Transgenerational effects of obesogenic diets in rodents: A meta‐analysis

Abstract

Obesity is a major health condition that affects millions worldwide. There is an increased interest in understanding the adverse outcomes associated with obesogenic diets. A multitude of studies have investigated the transgenerational impacts of maternal and parental obesogenic diets on subsequent generations of offspring, but results have largely been mixed.We conducted a systematic review and meta-analysis on rodent studies to elucidate how obesogenic diets impact the mean and variance of grand-offspring traits. Our study focused on transgenerational effects (i.e., F2 and F3 generations) in one-off and multigenerational exposure studies. From 33 included articles, we obtained 407 effect sizes representing pairwise comparisons of control and treatment grand-offspring groups pertaining to measures of body weight, adiposity, glucose, insulin, leptin, and triglycerides. We found evidence that male and female grand-offspring descended from grandparents exposed to an obesogenic diet displayed phenotypes consistent with metabolic syndrome, especially in cases where the obesogenic diet was continued across generations. Further, we found stronger evidence for the effects of grand-maternal than grand-paternal exposure on grand-offspring traits. A highfat diet in one-off exposure studies did not seem to impact phenotypic variation, whereas in multigenerational exposure studies it reduced variation in several traits.

Intergenerational effects of overfeeding on aversive learning in zebrafish (Danio rerio)

“…In contrast, the treatment group (F1T) had the least amount of variation, followed by the F1P group, suggesting a canalization effect (Wells, 2014 ). A recent meta‐analysis of rodent studies discussed a similar pattern, suggesting a ceiling effect, whereby levels are at their physiological capacity, effectively reducing the amount of variation (Anwer, Morris, et al, 2022 ). Intriguingly, these two groups F1T and F1P were less repeatable in the anxiety assay, indicating some relationship between glucose levels and anxiety‐related behavior.…”

The impact of excessive maternal weight on the risk of neuropsychiatric disorders in offspring—a narrative review of clinical studies

“…The number of papers investigating the issue of inadequate maternal BMI and its consequences in children clearly indicates that this topic has gained interest. The issue of parental obesity may be of even greater public health concern as there are animal studies [ 12 , 60 ] and epidemiological studies [ 61 ] reporting multi-generational adverse effects of excess body weight. Most of the data confirms significant adverse neurodevelopmental outcomes in children caused by MOv/MOb and/or excessive GWG.…”

Realism and robustness require increased sample size when studying both sexes

“…Therefore, even if there are no sex differences in mean, we should expect heteroscedasticity between the 2 sexes. The offspring adiposity data is taken from a meta-analysis of 12 studies on the transgenerational effects of obesogenic diets in mice and rats [5]. Data for female and male offspring is plotted separately, correlations are calculated for both sexes, point size represents sample sizes.…”

“…The law was first used to describe organismal aggregation patterns, but this mean–variance relationship seems to be ubiquitous [ 4 ]. Often correlations are over 0.9 between mean and variance (standard deviation) on the logarithm scale, as shown in an example data from a meta-analysis on rodent diet manipulations [ 5 ] ( Fig 1A–1C ). Taylor’s law means that when there are sex differences in mean, there are also unavoidable differences in variances (i.e., heteroscedasticity).…”