Examining the effect of minimal plastics exposure strategies on Plastic-Associated Chemicals (PAC) Excretion in healthy adults.

Many plastic products contain endocrine disrupting chemicals, in this trial referred to as plastic-associated chemicals or PAC. This trial is particularly concerned with bisphenols and phthalates where humans are exposed through contact with food contaminated either by the leaching of plasticisers from packaging or contaminated with plastic particles. In addition, commonly used personal care and cleaning products, and materials used in construction, may contain PAC which can be inhaled or absorbed through the skin. In this trial low PAC food is defined as minimally processed (according to NOVA Classification) fresh produce where the supply chain is either known to be free, or likely to be free of potential plastic contamination. Foods that are canned, pickled, use plastic storage containers will be either avoided or substituted, for example olive oil, where possible with glass. Plastic utensils used in the preparation of food will be substituted for non-plastic. While foodstuffs will be supplied, participants will be free to assemble meals of their choice. Commonly used personal care products e.g. shampoo and soaps that are declared to be free of PAC will also be used in the study. The participants (N=60) will attend the research clinic in the Harry Perkins Institute for Medical Research (Nedlands, Western Australia) (Visit 1) and, following consent, will be randomised to one of five parallel groups, (n=12 per group), to receive an low plastic-associated chemicals (PAC) intervention in their homes, over a 7-day period. The total duration of the study is between 8 and 21 days. Two visits of up to two hour's duration, over a 14-day period, at the Harry Perkins Research Institute will be required. In addition there will be five telephone interviews over the study period of up to one hour's duration. The 60 participants will be randomised into one of the following groups: Group 1: low PAC food only Group 2: low PAC food + low risk utensils + low risk food preparation practices Group 3: low PAC personal products only Group 4: low PAC food + low risk utensils + low risk food preparation practices + low PAC personal products Group 5: Control group Following randomisation at Visit 1, participants will be assigned to a research dietitian who will, depending on participant allocation to the intervention, provide education concerning the avoidance of certain foods, food preparation and cooking practices, and personal care products, and supply participants with a list of the approved foods and products they can order from the approved supplier (the ‘Providore’). Some utensils will be supplied to substitute the participants own e.g. a metal kettle and glass containers. For consistency of communication and rapport a single dietitian will be the point of contact for the participant over the intervention period. At Visit 1 participants will also provide a spot urine sample and a blood sample will be drawn by the study nurse. On the last day of the intervention, participants will attend the clinic (Visit 2) for another blood draw. Biological samples specifically, urine, stool and nasal lavage samples will be self-collected at three time points by the participants who will be provided (at Visit 1) with sample containers and storage boxes fit for purpose to retain their samples prior to research clinic attendance on day 7 (Visit 2). The interventions Intervention A, Dietary intervention Participants from Groups 1, 2 and 4 will select fresh foods and condiments from a list assembled by the dietetic research team, and sourced from suppliers approved by the appropriate Western Australian local regulatory authority. The senior dietitian will liaise directly with the suppliers and the contracted Providore. Food stuffs available for the participant to order will allow for participant preference (e.g. sufficient choices for vegetarian vs omnivore diets), balanced and nutritious. Each participant will be assigned to a single dietitian as a contact person throughout the intervention period. The researchers will pay for the food and assist with ordering from the nominated Providore, who will arrange delivery to the participants’ homes. Participants from Groups 2 and 4 will, in addition to consuming exclusively the provided low PAC food, use non-plastic cooking utensils provided by the researchers, and follow guidance concerning the preparation of their food. Menu cards will be made available for convenience but participants will be free to assemble meals of their choice. Group 1 participants will not be asked to change their food preparation methods or utensils. Should results of urine tests for PAC indicate contamination from an unexpected source, it may be necessary to test some food products retrospectively. Therefore it is planned for some trial foods to be sampled at the nominated Providore by a qualified food scientist, and in liaison with the senior dietitian. Delivery of products to participants’ homes will take place the day before the intervention begins, and at pre-determined time-points throughout the study, as required. Participants will be supplied with a comprehensive schedule, and instructions for the 7-day intervention, and contacted at four pre-agreed times for assessments. The 24HR-DR conducted by telephone interview during the intervention week will facilitate assessments of deviations from the protocol, and enable the assessment of energy, macro and micronutrient intake. Intervention B, Personal care products intervention Participants from Groups 3 and 4 will use only those products supplied by the dietetic research team. Personal care products include, but are not limited to shampoo, conditioners, face moisturisers, cleansers, serums, make-up and sunscreens, deodorant, tampons and applicators. The 15-item 24HR-PPR recall questionnaire for personal care products usage will be sent to participants as a scheduled electronic survey. The assessment tools 24-hour dietary recall interview (24HR-DR) This assessment is a researcher-administered, computer-assisted, 24-hour dietary recall interview. The method assesses dietary intake on the preceding 24-hour period. The method is adapted to gather additional information concerning the packaging, storage, and preparation of food by the participants. Trained dietitians will carry out the interviews by either telephone or video (Microsoft Teams) to provide the option of face-to-face communication. The interviews will vary in length between 15 and 60 minutes depending on the stage of the study, and the complexity of each participants’ diet. They will be carried out three times during the 7-day intervention, and a fourth time on day 8. 24-hour personal care product recall (24HR-PPR) This is a self-administered, pilot questionnaire for the 24-hour recall of personal care products use. This assessment will be sent to participants as an automated, scheduled survey three times during the 7-day intervention and a fourth time on day 8. The questionnaire consists of 15 questions and will take between 2 and 5 minutes to complete. Qualitative research Up to 21 days following the 7-day intervention, trained interviewers will conduct short tele-interviews with participants to assess the tolerability and feasibility of the trial interventions, and uncover aspects that will encourage participation and adherence to future studies. An interview guide consists of a series of closed and open-ended questions. Data will be collated in a qualitative software and analysed be three researchers independently of others. Adherence/Fidelity Adherence to the interventions will be captured during the 24HR-DR interviews, and using the 24HR-PPR questionnaire which will be administered three times during the 7-day intervention, and a fourth time on day 8. It is expected that the qualitative interviews will also capture any difficulties experienced by the participants that might have affected their adherence to the intervention and procedures.