Why are sperm counts plunging in the developed world?

The UK's fertility could be under threat as sperm rates continue to plunge in a “shocking” downward spiral, a study has warned. Scientists recorded the concentration of sperm in the ejaculate of men in western countries has fallen by an average of 1.4% a year, leading to an overall drop of just over 52% between 1973 and 2011 and they are still falling at a rate of two per cent every year.

Trend seems to be specific to western countries

The same trend was not seen in other parts of the world such as South America, Africa and Asia, although the scientists said fewer studies had been carried out there.

"This study is an urgent wake-up call for researchers and health authorities around the world to investigate the causes of the sharp ongoing drop in sperm count," said Hagai Levine, who co-led the work at the Hebrew University-Hadassah Braun School of Public Health and Community Medicine in Jerusalem.

Causes remain unclear

Pesticides, hormone-disrupting chemicals, diet, stress, smoking and obesity have all been suggested as possible reasons behind the dramatic decline.

"Decreasing sperm count has been of great concern since it was first reported twenty-five years ago. This definitive study shows, for the first time, that this decline is strong and continuing," explained Dr Shanna H Swan from Mount Sinai Hospital in New York. "The fact that the decline is seen in Western countries strongly suggests that chemicals in commerce are playing a causal role in this trend."

Professor Richard Sharpe at Edinburgh University comments:

“The end of humanity is not approaching, but at the individual level, for affected people, this trend could be tragic. We have no treatments for improving sperm production in infertile men, and we have no idea about what is the cause of the condition. We cannot remedy it. So we are completely hamstrung.”

"The problem is particularly urgent in the west, where couples are having families much later in life. In 2014, 52% of all live births in the UK were to mothers aged 30 and over (67% of fathers fell into this age group). However, when a woman reaches the age of 32 her chances of conceiving start to decrease gradually but significantly until, by 40, they have fallen by half. At the same time, more and more men now have sperm counts low enough to impair their fertility.

“This creates a double whammy for fertility in modern western societies. Couples wait until they are over 30 and then find that one or both have reproduction problems. In some cases, they may not discover these problems until they are in their late 30s – by which time they have little time left to take advantage of assisted reproductive techniques such as IVF."

The issue is further complicated because the underlying cause of these declining sperm counts remains a mystery.  Professor Allan Pacey of Sheffield University says:

“Almost every aspect of modern life – from mobile phones to smoking and oral contraceptives [contaminating drinking water] – has been blamed for declining sperm counts, but no convincing evidence has emerged to link any of them to the problem.”

Sharpe, warns that the field is still bedevilled by a lack of research investment.

“We need a critical mass of scientists trying to find out what is happening and why it is happening. Unfortunately, we still do not have that. Not enough research is being done. Yet I believe the problem is getting worse.”

Who is at risk?

Scientists warn that painters, decorators, printers, welders, builders, taxi drivers and office workers could also be at risk from male infertility.

A study published in September 2001 by Canadian researchers found that men who were regularly exposed to organic solvents, found in paints, printing inks and thinners, were more than twice as likely to have low sperm counts. The solvents contain glycol ethers, which researches have found affect the reproductive systems of animals. In fact, the risk of infertility associated with these solvents is so great, that experts are advising men who work with them and are trying for a baby to make an appointment with their GP as soon as possible.

Welders may be risking infertility because of the high temperatures associated with their work as well as the risk of exposure to toxic metals such as lead. Heat causes the temperature of the testicles to rise which in turn can cause a decline in sperm levels - scientists have also recently discovered a link between high lead levels in semen and low fertility levels.

Taxi drivers and long-haul lorry drivers are thought to be at risk from sitting in the same position for long periods of time. This can raise the temperature of the testicles, causing sperm levels to drop. A study conducted in 2001 comprising of 200 Italian taxi drivers found they had much lower sperm counts than normal levels. The drivers were also at risk from inhaling lead and toxic exhaust fumes which can also have an effect on male fertility levels.

Those who work in an office and therefore spend hours sitting in front of a computer are also at risk from an increase in testicular temperature. Scientists say you should take a break every 20 to 30 minutes to get away from your desk and help regulate the temperature of the testicles.

High stress levels could also be a factor - a study presented at the British Psychological Society conference in 1999 revealed that men who 'bottle up' their feelings could be at risk of lower fertility levels. High stress levels can cause the body to release the hormone cortisol which is thought to interfere with sperm production. More research into the effects of stress on fertility is needed however.

Ways to boost male fertility

Researchers found that men who took antioxidants in supplement form had less DNA damaged sperm than men who did not take antioxidants. You can try to add more of the following foods into your diet or consider taking a supplement.

• Zinc - food sources include found in oysters, crab, red meat, poultry, and beans or take a supplement.
• Vitamin C - this is found in many fruits and vegetables, with the highest levels found in red peppers, kiwi, oranges, and grapefruit. Or opt for a supplement.
• Selenium - this is found in high amounts in Brazil nuts (1 oz provides 780% of your daily recommended value so be careful not to overdo it). It is also found in tuna, cod, beef, turkey, and chicken. Or opt for a supplement.
• Vitamin E - food sources include nuts, seeds, oils, and leafy greens. Or you can opt for a supplement.
• Folic Acid - food sources include beef liver, leafy green vegetables, fruits, beans, and peas, and often in fortified grains. Or opt for a supplement.
• Lycopene - this is found in tomatoes (cooked), apricots, pink grapefruit, and watermelon. Or opt for a supplement.

Too much soy may impact your sperm counts, according to a research study that looked at eating habits. The study found men who ate high amounts of soy had lower sperm counts than men who did not.

Studies on smoking and semen quality found that smoking affects many aspects of sperm health, including decreased sperm counts, decreased sperm motility (the swimming ability of the sperm), and sperm shape.

• Avoid hot tubs or taking long hot baths.
• Sitting for long periods of time results in increased scrotal temperatures, according to research. If you have a desk job, or have to commute a long distance to work, make sure you get up and walk around regularly.
• don't turn on your seat heater in the winter during long commutes.
• don't sit with your laptop in your lap.