It’s the time of the year when men’s thoughts turn, if only fleetingly, to fitness. You might also have been prompted recently to consider your prowess in quite a different sporting arena — just how fit are your sperm?
Last year experts warned us that we were facing a “fertility time-bomb” because fertility clinics’ records reveal that not only are men producing fewer sperm but that the ones we do release are more bent and deformed and swim less vigorously. In fact males are now, for the first time, more likely to be the infertile half of couples attending fertility clinics, according to a recent report from the European Society for Human Reproduction and Embryology.
Then this month came the launch of a kit that allows you to check the fitness of your sperm in your home. The Fertell test (available from chemists at £79.99), works by forcing the sperm to swim through mucus which mimics that found in the cervix; if ten million per millilitre get through you are normal, according to the World Health Organisation guidelines.
If you can’t manage the numbers, the ultimate fix is a technique known as ICSI (intracytoplasmic sperm injection), which can freight a single sperm, however much of a couch potato, directly into an egg. In fact modern reproductive technology appears to be rendering men’s role increasingly peripheral. All ICSI is interested in is the DNA compacted into the sperm’s head, while researchers are now working on making sperm totally redundant by generating them from embryonic stem cells in the lab.
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But by narrowly focusing on the athletic potential of individual sperm and their genetic load we could be ignoring other causes of infertility.
Obviously numbers and performance are vital but more than 30 per cent of men having trouble conceiving have perfectly adequate sperm; something else is going on.
What the current sperm fitness obsession misses is the other 99 per cent of an ejaculation. This is seminal fluid, a rich mix of chemicals that includes proteins, minerals and vitamins. It is discarded by the fertility clinics as being largely the sperm’s energy pack; some researchers believe, however, that it is a key player in normal fertilisation.
“We have become very sophisticated about the mechanics of artificially fertilising an egg,” says Dr Stewart Irvine, consultant gynaecologist at the Royal Infirmary Edinburgh, “but we still know very little about the far more complicated dance that has to be done right if couples are going to conceive naturally.”
If we knew more about how that works, he says, a significant proportion of those who have to endure the gruelling process of IVF might be able to get pregnant far more enjoyably.
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Recently there have been some intriguing glimpses of the kind of things to which Dr Irvine is referring. For starters, sperm would normally be regarded by the woman’s immune system as invading alien protein, and so would be rapidly destroyed. How do sperm get a safe-conduct pass?
Research by Sarah Robertson, a reproductive biologist at the University of Adelaide, has shown how one of the many peptides in semen called TGF-beta is vital for ensuring that perm doesn’t get tagged for destruction by the woman’s killer cells. In a paper last year in Cell and Tissue Research she suggested that some cases of male infertility could be the result of faulty interactions between the woman’s body and TGF-beta and related peptides. “There is growing evidence for what’s been called ‘male priming’,” she says. “Being exposed to sperm seems to make conception more likely and increase the chance of a successful pregnancy.”
Another of these proteins found in semen is known as PLCzeta and it has an equally vital function. At the end of the journey, once the sperm has penetrated the egg, it triggers a calcium cascade that allows the egg to start growing. “Faulty functioning of PLCzeta could be a root cause of male infertility,” suggests Professor Tony Lai, a cardiologist at Cardiff University who discovered calcium signalling.
But these are just two of 83 proteins from the semen cocktail that have been found to play a crucial role in conception. Some are needed to follow the chemical trail that leads to the ovum while others help to fight bacteria. But there is something else remarkable about these proteins; the genes controlling them are mutating faster than any others in the body, except for the corresponding ones in females. It’s this discovery that could lead to a much broader understanding of male fertility.
“These reproductive proteins seem to be involved in an arms race,” says Willie Swanson, geneticist and professor of Genome Sciences at the University of Washington, whose major review of this new field has been published this month in the journal Reproduction.
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“When it comes to fertilisation, the interests of the male and female genes are not at all the same,” she says. While the sperm’s genes are all focused on fertilisation, the female’s, with only a limited number of conceptions possible, have developed to be more cautious and have developed ways of delaying fertilisation.
“Many fertility problems could be about a mismatch between sperm-egg recognition molecules,” Professor Swanson says. “As in transplants, or skin grafts, some people’s immune systems tolerate each other more easily; I suspect something similar is going on with the reproductive proteins in couples with fertility problems.”
The success of IVF means that funding for research into the complexities of the natural version is hard to come by. But the long-term health of IVF babies is still unclear and all infertile couples would undoubtedly welcome a less drastic and gruelling solution.
Where you live and what you eat can affect sperm health
Testicles are a 24/7 production line, churning out 1,000 sperm from each testicle each second — 200 million a day. Each sperm takes 72 days to move through the coiled “seminiferous tubules”, which if ironed out would stretch for 360m (1,181ft). If a sperm is not ejaculated within ten days of completion it’s reabsorbed.
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This constant production is a reason why sperm is so vulnerable to the man’s lifestyle and to toxins in the environment. Indeed, sperm might be seen as a marker for good health — factors that have recently been implicated in reducing its fitness include: being overweight, smoking, excessive amounts of alcohol, coffee, pesticides, too much soy, traffic pollution and cannabis.
What this means is that changes in what you eat and where you live can directly affect sperm fitness. “It can vary by 200 per cent over a couple of months,” says Dr Stewart Irvine. “That can be the difference between being infertile or potent.”
Compared with the high-tech of IVF, official advice on boosting sperm fitness is pretty basic: a healthy lifestyle and loose underpants to keep testicles cool. There’s evidence that taking some herbs work, although some studies have failed to support this folk wisdom.
However, a recent double-blind study indicates that a mix of ten Indian herbs taken for three months by 50 infertile men was far more effective than drugs in increasing sperm numbers and their activity levels. A study last year found that a vitamin C supplement caused a rise in sperm numbers while vitamin E raised the activity level.
But you can’t fight the effects of ageing: once over 35, production starts to flag, while the number of abnormal sperm has been estimated to rise by 17 per cent for every ten years over the age of 24.