Wednesday January 6 2010
While bacon and eggs contain choline, so do many other foods
Bacon and eggs could help pregnant women boost the intelligence of their unborn child, according to The Daily Telegraph. Several other papers have also made the link between the results of complex animal research and the supposed benefits of a fry-up.
This research looked at the biological role of choline, a nutrient that is found in various foods including eggs, bacon and liver. It found that feeding pregnant mice a diet without choline affected the nerve cells in their offspring’s brains. Although this gives us greater insight into the effects of choline deficiency on foetal brain development in mice, the effects may be different in humans. In addition, the research did not test the offspring's intelligence.
These findings do not mean that pregnant women who eat foods high in choline can increase the intelligence of their baby. People who eat a healthy balanced diet are likely to be getting enough choline. Pregnant women should not rush out to have a fry-up on the basis of this research.
Where did the story come from?
Dr Mihai G Mehedint and colleagues from the University of North Carolina carried out this research. The study was funded by the National Institutes of Health in the US, and was published in the peer-reviewed journal of the Federation of American Societies for Experimental Biology (FASEB).
The Daily Telegraph, Daily Mirror, Daily Express and Daily Mail have reported on this research. They all feature claims that bacon and eggs or a fry-up may be good for expectant mothers, and some suggest they could boost child intelligence. However, it is tenuous to use the results of this complex laboratory study in mice to claim that these foods boost intelligence in human offspring. While the newspapers have mentioned that this study was in mice, none of them mentions the fact that this research did not feature any form of intelligence or memory test on the mice.
What kind of research was this?
This was an animal study looking at how the brains of mouse foetuses were affected by the level of choline in their mothers’ diets. Choline is a nutrient found in a variety of foods, with high levels found in eggs, wheatgerm, bacon and liver.
Choline is required for various functions in the body, including transferring signals between nerve cells. The researchers report that if pregnant mice consume a diet deficient in choline it can increase the risk of neural tube birth defects in their offspring and can affect the development of the cells in certain areas of the brain. Some studies suggest that this may also be the case in pregnant women. In this study, the researchers wanted to look at exactly how choline deficiency has these effects, concentrating on its actions on the genes and cells in the brain.
This research aimed to look at the complex ways in which a lack of choline in pregnant mice has an effect on the developing brains of their offspring. Animal research plays an important role in establishing exactly how biological systems work and how different conditions affect these systems. However, while these studies give a basic idea of how these systems may work in humans, there may also be differences between the species.
What did the research involve?
The researchers took pregnant mice and randomly assigned them into two groups. After day 11 of their pregnancies one group was given a normal diet and the other a diet with no choline in it. Randomly assigning the animals into either group means that the groups should be balanced for factors that might affect the results of the experiment. The researchers then looked at the brains of the foetuses on day 17 of the pregnancy. In particular they looked at the hippocampus, a region of the brain involved in memory.
One area the researchers concentrated on was specific chemical changes in proteins called histones, which interact with the DNA in the cell. The cell’s DNA is wound around histones and changes in histones can affect which genes in the DNA are switched on and off, which could in turn affect how cells and tissues develop. They also looked at whether a mother’s diet could affect how the developing hippocampus brain cells of the foetus behaved when they were extracted and grown in the lab.
What were the basic results?
The researchers found that the foetuses of mothers fed no choline had changes to the histone proteins in their brains that were not seen in the foetuses of mothers fed a normal diet. Foetal hippocampus brain cells from mothers fed no choline divided less when grown in the lab, and more of these cells died.
How did the researchers interpret the results?
The researchers concluded that choline deficiency affects the chemical make-up of histone proteins in the developing nerve cells of the brain. They say this could explain how choline deficiency has an effect on the developing brain.
This research looked at how choline deficiency in the diet of pregnant mice affects the developing nerve cells in their foetuses’ brains. Although this research may give the scientific community greater insight into the effects choline has on foetal brain cells in mice, these results may not be representative of what happens in humans.
Choline is thought to be an essential nutrient in our diets and it is unsurprising that a diet with no choline in it has adverse effects. However, people who eat a healthy balanced diet are likely to be getting enough choline. Equally, the mice were not subjected to intelligence tests in this study, so the results cannot be taken to mean that consuming foods high in choline in pregnancy will increase the intelligence of a baby. Pregnant women, and indeed pregnant mice, do not need to rush out to have a fry-up on the basis of this research.