Plastic exposure may be affecting children in ways we're only beginning to understand.

And some of this exposure may be coming from our kitchen—even from healthy fruits and vegetables.

In a new study, higher exposure to certain PFAS, or "forever chemicals," during childhood was associated with lower bone mineral density in adolescence, raising concerns that these compounds may interfere with how kids build bone during a crucial period of development.

A second study finds that ordinary healthy dietary staples—fruit, vegetables, and grains—may be among the largest dietary sources of microplastics. Not because they're so highly concentrated, but because they make up a large portion of people's diets.

The good news? Exposure is modifiable. Researchers tested a 7-day "low-plastic" diet and found that reducing plastic contact during food sourcing, packaging, storage, and preparation lowered several common plastic-associated chemicals in the body within just one week.

If plastic-associated chemicals are affecting children's health, understanding where these exposures come from and how to reduce them matters now. 

That's what today's newsletter is about.

Linking PFAS to Bone Density Harms

The Health Outcomes and Measures of the Environment (HOME) study measured serum levels of four PFAS—PFHxS, PFOS, PFOA, and PFNA—in 218 children at birth, age 3, age 8, and age 12, then measured bone mineral density (BMD) at age 12. 

This time frame is important because adolescence is one of the most important windows for building a strong skeleton—peak bone accretion occurs at about age 12 in girls and age 14 in boys, and nearly 40% of total body bone mineral is acquired during the four years surrounding that peak.

So when something interferes with bone accrual during this period, it matters.

Higher PFOA at any of those time points—and cumulative exposure from birth through age 12—was associated with lower bone mineral density at the 1/3 distal radius, a site in the forearm. The other PFAS did not behave so cleanly. PFHxS, PFOS, and PFNA showed age-specific effects.

• At age 3, higher levels were paradoxically associated with higher BMD at sites like the whole body, hip, and femur.

• By ages 8 and 12, the pattern shifted in the opposite direction, where higher PFOS at ages 8 and 12 was associated with lower BMD at the radius, and higher PFNA at age 12 was associated with lower BMD at the whole body, hip, femur, and radius.

• When the researchers looked at cumulative exposure to the mixture of all four PFAS across childhood, that too was associated with lower radial BMD, with the signal appearing especially strong in females.

The magnitude here is not trivial. The authors note that the BMD differences linked to PFAS exposure ranged from roughly 0.2 to 0.8 standard deviations for every category increase in PFAS exposure. For context, a 1 standard deviation change in BMD has been associated with 1.3 to 1.4 times greater odds of forearm fracture in children. That does not prove these children will go on to fracture more often. But it does tell us that these are not tiny shifts.

Another important point is timing. The study adds to a growing body of evidence suggesting that childhood exposure may matter more than prenatal exposure for bone health. That is biologically plausible. Bone is being actively remodeled and mineralized throughout childhood and especially during adolescence. The stronger female signal may also make biological sense, because by age 12 girls have generally accrued more of their total bone mineral than boys, so disruption during that window may be easier to detect.

What intrigues me most, though, is the mechanistic angle, because it offers a plausible explanation for why PFOA in particular emerged as the most consistent chemical signal linked to lower bone density.

A 2020 paper found that PFOA can compete with calcitriol, the active form of vitamin D, for the same binding site on the vitamin D receptor, alter vitamin D–responsive gene activity, and reduce mineralization in human bone-building cells called osteoblasts.[1] In other words, PFOA interferes with vitamin D signaling itself at the receptor level.

PFOA is probably not the only PFAS that can interfere with vitamin D biology, it's just the one for which we currently have especially direct mechanistic evidence, and in this adolescent cohort it also happened to be the one with the most consistent link to bone health.

This raises the serious possibility that exposure to forever chemicals during childhood may quietly compromise how kids build bone during one of the most important stages of skeletal development. It does not prove future osteoporosis. It does not prove causality either. But it does add to the case that bone should be on the (ever-growing) shortlist of organ systems we worry about when it comes to PFAS.

And what the paper does not tell us is just as important: where are these exposures coming from? The most relevant exposures may be hiding in foods and beverages kids (and adults) consume every single day—even some that we all consider to be healthy.

Differences in forearm BMD scores at age 12 per category increase in PFAS concentrations and the PFAS mixture.

Estimated dietary intake and microplastic concentration of common foods/food categories. Hayder et al. (2026). DOI: 10.1016/j.jhazmat.2025.140657

How to Reduce Your Exposure

These studies point to the somewhat frustrating reality that the biggest sources of exposure are not unique or occasional foods, but the staples that our families rely on every day. And if it's not the foods themselves, it's the ways in which they're packaged, stored, or prepared.

Our kitchen is an enormous potential "touchpoint" in our food supply.

That makes the problem hard to ignore (we all have to eat), but it also means that there are every day opportunities to reduce exposure. By changing the way food is sourced, packaged, stored, and prepared, it may be possible to lower the body's burden of certain plastic-associated chemicals in as little as one week.³

In a fascinating new proof-of-concept study, participants were put on a "plastic-free" diet for 7 days, with the goal of minimizing plastic "touchpoints" in their food supply. This led to dramatic changes in their body's chemical burden, increasing the excretion of several phthalates by up to 54% and BPA by up to 60%.

I think a valuable conclusion to this newsletter would be to lay out the exact strategies they used. Many of them (or variations of them) are ones I’ve discussed at length and have even used myself—and most of them are simple, effective, and can be implemented today. This does not require an entire overhaul of your kitchen.

• Cut out canned foods. Replace canned beans, canned soups, canned tomatoes, canned fruit, and canned drinks with fresh, frozen, dried, or glass-packaged versions whenever possible. Canned foods are one of the important modifiable contributors to exposure, and the groups in the study effectively lowered their bisphenols while avoiding canned foods and plastic-packaged produce (proof that it works!)

• Pull back on highly processed and heavily packaged foods. That means fewer convenience foods, individually wrapped snacks, ready-to-eat packaged meals, and fast-food style items.

• Keep eating fruits and vegetables, but choose versions with less plastic contact. Participants in the study lowered bisphenols without eating fewer fruits and vegetables. The change was in the packaging and handling, not in cutting out produce. Choose loose produce instead of plastic-wrapped produce, avoid canned fruit and vegetables, and reduce plastic contact during storage and prep.

• Use low-plastic cookware and utensils. Participants were given utensils made from metal, glass, or uncoated wood and explicitly avoided silicone and plant-based plastic alternatives. A practical home version would be to lean more on stainless steel, glass, ceramic, and untreated wood—and less on plastic spatulas, plastic cutting boards, silicone bakeware, flexible storage containers, and even “eco-plastic” swaps.

• Microwave only in glass. This is one of the easiest rules to apply at home. No microwaving in plastic containers, plastic wrap, takeout containers, or soft plastic pouches.

• Rethink how food is stored in the fridge. The study included detailed storage instructions, including lining fridge drawers and shelves with paper towels. That might sound fussy, but it reflects the bigger principle that once food enters your home, you control a lot of the remaining plastic-food contact points.

• Hand-wash dishes with a simpler, lower-plastic cleaning product. Participants were told to use a low-plastic dish bar instead of a dishwasher. The kitchen-cleaning environment itself was treated as another opportunity to reduce plastic-associated chemical exposure. At home, that could mean simplifying what you wash with and hand-washing the key items you use during the week.

• Pause non-prescription supplements and heavily packaged “health” products if you can. Powders, protein bars, gummies, capsules, and other convenience “wellness” products may add packaging and processing-related exposure you do not think much about.

Warm regards

— Rhonda and the FoundMyFitness team