Microplastics in Breast Milk: What New Mothers Need to Know

Microplastics - tiny plastic particles - have been found in breast milk, placenta, and even amniotic fluid, exposing babies to these particles before birth and during nursing. Studies indicate that up to 75% of breast milk samples contain microplastics like polyethylene (PE), polypropylene (PP), and polyvinyl chloride (PVC), which come from everyday items like baby bottles, food packaging, and plastic wrap. Infants consuming breast milk stored in plastic may ingest up to 0.89 mg of microplastics daily.

Despite this, experts emphasize that breastfeeding remains the healthiest option for infants due to its nutritional and immune benefits. To minimize microplastic exposure, mothers can make small changes, such as using glass or stainless steel containers, avoiding heating food in plastic, and selecting natural-fiber clothing. These steps can help protect your baby while continuing to breastfeed safely.

What Are Microplastics and How Do They Enter the Body?

Where Microplastics Come From

Microplastics are tiny plastic particles measuring less than 5 millimeters in diameter. Among these, nanoplastics are even smaller - less than 1 micrometer (1,000 nanometers) - and pose unique risks. Their size allows them to pass through cellular membranes and biological barriers like the blood-brain barrier and even the placenta.

These particles originate from two primary sources. Primary microplastics are intentionally manufactured, such as microbeads found in facial scrubs, industrial pellets, and fibers from synthetic fabrics. Secondary microplastics, on the other hand, result from the breakdown of larger plastic items - like bottles, bags, tires, and fishing gear - due to factors like UV light, mechanical wear, or microbial activity. As Dr. Desiree LaBeaud from Stanford Medicine points out:

Plastic never goes away - it just fragments into smaller particles.

It's estimated that 10 to 40 million metric tons of microplastics are released into the environment every year, contaminating air, water, and soil. In January 2024, researchers at Columbia University introduced a laser imaging technique to study microplastics. Their findings, published in the Proceedings of the National Academy of Sciences, revealed an average of 240,000 plastic fragments per liter in three popular bottled water brands sold in the U.S. Shockingly, about 90% of these fragments were nanoplastics, primarily made of polyethylene terephthalate (PET) and polyamide.

How Microplastics Enter a Mother's System

Microplastics can enter the body through ingestion, inhalation, and dermal contact. Drinking water is a major source, particularly bottled water, which contains about 325 particles per liter compared to just 5.5 particles per liter in tap water. Foods like seafood (especially shellfish), salt, instant rice, and honey are also common culprits.

Airborne microplastics are another concern. You breathe them in from household dust and fibers shed by synthetic clothing, such as polyester and nylon. Indoor air typically contains more microplastic fibers than outdoor air. Additionally, personal care products like facial scrubs, toothpaste, and cosmetics can expose you to plastic through your skin or mouth, with some products containing up to 90% plastic.

On average, humans ingest about 5 grams of plastic per week - the weight of a credit card. In 2023, a study from the University of Nebraska-Lincoln published in Environmental Science & Technology revealed that microwaving "microwave-safe" plastic baby food containers for three minutes could release up to 4.22 million microplastic particles per square centimeter of plastic.

Once these particles enter the bloodstream, they can circulate and eventually make their way into breast milk.

How Microplastics Transfer to Breast Milk

After entering the bloodstream through the gut or lungs, microplastics can cross the blood-milk barrier. Particles smaller than 150 micrometers move through the lymphatic and circulatory systems, while nanoplastics can penetrate cell membranes directly.

Research in Nature Communications shows that nanoplastics not only transfer through the placenta but also into breast milk. The blood-milk barrier allows a wider range of particle sizes to pass compared to the placental barrier. This means nursing mothers are exposed to microplastics from two sources: those already circulating in their bodies and additional particles from using plastic baby products like breast pumps, storage bags, and bottles. Heating or shaking these items can release even more microplastics.

Studies have identified polypropylene (PP), polyethylene (PE), and polyvinyl chloride (PVC) in breast milk samples - materials commonly found in baby care products. Dr. Philip Landrigan, Director of the Program for Global Public Health and the Common Good at Boston College, highlights the emerging concern:

Microplastics are a new source of chronic, low-level inflammation that we are only beginning to understand.

Health Risks for Infants

Why Infants Are More Vulnerable

An infant's body is not equipped to handle environmental contaminants the way an adult's body can. Babies grow at an incredible pace, with their organs developing rapidly and their detoxification systems still immature. This makes them especially vulnerable to pollutants like microplastics.

Studies reveal that infants tend to have higher levels of plastic particles in their feces compared to adults, indicating greater exposure relative to their body weight. For instance, one-year-old babies are estimated to encounter about 83,000 nanograms of polyethylene terephthalate (PET) microplastics per kilogram of body weight daily. Their developing bodies struggle to eliminate these particles effectively. In some early studies, microplastics were found in 100% of meconium samples (a newborn’s first stool), with a median concentration of 54.1 particles per gram.

Nanoplastics - extremely tiny particles less than 1 micrometer in size - are particularly concerning. Their small size allows them to penetrate cell membranes and reach essential organs, including the brain. This unique vulnerability underscores the importance of understanding how microplastics may affect infants' health.

What Research Shows About Health Effects

Emerging studies are uncovering the potential health impacts of microplastics on infants. For example, microplastics have been found in breast milk, raising concerns about their systemic effects. These particles can activate immune responses, leading to the release of pro-inflammatory cytokines, which can cause chronic, low-grade inflammation.

"Infants, due to their rapid growth and development, may be more susceptible to the toxic effects of MPs compared to adults."

Some reviews have linked microplastic exposure to adverse outcomes such as lower birth weight, shortened gestation, and smaller head circumference. The gut appears especially vulnerable. Microplastics can disrupt the gut microbiome, shifting it toward more pro-inflammatory bacteria. This can lead to increased intestinal permeability - often referred to as "leaky gut" - which allows harmful substances to enter the bloodstream more easily.

The risks extend beyond the digestive system. Laboratory research suggests microplastics can cross the blood-brain barrier, potentially causing neuroinflammation and even cognitive issues. Additionally, microplastics often carry chemicals like phthalates and bisphenols, which are known endocrine disruptors. These chemicals can interfere with hormones critical for a baby’s growth and metabolic health. Early exposure has been linked to metabolic issues such as lipid imbalances and a higher likelihood of obesity later in life.

While long-term human studies are still lacking, animal research provides clear evidence of harm. Small-scale human studies have also found plastic particles in about 39% of breast milk samples, highlighting the need for caution and further investigation. These findings, though preliminary, suggest that taking preventive measures may be wise.

How to Reduce Microplastic Exposure

You can cut down on microplastic exposure by making some simple changes to your diet and daily habits.

Changes to Your Diet

Switch to filtered tap water instead of bottled water. Bottled water contains an average of 240,000 plastic particles per liter - about 100 times more than earlier estimates. Tap water, on the other hand, has around 5.5 particles per liter. Installing a reverse osmosis (RO) filtration system can remove over 99% of microplastics and nanoplastics. If that’s not an option, consider using NSF/ANSI 401 certified solid carbon block filters.

Stop heating food in plastic containers, even if they’re labeled "microwave safe." Instead, transfer your food to glass, ceramic, or stainless steel containers before warming. Opt for wood or bamboo cutting boards instead of plastic ones, as plastic boards can shed particles into your food.

Cut back on shellfish and deep-sea fish, which tend to carry higher microplastic loads. Also, be sure to wash rice thoroughly before cooking. Reduce your intake of ultra-processed foods, as they often come into contact with plastic machinery and packaging. Avoid plastic tea bags altogether - a single pyramid-style tea bag can release billions of micro- and nanoparticles when steeped in hot water. Switch to loose-leaf tea with a metal infuser.

Beyond diet, small adjustments to your daily habits can also help minimize exposure.

Daily Habits to Adjust

If you're breastfeeding, some simple changes can significantly reduce microplastic exposure for your baby.

Breastfeeding directly is the best way to limit microplastic exposure for infants. This avoids the need for plastic bottles, storage bags, or heating processes that can release plastic particles. If you use pumped milk, cool it in glass or stainless steel containers before transferring it to storage bags. Thaw frozen milk in the fridge and move it to a non-plastic container for warming.

Hand-wash pump parts and bottles with cool, filtered water after sterilizing or dishwashing to rinse away loose particles. Avoid shaking plastic bottles or storage bags too much - a single twist of a plastic bottle cap can release up to 500 microplastic particles.

Choose natural-fiber clothing like organic cotton, wool, or hemp instead of synthetic fabrics like polyester or nylon, which shed microfibers that can be inhaled or ingested. This applies to nursing pads, bedding, and towels as well.

In addition to these habits, selecting safer products can make a big difference.

Selecting Safer Products

When it comes to baby bottles, use glass, stainless steel, or food-grade silicone instead of plastic. If plastic is your only option, choose hard polypropylene labeled #5, and check regularly for cracks, cloudiness, or wear - these are signs the item needs replacing.

Be mindful of personal care products. Many cosmetics, scrubs, and toothpastes contain microplastic particles or polymers like "polyethylene" or "polypropylene." Look for microbead-free, natural alternatives. Opt for organic crib mattresses to reduce exposure to harmful chemicals.

"We would like to advise pregnant women to pay greater attention to avoiding food and drink packaged in plastic, cosmetics and toothpastes containing microplastics, and clothes made of synthetic fabrics." - Dr. Valentina Notarstefano, PhD

Store food in glass or stainless steel containers, especially acidic items like tomato sauce or citrus, which can speed up plastic leaching. Avoid single-use cling wraps for fatty or acidic foods. For hot drinks, use ceramic mugs or stainless steel travel containers instead of plastic-lined paper cups, which can release up to 25,000 microplastic particles into hot liquids within 15 minutes.

Other Ways to Support Your Baby's Health

Taking care of your baby's health goes beyond reducing microplastic exposure. Nutrition and immune support play a big role in keeping your little one healthy and thriving.

Nutrition for Nursing Mothers

Breastfeeding moms need an extra 330–400 calories a day. But it’s not just about eating more - it’s about choosing foods that help your baby grow and develop.

Focus on key nutrients like iodine (290 micrograms daily) and choline (550 milligrams daily), which are crucial for brain development. You can find iodine in dairy, eggs, seafood, and iodized salt, while choline is abundant in meat, eggs, beans, and lentils. If you’re vegan or vegetarian, you might need supplements for Vitamin B12, iron, zinc, and omega-3 fatty acids to avoid deficiencies that could affect your baby.

Adding 8–12 ounces of low-mercury seafood like salmon or sardines each week provides DHA and EPA, essential for brain development. To improve iron absorption, pair iron-rich foods with a source of vitamin C. And don’t forget to stay hydrated - aim for 8–12 cups of water daily while nursing.

"As long as a person is eating a varied diet, they're going to do just fine." - Sue Hudson, Certified Nurse Midwife, Cleveland Clinic

While good nutrition is essential, building your baby's immune system is just as important.

Building Your Baby's Immune System

The CDC and American Academy of Pediatrics recommend exclusive breastfeeding for the first six months. After that, breastfeeding alongside solid foods for one to two years continues to offer immune protection.

"Human milk is the best source of nutrition for most infants" - Agency for Toxic Substances and Disease Registry

Breastfeeding offers more than just nutrition - it provides immune-boosting cells that formula can’t replicate. Plus, direct breastfeeding reduces exposure to plastics. Your breast milk even adapts to your baby's needs during each feeding. To further support your baby's immune system, stick to routine well-child checkups and stay up-to-date on recommended vaccinations. These steps, combined with breastfeeding, help ensure your baby's immune system develops strong and healthy.

Conclusion

The presence of microplastics in breast milk has raised valid concerns, but practical changes can help protect your baby while preserving the proven benefits of breastfeeding. Research consistently shows that breastfeeding's advantages far outweigh the potential risks posed by microplastics. As Valentina Notarstefano, PhD, points out:

It must be stressed that the advantages of breastfeeding are much greater than the disadvantages caused by the presence of polluting microplastics.

Simple adjustments - like breastfeeding directly and avoiding plastic storage - can make a meaningful difference. Switching to glass or stainless steel containers, steering clear of heating plastics, and hand-washing pump parts are manageable steps to reduce your baby's exposure. These small but impactful actions, discussed earlier, equip you to prioritize your baby's health without overhauling your entire lifestyle.

Perfection isn’t the goal here, nor is it necessary. Focus on changes that have the most impact and fit into your daily routine. For instance, using filtered tap water and choosing natural fiber clothing for you and your baby are straightforward yet effective choices. These habits reflect a broader effort to safeguard your child's well-being. As Dr. Kara Meister from Stanford Medicine wisely notes:

Just because you have a little plastic in you doesn't necessarily mean doomsday. Giving your body the best shot to deal with whatever might come along is the best you can do.

FAQs

Should I keep breastfeeding if microplastics are in breast milk?

Breastfeeding continues to offer immense benefits for infants, even with the detection of microplastics in breast milk. While studies have identified microplastics in human tissues, there's currently no solid evidence showing immediate harm to babies.

The nutritional value and immune-boosting properties of breast milk remain unmatched, making it an essential choice for infant health. If you're concerned about microplastic exposure, you can take steps to minimize it. For example:

• Reduce the use of plastic containers and utensils for food storage and preparation.
• Opt for fresh, unprocessed foods to decrease exposure from packaging.
• Avoid heating food in plastic containers, as this can release microplastics.

For tailored guidance, it's always a good idea to discuss any concerns with your healthcare provider. They can help you make informed decisions that balance risks and benefits effectively.

What are the biggest everyday sources of microplastics for nursing moms?

Microplastics can sneak into daily life from a surprising range of sources. For nursing moms, some of the most common include:

• Synthetic clothing: Washing garments made from materials like polyester or nylon can release microfibers into the water.
• Car tires: As tires wear down, they shed tiny plastic particles that end up in the environment.
• City dust: Urban areas often have microplastics in the air, originating from various sources like construction materials and vehicle emissions.
• Road markings: Paint used on roads often contains plastic, which breaks down over time.
• Marine coatings: Paints and finishes on boats can contribute microplastics to waterways.
• Personal care products: Items like exfoliants or face washes with microbeads are a direct source of these particles.

Since these tiny plastics can come from everyday items and environmental factors, being mindful of their sources is an important step for reducing exposure.

What are the top 3 changes to reduce my baby’s exposure fast?

Here are three simple steps to help reduce your baby’s exposure to microplastics:

• Switch to microplastic-free feeding products: Steer clear of plastic bottles, pump components, and storage bags - especially when they’re exposed to heat.
• Opt for glass or stainless steel: Use non-plastic alternatives like glass or stainless steel containers for storing breast milk.
• Avoid heating plastic items: Refrain from heating or microwaving plastic bottles, pump parts, or storage bags, as this can release microplastics.

These small changes can make a big difference in limiting your baby’s contact with microplastics.