Both food restriction and high-fat diet during gestation induce low birth weight and altered physical activity in adult rat offspring: the "Similarities in the Inequalities" model.
In plain language
Different prenatal diets can lead to similar changes in adult activity
Undernutrition and a high-fat diet appear to be opposite nutritional conditions. This study asked whether they can nevertheless produce some similar developmental outcomes, an experimental version of the “similarities in the inequalities” idea.
Separating prenatal exposure from later feeding. Pregnant rats received standard food freely, half the usual amount of food, or a high-fat diet. Within a day of birth, offspring from the different prenatal groups were placed with mothers receiving standard food. This cross-fostering step helped distinguish effects associated with the prenatal diet from continued exposure to that diet through the nursing mother.
When the offspring were adults, researchers gave them access to running wheels for a week and measured voluntary activity. They also examined growth, abdominal fat and metabolic measures, as well as dopamine D2 receptors in the dorsal striatum, a region involved in movement and behavior.
Both nutritional extremes were associated with smaller size at birth. Offspring exposed prenatally to food restriction and those exposed to the high-fat diet were smaller than controls. The two groups also showed a similar direction of change in voluntary activity within each sex: males were less active than control males, whereas females were more active than control females.
This result is more specific than saying that adverse prenatal nutrition reduces exercise. The direction depended on sex, and different prenatal diets could converge on a similar behavioral outcome while acting through different biological processes.
The experiment supports studying early development as one influence on later willingness to be active. It also gives the “similarities in the inequalities” model a testable form: distinct starting conditions can produce overlapping outcomes. Running-wheel behavior in rats cannot capture all the social and practical influences on human physical activity, but it allows prenatal conditions and later opportunities for activity to be studied under controlled circumstances.
Original abstract
We have previously described a theoretical model in humans, called "Similarities in the Inequalities", in which extremely unequal social backgrounds coexist in a complex scenario promoting similar health outcomes in adulthood. Based on the potential applicability of and to further explore the "similarities in the inequalities" phenomenon, this study used a rat model to investigate the effect of different nutritional backgrounds during gestation on the willingness of offspring to engage in physical activity in adulthood. Sprague-Dawley rats were time mated and randomly allocated to one of three dietary groups: Control (Adlib), receiving standard laboratory chow ad libitum; 50% food restricted (FR), receiving 50% of the ad libitum-fed dam's habitual intake; or high-fat diet (HF), receiving a diet containing 23% fat. The diets were provided from day 10 of pregnancy until weaning. Within 24 hours of birth, pups were cross-fostered to other dams, forming the following groups: Adlib_Adlib, FR_Adlib, and HF_Adlib. Maternal chow consumption and weight gain, and offspring birth weight, growth, physical activity (one week of free exercise in running wheels), abdominal adiposity and biochemical data were evaluated. Western blot was performed to assess D2 receptors in the dorsal striatum. The "similarities in the inequalities" effect was observed on birth weight (both FR and HF groups were smaller than the Adlib group at birth) and physical activity (both FR_Adlib and HF_Adlib groups were different from the Adlib_Adlib group, with less active males and more active females). Our findings contribute to the view that health inequalities in fetal life may program the health outcomes manifested in offspring adult life (such as altered physical activity and metabolic parameters), probably through different biological mechanisms.
Reproduced from the original publication under CC BY (version unspecified). Wording unchanged; layout and typography normalized.
Cunha Fda S, Dalle Molle R, Portella AK, Benetti Cda S, Noschang C, Goldani MZ, Silveira PP. Both food restriction and high-fat diet during gestation induce low birth weight and altered physical activity in adult rat offspring: the "Similarities in the Inequalities" model. PloS one. 2015;10(3):e0118586.
Read the original publication and abstract