John E Hayes

• Pennsylvania State University

Xerostomia (perceived oral dryness) is a common problem in older adults, often due to hyposalivation, which can cause difficulty in eating and swallowing, resulting in insufficient dietary fiber intake. Recent work shows salivary flow rate, particle size, and concentration are major factors for particle perception in beverages. Given that disliking...

Millions of people in the United States experience a reduced or distorted ability to smell or taste. Chemosensory disorders such as anosmia (the inability to smell), parosmia (distorted smell), or dysgeusia (altered taste) have major impacts on health and quality of life including difficulty sensing dangers such as fire or spoilage, a diminished pa...

Large amounts of money, time and effort are devoted to sensory and consumer research in food and beverage companies in an attempt to maximize the chances of new products succeeding in the marketplace. Many new products fail due to lack of consumer interest. Answers to what causes this and what can be done about it are complex and remain unclear. Th...

It is widely accepted that milk provides the greatest relief from capsaicin burn, an effect typically attributed to its fat content and temperature. Previously, Lawless et al. reported partitioning lipophilic capsaicin in fat reduces burn, whereas Green showed lower temperature reduces burn. Recent research shows that dairy and nondairy proteins al...

Despite its importance as an undesirable food texture, the phenomenon of chalkiness remains understudied. Chalky sensations presumably arise from fine particulates found in foods, but semantic overlap with other common descriptors of small particles, like gritty or sandy, is unclear. Here, we compare the usage of Chalky with related descriptors, an...

Bitterness from phenylthiocarbamide and 6-n-propylthiouracil (PROP) varies with polymorphisms in the TAS2R38 gene. Three SNPs form two common (AVI, PAV) and four rare haplotypes (AAI, AAV, PVI, and PAI). AVI homozygotes exhibit higher detection thresholds and lower suprathreshold bitterness for PROP compared to PAV homozygotes and heterozygotes, an...

The Teruel Orthorexia Scale (TOS) defines two related but distinct constructs: Orthorexia Nervosa (OrNe), a pathological fixation on a healthy diet, and Healthy Orthorexia (HeOr), an interest in a healthy diet independent of psychopathology. Here, we (a) assessed both types of Orthorexia in a large North American sample using the TOS and (b) explor...

Over the last half-century, variable responses to sweetness have repeatedly been shown to fall into a small number of hedonic responses, implying that looking only at group means may can obfuscate meaningfully different response patterns. Comparative data for sourness is quite sparse, especially in adults. While increased liking with higher acid co...

Consumer concern about intake of added sugars has increased commercial demand for sugar‐reduced chocolates. However, substitution with high‐potency sweeteners is not possible as sugar serves as an important bulking agent. Here, we investigated replacement of sucrose in chocolate compound with oat or rice flours, with starch granules smaller than 10...

Responses to capsaicin are reduced following repeated exposure, a phenomenon known as capsaicin desensitization. Heavy consumers of chilies consistently report reduced oral burn relative to infrequent consumers, presumably due to chronic desensitization. However, the mechanism(s) underlying capsaicin desensitization remain poorly understood. We hyp...

Food texture properties and consumer characteristics influence oral processing behaviors. Little is known about oral processing behavior of pungent spicy foods. In two experiments, we investigated how adding ground dried chilies to tomato soup or beef patties and curried rice altered oral processing behaviors. In Experiment One, tomato soups differ...

This study explores the use of food texture terms by adults in the northeastern United States. The purpose of the study was to compare the effect of food texture on food liking and texture term usage among age groups via two complementary online surveys that differed in the specific task given to participants. Survey 1 gathered common food items as...

Transient loss of smell is a common symptom of influenza and other upper respiratory infections. Loss of taste is possible but rare with these illnesses, and patient reports of 'taste loss' typically arise from a taste / flavor confusion. Thus, initial reports from COVID-19 patients of loss of taste and chemesthesis (i.e., chemical somatosensation...

Background There is a prevailing view that humans’ capacity to use language to characterize sensations like odors or tastes is poor, providing an unreliable source of information. Methods Here, we developed a machine learning method based on Natural Language Processing (NLP) using Large Language Models (LLM) to predict COVID-19 diagnosis solely ba...

Background: Foods lower in saturated fat, sodium, and added sugars (i.e., overconsumed dietary components) must have an acceptable flavor profile to promote intake. Objective: The aim of this research was to model the impact of using herbs/spices as flavor-enhancers when reducing overconsumed dietary components in commonly consumed foods and eva...

People often confuse smell loss with taste loss, so it is unclear how much gustatory function is reduced in patients self-reporting taste loss. Our pre-registered cross-sectional study design included an online survey in 12 languages with instructions for self-administering chemosensory tests with ten household items. Between June 2020 and March 20...

Anosmia is common with respiratory virus infections, but loss of taste or chemesthesis is rare. Reports of true taste loss with COVID-19 were viewed skeptically until confirmed by multiple studies. Nasal menthol thresholds are elevated in some with prior COVID-19 infections, but data on oral chemesthesis are lacking. Many patients recover quickly,...

Background and aims: Physiological changes that occur during pregnancy can have long-term impacts on metabolism and neurosensory responses to food, which can impact nutrition and health outcomes. The ENERGY cohort is a longitudinal study that aims to capitalizes on pregnancy as a natural model of metabolic reprogramming in order to understand the...

People often confuse smell loss with taste loss, so it is unclear how much gustatory function is reduced in patients self-reporting taste loss. Our pre-registered cross-sectional study design included an online survey in 12 languages with instructions for self-administering chemosensory tests with ten household items. Between June 2020 and March 20...

This study focused on the effect of binding of capsaicin by milk proteins on oral burn. The concentration of free, unbound capsaicin in 5 ppm capsaicin solution containing 0–5% (w/w) micellar casein or whey protein isolate was measured by extraction into hexadecane. The concentration of free capsaicin decreased linearly with protein concentration a...

Many widely used psychophysical olfactory tests have limitations that can create barriers to adoption. For example, tests that measure the ability to identify odors may confound sensory performance with memory recall, verbal ability, and prior experience with the odor. Conversely, classic threshold-based tests avoid these issues, but are labor inte...

The bulk vegetable oil–water partition coefficient of caffeine and quinine was determined by a shake‐flask method as log Kow = −1.32 and 2.97. These values were consistent with the effect of oil concentration on the distribution of the bitterants in an oil‐in‐water emulsion (0–2 and 0–20 wt% oil stabilized with 0.125 and 1 wt% whey protein isolate,...

Background Menthol upregulates nicotinic acetylcholine receptors and is associated with tobacco dependence. The effects of menthol when smoking cigarettes with varying low nicotine content up to 98% (e.g., non-addicting) less than commercial cigarettes is not well understood. The U.S. Food and Drug Administration is considering two tobacco product...

For pharmaceuticals to deliver their full benefits with maximum efficacy, patients need to follow recommended dosing schedules, in terms of amount and frequency. Unfortunately, the aversive taste of many drugs, especially bitterness, can reduce patient compliance in oral liquid formulations. Given common genetic differences in bitter taste receptor...

Thousands start smoking or vaping daily, despite long-standing efforts by public health authorities to curb initiation and use of nicotine containing products. Over the last 15 years, use of electronic nicotine delivery systems has increased dramatically, with a diverse range of products on the market, including pod-based, disposable, and refillabl...

Background: The United States Food and Drug Administration (FDA) announced its commitment to prohibiting menthol as a characterizing flavor in tobacco. The relationship between cigarette menthol and exposure to toxic substances in mainstream tobacco smoke is not well characterized. Methods: Data from the National Health and Nutrition Examination...

Here we report synergistic and antagonistic mixture interactions between sucrose, vanillin, and cocoa powder as a potential added sugar reduction strategy in chocolate milk. Objectives of this project were to (i) model consumer perception of relevant sensory attributes as a function of sucrose, vanillin, and cocoa powder in chocolate milk, (ii) tes...

Starch-guest inclusion complexes (ICs) are a novel, clean-label flavor encapsulation system with the potential to improve stability of aroma volatiles. While amylase has been shown to modulate guest release in vitro, release by sensory perception has not been evaluated. Here, Temporal Check-All-That-Apply (TCATA) and CATA were used to compare flavo...

Liking plays a primary role in determining what and how much children eat. Despite this, the relationship between liking and intake of foods and beverages served as part of a meal is not often reported, even though pediatric feeding studies frequently collect such data. In addition, few studies have reported on the test-retest reliability of both h...

Background: Sudden smell loss is a specific early symptom of COVID-19, which, prior to the emergence of Omicron, had estimated prevalence of ~40% to 75%. Chemosensory impairments affect physical and mental health, and dietary behavior. Thus, it is critical to understand the rate and time course of smell recovery. The aim of this cohort study was t...

Purpose Many widely-used psychophysical tests of olfaction have limitations that can create barriers to adoption outside research settings. For example, tests that measure the ability to identify odors may confound sensory performance with memory recall, verbal ability, and past experience with the odor. Conversely, threshold-based tests typically...

Increasing childhood obesity rates in both the United States and worldwide demonstrate a need for better prevention and intervention strategies. However, little is understood about what factors influence children's ability to sense and respond to hunger and fullness cues, a critical component of self-regulation of energy intake and maintenance of a...

Food variety, complexity, and portion size each influence food choice and consumption, but their relative importance is poorly understood. In an online discrete choice-experiment, we investigated the relative importance of variety, complexity, and portion size in consumer preferences by systematically varying ice cream offerings. Complexity was def...

We identified associations between self-reported olfactory dysfunction (OD) and dietary attributes in participants aged ≥40 years (n = 6,356) from the nationally representative 2011–2014 National Health and Nutrition Examination Survey (NHANES). The chemosensory questionnaire and 24-hour dietary recalls were administered by trained interviewers. OD...

p>This is a correction notice for article bjaa041 (DOI: https:// doi.org/10.1093/chemse/bjaa041), published 20 June 2020. An incorrect version of the caption to Figure 5 was mistakenly included in the published paper. An updated version is given below. Neither the data nor the paper's conclusions were affected by this correction. The authors sincer...

Hops, the flowers of the Humulus lupus plant, are almost exclusively used in beer production, where they add important flavor qualities, such as bitter taste and a variety of aromas, to the finished product. Depending on concentration, variety, and time of addition, different beer styles are created, appealing to a broad range of consumer needs. Co...

In March 2020, the Global Consortium of Chemosensory Research (GCCR) was founded by chemosensory researchers to address then emerging reports of unusual smell and taste dysfunction arising from the SARS-CoV-2 pandemic. Over the next year, the GCCR used a highly collaborative model, along with contemporary Open Science practices, to produce multiple...

In March 2020, the Global Consortium of Chemosensory Research (GCCR) was founded by chemosensory researchers to address then emerging reports of unusual smell and taste dysfunction arising from the SARS-CoV-2 pandemic. Over the next year, the GCCR used a highly collaborative model, along with contemporary Open Science practices, to produce multiple...

The trigeminal nerve transduces both chemical irritation and textural sensations suggesting that perception in one may influence perception in the other. Little is known about how the oral burn of capsaicin may affect texture sensitivity. The aim of this study was to determine the effect of burning sensations on thickness discrimination thresholds...

Importance: Sudden smell loss is a specific early symptom of COVID-19, with an estimated prevalence of ~40% to 75%. Smell impairment affects physical and mental health, and dietary behavior. Thus, it is critical to understand the rate and time course of smell recovery. Objective: To characterize smell function and recovery up to 11 months post COVI...

We identified associations between cigarette-smoking and taste function in the U.S. NHANES 2013-2014. Adults ≥40 years (n=2849, nearly half former or current smokers) rated whole-mouth and tongue-tip bitter (1mM quinine) and salt (1M NaCl, 0.32 M NaCl) intensities and reported smoking history (pack years, PY), dependence (time to first cigarette, T...

Three separate sensory systems – taste, smell, and chemesthesis – contribute to the overall flavor perception of foods and beverages. Psychophysics has led to the quantification of individual differences in perception, which have potentially important implications for food liking and intake, along with human health. Carefully designed studies using...

Background Infants are born with the biological predisposition to reject bitterness. Dark green vegetables contain essential nutrients but also bitter compounds, making them more difficult to like. Objective The Good Tastes Study was designed to determine whether reducing bitterness by adding small amounts of sugar or salt would alter infant accep...

Objectives To identify associations of self-reported olfactory dysfunction (OD) with attributes of diet quality in a nationally-representative sample of US adults. Methods In this cross-sectional study, we utilized self-reported taste and smell, and dietary data collected from participants 40 years and older (n = 6356) in the NHANES 2011–2014. In...

Although sensory-guided product design is most traditionally used by food and beverage companies, the approach has widespread application for many other products, including pharmaceuticals and medical devices. Previously, our team used sensory methods to explore preclinical optimization of soft-gel vaginal microbicides. Past clinical trials suggest...

There are well known phenotypic differences in sweet-liking across individuals, but it remains unknown whether these are related to broader underlying differences in interoceptive abilities (abilities to sense the internal state of the body). Here, healthy women (N = 64) classified as sweet likers (SLs) or sweet dislikers (SDs) completed a bimodal...

Hops, the flowers of the Humulus lupus plant, is almost exclusively used in beer production, where they add important flavor qualities, such as bitter taste and a variety of aromas, to the finished product. Depending on concentration, variety, and time of addition, different beer styles are created, appealing to a broad range of consumer needs. Con...

Fluid dairy milk consumption has decreased over the last 4 decades, and this drop has accelerated with the introduction of many competing beverage alternatives, such as plant-based milks and bottled water. Conversely, flavored milk sales remain strong, but many adults avoid flavored milk because of concerns about added sugar and calories and/or exc...

Electronic cigarette use—vaping—is increasingly popular. Various product factors may influence an individual’s choice of e-cigarette. To provide an evidence base for e-cigarette regulation, a better understanding of the role different product attributes play in product preferences is needed. Here, we used conjoint analysis to quantify different fac...

Objective To investigate the alignment between vegetables and fruits listed in the ingredients of commercially produced infant and toddler food (ITF) and inclusion in front-of-package product names. Design A database of commercial ITF containing vegetables (n = 548) was created. Inclusion of each vegetable or fruit in the product name (yes/no), fo...

In a preregistered, cross-sectional study, we investigated whether olfactory loss is a reliable predictor of COVID-19 using a crowdsourced questionnaire in 23 languages to assess symptoms in individuals self-reporting recent respiratory illness. We quantified changes in chemosensory abilities during the course of the respiratory illness using 0–100...

A variety of factors can influence satiation, and individual differences in reasons for meal termination may help to explain variability in food intake and susceptibility to overconsumption. We developed and validated a questionnaire to characterize the Reasons Individuals Stop Eating (RISE-Q). The initial RISE-Q was created by reviewing the publis...

Determinants of food choice are broad and include policies, prices, settings and context, as well as interpersonal factors, such as family, cultural, and peer effects. This review focuses more narrowly on food choices at the individual level by providing an overview of various methods and tools that have been used to understand psychological, cogni...

Valid measurement of taste is critical for advanced understanding of how variation in taste perception and alterations in taste perception influence dietary behaviors, health, and well-being. Psychophysical procedures exist for measuring the concentration of taste required for detection or recognition, but changes in perceived intensity and liking...

In a preregistered, cross-sectional study we investigated whether olfactory loss is a reliable predictor of COVID-19 using a crowdsourced questionnaire in 23 languages to assess symptoms in individuals self-reporting recent respiratory illness. We quantified changes in chemosensory abilities during the course of the respiratory illness using 0-100...

Various global public health agencies recommend minimizing exposure to sweet-tasting foods or beverages. The underlying rationale is that reducing exposure to the perception of sweet tastes, without regard to the source of sweetness, may reduce preferences for sweetness, added sugar intake, caloric intake, and body weight. However, the veracity of...

In response to the COVID-19 pandemic, many governments have taken drastic measures to avoid an overflow of intensive care units. Accurate metrics of disease spread are critical for the reopening strategies. Here, we show that self-reports of smell/taste changes are more closely associated with hospital overload and are earlier markers of the spread...

Introduction Electronic cigarette (eCig) use is increasing in popularity, and thousands of flavors are available. Adolescent vaping rates in the United States have nearly doubled in the past year. Unlike combustible tobacco, added flavors are not currently regulated for electronic cigarette products. Here, we investigated the role of flavor in eCig...

Introduction: Electronic cigarette ("eCig") use, or "vaping," is increasingly prevalent. Factors such as flavor and nicotine level may influence selection and use of eCigs. A better understanding of the role product attributes play in eCig preferences is necessary to inform evidence-based regulation of electronic nicotine delivery systems (ENDS). M...

Taste hedonics drive food choices, and food choices affect weight maintenance. Despite this, the idea that hyper-palatability of sweet foods is linked to obesity development has been controversial for decades. Here, we investigate whether interpersonal differences in sweet-liking are related to body composition. Healthy adults aged 18-34 years from...

Rotundone is an aromatic compound found in the skin of some grapes (e.g., Shiraz, Noiret) that contributes peppery notes to wines made with these varieties. There may be a specific anosmia for rotundone, as some individuals are unable to detect it even at high concentrations, despite otherwise normal olfaction. This may affect perception of and pre...

Now published in Chemical Senses doi: 10.1093/chemse/bjaa081. Background: COVID-19 has heterogeneous manifestations, though one of the most common symptoms is a sudden loss of smell (anosmia or hyposmia). We investigated whether olfactory loss is a reliable predictor of COVID-19. Methods: This preregistered, cross-sectional study used a crowdsou...

Prior data suggest humans can distinguish between isointense bitter stimuli (i.e., bitterness may not be unitary). Cues for such discrimination remain unclear but temporal and regional differences have both been implicated. Here, ten bitterants – caffeine, quinine, L-phenylalanine, L-tryptophan, urea, naringin, SOA (sucrose octaacetate), and 3 hop...

Background: COVID-19 has heterogeneous manifestations, though one of the most common symptoms is a sudden loss of smell (anosmia or hyposmia). We investigated whether olfactory loss is a reliable predictor of COVID-19. Methods: This preregistered, cross-sectional study used a crowdsourced questionnaire in 23 languages to assess symptoms in individu...

Recent anecdotal and scientific reports have provided evidence of a link between COVID-19 and chemosensory impairments such as anosmia. However, these reports have downplayed or failed to distinguish potential effects on taste, ignored chemesthesis, and generally lacked quantitative measurements. Here, we report the development, implementation and...

In response to the COVID-19, many governments have taken unprecedented measures in peacetime, to avoid an overflow of intensive care units and critical care resuscitation units (CCRUs). Due to the heavy societal and economic impact of measure such as the lockdown1, accurate means to characterize the spread of the disease would be extremely helpful...

To learn more about the mechanisms of human dietary fat perception, 398 human twins rated fattiness and liking for six types of potato chips that differed in triglyceride content (2.5, 5, 10, and 15% corn oil); reliability estimates were obtained from a subset (n = 50) who did the task twice. Some chips also had a saturated long-chain fatty acid (h...

Bitterness is classically considered undesirable in foods and beverages. Yet, widespread commercial success of beers (like Bitters in the UK or IPAs in the US) indicate bitterness is desirable for some consumers. Here, we tested whether personality traits influence beer liking and intake. Under laboratory conditions, beer consumers (n=109) rated li...

Prior work suggests humans can differentiate between bitter stimuli in water. Here, we describe three experiments that test whether beer consumers can discriminate between different bitterants in beer. In Experiment 1 (n = 51), stimuli were intensity matched; Experiments 2 and 3 were a difference from control (DFC)/check-all-that-apply (CATA) test...

Now published in Chemical Senses doi: 10.1093/chemse/bjaa041. Recent anecdotal and scientific reports have provided evidence of a link between COVID-19 and chemosensory impairments such as anosmia. However, these reports have downplayed or failed to distinguish potential effects on taste, ignored chemesthesis, generally lacked quantitative measure...

Genetic variability in the ability to taste thiourea compounds has been studied for 80+ years. Over the last 3 decades, many studies have reported perceived intensity of concentrated propylthiouracil (PROP) associates with greater intensity from a broad range of stimuli, including non-bitter tastants, irritants, and retronasally delivered odorants....

Previously, we found bitter and sweet tastes to be positive and negative predictors of vegetable liking and intake. Here, we examined interactions between retronasal olfactory sensations (flavor) and tastes as potential predictors of vegetable liking and intake. Adults (n=97), diverse in bodyweight (40% overweight/obese), rated green vegetables (as...

Genetic variability in the ability to taste thiourea compounds has been studied for 80+ years. Over the last 3 decades, many studies have reported perceived intensity of concentrated propylthiouracil (PROP) associates with greater intensity from a broad range of stimuli, including non-bitter tastants, irritants, and retronasally delivered odorants....

Vegetables are an important but under consumed part of a healthy diet. There is growing interest in promoting vegetable acceptance and consumption among infants to help establish life-long healthy eating patterns. A recent survey of commercial baby food products in the United States (U.S.) by Moding and colleagues revealed a lack of variety in the...

To learn more about the mechanisms of human dietary fat perception, 398 human twins rated fattiness and liking for six types of potato chips that differed in triglyceride content (2.5, 5, 10, and 15% corn oil); reliability estimates were obtained from a subset (n = 50) who did the task twice. Some chips also had a saturated long-chain fatty acid (h...

Introduction: Electronic cigarette (eCig) use is increasing in popularity, and thousands of flavors are available. Adolescent vaping rates in the United States have nearly doubled in the past year. Unlike combustible tobacco, added flavors are not currently regulated for electronic cigarette products. Here, we investigated the role of flavor in eCi...

Introduction: Electronic cigarette (“eCig”) use – vaping – is increasingly popular. Factors like flavor, nicotine level, and device style may influence an individual’s decision to use eCigs. Here, we use choice-based conjoint analysis to quantify factors that drive acceptability of eCigs in adults, including flavors, device style, customizability,...

The ingredients and nutrients of infant and toddler foods (ITFs) sold in pouches were compared with products available in other packages, such as jars/packs and other containers. Company websites (n = 21) and in-store shelf inventory (n = 3) were used to create a database of commercial ITFs containing vegetables (n = 548) sold in the United States....

We examined associations of olfactory dysfunction with anthropometric and cardiometabolic measures in a nationally representative sample of US adults. In the 2013-2014 National Health and Nutrition Examination Survey (NHANES), 3,815 participants, 40 years and older, completed a standardized taste and smell protocol, which consisted of an 8-item odo...

Despite widespread and persistent myths of a tongue map, all five prototypical taste qualities are sensed over the entire tongue. However, modern psychophysical data also suggest there may be more nuanced differences in suprathreshold intensity across oral loci, especially for bitterness. Here, we test whether bitter stimuli matched for whole-mouth...

The chemical senses and pharmaceuticals fundamentally depend on similar biological processes, but novel molecule discovery has classically been approached from vastly different vantagepoints. From the perspective of ingredient and flavor companies, there are countless ingredients that act via largely unknown mechanisms, whereas the pharmaceutical i...

This study explored how product familiarity and physiological characteristics of participants affect detectability of microparticles in viscous and semi-solid foods. Cellulose particles differing in size (50-780 µm) were added (1.5% w/w) to two dairy products, quark (viscous curd cheese) and processed cheese. Discrimination thresholds for added mic...

Vanillin may modulate perception of noxious oral stimuli via TRP receptor interactions; separately, vanillin has also been shown to have top-down influences on flavor perception. Here, we ask whether added vanillin decreases the perceived burn of ethanol either via peripheral or cognitive mechanisms. Participants rated the burn of ethanol with 0, 1...

Methyl anthranilate (MA) and 2-aminoacetophenone (2AAP) are commonly associated with the flavor of wines made from V. labruscana grapes. It is widely assumed that wine experts and consumers find these flavors to be objectionable, at least in wines vinified from V. vinifera grapes. Here, a two-alternative forced-choice task was used to compare prefe...

Objectives: Young children need repeated exposure to learn to like new foods but can eat only foods caregivers offer. Thus, caregiver feeding decisions are central in determining whether children receive sufficient exposure to learn to like new foods. We undertook an exploratory study to: 1) examine child behaviors that influence caregiver percept...

Objectives: To examine: 1) product names of commercially produced infant and toddler foods (ITF) that contain vegetables, 2) specific vegetable forms in ITF, and 3) the presence of fruit juice/concentrates in the ITF. Methods: A database of commercial ITF containing vegetables (n = 517) from company websites (n = 19) was created. The vegetable a...