Pregnant Woman's Eating Habits may Affect her Baby’s Health Even Gender
At each stage, we have a different profile of risk or benefit. At the beginning of the life span, when tissues in our bodies are being organized in utero and in the first months of life, there is good reason to believe -- based on animal studies and in some human observations -- that sex hormones are very important in getting things organized properly.
These hormones influence the way the brain is organized, the way the reproductive organs and cells develop, even the way immune function develops. Therefore, if mom is eating something or has in her body fat something that can act like sex hormones, it is logical to wonder if that could change the baby’s development. If there is an impact, is it positive, negative or irrelevant?
"Future mothers should be aware that pregnancy and lactation are not the time to over-indulge on fatty and sugary treats on the assumption that they are 'eating for two;" said Professor Neil Stickland; Royal Veterinary College. In a study he found mothers who eat junk food during pregnancy may be condemning their children to crave the same diet.
If you're pregnant, what you eat — or don't eat — may determine whether or not your baby faces a lifetime of obesity. In the study, Gluckman and his colleagues at Auckland University's Liggins Institute in New Zealand looked at two groups of female rats — one group whose mothers had been malnourished during pregnancy, and another whose mothers received normal nutrition.
Researchers said, is that if a mother has a poor diet during pregnancy, her offspring may have metabolisms preprogrammed to store and conserve fat — a potentially useful trait if you happen to be born into a life in which food is scarce.
AUSTRALIAN scientists have made the world-first discovery that a pregnant woman's diet determines whether her baby grows into a fat adult or a skinny one. The research suggests women who are overweight before they fall pregnant, and during it, may condemn their children to a life of overeating and obesity.
It reveals that a mother's diet during pregnancy affects the baby's brain circuits, determining appetite and energy expenditure in their offspring. "This suggests that mothers should think twice about overindulging, or using the excuse that they're eating for two during pregnancy," University of NSW professor Margaret Morris said.
A joint study conducted by Harvard School of Public Health, University of Athens,University of Massachusetts, Karolinska Institutet, Stockholm, SE-171 77, Sweden found same like; published in the BMJ and commented; "The birth weight of boys is about 100 g heavier than the birth weight of girls, and this seems to be consistent across populations. No study, has examined whether the difference is because the pregnant woman has a higher energy intake or more efficient energy utilization if she is carrying a male embryo than if she is carrying a female embryo. We report data to support the first hypothesis—that the pregnant woman carrying a boy has a higher energy intake.
But the researchers warn that putting on weight in an attempt to influence the sex of the baby is not a wise measure.
"Weight gain before pregnancy carries significant risks to the mother and the baby, and should not be practiced to influence the odds of having a boy. Other factors of which weight gain is only an indicator could be at play here." said Villamor.
Recent researches showed that higher weight in mothers during pregnancy exposes the child to a higher risk of obesity during the adult life.
The first evidence that women can influence the sex of their child by what they eat before they become pregnant is published recently. The study, which links higher energy intake around conception to the birth of sons, provides the first explanation of why the number of boy babies is in decline in the west, suggesting it is the result of women consuming low fat foods and skipping breakfast, among other things.
The research shows a higher calorie intake around the time of conception can shift the odds of having a son from ten to 11 boys in every 20 births. The effect was such that the more women ate, the more likely she was to have a boy.
As well as consuming more calories, women who had sons were more likely to have eaten a higher quantity and wider range of nutrients, including potassium, calcium and vitamins C, E and B12.
In other words, women who want a son should eat a generous bowl of cereal for breakfast, munch bananas, use more salt and boost their overall daily calories by 400 calories - the equivalent of a meal.
Although the DNA in sperm determines sex, it seems that in the never ending battle of the sexes mothers can favor the development of one sex of infant rather than another, a faculty that nature uses to fine tune the sex ratio in Stone Age days to suit times of feast and famine, says the team from the Universities of Exeter and Oxford.
To reveal how you are what your mother eats, the team focused on 721 first-time pregnant mothers in the UK, who did not know the sex of their unborn child and were asked to provide records of their eating habits before and during the early stages of pregnancy.
They completed detailed questionnaires which asked about their usual consumption of more than 150 common items, and recorded details on the types and quantities of breakfast cereals, margarines and milk they used. During pregnancy they also kept food diaries.
They were split into three groups according to the number of calories consumed per day around the time they conceived, revealing that 56 per cent of the women in the group with the highest energy intake at conception had sons, compared with 45 per cent in the lowest group.
"The effect was linear, that is the more women ate, the more likely she was to have a boy - so the effect might be even larger if women had particularly high intakes" says Dr Fiona Mathews of Exeter, lead author of the study in the journal Proceedings of the Royal Society B: Biological Sciences.
An additional son per 20 births was down to eating more than 2200 calories compared with fewer than 1850 calories of the low intake group and there was an average difference between the mothers of boys and girls of 130 calories per day.
Dr Mathews says this could explain why over the last 40 years there has been a small but consistent decline, of about one per 1000 births annually, in the proportion of boys being born in industrialized countries, including the UK, the US and Canada.
This decline mirrors the fall in average energy intake in the developed world (the obesity epidemic is driven by burning fewer calories in everyday life, due to less overall exercise, and eating high fat diets).
"This research may help to explain why in developed countries, where many young women choose to have low calorie diets, the proportion of boys born is falling," says Dr Mathews, adding that there is also a link between higher national incomes and fewer boys.
There is also evidence that skipping breakfast is now common in the developed world: in the USA, the proportion of adults eating breakfast fell from 86 per cent to 75 per cent between 1965 and 1991.
Eating salty food and bananas ("bananas for a boy") is linked with males, and lots of calcium and desserts should help to conceive a daughter, according to folk wisdom.
Dr Mathews says there is "tremendous interest" in the popular literature in the link between dietary mineral and gender and this did, at last, seem to have some support.
When it comes to salt, the study does provide some support ("bacon for boys", as some put it) and also for high potassium food, such as bananas.
"There was a highly significant link between potassium and the sex of the baby, with mothers of boys consuming an average of 300mg/day less - a small banana's worth."
However, there was no link between calcium, found in dairy products, and girls, as expressed by the claim "milk for girls".
"Boys breast feed for longer and for more," she says. "There is evidence from traditional societies that mothers invest more time in bringing up boys. And if a mother has plentiful resources then it can make sense to invest in producing a son because he is likely to produce more grandchildren than would a daughter. However, in leaner times having a daughter is a safer bet."
The phenomenon, where lean times are linked with daughters, have been most extensively studied in insects, but is also seen in horses, cows and some species of deer.
Females, on the other hand, reproduce more consistently. The mechanism is not yet understood in mammals, but it is known from IVF research that high glucose levels encourage the development of male embryos while inhibiting female embryos. In humans, skipping breakfast depresses glucose levels and so may be interpreted by the body as indicating poor environmental conditions and low food availability.
The findings showed no evidence of a link between the gender and a mother smoking and drinking caffeine prior to pregnancy. Nor was there a correlation between the body mass index (BMI) of a mother and the sex of her child.
Professor Stuart West, from the University of Edinburgh, comments: "This is an interesting result that is consistent with what appears to be going on some animals, such as red deer. However, I would be extremely cautious about using diet to try and influence offspring sex.
"First, the effect appears to be relatively small, with the sex ratio varying from only 45 per cent sons with low calorie diets, to 55 per cent sons with high quality diets.
"Second, similar data in animals such as non-human primates shows huge variation between studies, and so it would be key to determine the repeatability of these results. Third, diet will have other effects for both the parent and offspring."
Another study by the University of Rochester found men whose mothers ate a lot of beef during pregnancy had lower sperm counts. The Human Reproduction study found they were three times more likely to have a sperm count so low they could be classified as sub-fertile.
The Rochester team examined sperm counts among US men born between 1949 and 1983. They found those whose mothers ate more than seven beef meals a week had an average sperm concentration of 43.1 million sperm per milliliter of seminal fluid. In contrast, the sons of mothers who ate less beef had an average of 56.9 million sperm.
Among sons of mothers who ate a lot of beef, 17.7% had a sperm concentration below the World Health Organization sub-fertility threshold of 20 million sperm per milliliter of seminal fluid. The figure for the sons of lower beef consumers was 5.7%.
Lead researcher Professor Shanna Swan said the findings suggested that exposure to growth promoters contained in the beef eaten by the boys' mothers was to blame.