Genetic variations of the bitter taste receptor TAS2R38 are associated with obesity and impact on single immune traits

Abstract

Scope: Changes in genetic variations affecting the taste receptor, type 2, member 38 (TAS2R38) may identify the interacting mechanism leading to obesity and potential associations with proteins partaking in innate immunity, such as surfactant protein D (SPD) and mannanbinding lectin (MBL). Methods and results:We evaluated haplotypes of the bitter-taste receptor TAS2R38 in an identification sample of 210 women in different weight conditions, including anorexia nervosa and obesity. The association with SPD and MBL was tested in an independent sample picturing general population (n = 534). The relationship with obesity was validated in an extended final sample of 1319 participants. In the sample comprised of women in extreme weight conditions, increased obesity was identified in AVI/AVI subjects (OR = 2.5 [1.06-6.11], p = 0.035). In the sample picturing general population, increased SPD and MBL concentrations were found in nonsmoking AVI carriers. In this cohort, smoking and obesity blunted associations between TAS2R38 haplotypes and SPD and MBL. In the extended sample, the association of AVI/AVI haplotypes with increased obesity was also identified (OR = 1.4 [0.99/1.85], p = 0.049), being more robust in subjects aged <40 years (OR = 1.9 [1.06/3.42], p = 0.031). Mol. Nutr. Food Res. 2016, 00, 1-11 Conclusion: Current data reinforce the impact of TAS2R38 gene on phenotypic and clinical outputs affecting obesity, showing significant associations with extreme weight conditions (i.e., obesity and anorexia nervosa), and changes in both olfactory capacity and immune traits.

Taste sensitivity in anorexia nervosa: A systematic review

“…Two papers (Fernandez‐Aranda et al, 2016; Ortega et al, 2016) were confirmed through correspondence with the authors to have reported on overlapping samples, with some of the cases and controls taking part in both studies. As this review did not incorporate a meta‐analysis, both studies were retained in the review, with the limitations and implications of their overlapping sample highlighted in the results and the discussion.…”

“…Additionally, unlike many of the studies in this review, Fernández‐Aranda et al controlled for a number of potential variables in their study design, including smoking and medication use. Nonetheless, that a subsequent study using a similar design and an overlapping sample found no significant differences highlights the difficulty in replicating these findings (Ortega et al, 2016). …”

“…All studies measured the ability of participants to recognize the presence of sweet, sour, bitter and salty taste stimuli, except for one study (Goldzak‐Kunik et al, 2012) which used commercially available preparations of different food and nonfood tastes (e.g., apple, chicken, toothpaste, coffee). Four studies (Aschenbrenner, Scholze, Joraschky, & Hummel, 2008; Dazzi et al, 2013; Fernandez‐Aranda et al, 2016; Ortega et al, 2016) used taste strips to measure taste recognition abilities for sweet, bitter, salty, and sour tastes (Mueller et al, 2003). This method involves the placing of strips of filter paper soaked in different taste solutions at four different concentrations on the tongue.…”

“…To an extent this may reflect methodological issues. Sample power across the studies were typically small, with only one study using sample sizes of over n  = 30 in every group (Fernandez‐Aranda et al, 2016; Ortega et al, 2016 discounted due to the sample overlapping with Fernandez‐Aranda). Additionally, unlike many of the studies in this review, Fernández‐Aranda et al controlled for a number of potential variables in their study design, including smoking and medication use.…”

“…In line with this, only one study specified vomiting as an exclusion criteria (Nozoe et al, 1996). In addition, only a minority of studies controlled for smoking in their study design or analysis (Fernandez-Aranda et al, 2016;Ortega et al, 2016). This is despite research suggesting that smokers exhibit lower taste sensitivity compared to nonsmokers (Ch eruel, Jarlier, & Sancho-Garnier, 2017).…”