Driving Along the Zinc Road

Long-tailed macaques: an unfairness model for humans

The current study was designed to predict why human primates often behave unfairly (equity aversion) by not exhibiting equity preference (the ability to equally distribute outcomes 1:1 among participants). Parallel to humans, besides inequity aversion, lab monkeys such as kin of long-tailed macaques (Macaca fascicularis) also demonstrate equity aversion depending on their preference for the outcome (food) type. During the pre-experiment phase, a food-preference test was conducted to determine the most preferred income per individual monkey. Red grapes were the most preferred outcome (100%) when compared to vanilla wafers (0%). The first set of experiments used a 1:1 ratio (equity condition) of grape distribution among six kin-pairs of female long-tailed macaques, and we compared their aversion (Av) versus acceptance (Ac). In the second experiment, we assessed the response to the 0:2 and 1:3 ratio distribution of grapes (inequity condition). A total of 60 trials were conducted for each condition with N = 6 pairs. Our results show aversion to the inequity conditions (1:3 ratios) in long-tailed macaques was not significantly different from aversion to the equity conditions (1:1 ratios). We suggest that the aversion observed in this species was associated with the degree of preference for the outcome (food type) offered rather than the distribution ratio. The subjective preferences for outcome types could bring this species into irrationality; they failed to share foods with an equal ratio of 1:1.

From personalised nutrition to precision medicine: the rise of consumer genomics and digital health

Advances in genomics generated the concept that a better understanding of individual characteristics, e.g. genotype, will lead to improved tailoring of pharmaceutical and nutritional therapies. Subsequent developments in proteomics and metabolomics, in addition to wearable technologies for tracking parameters, such as dietary intakes, physical activity, heart rate and blood glucose, have further driven this idea. Alongside these innovations, there has been a rapid rise in companies offering direct-to-consumer genetic and/or microbiome testing, in combination with the marketing of personalised nutrition services. Key scientific questions include how disparate datasets are integrated, how accurate are current predictions and how these may be developed in the future. In this regard, lessons can be learned from systems biology, which aims both to integrate data from different levels of organisation (e.g. genomic, proteomic and metabolomic) and predict the emergent behaviours of biological systems or organisms as a whole. The present paper reviews the origins and recent advancement of 'big data' and systems approaches in medicine and nutrition. Conclusions are that systems integration of multiple technologies has generated mechanistic insights and informed the evolution of precision medicine and personalised nutrition. Pertinent ethical issues include who is entitled to access new technologies and how commercial companies are storing, using and/or re-mining consumer data. Questions about efficacy (both long-term behavioural change and health outcomes), cost-benefit and impacts on health inequalities remain to be fully addressed.

Dietary normalization from a fat, fructose and cholesterol-rich diet to chow limits the amount of myocardial collagen in a Göttingen Minipig model of obesity

Background

Dietary interventions have been shown to attenuate some of the myocardial pathological alterations associated with obesity. This study evaluated the effect of dietary normalization from a fat/fructose/cholesterol-rich diet to chow on left ventricular (LV) myocardial fibrosis, fat infiltration and hypertrophy but also the specific influence of obesity, plasma lipids and glucose metabolism markers on heart morphology in a Göttingen Minipig model of obesity.

Methods

Forty castrated male Göttingen Minipigs were assigned to three groups fed either standard minipig chow (SD, n = 8) for 13 months, fat/fructose/cholesterol-rich diet (FFC, n = 16) for 13 months or fat/fructose/cholesterol-rich diet for 7 months and then changed to standard minipig chow for the remaining 6 months (FFC/SD, n = 16). Body weight, body fat percentage, plasma lipids and glucose metabolism markers were evaluated in all three groups after 6–7 months (prior to diet adjustment for FFC/SD) and again before termination. Further, biochemical quantification of myocardial collagen and triglyceride content, semi-quantitative histological evaluation of fibrosis and fat infiltration and quantitative histological analysis of collagen and cardiomyocyte diameter were performed and heart weight was obtained after termination. Group differences were evaluated using Kruskal-Wallis test and Fisher’s exact test for categorical variables. Pearson correlation analysis was performed to test for correlations between myocardial changes and selected explanatory variables. For non-parametric response variables, a Spearman correlation analysis was applied.

Results

Myocardial collagen content quantified biochemically was significantly lower in FFC/SD compared to FFC (P = 0.02). Furthermore, dietary normalization from a fat/fructose/cholesterol-rich diet to chow caused stagnation of body weight and body fat percentage, normalized intravenous glucose tolerance index (K_G) and plasma lipid levels.

Conclusion

Dietary normalization led to lower LV collagen content in obese Göttingen Minipigs. Despite gross obesity and significant deteriorations in glucose and lipid metabolism, only mild myocardial changes were found in this model of obesity and therefore further model optimization is warranted in order to induce more severe myocardial changes before dietary or pharmacological interventions.