June 28, 2004
A moderately high protein diet could reduce a woman’s chances of becoming pregnant, according to new research carried out in mice.
Researchers from the US have found that a diet containing 25 percent protein disrupted the normal genetic imprinting pattern in mice embryos at a very early stage in their development. The diet also adversely affected subsequent embryo implantation in the womb, as well as fetal development itself.
The research findings were presented at the 20th annual conference of the European Society of Human Reproduction and Embryology on June 28, 2004.
‘Although our investigations were conducted in mice, our data may have implications for diet and reproduction in humans,’ said Dr. David Gardner, scientific director of the Colorado Center for Reproductive Medicine and lead researcher in the study.
Previous research has shown that the amount of protein in the diet affects the levels of ammonium within the female reproductive tract in cows and mice. Ammonium is a naturally occurring substance that has been found to have a negative effect on embryos. It does this by altering genetic information and by holding back fetal development. The gene that is altered — the H19 gene — is a very important factor in normal growth.
Gardner fed mice a diet containing either 25 percent protein (moderately high) or 14 percent protein (an amount considered average for the North American diet) for four weeks. The mice were mated and 42 of the resulting embryos were examined to discover the imprinting status of the H19 gene.
‘We found that only 36 percent of embryos developed in mothers on the 25 percent protein diet showed a normal imprinting pattern, compared to 70 percent in the control group (those that were fed only 14 percent protein),’ said Gardner.
‘Furthermore, only 65 percent of the embryos in the high protein group developed into fetuses once they had been transferred, compared to 81 percent in the control group,’ Gardner said, adding that only 84 percent of the embryos from the high protein group developed further, whereas in the control group 99 percent of the embryos that were implanted continued to develop normally.
‘Analysis of fetal development on the fifteenth day of gestation showed that fetuses from the high protein group were a third of a day behind the control group in their development, and one fetus had a neural tube defect (a birth defect occurring in the brain or spinal cord which can cause spina bifida).
Gardener concluded that eating a moderately high protein diet can adversely affect the chances of an embryo being successfully implanted in the uterus, as well as the normal development of that embryo.
‘These findings, together with similar work carried out in cows, mean that it would be prudent to advise couples who are trying to conceive to ensure that the woman’s protein intake is less than 20 percent of their total energy consumption,’ he said.
‘The available data certainly indicate that a high protein diet is not advisable while trying to conceive.’
Source: European Society of Human Reproduction and Embryology