It is estimated that 20%–67% of those with COVID-19 develop olfactory disorders, depending on the SARS-CoV-2 variant. However, there is an absence of quick, population-wide olfactory tests to screen for olfactory disorders. The purpose of this study was to provide a proof-of-concept that SCENTinel 1.1, a rapid, inexpensive, population-wide olfactory test, can discriminate between anosmia (total smell loss), hyposmia (reduced sense of smell), parosmia (distorted odor perception), and phantosmia (odor sensation without a source). Participants were mailed a SCENTinel 1.1 test, which measures odor detection, intensity, identification, and pleasantness, using one of 4 possible odors. Those who completed the test (N = 287) were divided into groups based on their self-reported olfactory function: quantitative olfactory disorder only (anosmia or hyposmia, N = 135), qualitative olfactory disorder only (parosmia and/or phantosmia; N = 86), and normosmia (normal sense of smell; N = 66). SCENTinel 1.1 accurately discriminates quantitative olfactory disorders, qualitative olfactory disorders, and normosmia groups. When olfactory disorders were assessed individually, SCENTinel 1.1 discriminates between hyposmia, parosmia, and anosmia. Participants with parosmia rated common odors less pleasant than those without parosmia. We provide proof-of-concept that SCENTinel 1.1, a rapid smell test, can discriminate quantitative and qualitative olfactory disorders, and is the only direct test to rapidly discriminate parosmia.

The purpose of this study was to determine if the mixed evidence of almond consumption on HbA1c stems from testing people with different body fat distributions (BFD) associated with different risks of glucose intolerance. A 6-month randomised controlled trial in 134 adults was conducted. Participants were randomly assigned to the almond (A) or control (C) group based on their BFD. Those in the almond group consumed 1·5 oz of almonds with their breakfast and as their afternoon snack daily. Those in the control group continued their habitual breakfast and afternoon snack routines. Body weight and composition were measured and blood samples were collected for determination of HbA1c, glycaemia and lipaemia at 0 and 6 months. Appetite ratings, energy intake and diet quality were collected at 0, 2, 4 and 6 months. Participants consuming almonds ingested 816 (sem 364) kJ/d more than participants in the control group (P = 0·03), but this did not result in any differences in body weight (A: –0·3 (sem 0·4), C: –0·4 (sem 0·4); P > 0·3). Participants in the almond, high android subcutaneous adipose tissue (SAT) group had a greater reduction in android fat mass percentage (A: –1·0 (sem 0·6), C: 1·1 (sem 0·6); P = 0·04), preserved android lean mass percentage (A: 0·9 (sem 0·6), C: –1 (sem 0·6); P = 0·04) and tended to decrease android visceral adipose tissue mass (A: –13 (sem 53) g, C: 127 (sem 53) g; P = 0·08) compared with those in the control, high SAT group. There were no differences in HbA1c between groups (A: 5·4 (sem 0·04), C: 5·5 (sem 0·04); P > 0·05). Thus, BFD may not explain the mixed evidence on almond consumption and HbA1c. Long-term almond consumption has limited ability to improve cardiometabolic health in those who are overweight and obese but otherwise healthy.

Millions of people will now suffer from long-term smell loss as a result of infection with the SARS-CoV-2 virus. Smell is an integral component of the flavor of foods, which is one of the primary drivers of ingestive behavior. When individuals lose their sense of smell, they find food to be less flavorful and less enjoyable, which negatively impacts their quality of life. To compensate, many individuals alter their diet by focusing on tastes, chemesthesis (e.g., chili pepper heat, menthol cooling), and the texture of foods to make it more palatable. Some diet alterations, such as increasing salt use, can result in a lower diet quality, and an increased risk for chronic disease. Sensory nutrition is an area of research that focuses on how the chemical senses (e.g. taste, smell, chemesthesis) and oral somatosensation) affect dietary choices and health. Sensory nutrition strategies designed for individuals with smell loss may help improve the flavor and liking of foods while improving diet quality, and are a necessary area of future research to help improve health and quality of life in the growing population with smell loss.

World-wide some 658 million people were infected with COVID-19 and millions suffer from chemosensory impairment associated with long COVID. Current treatments for taste and smell disorders are limited. Involving patients has the potential to catalyze the dynamic exchange and development of new ideas and approaches to facilitate biomedical research and therapeutics. We assessed patients’ perceptions of the efficacy of treatments for chemosensory impairment using an online questionnaire completed by 5,815 people in the U.S. Logistic regression determined variables predictive of reported treatment efficacy for patients aged 18-24, 25-39, 40-60 and 60+ yrs. who were treated with nasal steroids, oral steroids, zinc, nasal rinse, smell training, theophylline, platelet rich plasma, and Omega 3. The most consistent predictor was age, with the majority of those 40-60 and 60+ reporting that nasal steroids, oral steroids, zinc, nasal rinse and smell training were only slightly effective or not effective at all. Many of these treatment strategies target regeneration and immune response, processes compromised by age. Only those under 40 reported more than slight efficacy of steroids or smell training. Findings emphasize the need to include patients of all ages in clinical trials. Older adults with olfactory impairment are at increased risk for Alzheimer’s disease (AD). We speculate that olfactory impairment associated with long COVID introduces the potential for a significant rise in AD. Long COVID-associated chemosensory impairment increases the urgency for translational and clinical research on novel treatment strategies. Suggestions for high priority areas for epidemiological, basic, and clinical research on chemosensory impairment follow.

SCENTinel^®, a rapid smell test designed to screen for olfactory disorders, including anosmia (no ability to smell an odor) and parosmia (distorted sense of smell), measures four components of olfactory function: detection, intensity, identification, and pleasantness. Each test card contains one of nine odorant mixtures. Some people born with genetic insensitivities to specific odorants (i.e., specific anosmia) may fail the test if they cannot smell an odorant but otherwise have a normal sense of smell. However, using odorant mixtures has largely been found to prevent this from happening. To better understand whether genetic differences affect SCENTinel^® test results, we asked genetically informative adult participants (twins or triplets, N=630; singletons, N=370) to complete the SCENTinel^® test. A subset of twins (n=304) also provided a saliva sample for genotyping. We examined data for differences between the nine possible SCENTinel^® odors; effects of age, sex, and race on SCENTinel^® performance, test-retest variability; and heritability using both structured equation modeling and SNP-based statistical methods. None of these strategies provided evidence for specific anosmia for any of the odors, but ratings of pleasantness were, in part, genetically determined (h²=0.40) and were nominally associated with alleles of odorant receptors (e.g., OR2T33 and OR1G1; p<0.001). These results provide evidence that using odorant mixtures protected against effects of specific anosmia for ratings of intensity but that ratings of pleasantness showed effects of inheritance, possibly informed by olfactory receptor genotypes.