High saturated fat and low carbohydrate diet decreases lifespan independent of body weight in mice

Reversal of high-fat diet-induced cognitive impairment and oxidative stress in the brain through Zingiber officinale supplementation

Obesity is a significant health concern that is correlated with various adverse health outcomes. Diet-induced obesity (DIO) is associated with impaired cognitive function. Pharmacological treatments for obesity are limited and may have serious adverse effects. Zingiber officinale (ZO) has anti-inflammatory and antioxidant effects, in addition to metabolic effects. This study aimed to assess the effects of Zingiber officinale supplementation on cognitive function, anxiety levels, neurotrophin levels, and the inflammatory and oxidative status in the cortex following DIO in mice. Two-month-old male Swiss mice were fed DIO or standard chow for 4 months and subsequently subdivided into the following groups (n = 10 mice/group): (i) control - vehicle (CNT + vehicle); (ii) CNT supplemented with ZO (CNT + ZO); (iii) obese mice (DIO + vehicle); and (iv) obese mice supplemented with ZO (DIO + ZO) (n = 10). Zingiber officinale extract (400 mg/kg/day) was administered for 35 days via oral gavage. The DIO + vehicle group exhibited impaired recognition memory. The CNT + ZO group presented a greater number of crossings in the open field. No difference between the groups was observed in the plus maze test. DIO + vehicle increased the DCFH and carbonylation levels in the cortex. The DIO + vehicle group presented a reduction in catalase activity. The expression of inflammatory or neurotrophin markers in the cerebral cortex was not different. In conclusion, our findings indicate that supplementation with ZO reverses the cognitive impairment in DIO mice and enhances the antioxidant status of the cerebral cortex.

Gene-by-environment modulation of lifespan and weight gain in the murine BXD family

How lifespan and body weight vary as a function of diet and genetic differences is not well understood. Here we quantify the impact of differences in diet on lifespan in a genetically diverse family of female mice, split into matched isogenic cohorts fed a low-fat chow diet (CD, n = 663) or a high-fat diet (HFD, n = 685). We further generate key metabolic data in a parallel cohort euthanized at four time points. HFD feeding shortens lifespan by 12%: equivalent to a decade in humans. Initial body weight and early weight gains account for longevity differences of roughly 4-6 days per gram. At 500 days, animals on a HFD typically gain four times as much weight as control, but variation in weight gain does not correlate with lifespan. Classic serum metabolites, often regarded as health biomarkers, are not necessarily strong predictors of longevity. Our data indicate that responses to a HFD are substantially modulated by gene-by-environment interactions, highlighting the importance of genetic variation in making accurate individualized dietary recommendations.

Effect of Long-Term Treatment with C60 Fullerenes on the Lifespan and Health Status of CBA/Ca Mice

Several studies claimed C₆₀ fullerenes as a prospective geroprotector drug due to their ability to capture free radicals effectively and caused a profound interest in C₆₀ in life extension communities. Multiple additives are already sold for human consumption despite a small body of evidence supporting the beneficial effects of fullerenes on the lifespan. To test the effect of C₆₀ fullerenes on lifespan and healthspan, we administered C₆₀ fullerenes dissolved in virgin olive oil orally to 10-12 months old CBA/Ca mice of both genders for 7 months and assessed their survival. To uncover C₆₀ and virgin olive effects, we established two control groups: mice treated with virgin olive oil (vehicle) and mice treated with drinking water. To measure healthspan, we conducted daily monitoring of health condition and lethality and monthly bodyweight measurements. We also assessed physical activity, glucose metabolism, and hematological parameters every 3 months. We did not observe health deterioration in the animals treated with C₆₀ compared with the control groups. Treatment of mice with C₆₀ fullerenes resulted in an increased lifespan of males and females compared with the olive oil-treated animals. The lifespan of C₆₀-treated mice was similar to the mice treated with water. These results suggest that the lifespan-extending effect in C₆₀-treated mice appears due to the protective effect of fullerenes in opposition to the negative effect of olive oil in CBA/Ca mice.

Fasted exercise does not improve postprandial lipemia responses to different meals in lean and obese subjects: A crossover, randomized clinical trial

INTRODUCTION

Persistent episodes of postprandial hyperlipemia (PPL) and hyperglycemia (PPG) are considered risk factors for coronary heart disease (CHD) and premature death; whereas physical exercise improves lipid profile and glucose tolerance thus decreasing cardiovascular risks.

OBJECTIVE

To investigate the effects of low-intensity fasted aerobic exercise on the magnitude of the PPL and PPG responses to meals with different energy content, in normal and obese subjects.

METHODS

The study used a randomized crossover design. Twenty-one male (Lean: n = 9, BMI: 24.3 ± 2.2; and obese: n = 12, BMI 32.31 ± 2.1) volunteers aged 20-30 years, performed three interventions, separated by 7 days each: (i) 45 min at rest and isocaloric high-fat meal (60% lipids, 30% carbohydrates and 10% protein); (ii) fasted low-intensity aerobic exercise (50% VO_2max) for 45 min followed by an isocaloric or (iii) calorie deficit high-fat meal. Subjects were serially assessed for blood triglycerides, and glucose levels.

RESULTS AND CONCLUSIONS

Low-intensity fasted aerobic exercise had no acute effect on PPL in lean and obese subjects. Glucose concentrations were reduced only in lean subjects. There is a significant difference in PPL values when comparing lean to obese subjects, implying that the nutritional status influences lipid and carbohydrate after fasted low-intensity aerobic exercise. Registered under ClinicalTrials.gov Identifier no. NCT00929890.

Dietary reversal of neuropathy in a murine model of prediabetes and metabolic syndrome

Patients with metabolic syndrome, which is defined as obesity, dyslipidemia, hypertension and impaired glucose tolerance (IGT), can develop the same macro- and microvascular complications as patients with type 2 diabetes, including peripheral neuropathy. In type 2 diabetes, glycemic control has little effect on the development and progression of peripheral neuropathy, suggesting that other metabolic syndrome components may contribute to the presence of neuropathy. A parallel phenomenon is observed in patients with prediabetes and metabolic syndrome, where improvement in weight and dyslipidemia more closely correlates with restoration of nerve function than improvement in glycemic status. The goal of the current study was to develop a murine model that resembles the human condition. We examined longitudinal parameters of metabolic syndrome and neuropathy development in six mouse strains/genotypes (BKS-wt, BKS-Leprdb/+ , B6-wt, B6-Leprdb/+ , BTBR-wt, and BTBR-Lepob/+ ) fed a 54% high-fat diet (HFD; from lard). All mice fed a HFD developed large-fiber neuropathy and IGT. Changes appeared early and consistently in B6-wt mice, and paralleled the onset of neuropathy. At 36 weeks, B6-wt mice displayed all components of the metabolic syndrome, including obesity, IGT, hyperinsulinemia, dyslipidemia and oxidized low density lipoproteins (oxLDLs). Dietary reversal, whereby B6-wt mice fed a HFD from 4-20 weeks of age were switched to standard chow for 4 weeks, completely normalized neuropathy, promoted weight loss, improved insulin sensitivity, and restored LDL cholesterol and oxLDL by 50% compared with levels in HFD control mice. This dietary reversal model provides the basis for mechanistic studies investigating peripheral nerve damage in the setting of metabolic syndrome, and ultimately the development of mechanism-based therapies for neuropathy.

Impact of high-fat, low-carbohydrate diet on myocardial substrate oxidation, insulin sensitivity, and cardiac function after ischemia-reperfusion

High-fat, low-carbohydrate Diet (HFLCD) impairs the myocardial response to ischemia-reperfusion, but the underlying mechanisms remain elusive. We sought to determine the magnitude of diet-induced alterations in intrinsic properties of the myocardium (including insulin sensitivity and substrate oxidation) and circulating substrate and insulin differences resulting from diet, leading to this impaired response. Rats were fed HFLCD (60% kcal from fat/30% protein/10% carbohydrate) or control diet (CONT) (16%/19%/65%) for 2 wk. Isolated hearts underwent global low-flow ischemia followed by reperfusion (I/R). Carbon-13 NMR spectroscopy was used to determine myocardial substrate TCA cycle entry. Myocardial insulin sensitivity was assessed as dose-response of Akt phosphorylation. There was a significant effect of HFLCD and I/R with both these factors leading to an increase in free fatty acid (FFA) oxidation and a decrease in carbohydrate or ketone oxidation. Following I/R, HFLCD led to decreased ketone and increased FFA oxidation; the recovery of left ventricular (LV) function was decreased in HFLCD and was negatively correlated with FFA oxidation and positively associated with ketone oxidation. HFLCD also resulted in reduced insulin sensitivity. Under physiologic ranges, there were no direct effects of buffer insulin and ketone levels on oxidation of any substrate and recovery of cardiac function after I/R. An insulin-ketone interaction exists for myocardial substrate oxidation characteristics. We conclude that the impaired recovery of function after ischemia-reperfusion with HFLCD is largely due to intrinsic diet effects on myocardial properties, rather than to diet effect on circulating insulin or substrate levels.

Context- and dose-dependent modulatory effects of naringenin on survival and development of Drosophila melanogaster

Naringenin, the predominant bioflavonoid found in grapefruit and tomato has diverse bioactive properties that encompass anti-carcinogenic, anti-inflammatory, anti-atherogenic, anti-estrogenic, anti-hyperlipidemic and anti-hyperglycemic characteristics. Naringenin has not been explored for its pro-longevity traits in fruit flies. Therefore, the current study explores its influence on longevity, fecundity, feeding rate, larval development, resistance to starvation stress and body weight in male and female wild-type Drosophila melanogaster Canton-S flies. Flies were fed with normal and high fat diets respectively. The results implied hormetic effects of naringenin on longevity and development in flies. In flies fed with standard and high fat diets, lower concentrations of naringenin (200 and 400 µM) augmented mean lifespan while higher concentrations (600 and 800 µM) were consistently lethal. However, enhanced longevity seen at 400 µM of naringenin was at the expense of reduced fecundity and food intake in flies. Larvae reared on standard diet having 200 µM of naringenin exhibited elevated pupation and emergence as flies. Eclosion time was hastened in larvae reared on standard diet having 200 µM of naringenin. Female flies fed with a standard diet having 200 and 400 µM of naringenin were more resistant to starvation stress. Reduction in body weight was observed in male and female flies fed with a high fat diet supplemented with 200 and 400 µM of naringenin respectively. Collectively, the results elucidated a context- and dose-dependent hormetic efficacy of naringenin that varied with gender, diet and stage of lifecycle in flies.

Revisiting an age-old question regarding oxidative stress

Significant advances in maintaining health throughout life can be made through a clear understanding of the fundamental mechanisms that regulate aging. The Oxidative Stress Theory of Aging (OSTA) is probably the most well studied mechanistic theory of aging and suggests that the rate of aging is controlled by accumulation of oxidative damage. To directly test the OSTA, aging has been measured in several lines of mice with genetic alterations in the expression of enzymatic antioxidants. Under its strictest interpretation, these studies do not support the OSTA, as modulation of antioxidant expression does not generally affect mouse life span. However, the incidence of many age-related diseases and pathologies is altered in these models, suggesting that oxidative stress does significantly influence some aspects of the aging process. Further, oxidative stress may affect aging in disparate patterns among tissues or under various environmental conditions. In this review, we summarize the current literature regarding aging in antioxidant mutant mice and offer several interpretations of their support of the OSTA.