Non-food-exposures (NFEs) — including environmental conditions — are so numerous and variable that a precise replication of those is impractical and, perhaps, impossible. See: Reducing Non-Food Exposures in dietary intervention studies.
Plastic contamination is inescapable. Plastic micro-and nanoparticles — as well as the chemical compounds used to produce the polymers — are ubiquitous in the environment and present formidable confounding factors that make it impossible to establish causal relationships between a single chemical and measured human health outcomes.
Expense and Practicality Issues
As we proceeded to implement our original study protocol, we were continually confronted with a self-reinforcing cascade of confounding factors.
Among these confounding factors we discovered were:
- Extreme variations among published studies that measured BPA and phthalate concentrations in many common food items.[i],[ii],[iii],[iv],[v],[vi],[vii]
- Evidence of inherent contamination in production and processing and not solely from food contact materials.[viii],[ix],[x],[xi],[xii],[xiii],[xiv]
- Ubiquitous contamination of all commonly available foods. See Appendix 3.
- The necessity to test every food ingredient for nutrition and contamination levels.
- Substantial controls that needed to be imposed on non-food contamination sources.
- Lengthy testing regime a barrier to subject compliance.
Those chemicals exist in, and are mostly inseparable from:
- the air,
- non-stick coatings,
- surroundings (floors, walls, draperies, fabric coverings etc.),
- polymer gloves,
- thermal cash register receipts and
- an unknowable number of other sources.
What’s more, the consistency of those contaminants change over time and place and will vary from person to person.
Given the vast nature of confounding factors, it is not surprising that dietary intervention studies studying the effects of Bisphenol A (BPA) are inconsistent, not replicable and, on the whole, incapable of supporting a causal relationship.
Without a valid, causal relationship, it is not possible for a clinician or other health professional to make fact-based recommendations to their patients and clients. Likewise, regulatory decisions based upon those are not based on solid science and subject to endless arguments among scientists.
What factors need to be considered?
Within the bounds of the possible, a proper dormitory environment will will minimize confounding factors by providing the same environment — air, water, food — for all study participants.
- Minimize the use of, and contact with plastic.
- Towels, napkins and all other cloth material will be 100% cotton.
- All cotton fabric will be sourced from that which is grown organically, without pesticides. All items will be laboratory tested for pesticide and plastic residues.
- Bedding will be 100% cotton. Multiple layers will be installed to minimize migration of plastic from sanitary mattress covers which are expected to block migration from mattress materials.
- Subjects will be provided with a choice of all-cotton under-garments (possibly scrubs).
- All cotton outerwear will be provided. All garments will be pre-washed multiple (TBD) times to reduce/remove sizing or possible plastics contamination.
- All garments will be changed daily.
- Study-issued socks and slippers will be issued. Exercise shoes and cotton socks to be allowed in the ventilated exercise area only. Shoes must not be worn outside that area.
- Rooms will be identically equipped and all surfaces cleaned with an acceptable detergent and implements.
- If dormitory flooring is vinyl or polymer based, all chair legs will be covered with a sock-like cotton covering to reduce microplastic contamination. No chairs with rolling wheels will be permitted.
- Air monitoring for PM 2.5
- New HVAC air filters will be installed.
- Portable HEPA air filters will be employed. Number TBD
- Access to the dormitory will be restricted to study-related personnel
- Tub bathing will be allowed every 2 days.
- No showers will be allowed due to aerosolization of plastic chemicals and nanoparticles.
- Opportunities for exercise must be investigated, but remain problematic because of the use of plastics in exercise equipment. This may be possible by the use of proper ventilation to remove plastic contamination from leaching and frictional shedding of micro/nanoplastics.
- Psychological factors must be considered and resolved including need for privacy, minimum stress (to reduce cortisol levels), possible conflicts among study participants.
- This will be particularly important for sleeping arrangements unless it’s possible to provide a private room for each participant. Creative partitioning in multiple-occupant rooms might provide a solution.
- In addition to other screening requirements for potential participants, should study subjects be screened psychologically for their suitability to comply with the protocol and to interface appropriately with other subjects.
- Broadband internet access
[i] Fasano, E., Bono-Blay, F., Cirillo, T., Montuori, P., and Lacorte, S. 2012. Migration of phthalates, alkylphenols, bisphenol A and di(2-ethylhexyl)adipate from food packaging. Food Control 27(1): 132-138.
[iii] Guart, A., Bono-Blay, F., Borrell, A., and Lacorte, S. 2011. Migration of plasticizers phthalates, bisphenol A and alkylphenols from plastic containers and evaluation of risk. Food Additives & Contaminants Part A: Chemistry, Analysis, Control, Exposure & Risk Assessment 25(5): 676-685.
[iv] Bhunia, K., Sablani, S.S., Tang, J., and Rasco, B. 2013. Migration of chemical compounds from packaging polymers during microwave, conventional heat treatment, and storage. Comprehensive Reviews in Food Science and Food Safety 12(5): 523-545.
[v] Bang, D.Y., Kyung, M., Kim, M.J., Jung, B.Y., Cho, M.C., Choi, S.M., Kim, Y.W., Lim, S.K., Lim, D.S., Won, A.J., Kwack, S.J., Lee, Y., Kim, H.S., and Lee, B.M. 2012. Human risk assessment of endocrine-disrupting chemicals derived from plastic food containers. Comprehensive Reviews in Food Science and Food Safety 11(5): 453-470.
[vi] Groh, K.J., Geuke, B., and Muncke, J. 2017. Food contact materials and gut health: Implications for toxicity assessment and relevance of high molecular weight migrants. Food and Chemical Toxicology 109(1): 1-18.
[vii] Bittner, G.D., Denison, M.S., Yang, C.Z., Stoner, M.A., and He, G. 2014. Chemicals having estrogenic activity can be released from some bisphenol a-free hard and clear, thermoplastic resins. Environmental Health 13: 103.
[viii] Schecter, A., Lorber, M., Guo, Y., Wu, Q., Yun, S.H., Kannan, K., Hommel, M., Imran, N., Hynan, L.S., Cheng, D., Colacino, J.A., and Birnbaum, L.S. 2013. Phthalate concentrations and dietary exposure from food purchased in New York State. Environmental Health Perspectives 121(4): 473-479.
[ix] Cariou, R., Larvor, F., Monteau, F., Marchand, P., Bichon, E., Dervilly-Pinel, G., Antignac, J-P., and Le Bizec, B. 2016. Measurement of phthalates diesters in food using gas chromatography-tandem mass spectrometry. Food Chemistry 196: 211-219.
[x] Van Holderbeke, M., Geerts, L., Vanermen, G., Servaes, K., Sioen, I., De Henauw, S., and Fierens, T. 2014. Determination of contamination pathways of phthalates in food products sold on the Belgian market. Environmental Research 134: 345-352.
[xi] Fasano, E., Bono-Blay, F., Cirillo, T., Montuori, P., and Lacorte, S. 2012. Migration of phthalates, alkylphenols, bisphenol A and di(2-ethylhexyl)adipate from food packaging. Food Control 27(1): 132-138.
[xii] Cirillo, T., Latini, G., Castaldi, M.A., Dipaola, L., Fasano, E., Esposito, F., Scognamiglio, G., Di Francesco, F., and Cobellis, L. 2015. Exposure to di-2-ethyhexyl phthalate, di-N-butyl phthalate and bisphenol A through infant formulas. Journal of Agricultural and Food Chemistry 63(12): 3303-3310.
[xiii] Fierens, T., Vanermen, G., Van Holderbeke, M., De Henauw, S., and Sioen, I. 2012. Effect of cooking at home on the levels of eight phthalates in foods. Food and Chemical Toxicology 50(12): 4428-4435.