Skip to main content

Table 3 Effects of diet on microglia

From: Lifestyle-dependent microglial plasticity: training the brain guardians

Species Brain region Experimental paradigm Microglial changes References
Mice Hypothalamus and total brain LFD (6.5% fat), HFD (42% fat) and caloric restriction (40% less) for 6 and 24 months HFD increased the number of microglia in the hypothalamus and both number and soma size of microglia were increased in the cerebellum during aging in HFD mice. Under basal- or LPS-induced inflammatory conditions, gene expression analysis of the total brain microglia population or hypothalamus tissue showed similar findings in HFD and LFD mice. Caloric restriction in LFD mice prevented the increased expression of phagocytic markers in white matter microglia with aging, and this protective effect of caloric restriction was not observed in HFD mice. Because running wheel access did not affect white matter microglia activation in either diet, dietary fat as well as caloric content may play an important role in the inflammatory process in brain aging [123]
Mice Hypothalamus Standard diet (13,2% fat) or HFD (42% fat) for 28 days HFD led to microglial reactivity and neuronal stress in the mediobasal hypothalamus. Microglial depletion abrogated HFD-induced hypothalamic inflammation besides to enhance leptin signalling and reduce food intake [147]
Mice Hippocampus and amygdala HFD (60.3% fat) for 3 days In the hippocampus, HFD induced enlarged synaptophysin boutons, indicative of neurodegeneration. In the amygdala, HFD exacerbated the effects of ageing on microglial priming (morphology) and significantly suppressed microglial phagocytosis [115]
Mice White matter Western diet (42% fat) WD diet induced an ageing-related metabolic dysfunction associated with impaired myelin-debris clearance in microglia, which is mediated by TGF-β signalling and disrupts lesion recovery after demyelination. Blocking TGF-β restores microglia responsiveness and myelin-debris clearance following demyelinating injury [148]
Mice Nucleus accumbens high-caloric chocolate cafeteria diet for 43 days This high-caloric diet led to microglial reactivity with increased expression of pro-inflammatory factors and abnormal responses after amphetamine-induced hyperlocomotion. Chronic inhibition of microglial reactivity normalised these behavioural alterations [149]
Mice and Human Hypothalamus Mice: HFD (60% fat) for 8 weeks
Human: post-mortem samples from obese individuals (BMI > 30)
HFD induced microglia number in the hypothalamus of mice. Gene expression analysis of isolated microglia found downregulation of genes important for sensing signals in microenvironment. In obese humans, it was found signs of hypothalamic gliosis and exacerbated microglial dystrophy [111]
Mice Hippocampus HFD (60% fat) for 8 weeks HFD partially disrupted the rhythmicity of circadian clock genes in microglia, besides disruption on microglial immune gene expression. HFD induced a shift of substrate utilisation on microglia, with decreased glutamate and glucose metabolism and an overall increase of lipid metabolism during active period of the animals [150]
Mice Hypothalamus Caloric restriction (40% of the ad libitum food intake) in HFD and LFD animals for 23 months Caloric restriction in combination with LFD affected microglial morphology and decreased expression of phagocytic markers (Mac2/Lgals3, Dectin-1/Clec7a and CD16/CD32 in microglia [123]
Mice Hippocampus Luteolin intake (20 mg/d) for 4 weeks In aged animals, luteolin food supplement improved spatial memory and restored expression of inflammatory markers compared with that of young animals [131]
Rat - EO and EP intake (2%) for 8 weeks In aged animals, this diet improved working memory. Then, blood serum was used to assess microglial response in vitro. BV-2 microglia treated with blood serum from EO- and EP-fed rat showed reduced expression of NO and TNF-α respectively [133]
Mice Hippocampus HFD and LFD with or without blueberry (4%) for 5 months HFD supplemented with blueberry had fewer microglia compared to LFD and HFD ones. BV-2 microglia treated with serum collected from mice fed the diets with blueberry produced less NO compared to HFD mice. HFD + blueberry mice presented higher levels of hippocampal BDNF and DCX-positive cells compared to mice fed HFD [139]
Mice Frontal cortex Caloric restriction (70% of the ad libitum food intake) for 6 weeks and 6 and 12 months Caloric restriction for 6- and 12 months counteracted ageing-induced microglial changes such as Ca2+ signalling and processes motility toward a younger phenotype. Even shot-term caloric restriction (6 weeks) beginning in old age significantly improved microglial motility and Ca2+ signalling [124]
  1. LFD low-fat diet, HFD high fat diet, EO Euterpe oleracea, EP Euterpe precatoria, WD Western diet