Poor diet during pregnancy may result in having children who are more prone to age-related diseases than expectant mothers who follow a healthy diet, according to scientists.
The warning follows recent research that found that rats with poor nutrition during pregnancy gave birth to young with a higher risk of type 2 diabetes, a disease that typically strikes in middle age.
Research by scientists at University of Cambridge provides significant insight into why children born to mothers with unhealthy diets during pregnancy have an increased risk of type 2 diabetes.
“What is most exciting about these findings is that we are now starting to really understand how nutrition during the first nine months of life spent in the womb shape our long term health by influencing how the cells in our body age,” said Dr Susan Ozanne, the senior author of the research and British Heart Foundation Senior Fellow from the Institute of Metabolic Science at the University of Cambridge.
The researchers traced back the effect to subtle genetic changes that normally accrue with age. They said similar changes are likely to occur in humans.
The work is believed to be the first evidence that poor diet during pregnancy can make people more vulnerable to the effects of aging.
The team found that a poor maternal diet led to so-called epigenetic changes that reduced the activity of a gene called Hnf4a in a mother’s offspring. The gene governs how many insulin-producing cells grow in the pancreas and the organ’s ability to respond to high levels of glucose in the blood.
“It’s well known that maternal diet and growth of the fetus in the womb impact on the risk of developing type 2 diabetes and cardiovascular disease in later life, but we haven’t known the mechanism before,” Ozanne told The Guardian.
Previous studies have shown that Hnf4a plays an important role both during development of the pancreas and later in the production of insulin. The researchers theorized that diet during pregnancy influences the expression of this gene later in life, thereby influencing the risk of diabetes.
To test the theory, the team used a well-established rat model. By altering the protein content of the mother’s diet during pregnancy, the offspring developed type 2 diabetes as they got old.
The researchers first studied the RNA from insulin secreting cells in the pancreas from offspring of normally fed as well as malnourished mothers in young adult life and in old age. When they compared the two, they discovered that there was a huge decrease in the expression of the Hnf4a gene in the offspring prone to type 2 diabetes. The expression of Hnf4a also decreased with age in both groups.
They then studied the DNA and found that the decrease of Hnf4a was caused by epigenetic changes. The age associated epigenetic silencing was more pronounced in rats exposed to poor maternal diet. They concluded that the epigenetic changes resulting from maternal diet and aging lead to the reduced expression of the Hnf4a gene, decreasing the function of the pancreas and therefore its ability to make insulin (and thereby increasing the risk of diabetes).
The scientists then studied the DNA from insulin secreting cells from human pancreases to show that expression of this important gene was controlled in the same way in humans.
“It is remarkable that maternal diet can mark our genes so they remember events in very early life,” said Dr Miguel Constancia, the senior co-author on the paper from the Department of Obstetrics and Gynecology and Metabolic Research Laboratories at the University of Cambridge.
“Our findings reveal a novel mechanism by which maternal diet and aging interact through epigenetic processes to determine our risk of age-associated diseases,” he said in a statement.
Ozanne said that people born to mothers who had unhealthy diets during pregnancy are not destined to develop diabetes. “Diabetes is a very multifactorial disease and poor nutrition and growth in early life is just one risk factor,” she noted.
“It doesn’t mean you will definitely get type 2 diabetes, it just increases your risk. If you have that risk, it is probably a good idea to ensure your adult lifestyle is going to reduce other risks, for example by having a very active life, eating a good diet and not smoking,” she said.
“We already know that a healthy pregnancy is important in shaping a child’s health, and their risk of heart disease as they grow up,” said Professor Jeremy Pearson, Associate Medical Director at the British Heart Foundation.
“The reasons why are not well understood, but this study in rats adds to the evidence that a mother’s diet may sometimes alter the control of certain genes in her unborn child. It’s no reason for expectant mothers to be unduly worried. This research doesn’t change our advice that pregnant women should try to eat a healthy, balanced diet,” said Pearson.
Professor Douglas Kell, Chief Executive, BBSRC said: “Epigenetics is a relatively young field of research with tremendous potential to underpin our understanding of many biological processes in all organisms. The fact that there is a relationship between the biology of a pregnant mother and the long term health of her child has been known for some time but our understanding of the biological processes behind some of the more subtle effects is still at a nascent stage.”
“This study uncovers ““ through epigenetics and molecular biology research ““ an important piece of this puzzle and shows us how apparently minor changes within cells at the very earliest stages of development can have a major influence on our health into old age,” Kell added.
The University of Cambridge research is published in the journal Proceedings of the National Academy of Sciences.
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