Modification of appetite by bread consumption: A systematic review of randomized controlled trials

The inclusion of different ingredients or the use of different baking technologies may modify the satiety response to bread, and aid in the control of food intake. The aim of this study was to perform a systematic search of randomized clinical trials on the effect of bread consumption on appetite ratings in humans. The search equation was (“Bread”[MeSH]) AND (“Satiation”[MeSH] OR “Satiety response”[MeSH]), and the filter “clinical trials.” As a result of this procedure, 37 publications were selected. The satiety response was considered as the primary outcome. The studies were classified as follows: breads differing in their flour composition, breads differing in ingredients other than flours, breads with added organic acids, or breads made using different baking technologies. In addition, we have revised the data related to the influence of bread on glycemic index, insulinemic index and postprandial gastrointestinal hormones responses. The inclusion of appropriate ingredients such as fiber, proteins, legumes, seaweeds and acids into breads and the use of specific technologies may result in the development of healthier breads that increase satiety and satiation, which may aid in the control of weight gain and benefit postprandial glycemia. However, more well-designed randomized control trials are required to reach final conclusions.     

Dietary variety, energy regulation, and obesity.

Increased variety in the food supply may contribute to the development and maintenance of obesity. Thirty-nine studies examining dietary variety, energy intake, and body composition are reviewed. Animal and human studies show that food consumption increases when there is more variety in a meal or diet and that greater dietary variety is associated with increased body weight and fat. A hypothesized mechanism for these findings is sensory-specific satiety, a phenomenon demonstrating greater reductions in hedonic ratings or intake of foods consumed compared with foods not consumed. Nineteen studies documenting change in preference, intake, and hedonic ratings of food after a food has been eaten to satiation in animals and humans are reviewed, and the theory of sensory-specific satiety is examined. The review concludes with the relevance of oral habituation theory as a unifying construct for the effects of variety of sensory-specific satiety, clinical implications of dietary variety and sensory-specific satiety on energy regulation, and suggestions for future research. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Satiety-responsive neurons in the medial orbitofrontal cortex of the macaque.

Feeding-related gustatory, olfactory, and visual activation of the orbitofrontal cortex (OFC) decreases following satiety. Previous neurophysiological studies have concentrated on the caudolateral OFC (clOFC). We describe satiety-induced modulation of 23 gustatory, 5 water, and 15 control neurons in the medial OFC (mOFC), where gustatory neurons represent a much larger percentage of the population. For 15 of the 23 gustatory neurons (65%), every significant taste response evoked during pre-satiety testing decreased following satiety (X=70%). Responses evoked by the ineffective taste stimuli during pre-satiety testing were unchanged following satiety. The graded response decrements of the mOFC gustatory neurons stand in marked contrast to the clOFC responses, which are almost completely suppressed by satiety. Two other novel findings are reported here. First, all significant pre-satiety taste responses of four gustatory neurons increased following satiety (X=51%). Second, post-satiety emergent taste responses were observed in 7 of 15 neurons (47%) classified as non-responsive during pre-satiety testing. The presence of increased responsiveness and emergent gustatory neurons in the mOFC suggests that meal termination may require active processes as well as the passive loss of hedonic value. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Are intuitive eating and eating disorder symptomatology opposite poles of the same construct?

Two studies explored whether intuitive eating (i.e., eating based on physiological hunger and satiety cues rather than situational and emotional cues) is a distinct construct from low levels of eating disorder (ED) symptomatology among college women. Previous research has demonstrated that high levels of ED symptomatology are related to lower levels of well-being. Therefore, if intuitive eating is a distinct construct, then it should be associated with indices of well-being above and beyond the variance accounted for by ED symptomatology. Findings revealed that two intuitive eating components (i.e., eating for physical rather than emotional reasons and reliance on internal hunger and satiety cues) made unique contributions to each well-being measure, whereas the remaining intuitive eating component (i.e., unconditional permission to eat) overlapped substantially with low levels of ED symptomatology. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

不同质构特性西蓝花对口腔加工行为和米饭餐饱腹感的影响

为探究同样原料不同质构蔬菜对口腔加工行为、食物摄入和饱腹感的影响,以两种熟西蓝花为研究对象,分析健康受试者同时食用西蓝花与米饭或先食用西蓝花、后食用米饭时的口腔加工行为,并测定食物摄入量及餐后饱腹感相关指标。结果表明：与同时进食软西蓝花和米饭相比,先进食硬西蓝花、后进食米饭的处理可增加44%的咀嚼次数、34%的口腔感官暴露时间、57%的单位质量咀嚼次数,进食速率和米饭摄入量分别降低25%和20%,并有效抑制餐后饥饿感。结论：较硬西蓝花可通过促进口腔加工效应从而降低食物摄入并抑制餐后饥饿感,而这种效应在先进食西蓝花时表现得更为显著。     

Polar Lipids Reduce In Vitro Duodenal Lipolysis Rate of Oat Oil and Liquid Oat Base Products

Alternative ways for increased appetite control are today widely sought for due to the growing global health issues connected to obesity. In in vivo studies, oat has been proven an attractive candidate for inducing satiety. Oat is rich in polar lipids, of which the galactolipids are especially interesting, and a hypothesis is that these lipids play an important role for the ileal brake mechanism. In this study, the aim is to investigate the role of polar oat lipids on pancreatic lipolysis rate, using a pH-stat based in vitro digestion model of the duodenum. Lipolysis of oat oil, a mix of oat oil/rapeseed oil (RSO), as well as a liquid oat base (OB) simulating an oat drink with different polar lipid content are investigated, and compared with RSO as control. Increasing the polar lipid content of the product digested leads to a significantly decreased lipolysis rate, and this effect is even observed when mixing RSO with a low amount of oat oil (10%). The results support the hypothesis that polar lipids can delay lipolysis also in a complex, natural system like the liquid OB, and even a minor amount of oat lipids can have large effect on lipolysis rates. Practical applications: The number of studies connecting galactolipids with a decreasing effect on duodenal lipolysis is growing; however, the mechanism behind this phenomenon is still not clarified. Here, the same effect is seen in a complex, natural food system. These findings open up for interesting future food products, where inclusion of oat oil, even at low concentrations, can have a prolonging effect on satiety. Oat for human consumption is an increasing market, thanks to the positive health benefits oat has been connected to, in combination with the current trend toward climate-friendly plant-based options for meat and dairy products. It is believed that oat oil can be attractive as an ingredient in various food products, for example, protein bars and spreads. More studies are needed to confirm the results in vivo. However, a great potential is seen for the use of oat oil to enhance appetite control.     

The texture and taste of food in the brain

Oral texture is represented in the brain areas that represent taste, including the primary taste cortex, the orbitofrontal cortex, and the amygdala. Some neurons represent viscosity, and their responses correlate with the subjective thickness of a food. Other neurons represent fat in the mouth, and represent it by its texture not by its chemical composition, in that they also respond to paraffin oil and silicone in the mouth. The discovery has been made that these fat-responsive neurons encode the coefficient of sliding friction and not viscosity, and this opens the way for the development of new foods with the pleasant mouth feel of fat and with health-promoting designed nutritional properties. A few other neurons respond to free fatty acids (such as linoleic acid), do not respond to fat in the mouth, and may contribute to some “off” tastes in the mouth. Some other neurons code for astringency. Others neurons respond to other aspects of texture such as the crisp fresh texture of a slice of apple versus the same apple after blending. Different neurons respond to different combinations of these texture properties, oral temperature, taste, and in the orbitofrontal cortex to olfactory and visual properties of food. In the orbitofrontal cortex, the pleasantness and reward value of the food is represented, but the primary taste cortex represents taste and texture independently of value. These discoveries were made in macaques that have similar cortical brain areas for taste and texture processing as humans, and complementary human functional neuroimaging studies are described.     

糯小米和大黄米的餐后血糖反应和饱腹感评价

为了研究糯性杂粮的餐后生理反应,选择糯小米和糯大黄米为研究对象,以非糯性的普通小米作为对照,测定三种样品在鲜热、冷藏、回热之后的人体餐后血糖反应和饱腹感反应,计算血糖生成指数(GI)与饱腹感指数(SI)。参比食物为葡萄糖和粳米饭。结果表明,新鲜烹调的糯小米和大黄米样品GI值分别为108和111,冷藏和回热样品的GI值也与参比葡萄糖相当,远高于各处理小米和参比食物粳米。回热大黄米的SI显著高于其他样品。因此,糯小米和大黄米尽管为全谷食物,但仍属高血糖反应食物,且冷藏处理不能有效降低其餐后血糖反应。