Nuts and Olestra for Persistent Organic Pollutant Reduction (NO-POPs) Trial

Persistent organic pollutants (POPs) are mostly fat-soluble halogenated chemicals with very long half-lives. POPs are endocrine disruptors, associated with increased risk for diabetes, alterations in thyroid function, and cardiovascular disease in humans. POPs concentrations increase with age because of their persistence, bioaccumulation and poor excretion. The almost ubiquitous presence of endocrine disrupting POPs in US adults is a substantial public health concern, particularly because there is no established treatment to reduce body concentrations of POPs. Most POPs are excreted in bile due to their lipophilic nature. However, a substantial amount is reabsorbed in the small intestine and returns to the blood stream (entero-hepatic circulation). The objective of this pilot study is to conduct a 6-month randomized controlled trial of Nuts and Olestra to enhance the excretion of POPs among 45 healthy adults aged 45 to 70 years with BMIs between 18-30 kg/m2. This study has 3 treatment arms: A) Whole nuts with high fat content (almonds and walnuts; 110g total/day, n=15), B) Olestra: Fat Free PringlesTM potato chips (≈29 crisps, 18g of Olestra/day; n=15), C) Vegetable oil: Original PringlesTM potato chips (≈29 crisps, 17.4g of oil/day; n=15). The investigators aim to measure change in concentrations of 24 POPs in feces after 4 days of treatment and in blood at 6 months.

Persistent organic pollutants (POPs) are mostly fat-soluble halogenated chemicals with very long half-lives. POPs are endocrine disruptors, and have been associated with increased risk for diabetes, alterations in thyroid function, hypertension, dyslipidemia and neurobehavioral alterations in studies of children, and adults including the elderly. Some of the most prevalent POPs include organochlorine pesticides, polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs).

Most POPs are excreted in bile due to their lipophilic nature. However, a substantial amount is reabsorbed in the small intestine and returns to the blood stream (entero-hepatic circulation). Two small clinical trials found that bile acid sequestrants (cholestyramine, cholestimide) enhanced the fecal excretion of organochlorines after 2-3 days of treatment and significantly lowered their blood concentrations at 6 months. One pilot trial reported decreases in blood PCB concentrations in adults after a 1 year treatment with fat-free potato crisps made with olestra, a non-absorbable synthetic fat, versus standard potato crisps. POPs were thought to bind to olestra and be excreted in the feces. Replication of this finding is needed. Nuts, could yield similar effects. Nuts are foods with high-fat content which are incompletely absorbed in the intestine (21-24% of calorie not absorbed).

As people age, the body burdens of POPs increase. The almost ubiquitous presence of endocrine disrupting POPs in US adults is a substantial public health concern, particularly because there is no established treatment to reduce body concentrations of POPs. There is potential for dietary interventions to have an important role in the reduction of POPs at a population level due to their and low cost and wide use.

The investigators aim to measure 24 POPs (9 OC pesticides, 10 PCBs, 5 PBDEs) in blood (all participants) and in stool samples (only in a subset of 10 participants per treatment arm) before and during the treatment period. The specific aims of this pilot study are to:

1. Assess the effectiveness of recruitment strategies, acceptance and compliance of the treatment arms, and establishing the feasibility of conducting a larger trial.
2. Conduct preliminary testing of the hypotheses: Consumption of olestra (fat free Pringles): A) increases the fecal content (excretion) of POPs, and B) decreases blood levels of POPs, compared to the control arm (standard crisps).
3. Conduct preliminary testing of the hypotheses: Consumption of nuts: A) increases the fecal content (excretion) of POPs, and B) decreases blood levels of POPs, compared to the control arm (standard crisps).

Eligibility Criteria:
Inclusion Criteria:

* Reside in the San Diego area
* BMI ≥18.0 kg/m2 and ≤30 kg/m2
* Non-smoker
* Willing and able to participate in clinic visits, bi-monthly supply pick-up, telephone and Internet communications at specified intervals
* Able to provide data through questionnaires and by telephone
* Willing to maintain contact with the investigators for 6 months
* Willing to allow blood collections
* Willing to provide stool samples
* No known allergy to tree nuts
* No digestive issues with olestra, chips, or nuts

Exclusion Criteria:

* Nut allergies
* Smoker
* Diabetes, kidney disease or liver disease
* Concurrent acute or chronic gastro-intestinal conditions (e.g. inflammatory bowel disease, irritable bowel syndrome, concurrent diarrhea from any cause)
* Familial hypercholesterolemia
* Clotting problems or use of Coumadin,
* Inability to participate in physical activity because of severe disability
* History or presence of a co-morbid diseases for which diet modification may be contraindicated
* Self-reported pregnancy or breastfeeding or planning a pregnancy within the next year
* Currently actively involved in another diet intervention study or a weight loss program
* A history or presence of a significant psychiatric disorder or any other condition that, in the investigator's judgement, would interfere with participation in the trial