negative developmental outcomes. To date, it remains unclear how intrapersonal factors account for food choices in adolescents. Guided by the dual-pathway model, the current study aimed to: (1) examine the joint contribution of inhibitory control and attentional bias in predicting unhealthy food choices in adolescents, and (2) determine whether this mechanism is more pronounced in adolescents who experience loss of control over eating (LOC).

Materials and Methods

A community sample of 80 adolescents (65% female; 10–17 years old, M_age = 13.28, SD = 1.94) was recruited. Based on a self-report questionnaire, 28.7% of this sample reported at least one episode of LOC over the past month. Food choice was assessed using a computerized food choice task. Both inhibitory control and attentional bias were measured with behavioral tasks (go/no-go and dot probe task, respectively). Binary logistic regressions were conducted to address the research questions.

Results

Inhibitory control and attentional bias did not significantly interact to predict unhealthy food choices. However, there was a significant three-way interaction between inhibitory control, attentional bias and LOC. For adolescents without LOC, the combination of poor inhibitory control and low attentional bias was significantly associated with unhealthy food choice. Surprisingly, for adolescents with LOC, there was no significant association between unhealthy food choice and inhibitory control or attentional bias.

Discussion

Dual-pathway processes do not seem to add to the explanation of food choice behavior for adolescents with LOC. For adolescents who do not experience LOC, those with poor inhibitory control combined with low attentional bias might be at particular risk for making unhealthy food choices.

Understanding sweet-liking phenotypes and their implications for obesity: Narrative review and future directions

Building on a series of recent studies that challenge the universality of sweet liking, here we review the evidence for multiple sweet-liking phenotypes which strongly suggest, humans fall into three hedonic response patterns: extreme sweet likers (ESL), where liking increases with sweetness, moderate sweet likers (MSL), who like moderate but not intense sweetness, and sweet dislikers (SD), who show increasing aversion as sweetness increases. This review contrasts how these phenotypes differ in body size and composition, dietary intake and behavioural measures to test the widely held view that sweet liking may be a key driver of obesity. Apart from increased consumption of sugar-sweetened beverages in ESL, we found no clear evidence that sweet liking was associated with obesity and actually found some evidence that SD, rather than ESL, may have slightly higher body fat. We conclude that ESL may have heightened awareness of internal appetite cues that could protect against overconsumption and increased sensitivity to wider reward. We note many gaps in knowledge and the need for future studies to contrast these phenotypes in terms of genetics, neural processing of reward and broader measures of behaviour. There is also the need for more extensive longitudinal studies to determine the extent to which these phenotypes are modified by exposure to sweet stimuli in the context of the obesogenic environment.

A Genome-Wide Association Study Identifies the Association between the 12q24 Locus and Black Tea Consumption in Japanese Populations

Several genome-wide association studies (GWASs) have reported the association between genetic variants and the habitual consumption of foods and drinks; however, no association data are available regarding the consumption of black tea. The present study aimed to identify genetic variants associated with black tea consumption in 12,258 Japanese participants. Data on black tea consumption were collected by a self-administered questionnaire, and genotype data were obtained from a single nucleotide polymorphism array. In the discovery GWAS, two loci met suggestive significance (p < 1.0 × 10^-6). Three genetic variants (rs2074356, rs144504271, and rs12231737) at 12q24 locus were also significantly associated with black tea consumption in the replication stage (p < 0.05) and during the meta-analysis (p < 5.0 × 10^-8). The association of rs2074356 with black tea consumption was slightly attenuated by the additional adjustment for alcohol drinking frequency. In conclusion, genetic variants at the 12q24 locus were associated with black tea consumption in Japanese populations, and the association is at least partly mediated by alcohol drinking frequency.

Consequences of Obesity on the Sense of Taste: Taste Buds as Treatment Targets?

Premature obesity-related mortality is caused by cardiovascular and pulmonary diseases, type 2 diabetes mellitus, physical disabilities, osteoarthritis, and certain types of cancer. Obesity is caused by a positive energy balance due to hyper-caloric nutrition, low physical activity, and energy expenditure. Overeating is partially driven by impaired homeostatic feedback of the peripheral energy status in obesity. However, food with its different qualities is a key driver for the reward driven hedonic feeding with tremendous consequences on calorie consumption. In addition to visual and olfactory cues, taste buds of the oral cavity process the earliest signals which affect the regulation of food intake, appetite and satiety. Therefore, taste buds may play a crucial role how food related signals are transmitted to the brain, particularly in priming the body for digestion during the cephalic phase. Indeed, obesity development is associated with a significant reduction in taste buds. Impaired taste bud sensitivity may play a causal role in the pathophysiology of obesity in children and adolescents. In addition, genetic variation in taste receptors has been linked to body weight regulation. This review discusses the importance of taste buds as contributing factors in the development of obesity and how obesity may affect the sense of taste, alterations in food preferences and eating behavior.

Polygenic risk score for obesity and the quality, quantity, and timing of workplace food purchases: A secondary analysis from the ChooseWell 365 randomized trial

BACKGROUND

The influence of genetic risk for obesity on food choice behaviors is unknown and may be in the causal pathway between genetic risk and weight gain. The aim of this study was to examine associations between genetic risk for obesity and food choice behaviors using objectively assessed workplace food purchases.

METHODS AND FINDINGS

This study is a secondary analysis of baseline data collected prior to the start of the "ChooseWell 365" health-promotion intervention randomized control trial. Participants were employees of a large hospital in Boston, MA, who enrolled in the study between September 2016 and February 2018. Cafeteria sales data, collected retrospectively for 3 months prior to enrollment, were used to track the quantity (number of items per 3 months) and timing (median time of day) of purchases, and participant surveys provided self-reported behaviors, including skipping meals and preparing meals at home. A previously validated Healthy Purchasing Score was calculated using the cafeteria traffic-light labeling system (i.e., green = healthy, yellow = less healthy, red = unhealthy) to estimate the healthfulness (quality) of employees' purchases (range, 0%-100% healthy). DNA was extracted and genotyped from blood samples. A body mass index (BMI) genome-wide polygenic score (BMIGPS) was generated by summing BMI-increasing risk alleles across the genome. Additionally, 3 polygenic risk scores (PRSs) were generated with 97 BMI variants previously identified at the genome-wide significance level (P < 5 × 10-8): (1) BMI97 (97 loci), (2) BMICNS (54 loci near genes related to central nervous system [CNS]), and (3) BMInon-CNS (43 loci not related to CNS). Multivariable linear and logistic regression tested associations of genetic risk score quartiles with workplace purchases, adjusted for age, sex, seasonality, and population structure. Associations were considered significant at P < 0.05. In 397 participants, mean age was 44.9 years, and 80.9% were female. Higher genetic risk scores were associated with higher BMI. The highest quartile of BMIGPS was associated with lower Healthy Purchasing Score (-4.8 percentage points [95% CI -8.6 to -1.0]; P = 0.02), higher quantity of food purchases (14.4 more items [95% CI -0.1 to 29.0]; P = 0.03), later time of breakfast purchases (15.0 minutes later [95% CI 1.5-28.5]; P = 0.03), and lower likelihood of preparing dinner at home (Q4 odds ratio [OR] = 0.3 [95% CI 0.1-0.9]; P = 0.03) relative to the lowest BMIGPS quartile. Compared with the lowest quartile, the highest BMICNS quartile was associated with fewer items purchased (P = 0.04), and the highest BMInon-CNS quartile was associated with purchasing breakfast at a later time (P = 0.01), skipping breakfast (P = 0.03), and not preparing breakfast (P = 0.04) or lunch (P = 0.01) at home. A limitation of this study is our data come from a relatively small sample of healthy working adults of European ancestry who volunteered to enroll in a health-promotion study, which may limit generalizability.

CONCLUSIONS

In this study, genetic risk for obesity was associated with the quality, quantity, and timing of objectively measured workplace food purchases. These findings suggest that genetic risk for obesity may influence eating behaviors that contribute to weight and could be targeted in personalized workplace wellness programs in the future.

TRIAL REGISTRATION

Clinicaltrials.gov NCT02660086.

Oral Microbiota Profile Associates with Sugar Intake and Taste Preference Genes

Oral microbiota ecology is influenced by environmental and host conditions, but few studies have evaluated associations between untargeted measures of the entire oral microbiome and potentially relevant environmental and host factors. This study aimed to identify salivary microbiota cluster groups using hierarchical cluster analyses (Wards method) based on 16S rRNA gene amplicon sequencing, and identify lifestyle and host factors which were associated with these groups. Group members (n = 175) were distinctly separated by microbiota profiles and differed in reported sucrose intake and allelic variation in the taste-preference-associated genes TAS1R1 (rs731024) and GNAT3 (rs2074673). Groups with higher sucrose intake were either characterized by a wide panel of species or phylotypes with fewer aciduric species, or by a narrower profile that included documented aciduric- and caries-associated species. The inferred functional profiles of the latter type were dominated by metabolic pathways associated with the carbohydrate metabolism with enrichment of glycosidase functions. In conclusion, this study supported in vivo associations between sugar intake and oral microbiota ecology, but it also found evidence for a variable microbiota response to sugar, highlighting the importance of modifying host factors and microbes beyond the commonly targeted acidogenic and acid-tolerant species. The results should be confirmed under controlled settings with comprehensive phenotypic and genotypic data.

Taste, Nutrition, and Health

The sensation of flavour reflects the complex integration of aroma, taste, texture, and chemesthetic (oral and nasal irritation cues) from a food or food component. Flavour is a major determinant of food palatability—the extent to which a food is accepted or rejected—and can profoundly influence diet selection, nutrition, and health. Despite recent progress, there are still gaps in knowledge on how taste and flavour cues are detected at the periphery, conveyed by the brainstem to higher cortical levels and then interpreted as a conscious sensation. Taste signals are also projected to central feeding centers where they can regulate hunger and fullness. Individual differences in sensory perceptions are also well known and can arise from genetic variation, environmental causes, or a variety of metabolic diseases, such as obesity, metabolic syndrome, and cancer. Genetic taste/smell variation could predispose individuals to these same diseases. Recent findings have also opened new avenues of inquiry, suggesting that fatty acids and carbohydrates may provide nutrient-specific signals informing the gut and brain of the nature of the ingested nutrients. This special issue on “Taste, Nutrition, and Health” presents original research communications and comprehensive reviews on topics of broad interest to researchers and educators in sensory science, nutrition, physiology, public health, and health care.