Diets of fathers can affect future health of offspring, study finds
Low-protein paternal diet may affect heart health of children, researchers say
Men are advised to live a healthy lifestyle in order to keep their sperm in the best condition. Photograph: iStock
A father’s diet can have a significant effect on the future health of his offspring, affecting everything from blood pressure to heart function and putting them at greater risk of cardiovascular disease, according to research.
The lead author of a British study says the findings show that men who want to start a family should have a healthy, balanced diet from at least three months before conception.
A study from researchers at the University of Nottingham published in the Journal of Physiology shows that poor paternal diet, specifically one that is low in protein, may impact the heart health of the offspring by changing sperm, and the seminal fluid, which bathes sperm.
“We have known for a very long time that what a mother eats during pregnancy can influence how her child develops, and whether or not it will develop obesity, type two diabetes and heart disease,” explains senior author of the study, and lead researcher, Prof Adam Watkins, assistant professor in reproductive biology at the university’s faculty of medicine and health sciences. “However, the importance of the father’s diet on the health of the offspring has been largely ignored or overlooked. We were interested in investigating whether a father’s poor-quality diet at the time of conception might affect the long-term health of its offspring.”
Researchers carried out their study on male mice on a poor, low-protein diet, monitoring the cardiovascular health of their offspring. “The way mice produce sperm, the way the embryo develops, the way the foetus develops and the way a mouse’s blood and heart function are all very similar to humans. This means we can use mice to identify important biological processes which we can then look at in human patients.”
What his research found, he reports, was both that the way the mice’s blood vessels worked, and the level of certain important factors in their blood, which regulate heart and blood vessel function, were significantly altered in response to the poor diet of the father: “The blood vessels in the offspring did not work as well as they should do. This can ultimately affect blood pressure.”
“The normal proteins in the blood which would regulate blood vessels and heart function were altered,” says Prof Watkins, adding that essentially what this meant was that the young mice were at increased risk of developing cardiovascular ill-health or heart disease.
“We know that a poor lifestyle in men does have negative influences on sperm quality and that being overweight or smoking, or consuming excessive alcohol is not good for reproductive health. What we don’t know yet is what the long-term implications of a father’s poor diet or lifestyle might be,” he says.
“We know that the sperm provides genetic information from a father to the egg it fertilises, and we know that poor diet in males can change that. We also know that the seminal fluid in which sperm is carried, interacts with the uterus and initiates a range of responses in the maternal immune system. These responses prime the uterus for the embryo.
“We know that the sperm provides genetic information and that the seminal fluid primes the uterus for the embryo, so here are two possible ways that a father’s diet could influence how the offspring might develop.”
Essentially, Prof Watkins explains, the Nottingham research shows that the health of mice offspring is influenced by sperm and fluid and that both of them have an equal influence on offspring health.
However, he says, while the research has to date only been carried out on mice, it has significant implications for human fertility – in fact the researchers hope to run clinical trials on humans within the next two or three years.
“We know that it can take about 75 days to make a sperm, and that seminal fluid is reproduced every 24-48 hours,” says Prof Watkins.
If a man goes on a crash diet a week before getting his partner pregnant, he explains, the sperm will continue to reflect the old, poor quality diet,while the seminal fluid will reflect the newer, better-quality diet.
“Therefore there may be a situation where the sperm and the fluid are not compatible to each other, so we are saying that if the sperm and the fluid are different, we see the biggest effect on offspring health.”
The potential message is this, he warns: “If men and women are thinking about changing their lifestyle and becoming parents, we would say that ideally they begin the changes three months before trying to start a family. That is an ideal time frame to change over from a poor diet and lifestyle to a healthier one in terms of its implications for the man’s reproductive health.”
The Nottingham research findings have interesting implications for what we know about the role of seminal fluid and sperm DNA fragmentation (a term used for the presence of abnormal genetic material within the sperm, which may lead to male subfertility, in-vitro fertilisation failure and miscarriage) believes Dr Bart Kuczera, consultant gynaecologist and fertility expert at Beacon Care Fertility:
“What we know is that men with a poor lifestyle in terms of diet, smoking and drinking can have a condition called sperm DNA fragmentation.
Men are advised to live a healthy lifestyle in order to keep their sperm in the best condition, because, he explains: “Sperm DNA fragmentation can be affected by poor diet, stress and overeating, for example. This study would make the case for a good diet and lifestyle for men; that is, a normal balanced protein diet.”
Sperm quality of men in the western world, he warned, has been shown to have deteriorated in the last 40 years: “We believe this is very linked to lifestyle and the environment, to the sedentary lifestyle and a poor diet which reaches the recommended carbohydrate level but would not include a diversity of food.
“In the greater picture you could potentially have a population of children who would be affected in terms of physical health problems and weight gain as a result of the paternal diet at conception. It is important to spread the responsibility between the man and the woman at the time of conception,” he says, adding that this study suggests that the father may have an equally significant impact on his offspring’s health problems.
This study has implications for our knowledge about diet and lifestyle in terms of fertility – and men should be made aware of it, believes Dr Hans Arce, fertility consultant and medical director of ReproMed, a leading Irish fertility and IVF clinic network. “The majority of our knowledge in relation to diet and lifestyle in terms of fertility comes because we studied women. Women were the ones who got pregnant and they were the focus. We saw, for example, that women with obesity had children with a higher risk of obesity and diabetes.
“However this study showed the offspring of male mice with poor diets ended up having the expression of inflammation, and more of a tendency to high blood pressure, for example.”
Men should be made aware of this. “It’s something the schools, the public health service and the GP should be telling men about – that our diets can affect their future children’s health. Studies like these have implication for human beings,” he says, adding that the results “point in the direction” of the fact that the health of a man may have implications for the health of his offspring.
What this study says, he observes, is that a man’s diet will not just affect his own health, but potentially has implications for the health of his offspring: “We don’t have proper human studies yet – this is mice – but it is pointing in that direction!”
Lifestyle factors and sperm DNA
Lifestyle is the single biggest issue when it comes to fertility, believes consultant nutritionist Gaye Godkin.
Godkin believes the University of Nottingham study is a further endorsement of what she says, is “the role of epigenetics in health outcomes from pre-conception health across the life course.”
“There is a growing body of evidence showing just how much the father’s diet impacts on the pre-conception phase, in terms of its impact on sperm and seminal fluid and from there on to the long-term health of his offspring.”
Epigenetics, she explains, is the environment in which the sperm lives prior to penetrating the egg. “Sperm is produced around every 75 days or so but new seminal fluid is produced every 24 to 48 hours.
“If the man has a long-term poor diet, it will affect his sperm,” she says, adding however, that a man can have healthy sperm, while at the same time his seminal fluid could be of much lower quality because of a poor diet just before conception.
“Normal sperm carries DNA. A poor diet has a negative effect on the DNA and the DNA enzymes which in turn are crucial to the formation of a healthy foetus.
“In fertility clinics, they measure the level of a condition called DNA fragmentation in the male sperm. This test shows the quality of the sperm. For years I have worked with men who have high levels of DNA fragmentation in their sperm. I believe that it is strongly linked to diet, as well as to lifestyle factors such as smoking, alcohol consumption, excess weight and the effect of pesticides.”
While the Nottingham study was based on a mouse model, she says, its findings were “moving in the right direction in terms of our understanding of the volatility of sperm quality and what affects it, as well as its relationship with the internal environment of the male body.”
While there is no medical treatment available for DNA fragmentation, says Godkin, she has found that 90 days on a good-quality diet which also features a reversal of poor lifestyle factors can lead to fragmentation levels being significantly reduced to the extent that a couple are in a position to use their own sperm to achieve conception.