Life Health & Wellbeing

Monday 14 October 2019

From beer to processed meats: 6 things that are harming your sperm count

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Geraldine Gittens

Geraldine Gittens

Fertility has long been considered a female issue, but since 1973, sperm counts have been declining in western countries.

Stress levels and increased exposure to chemicals and pesticides are some of the things thought to have a detrimental effect on male fertility.

This week, a groundbreaking investigation was published by Harvard University. It looked at the childhood diets of 19-year-olds and found that a bad diet can have a detrimental effect on sperm count.

With nearly one-in-six couples in Ireland now experiencing infertility, here’s a list of six things that can harm sperm count and impact on your ability to start a family:

Junk Food:

The Harvard researchers accessed the data of nearly 3,000 men from the Danish armed forces who had a medical exam when they started national service in the Danish armed forces.

Four types of diet were identified among the cohort of men: a “Western” diet of red meat, processed meat, fatty and sugary food and drink; a “prudent” diet of mainly chicken, fish, vegetables and fruit; a “Smørrebrød” diet of cold processed meats, whole grains, mayonnaise, cold fish, condiments, and dairy; and a vegetarian diet, with lots of vegetables, soya milk and eggs.

Sperm health – which takes into account sperm concentration, volume and motility - was healthiest in men who ate the "prudent" diet. The next most successful diet for sperm count was the vegetarian diet, then the Smørrebrød diet. Those who ate a “western” diet had the worst sperm count readings.

Lack of sleep:

Fertility experts at Aarhus University in the Netherlands believe a lack of sleep provokes the immune system into overreacting and attacking healthy sperm.

It also puts men under physical and psychological stress.

The researchers studied 104 men with an average age of 34 over a two-year period. Even the difference between getting to sleep before 10.30pm and between 10.30pm and 11.30pm yielded a 2.75-time greater sperm health.


A 2014 Danish study which was published in the BMJ Open found that a weekly intake of 25 units had a detrimental effect on sperm quality. 

Excessive alcohol consumption can have a detrimental effect on male fertility because it limits the body’s absorption of zinc, which is important for healthy sperm.

Laptops and mobile phones:

There has long been concerns about male fertility among men who use laptops on their laps. Researchers at Stony Brook University in New York found that an hour of laptop use caused testicle temperature to increase by up to 2.5 degrees, reducing sperm quality over time. 

Phones too can be a problem. A study in Israel which analysed 100 men found that sperm quality and level is reduced in 47pc of men who keep their phone in their trouser pocket, compared with 11pc in the general population. The study was published in the journal Reproductive BioMedicine.


Smoking has been shown to affect fertility in both men and women. In a study published in the BJU International, researchers at the São Paulo Federal University analysed the sperm of 20 smokers and 20 nonsmokers and found that the smokers’ sperm was damaged in ways that could reduce the chance of fertilisation.

Processed meats:

Researchers at the Harvard Chan Public Health School found that regularly consuming processed meats hampers a man's ability to fertilise an egg. Eating more chicken and other poultry can reverse any infertility problems, the researchers said however. Men who ate the most amount of poultry had a 13pc higher fertilisation rate than those who ate the least amount of poultry.

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