Mothers could improve the health of their unborn babies by eating eggs
during pregnancy, according to new scientific research.
A research team in the United States has concluded that consuming greater amounts of choline – a nutrient found in eggs
– during pregnancy may lower an infant’s vulnerability to stress-related illnesses, such as mental health disturbances, and chronic conditions, like hypertension, later in life.
The scientists are now recommending that pregnant women should follow a diet that includes choline rich foods, As well as eggs, they include lean meat, beans and cruciferous vegetables like broccoli.
“The study is important because it shows that a relatively simple nutrient can have significant effects in prenatal life, and that these effects likely continue to have a long-lasting influence on adult life,” said Professor Eva K. Pressman, author of the study and director of the high-risk pregnancy program at the University of Rochester Medical Center in the United States. “While our results won’t change practice at this point, the idea that maternal choline intake could essentially change foetal genetic expression into adulthood is quite novel,” she said.
Choline is a relatively new nutrient. It was established as an essential nutrient as recently as 1998, but since then its importance to human health has been established in a series of studies. Scientists believe it is needed for optimal foetal brain development, that it reduces neural tube risk and lowers inflammation markers.
It can reduce the risk of heart disease and it can reduce both incidence of breast cancer and mortality rates.
One study has shown that the risk of breast cancer can be reduced by 40 per cent as a result of an adequate intake of choline. It has also been shown to help in slowing down the progression of alzheimer’s disease.
In the latest piece of research, Professor Pressman's team studied changes in epigenetic markers in a group of pregnant women. Epigenetic markers are chemicals which attach to our DNA and influence how our genes work.
The team, made up of nutrition scientists and obstetricians at Rochester and at Cornell University, found that higher than normal levels of choline in the diet during pregnancy changed these epigenetic markers.
"While epigenetic markers don’t change our genes, they make a permanent imprint by dictating their fate. If a gene is not expressed – turned on – it’s as if it didn’t exist," said the team in a report issued by Rochester Medical Center.
According to this report, the researchers were particularly excited to discover that the affected markers were those that regulated the hypothalamic-pituitary-adrenal or HPA axis, which controls virtually all hormone activity in the body, including the production of the hormone cortisol, which reflects our response to stress and regulates our metabolism.
More choline in the mother’s diet led to a more stable HPA axis and consequently less cortisol in the foetus. "Past research has shown that early exposure to high levels of cortisol, often a result of a mother’s anxiety or depression, can increase a baby’s lifelong risk of stress-related and metabolic disorders," said the report.
Professor Pressman, who advises pregnant women every day, said that choline was not something that people thought a great deal about because it was already present in many things we ate and there was usually no concern of choline deficiency.
However, a few very compelling studies sparked her interest, including animal studies on the role of choline in mitigating foetal alcohol syndrome and changing outcomes in Down's syndrome.
Together with researchers led by Professor Marie Caudill in the Division of Nutritional Sciences at Cornell University, Professor Pressman studied 26 pregnant women.
Some of the women took 480 mg of choline per day - an amount slightly above the standard recommendation of 450 mg per day. Others took double that amount, 930 mg per day. Their choline came from both diet and from supplements and was consumed up until delivery.
The team found that higher maternal choline intake led to a greater amount of DNA methylation - a process in which methyl groups are added to DNA. The addition of a single methyl group is all it takes to change an individual’s epigenome.
Measurements of cord blood and samples from the placenta showed that increased choline, through the addition of methyl groups, altered epigenetic markers that govern cortisol-regulating genes. The result was 33 per cent lower cortisol in the blood of babies whose mothers consumed 930 mg per day.
The researchers say the findings raise the possibility that choline may be used therapeutically in cases where excess maternal stress from anxiety, depression or other prenatal conditions may lead to the release of greater than expected amounts of cortisol.
Professor Caudill said that whilst more research was needed, her message to pregnant women would be to consume a diet that included choline rich foods such as eggs, lean meat, beans and cruciferous vegetables like broccoli.
For women who limited their consumption of animal products, which were richer sources of choline than plant foods, she said that supplemental choline may be warranted as choline was generally absent in prenatal vitamin supplements.
“One day we might prescribe choline in the same way we prescribe folate to all pregnant women,” said Professor Pressman. “It is cheap and has virtually no side effects at the doses provided in this study. In the future, we could use choline to do even more good than we are doing right now.”
In addition to Pressman and Caudill, several scientists and clinicians from the Division of Nutritional Science and the Statistical Consulting Unit at Cornell University and the Cayuga Medical Center in Ithaca participated in the research. The study was funded by the Egg Nutrition Center, the National Cattlemen’s Beef Association, the Nebraska Beef Council, the United States Department of Agriculture and the President’s Council of Cornell Women.