肥胖成因的解释--基于食物奖赏研究的视角

The cause of obesity: An explanation from food reward perspective

肥胖的形成和发展受生物、心理和社会因素的共同作用,其中食物奖赏对肥胖的产生有重要的作用。食物是一种自然奖赏,它指机体天生对食物的渴望和依赖。食物奖赏包括"wanting"、"liking"以及"learning&reinforcement"三个成分,每个成分由相应的神经通路表征。食物奖赏调控机体的摄食行为并以此调控体重变化。目前,关于肥胖与食物奖赏关系的理论模型主要有刺激—敏感化理论、奖赏过度理论以及奖赏不足理论。采用横断面设计、前瞻研究设计和纵向被试内重复测量设计,使用食物图片线索和直接给予美味奶昔的技术方法,人类脑成像研究从不同侧面为以上三个理论模型提供了证据。除此之外,食物奖赏还受基因的调控。目前,研究者关注较多的是多巴胺D2受体基因Taq IA rs1800497的多态性和FTO基因rs9939609的多态性对食物奖赏及体重改变的调控。

Food is a natural rewarding stimulus, which promotes human to seek for it because of their instinctive desire and need for reward. ＂Wanting＂, ＂liking＂ and ＂learning ＆ reinforcement＂ are three main components of food reward, and each of them is represented in its corresponding neural pathway. Food reward regulates food intake behavior and body weight. The association between food reward and obesity has predominantly been explained by three main theoretic models, namely the incentive sensitization theory of addiction, the reward-surfeit theory of obesity and the reward deficit theory of obesity. In human studies, the association between food reward and obesity has usually been studied by using a cross-sectional design, perspective design or longitudinal within-subjects design, in which either food pictures or palatable liquid foods （such as milkshake） were used as the experimental stimuli to obtain brain responses to food cues or actual foods, respectively. In addition, human brain response to both food cues and actual foods is regulated by the human genome. The role of single nucleotide polymorphisms （SNPs） in dopamine D2 receptor gene TaqlA rs1800497 and the FTO gene rs9939609 is discussed in the current review.