Microplastics Impact on Male Fertility
“Would you like some microplastic with your steak?” (source: X, formerly known as ‘twitter’)
Since the 1950s, plastic products have been used plenty in our daily lives. However, their durability, which causes them to take hundreds of years to decompose, has led to significant modern challenges, threatening both human health and the environment. Due to their physical and chemical properties, plastics break down into microplastics (MPs) smaller than 5 mm when they end up in the environment.
Chemicals such as Phthalates and Bisphenols are frequently released in the usage of plastic goods. One common plastic, Bisphenol A (BPA), is found in many everyday items. For instance, particles from polyester clothing can be released during washing and drying with heat, and microwaving food in plastic containers or using plastic cutlery can also contribute to the release of MPs.
Packaging that comes into contact with acidic foods can further lead to contamination. All these sources contribute to the presence of MPs in our food and water, posing significant health risks and environmental hazards.
A recent study, found that three coffees in disposable paper cups are enough to make us ingest about 75,000 microplastic particles. (1)
MICROPLASTICS FOUND IN THE MALE TESTIS
Over the past 80 years, there has been a significant decline in male sperm analysis parameters, though the reasons remain unclear. This increase in infertility rates has shifted the focus to gametogenesis and the quality of gametes.
Infertility, once largely regarded as a female issue, is now increasingly recognised as a male concern due to the recent deterioration in their sperm quality.
A study in 2022 reported that sperm concentration declined by 53.3% and sperm count by 56.3% in Western countries, thus representing the shocking male infertility crisis. (2)
The growing evidence of MPs being present in various biological systems, such as blood and lungs, has prompted researchers to explore the potential effects of MPs on the male reproductive system.
In a recent study, researchers identified 12 different microplastic types in dog and human testis samples. They found that higher amounts of a certain MP were associated with reduced sperm counts. (3)
MICROPLASTICS IMPACT ON MALE FERTILITY
Spermatozoa (SPZ) are the male sex cells responsible for carrying genetic material. They are typically very small and can only be observed under a microscope. Each ejaculation generally contains between 20 million and 600 million sperm. The structure of SPZ includes an oval head, a short middle section, and a long tail, which they use to propel themselves.
Research indicates that SPZ not only deliver a haploid nucleus to the egg but also play a role in early embryo development and fertility. This highlights the importance of sperm quality in embryo development and implantation, which directly affects the likelihood of pregnancy and the risk of miscarriage.
Oxidative stress, coupled with age-related declines in antioxidant activity and mitochondrial dysfunction, is a major cause of testicular and sperm damage. Excessive reactive oxygen species can lead to failures in spermatogenesis (the process of sperm maturation), oxidative DNA damage, disruptions in gene expression, and issues with post-transcriptional gene regulation, all of which contribute to poor sperm quality. These impairments can result in abnormal sperm morphology, such as underdeveloped tails, which affects sperm motility and viability.
Lifestyle factors like smoking, alcohol consumption, stress, and diet all contribute to oxidative stress. However, the most concerning environmental factor is exposure to plastic chemicals like BPA, which impacts spermatogenesis both centrally and locally. Research indicates that BPA exposure disrupts the initial stages of spermatogenesis, impairs the formation of the blood-testis barrier, and affects the expression profiles of non-coding RNAs and overall sperm quality.
A study found that men with higher exposure to BPA were associated with abnormal sperm tail morphology in a cohort of 161 men between the ages of 18-40 years old. (4)
Sperm heads with no/underdeveloped tails.
WHERE IT PAYS TO AVOID PLASTICS
Category 1: Food
With industrial companies moving away from using BPA and phthalates in products aimed directly at consumers, the focus has now shifted to the source of these chemicals. The main source of BPA and phthalate exposure is increasingly found in foods, particularly fast food and highly processed items. This is likely due to the use of plastics during food processing.
The more a food is processed, the longer it remains in contact with plastic equipment and storage containers. In factories and fast food restaurants, these plastics are often cleaned with hot water and strong chemicals, increasing the likelihood of MPs contamination for consumers.
To reduce this exposure, it's worthwhile to cut back on processed foods. This doesn’t mean avoiding them entirely but rather shifting towards a diet of more whole and natural foods, preferably prepared at home. This change can lead to better nutrition and blood sugar control, which may support hormone balance and benefit reproductive health.
Category 2: Packaging
Be cautious with plastic bottles used for oils, vinegars, and sauces, as these liquids — particularly those high in fat or acid — can leach BPA and phthalates from the plastic. It's a good idea to purchase these items in glass bottles instead. Also, consider the shelf life, products stored in plastic for extended periods, such as for months or years, pose a higher risk than fresher items like yogurt and milk.
Heat accelerates the leaching of MPs, so it’s best to avoid eating hot takeout food from plastic containers. Opt for cold foods like yogurt, sushi, or salads, or choose items packaged in cardboard containers when possible.
When drinking hot coffee from disposable paper cups, be aware that many of these cups have a plastic lining that can release MPs when exposed to hot liquids. To minimise exposure, bring your own stainless steel travel cup when ordering from a cafe.
Category 3: Kitchenware
It’s a good idea to replace plastic kitchen items, especially those frequently exposed to hot food or liquids. This includes reusable plastic storage containers, plastic bowls and plates used in the microwave, plastic tea kettles, plastic colanders, and plastic blenders used for soups.
Opt for glass or stainless steel alternatives with these items. While name-brand Ziploc bags and Glad plastic wraps are marketed as BPA and phthalate-free, it’s still advisable to let food cool before it comes into contact with these plastics. Using a glass plate cover when microwaving can also be a helpful precaution.
Category 4: Cosmetics and Personal Care Products
Phthalates are still prevalent in most perfumes and colognes, primarily because they serve as effective solvents for fragrances and help scents last longer. A labelling loophole allows companies to list phthalates under the generic term ‘fragrance’ in ingredient lists.
A 2020 study revealed that men who used cologne had eight times higher exposure to a specific phthalate compared to those who did not use cologne, and this exposure was linked to significantly lower sperm concentration.
To choose cleaner skincare products, opt for fragrance-free options and consider discontinuing the use of perfumes and colognes. Essential oil roll-ons can be a natural alternative to conventional perfume fragrances instead.
Microplastics under the microscope. (source: Alamy. Jinan, China).
With love, Wendy.
RESOURCES
1. Ranjan V.P., Joseph A., Goel S. Microplastics and other harmful substances released from disposable paper cups into hot water. J. Hazard Mater. 2021.
2. Levine H, et. al. Temporal trends in sperm count: a systematic review and meta-regression analysis of samples collected globally in the 20th and 21st centuries. Hum Reprod Update. 2023.
3. Chelin J.H., et. al. Microplastic presence in dog and human testis and its potential association with sperm count and weights of testis and epididymis, Toxicological Science. 2024.
4. Pollard S.H., et. al. Male exposure to bisphenol A (BPA) and semen quality in the Home Observation of Periconceptional Exposures cohort. Reprod Toxicol. 2019.