12 January - 20 June 2016

High fat maternal diet shown to reduce anxiety and stress in rats

02 July 14

In a recent paper published in Neuroscience, researchers at the University of Toronto suggest that being exposed to a high-fat diet in the womb may reduce anxiety behaviour in adolescent offspring.

Previous research has suggested that high fat diets can lead to higher rates of depression and anxiety in mice. The results of this paper, however, which studied the offspring of female rats on a controlled diet, contradicted these conclusions. In the study, 20 female rats were fed either a high fat diet which contained around 60% fat, or a control "house chow" diet which contained around 13.5% fat. The two groups followed these diets for 4 weeks before mating, then during pregnancy and lactation. Once the offspring had been weaned, all the mice were provided the same ad libitum (unrestricted) access to the control house chow diet. Whilst no significant differences in litter size, sex or weight of offspring was noted, offspring that had been exposed to the high fat diet before weaning gained weight at a higher rate than did the control group.

The offspring were then subjected to three behavioural tests designed to characterise their responses to stressful situations. In the first, each rat was placed in a dark box connected to a light box, and allowed to freely explore for 5 minutes whilst ANY-maze software recorded the frequency and duration of its visits to the light zone. Males exposed to the control house chow diet spent the most time in the light zone, whilst both males and females exposed to the high fat diet spent the least amount of time in the light zone.

In the "open field" task, rats were placed in a square box for 15 minutes whilst software recorded where in the box it spent its time, for example at the centre or the edge. Both male and female offspring exposed to the high fat diet spent significantly more time in the centre of the box then those offspring exposed to the control house chow diet. In the final test the rats' movements were tracked for 5 minutes after they were placed in the centre of the box which had four arms attached to it. These four arms were described as two "open" and two "closed," which were elevated to 80cm above the floor. The offspring of the high fat diet entered the open arms of the maze more than the offspring of the control chow house diet, which action according to the authors was "suggested to be an indicator of impulsive behaviour."

Glucocorticoid receptors (GR) can influence down-stream inflammatory processes which ultimately reduce or increase stress levels. Whilst this study revealed no significant differences in GR gene activity in the amygdala between the two groups of offspring, there was a greater abundance of GR found in the hippocampus of the rats exposed to the high fat diet, particularly in females. These findings support the behavioural task results, where it was believed that the offspring exposed to the high fat diet showed decreased anxiety.

This data suggests a potential 'developmental shift' of the effects of high fat diets between adolescence and adulthood on anxiety. The team adds that "additional studies are needed to establish the critical time window during perinatal development when high fat diet exposure influences the behavioural and neural responses observed in this study." [FoodNavigator]

share this article
RSSL endeavours to check the veracity of news stories cited in this free e-mail bulletin by referring to the primary source, but cannot be held responsible for inaccuracies in the articles so published. RSSL provides links to other World Wide Web sites as a convenience to users, but cannot be held responsible for the content or availability of these sites. This document may be copied and distributed provided the source is cited as RSSL's Food e-News and the information so distributed is not used for profit.

Previous editions

Load more editions

Make an Enquiry