Acute emotional stress and high fat/high fructose diet modulate brain oxidative damage through NrF2 and uric acid in rats

Studies focusing on the interaction of dietary and acute emotional stress on oxidative stress in cortex frontal and in brain mitochondria are scarce. Dietary-induced insulin resistance, as observed in Western diets, has been associated with increased oxidative stress causing mitochondrial dysfunction. We hypothesized that acute emotional stress could be an aggravating factor by impacting redox status in cortex and brain mitochondria. Thus, the aim of the present study was to evaluate the combination of an insulin resistance inducing high-fat/high-fructose (HF/HFr) diet and acute emotional stress on brain oxidative stress in rats. We measured several oxidative stress parameters (carbonyls, FRAP, TBARS assays, GSH, GSSG, oxidized DNA, mRNA expression of redox proteins (Nrf2), and uric acid). The HF/HFr diet resulted in increased oxidative stress both in the brain mitochondria and in the frontal cortex and decreased expression of the Nrf2 gene. The emotional stress induced an oxidative response in plasma and in brain mitochondria of the control group. In the HF/HFr group it triggered an increase expression of the redox transcription factor Nrf2 and its downstream antioxidant genes. This suggests an improvement of the redox stress tolerance in response to an enhanced production of reactive oxygen species. Accordingly, a blunted oxidative effect on several markers was observed in plasma and brain of HF/HFr-stressed group. This was confirmed in a parallel study using lipopolysaccharide as a stress model. Beside the Nrf2 increase, the stress induced a stronger UA release in HF/HFr which could take a part in the redox stress.

Zinc intake and status in middle-aged and older European subjects: the ZENITH study

OBJECTIVE

Inadequate intakes of micronutrients in elderly negatively affect the nutritional status. Zinc is an essential micronutrient in the elderly, especially in relation to its impact on immune function, bone mass, cognitive function and oxidative stress. However, data are lacking on zinc intake and status during normal ageing. In this study, we evaluate the intake and status of zinc in late middle-aged and older free-living subjects.

DESIGN

Dietary zinc intake and zinc status in 188 middle-aged subjects from Clermont-Ferrand (Fr) and Coleraine (UK), and in 199 older subjects from Grenoble (Fr) and Roma (It) were assessed at the entry in the ZENITH study.

RESULTS

In relation to the zinc RDA for people older than 55 y, zinc intakes in most of the middle-aged and older subjects (more than 96%) in the present study were adequate. Older people had significantly lower (P < 0.01) energy intakes as compared to middle-aged. Zinc intake expressed per MJ was also significantly (P < 0.01) higher in older people compared to middle-aged. Erythrocyte and urinary zinc concentrations were significantly (P < 0.001) higher in middle-aged subjects compared to older ones. The prevalence of biological Zn deficiency in free-living ageing European people was low (<5%).

CONCLUSION

The results of the present study showed a relatively low prevalence of zinc deficiencies in healthy free-living late middle-age and older subjects. These results should be useful for health professionals to have reference data on zinc intake and status for a healthy ageing.

The relationship between the zinc nutritive status and biochemical markers of bone turnover in older European adults: the ZENITH study

OBJECTIVE

To investigate the relationship between indices of zinc nutritive status and biochemical markers of bone turnover in older adult European subjects.

DESIGN

Use of baseline data from a multicentre prospective zinc intervention (ZENITH) study.

SETTING

Centres in France, Italy and Northern Ireland.

PARTICIPANTS

A total of 387 healthy adults, aged 55-87 y.

METHODS

Zinc intake was assessed by 4-day recall records. Circulating and urinary biochemical zinc status measures were assessed by atomic absorption spectrophometry. Serum bone-specific alkaline phosphatase and osteocalcin were assessed by ELISA and urinary pyridinoline (Pyr) and deoxypyridinoline (Dpyr) by HPLC.

RESULTS

Zinc intake was negatively correlated with urinary Pyr and Dpyr (r = -0.298 and -0.304, respectively; P < 0.0001), but was not correlated with bone formation markers. There was a tendency for serum zinc to be negatively correlated with urinary Dpyr (r = -0.211; P = 0.080). Erythrocyte zinc was negatively correlated with serum osteocalcin (r = -0.090; P < 0.0001). None of the other correlations were significant. After adjustment for confounder (age, gender and research centre) the only significant association that remained was between serum osteocalcin and erythrocyte zinc (beta = -0.124; P = 0.011).

CONCLUSIONS

There was some, albeit inconsistent, evidence of a relationship between zinc nutritive status and bone turnover in the older adult participants of the ZENITH study.

Age-related oxidative stress and antioxidant parameters in middle-aged and older European subjects: the ZENITH study

OBJECTIVE

Oxidative stress has been reported to increase with ageing. However, the data in healthy humans remain controversial and studies in free-living elderly people are scarce. The objective of the present study was to compare age-related oxidative stress in late middle-aged and older free-living subjects.

DESIGN

The effect of ageing on oxidative stress and antioxidant parameters was investigated in 188 middle-aged subjects from Clermont-Ferrand (France) and Coleraine (UK), and in 199 older subjects from Grenoble (France) and Roma (Italy). Plasma thiol (SH) groups, define definition (TBAR's) and total glutathione (GSH), define definition (FRAP), and superoxide dismutase (SOD) activity were measured at baseline of the ZENITH study.

RESULTS

Plasma SH groups and FRAP and, surprisingly, TBAR's were significantly lower in free-living older subjects compared to younger subjects (P < 0.001, P < 0.001, P < 0.01, respectively), but there was no significant differences in GSH levels.

CONCLUSION

European free-living healthy older do not appear to be exposed to an acute oxidative stress. However, the highly significant positive correlation between plasma SH group oxidation or decreased FRAP and ageing is predictive of an increased risk of oxidative stress in older subjects. Moreover, the comparison between middle-aged and older subjects regarding oxidative stress parameters suggests also a progressive and slow decline of antioxidant status in healthy free-living older elderly and underline the impact on life-style factors on successful ageing.

[Zinc and pregnancy]

Zinc, an essential trace element, plays a critical role in normal growth and development, cellular integrity and many biological functions, including protein synthesis and nucleic acid metabolism. Since all these are involved in cell division and growth, zinc is believed to be important for foetal growth and development. Zinc requirement is increased during pregnancy but the lack of a valid indicator precludes a true estimate of zinc deficiency in pregnancy even in developed countries. This review examines the possibility that a gestational deficiency of zinc can adversely affect the pregnancy outcome. Preliminary human data suggest a beneficial effect of prenatal zinc supplementation trials in particular on infant's neurobehavioral development. In the light of the currently available information, zinc supplementation at therapeutic load (30 mg/day) as it is proposed for the treatment of hormonal skin disorders to adolescents, cannot be toxic.

Faut-il supplémenter en fer les femmes enceintes ?

Considering that young women have a high risk of iron store deficiency, the iron supplementation is largely proposed during pregnancy. However, a selective supplementation reserved to anaemia women, must be preferred to a systematic supplementation which improves biological parameters of mothers but have no effect on newborns. Iron is a potentially toxic element and a not justified, supplementation could expose to high iron level and to an oxidative stress which is also observed in pregnancy pathologies (preeclamptia, gestational diabetes). Furthermore a non controlled increase of erythrocyte mass by iron supplementation could also alter the placenta exchange. As a precaution, iron supplementation may be reserved to anaemia women or with high anaemia risk. For others, nutritional advises must permit to reach iron recommendation.

Food and fluid intake of the SENECA population residing in Romans, France

OBJECTIVES

to provide information and data on food and fluid intake of free-living elderly aged of 81-86 years old residing in the south of France.

METHODS

using standardised methods data were collected from a random sample born between 1913 and 1918. The French study protocol again included data collection on dietary intake using a standardised modified dietary history consisting of a food frequency list and a 3-day estimated dietary record.

RESULTS

Total dietary intake was generally low as compared to the recommended daily intake for elderly subjects.

CONCLUSION

This descriptive part of the SENECA study gives the opportunity to have information on this growing segment of the population. These results should help to adapt the dietary guidelines for this category of the population.