Too many and too little micronutrients during pregnancy may lead to health risks in the next generation, according to a nutrition study led by researchers at the University of Guelph.
As the study was conducted on rats, a model for human obesity, Dr. Clara Cho, a nutritional science professor in the College of Biological Science, says her team's findings have broader implications for human health. They raise concerns for long-lasting impacts that can be programmed by the diet consumed during pregnancy.
"We have previously found that overconsumption of a complete mix of multivitamins during pregnancy can lead to excessive food intake in the offspring," says Cho, who is part of the Department of Human Health and Nutritional Sciences and holds the Tier II Canada Research Chair in Precision Nutrition. "This increases the likelihood that offspring develop obesity, high blood pressure and high blood sugar."
From this initial observation, the Cho lab sought to investigate specific factors in the maternal diet that were responsible for these health consequences.
Study in rats links folic acid, choline imbalance to health risks
In the study, published in The FASEB Journal, Cho and PhD candidate Gia Shelp examined pregnant rats over 12 weeks given differing concentrations of folic acid (vitamin B9) and choline, an essential nutrient. These micronutrients play key roles in fat metabolism, organ functioning and gene regulation and synthesis.
Cho and Shelp then assessed body weight gain, metabolism and the degree of gene regulation in the different offspring.
They found the following:
- Males whose mothers were fed excessive folic acid were heavier in weight whether choline was present or not.
- Female offspring only gained weight if choline was lacking alongside folic acid.
- Both male and female offspring had a higher body weight when their mothers' diets were high in folic acid but lacking in choline.
In short, too much folic acid and not enough choline - an imbalance of micronutrients - may be linked to obesity in offspring in the rat model studied, with further studies needed to confirm this trend in humans.
Cho says this may occur due to disruptions in gut bacteria as well as genetic pathways activated towards disordered eating in the hypothalamus, the part of the brain responsible for appetite. Her team's emerging data also indicate that parts of the nervous system are remodelled due to an imbalanced supply of micronutrients.
"Our next goal is to connect the communication between these two systems: the gut and the brain," she says.
Dr. Clara Cho (left) and PhD candidate Gia Shelp investigating micronutrients for disease prevention and treatment
Recommended levels of micronutrients crucial for pregnancy
"Based on our results, we would recommend pregnant people to follow the recommended intake levels for folic acid and adequate intake levels for choline," says Cho.
Though the researchers' rodent model is limited, these conditions mirror people's intake of multivitamins in a wider context. Those considering pregnancy are often advised to take folic acid daily to prevent birth defects.
"Given that our population often over-consumes folic acid but under-consumes choline, potential long-term consequences of this imbalance should be given a priority," she says.
It also suggests that imbalanced micronutrients in the womb can alter offspring's metabolism - though not necessarily in the same way for all offspring. Weight gain in males and females was associated with a decrease in gene regulation. Cho says gene regulation may be one way to account for the differing individual responses to the same diet.
Researchers to investigate micronutrients for personalized disease treatments
Ongoing diet-based research is important for developing targeted health care strategies, Cho says, which may need to start well before a child is born.
"We may be able to use micronutrients as personalized and targeted methods of disease treatment and prevention," says Cho.
Previous research in Cho's lab found similar results. Male rats were at greater risk of being overweight than female rats when maternal diets contained too much folic acid. As females have lower dietary requirements for choline, these contrasting responses motivated the current investigation into choline.
"I think that this will play a significant role in our ongoing medical research," Cho says. "We want to know how we can optimize this."
The study was supported by the Natural Sciences and Engineering Research Council of Canada-Discovery Grant, the U of G Team Building Grant and Utah Agricultural Experiment Station.
Shelp was supported by a Canadian Institutes of Health Research (CIHR) Canada Graduate Scholarship-Master.
