High-fat diets containing different types of fatty acids modulate gut-brain axis in obese mice

Dietary lipids shape cytokine and leptin profiles in obesity-metabolic syndrome implications: A cross-sectional study

BACKGROUND

Obesity, characterized by chronic energy imbalance and excessive adiposity, is a key component of metabolic syndrome and is associated with low-grade inflammation and altered adipokine secretion. This study aimed to evaluate the association between dietary fat consumption and its influence on interleukin (IL) and leptin levels in participants with obesity.

METHODS

Using the Asian obesity classification criteria, a cross-sectional study was conducted on 384 adults (18-59 years). Anthropometric measurements by bioelectrical impedance analyzer (BIA), blood biochemistry by colorimetric assay, inflammatory markers and hormones by ELISA test, and dietary intake were assessed by Semi-FFQ.

RESULTS

Obesity prevalence was 26.1% and 73.90% in males and females, respectively. Participants with obesity exhibited significantly higher inflammatory and hormonal marker levels. Positive correlations were observed between blood lipid, glucose, and tumor necrosis factor-α, IL-6, and leptin levels. Energy, carbohydrate, and sugar intake were positively correlated with leptin levels. High saturated fat intake was associated with increased IL-6 levels (odds ratio = 2.03, 95% confidence interval [CI] = 1.00-4.11, p < 0.047), whereas high total fat intake elevated leptin levels by 2.14-fold (95% CI = 1.12-4.10, p < 0.021) in participants with obesity.

CONCLUSIONS

This study demonstrates significant associations between dietary fat composition, inflammatory markers, and leptin levels in individuals with obesity. These findings suggest that modulating dietary fat intake can be a potential strategy for mitigating obesity-related inflammation and leptin resistance, highlighting the need for targeted nutritional interventions in obesity and metabolic syndrome management.

The Gut Microbiota Is Involved in the Regulation of Cognitive Flexibility in Adolescent BALB/c Mice Exposed to Chronic Physical Stress and a High-Fat Diet

Dysfunction in the prefrontal cortex can lead to cognitive inflexibility due to multifactorial causes as included cardiometabolic disorders, stress, inadequate diets, as well as an imbalance of the gut-brain axis microbiota. However, these risk factors have not been evaluated jointly. The purpose of this study was to evaluate the effect of physical stress (MS: Male Stress and FS: Female Stress) and high-fat diet (MD: Male Diet and FD: Female Diet) supplementation on the gut microbiota and cognitive flexibility.

METHODS

The study was performed on 47 mice, 30 male (M) and 17 female (F) BALBc, exposed to chronic stress physical (S) and high-fat diet (D). Cognitive flexibility was evaluated using the Attentional Set-Shifting Test (ASST) and the gut microbiota composition in terms of relative abundance (%) and alpha-beta diversity.

RESULTS

Results showed that S and D reduced cognitive flexibility in male and female mice (p < 0.0001). Significant changes occurred in Alistipes spp. (MM vs. MS:MD; p < 0.0001), Barnesiella spp. (FC vs. FS; p = 0.0002; FC vs. FD, p = 0.0033); Dorea spp. (MC vs. MD, p = 0.0008; MM vs. MD, p < 0.0001) and Lactobacillus spp. (MC vs. MD and FM vs. FS, p < 0.0001; FM vs. MD, p = 0.0393) genera among groups. Predictive functional analysis (QIIME2 and PICRUSt2) showed a significant increase in the expression of histidine kinase, alanine dehydrogenase, glutamine synthase, glutamate synthase, arginine succinyl synthase, and tryptophan synthase genes (p < 0.05), the latter being a precursor of serotonin (5-HT).

CONCLUSIONS

Chronic physical stress and a high-fat diet modify cognitive flexibility and the composition and predictive function of the gut microbiota.

Glucose intolerance induces anxiety-like behaviors independent of obesity and insulin resistance in a novel model of nutritional metabolic stress

OBJECTIVES

Type 2 diabetes (T2D) is a metabolic disease of major public health concern. It impacts peripheral tissues and the central nervous system, leading to systemic dysmetabolism and neurocognitive impairments, including memory deficits, anxiety, and depression. The metabolic determinants of these neurocognitive impairments remain unidentified. Here, we sought to address this question by developing a proprietary (P-) high-fat diet (HFD), in which glucose intolerance precedes weight gain and insulin resistance.

METHODS

The P-HFD model was nutritionally characterized, and tested in vivo in mice that underwent behavioral and metabolic testing. The diet was benchmarked against reference models. .

RESULTS

P-HFD has 42% kcal from fat, high monounsaturated/polyunsaturated fatty acid ratio, and 10% (w/v) sucrose in drinking water. When administered, from the early stages of glucose intolerance alone, animals exhibit anxiety-like behavior, without depression nor recognition memory deficits. Long-term P-HFD feeding leads to weight gain, brain glucose hypometabolism as well as impaired recognition memory. Using an established genetic model of T2D (db/db) and of diet-induced obesity (60% kcal from fat) we show that additional insulin resistance and obesity are associated with depressive-like behaviors and recognition memory deficits.

DISCUSSION

Our findings demonstrate that glucose intolerance alone can elicit anxiety-like behavior. Through this study, we also provide a novel nutritional model (P-HFD) to characterize the discrete effects of glucose intolerance on cognition, behavior, and the physiology of metabolic disease.