An Evolutionary Perspective on Food and Human Taste.

An evolutionary perspective on food and human taste.

Curr Biol. 2013 May 6; 23(9): R409-18
Breslin PA

The sense of taste is stimulated when nutrients or other chemical compounds activate specialized receptor cells within the oral cavity. Taste helps us decide what to eat and influences how efficiently we digest these foods. Human taste abilities have been shaped, in large part, by the ecological niches our evolutionary ancestors occupied and by the nutrients they sought. Early hominoids sought nutrition within a closed tropical forest environment, probably eating mostly fruit and leaves, and early hominids left this environment for the savannah and greatly expanded their dietary repertoire. They would have used their sense of taste to identify nutritious food items. The risks of making poor food selections when foraging not only entail wasted energy and metabolic harm from eating foods of low nutrient and energy content, but also the harmful and potentially lethal ingestion of toxins. The learned consequences of ingested foods may subsequently guide our future food choices. The evolved taste abilities of humans are still useful for the one billion humans living with very low food security by helping them identify nutrients. But for those who have easy access to tasty, energy-dense foods our sensitivities for sugary, salty and fatty foods have also helped cause over nutrition-related diseases, such as obesity and diabetes. HubMed – eating


Early influences on the development of food preferences.

Curr Biol. 2013 May 6; 23(9): R401-8
Ventura AK, Worobey J

The ability to perceive flavors begins in utero with the development and early functioning of the gustatory and olfactory systems. Because both amniotic fluid and breast milk contain molecules derived from the mother’s diet, learning about flavors in foods begins in the womb and during early infancy. This early experience serves as the foundation for the continuing development of food preferences across the lifespan, and is shaped by the interplay of biological, social, and environmental factors. Shortly after birth, young infants show characteristic taste preferences: sweet and umami elicit positive responses; bitter and sour elicit negative responses. These taste preferences may reflect a biological drive towards foods that are calorie- and protein-dense and an aversion to foods that are poisonous or toxic. Early likes and dislikes are influenced by these innate preferences, but are also modifiable. Repeated exposure to novel or disliked foods that occurs in a positive, supportive environment may promote the acceptance of and eventually a preference for those foods. Alternatively, children who are pressured to eat certain foods may show decreased preference for those foods later on. With increasing age, the influence of a number of factors, such as peers and food availability, continue to mold food preferences and eating behaviors. HubMed – eating


The use of the reinstatement model to study relapse to palatable food seeking during dieting.

Neuropharmacology. 2013 May 6;
Calu DJ, Chen YW, Kawa AB, Nair SG, Shaham Y

Excessive consumption of unhealthy foods is a major public health problem. While many people attempt to control their food intake through dieting, many relapse to unhealthy eating habits within a few months. We have begun to study this clinical condition in rats by adapting the reinstatement model, which has been used extensively to study relapse to drug seeking. In our adaptation of the relapse model, reinstatement of palatable food seeking by exposure to food-pellet priming, food-associated cues, or stress is assessed in food-restricted (to mimic dieting) rats after operant food-pellet self-administration training and subsequent extinction of the food-reinforced responding. In this review, we first outline the clinical problem and discuss a recent study in which we assessed the predictive validity of the reinstatement model for studying relapse to food seeking during dieting by using the anorexigenic drug fenfluramine. Next, we summarize results from our initial studies on the role of several stress- and feeding-related peptides (corticotropin-releasing factor, hypocretin, melanin- concentrating hormone, peptide YY3-36) in reinstatement of palatable food seeking. We then present results from our studies on the role of dopamine and medial prefrontal cortex in stress-induced reinstatement of food seeking. We conclude by discussing potential clinical implications. We offer two main conclusions: (1) the food reinstatement model is a simple, reliable, and valid model to study mechanisms of relapse to palatable food seeking during dieting, and to identify medications to prevent this relapse; (2) mechanisms of relapse to food seeking are often dissociable from mechanisms of ongoing food intake. HubMed – eating


Was the economic crisis of 2008 good for Icelanders? Impact on health behaviors.

Econ Hum Biol. 2013 Apr 6;
Asgeirsdóttir TL, Corman H, Noonan K, Olafsdóttir T, Reichman NE

This study uses the 2008 economic crisis in Iceland to identify the effects of a macroeconomic downturn on a range of health behaviors. We use longitudinal survey data that include pre- and post-reports from the same individuals on a range of health-compromising and health-promoting behaviors. We find that the crisis led to large and significant reductions in health-compromising behaviors (such as smoking, drinking alcohol or soft drinks, and eating sweets) and certain health-promoting behaviors (consumption of fruits and vegetables), but to increases in other health-promoting behaviors (consumption of fish oil and recommended sleep). The magnitudes of effects for smoking are somewhat larger than what has been found in past research in other contexts, while those for alcohol, fruits, and vegetables are in line with estimates from other studies. Changes in work hours, real income, financial assets, mortgage debt, and mental health, together, explain the effects of the crisis on some behaviors (such as consumption of sweets and fast food), while the effects of the crisis on most other behaviors appear to have operated largely through price increases. HubMed – eating