Relationships between dietary macronutrients and adult neurogenesis in the regulation of energy metabolism

Abstract

Of the environmental factors which have an impact on body weight, nutrients are most influential. Within normal limits, hypothalamic and related neuronal populations correct perturbations in energy metabolism, to return the body to its nutritional set-point, either through direct response to nutrients or indirectly via peripheral appetite signals. Excessive intake of certain macronutrients, such as simple carbohydrates and SFA, can lead to obesity and attendant metabolic dysfunction, also reflected in alterations in structural plasticity, and, intriguingly, neurogenesis, in some of these brain regions. Neurogenesis, previously thought to occur only in the embryo, is now known to take place in the adult brain, dependent on numerous stimulating and inhibiting factors, including dietary components. Because of classic associations between neurogenesis and the hippocampus, in learning and cognition, this brain region has also been the focus of attention in the study of links between diet and neurogenesis. Recently, however, a more complete picture of this relationship has been building: not only has the hypothalamus been shown to satisfy the criteria for a neurogenic niche, but appetite-related mediators, including circulating hormones, such as leptin and ghrelin, pro-inflammatory cytokines and the endocannabinoid intracellular messengers, are also being examined for their potential role in mediating neurogenic responses to macronutrients. The present review draws together these observations and investigates whether PUFA may exert their attenuating effects on body weight through the stimulation of adult neurogenesis. Exploration of the effects of nutraceuticals on neurogenic brain regions may encourage the development of new rational therapies in the fight against obesity.Key words: Macronutrients: Adult neurogenesis: High-fat diets: PUFA Maintenance of a healthy body weight and composition is important for the achievement of lifelong health and wellbeing (1) . It occurs through the successful balancing of energy expenditure and energy intake within a normal range, which is controlled by several complex regulatory systems (2) , themselves being governed by the interaction with both internal and external environmental factors. Internal factors include circulating metabolic and hormonal signals, whereas the nutrients that we consume are the most influential external factors. Their effects on body weight depend not only on the amount consumed, but also on their type. Thus, a diet high in carbohydrates and/or fat will encourage weight gain (3) ; however, genetic contribution notwithstanding (4) the nature of that gain -how much adipose tissue accrues and where it is deposited in the body -will depend on whether carbohydrates are simple or complex, and whether fats are saturated or polyunsaturated (5,6) .The current obesity epidemic is thought to be largely attributable to excessive consumption of palatable foods, high in refined (simple) sugars and saturated fats (3) . As part of a complex causation, including re...

Noncanonical Sites of Adult Neurogenesis in the Mammalian Brain

“…BrdU þ NeuN þ cells were routinely identified albeit at various percentages of the total BrdU þ cell population ranging from ,10% to 37%. Adult hypothalamic neurogenesis is significantly influenced by external stimuli, such as diet (for a review, see Yon et al 2013) and social environment (Fowler et al 2002), which could explain variabilities or discrepancies in the number of newborn neurons between studies. The number of newborn neurons is much lower than in the SVZ and SGZ.…”

Cognitive and autonomic determinants of energy homeostasis in obesity

“…13 These changes can occur during critical stages of development, as well as in adulthood, and unfavorably alter energy balance regulation. 11,12 Misprogramming of energy balance regulation during embryonic development has also been reported in rats polygenetically predisposed to high fat diet-induced obesity. 14,15 Finally, an obesogenic environment can alter the microbiota composition in the gut, where it influences energy balance and when dysfunctional is associated with metabolic complications.…”

“…Our modern lifestyle also produces epi genetic effects that contribute to obesity, 8,9 and an obesogenic environment can imprint on the neuronal circuits involved in the regulation of energy balance. [10][11][12] Unhealthy eating can in fact lead to unfavourable neuroplastic changes (that is, neurogenesis, synaptic plasticity and dendritic arborisation). 13 These changes can occur during critical stages of development, as well as in adulthood, and unfavorably alter energy balance regulation.…”

Relationships between dietary macronutrients and adult neurogenesis in the regulation of energy metabolism – CORRIGENDUM

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The purpose of this corrigendum is to clarify the nature of the PUFA that are discussed in this article (1) .The revised abstract is published below.

AbstractOf the environmental factors which have an impact on body weight, nutrients are most influential. Within normal limits, hypothalamic and related neuronal populations correct perturbations in energy metabolism, to return the body to its nutritional set-point, either through direct response to nutrients or indirectly via peripheral appetite signals.

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“…The purpose of this corrigendum is to clarify the nature of the PUFA that are discussed in this article (1) .…”