In 2017, Israeli researchers published a large and alarming study that found sperm counts in men in Western countries had dropped by more than 50 per cent since 1973.
The researchers, from the Hebrew University of Jerusalem, said the drop in sperm counts showed no sign of slowing down and issued a warning:
“These findings strongly suggest a significant decline in male reproductive health that has serious implications beyond fertility and reproduction, given recent evidence linking poor semen quality with higher risk of hospitalisation and death.
“Research on causes of this ongoing decline and their prevention is urgently needed.”
Smaller in number, and on the nose as they age
A Rutgers University study published in May found that poor sperm quality – notably that caused by ageing – has also been found to compromise the health of mothers and babies.
This is of concern because of the trend of men fathering children late in life.
The study found that men 45 and older can experience decreased fertility and, according to a statement from the university, put their partners at risk for increased pregnancy complications such as gestational diabetes, preeclampsia and preterm birth.
Infants born to older fathers were found to be at higher risk of premature birth, late stillbirth, low Apgar scores, low birth weight, higher incidence of newborn seizures and birth defects such as congenital heart disease and cleft palate. As they matured, these children were found to have an increased likelihood of childhood cancers, psychiatric and cognitive disorders, and autism.
The researchers suggested that men freeze their sperm by the age of 35 to avoid these nasties.
Any more bad news?
Until recently, recurrent miscarriage was thought to be caused by health issues with the mother, such as infection or immune problems. But an Imperial College London study published in January found multiple miscarriages may be linked to the poor quality of a man’s sperm.
The early stage study investigated the sperm quality of 50 men whose partners had suffered three or more consecutive miscarriages – and found that compared to men whose partners had not experienced miscarriages, the sperm of those involved in the study had higher levels of DNA damage.
What else is killing off the seeds of human life?
- Pesticides: A 2015 study and accompanying editorial from Oxford University Press revealed men who ate the highest amount of fruit and vegetables with high levels of pesticide residue had a 49 per cent lower sperm count and a 32 per cent lower quantity of normally-formed sperm than men who consumed the least amount.
- Diabetes: A 2007 study concluded sperm from diabetic men have greater levels of DNA damage than sperm from men who do not have the disease. Other studies have found diabetes negatively impacts male fertility via poor sperm motility, compromised sperm DNA integrity, and poor ingredients of seminal plasma.
- Triathletics: The 2009 annual conference of the European Society of Human Reproduction and Embryology heard that intensity training undertaken by triathletes has a significant impact on the quality of their sperm. The researchers, from the University of Cordoba, Spain, said the triathletes who did the most cycling training had the worst sperm morphology. The researchers believe the irritation and compression caused by friction of the testes against the bike’s saddle, or the localised heat produced by wearing tight clothing, are the main trouble-makers.
- Television: Healthy young men who watch TV for more than 20 hours a week have almost half the sperm count of men who watch very little TV, indicates a 2014 study in the British Journal of Sports Medicine. Conversely, men who did 15 or more hours of moderate to vigorous exercise every week were found to have sperm counts that are 73 per cent higher than those who exercise little.
- Tight underwear: Men who wear boxer shorts have higher sperm concentrations than men who wear tighter-fitting underwear, according to a large 2018 study that looked at semen quality, testicular function, reproductive hormones and sperm DNA damage.
- Booze: Moderate alcohol intake of at least five units every week is linked to poorer sperm quality in otherwise healthy young men, suggests research. And the higher the weekly tally of units, the worse the sperm quality seems to be, the findings indicate, “prompting the researchers to suggest that young men should be advised to steer clear of habitual drinking”.
- Stress: Psychological stress in the workplace and at home is harmful to sperm and semen quality, affecting its concentration, appearance, and ability to fertilise an egg, according to a Columbia University study. How? Stress may trigger the release of steroid hormones called glucocorticoids, which in turn could blunt levels of testosterone and sperm production. Another possibility is oxidative stress, which has been shown to affect semen quality and fertility.
Any good news at all?
Last month researchers from the University of Sheffield revealed a daily 14mg dose of lycopene – a pigment that gives tomatoes their red colour – increased the proportion of healthy shaped sperm (sperm morphology) and boosted fast-swimming sperm by about 40 per cent in a group of healthy volunteers.
It was widely reported that eating two tablespoons of lycopene-rich tomato puree would do the trick just as nicely – but this wouldn’t work because lycopene is poorly absorbed by the human body. The compound used for the trial was a commercially available formulation called LactoLycopene.
This was a double-blind trial, which means neither the researchers nor the volunteers knew who was receiving the LactoLycopene supplement and who was receiving the placebo. Sperm and blood samples were collected at the beginning and end of the trial.
The researchers didn’t investigate how Lycopene works to boost sperm quality – but noted that the pigment “is a known powerful antioxidant, so is potentially inhibiting the damage caused by oxidation of sperm which is a known cause of male fertility problems”.
They believed this antioxidant effect “was key in producing the improvements in sperm quality seen in the trial” – and were hoping to investigate this more.
However, last year the European Society of Human Reproduction and Embryology, at a conference, heard that a US clinical trial found an antioxidant formulation taken daily by the male partner for a minimum of three months made no difference to sperm concentration, motility or morphology, nor to the rate of DNA fragmentation. The men in that trial, however, were infertile – and theirs was a horse that couldn’t be flogged to life.
Best news of all. More sex helps
Daily sex (or ejaculating daily) for seven days improves men’s sperm quality by reducing the amount of DNA damage, according to an Australian study presented at the 2009 annual meeting of the European Society of Human Reproduction and Embryology in Amsterdam.
This was backed up by a study published last year from Centre for Reproductive Medicine of Shengjing Hospital in northeast China.
The researchers upended conventional wisdom that abstaining between efforts to conceive can improve a couple’s chances of success, and found that semen produced shortly after a man’s most recent ejaculation – within three hours or so – had faster and more motile sperm than if the man abstained for several days before ejaculating again.
How so? The short version: the longer sperm exist, the more vulnerable they are to DNA damage by reactive oxygen, which could harm their ability to form a viable embryo.