By Marianne Marchese, ND

Introduction

Obesity is a public health crisis in the United States. The CDC estimates that over 42% of adults and around 18% of children and adolescents are obese. Obesity is linked to cardiovascular disease, diabetes, cancers, gallbladder disease, pulmonary conditions, sleep apnea, arthritis, mental health problems, and premature death.  There are numerous factors linked to obesity such as dietary patterns, level of physical activity, socioeconomics, genetics, family history, medications and more. One factor that is common yet often overlooked is chemicals in the environment. Some toxicants present in our food, water, air, and personal care and cleaning products are considered obesogenic. Obesogenic chemicals contribute to weight gain, obesity, and subsequent health problems. It is important that health care providers be on the lookout for exposure to these toxicants to prevent and treat obesity.

Obesogenic Toxicants: The Main Culprits

Evidence is mounting that chemicals we are exposed to at low levels daily are linked to obesity. These chemicals are called obesogens and can interfere with normal function of hormones and other cell signaling molecules. These chemicals can alter metabolism, thyroid function, and the formation of fat cells.^1-4 These processes can be triggered by chemical exposure prenatally, in-utero, through lactation, in early childhood, or as an adult. The effects can happen at any point in time and may be cumulative. 

The main toxicants linked to obesity include the following:

• Bisphenol A (BPA)
• Phthalates
• Polybrominated diphenyl ethers (PBDEs)
• Polyfluoroalkyl chemicals (PFCs)
• Organochlorine (OC) pesticides
• Polychlorinated biphenyls (PCBs) ⁵

There are several proposed mechanisms of action of these chemicals on the body, leading to obesity. These toxicants can disrupt homeostasis of energy metabolism, glucose and lipid metabolism, and control of adipogenesis.⁵ They alter thyroid and sex steroid hormones; interfere with leptin, ghrelin, melanocyte-stimulating hormones, neuropeptide Y, and other key proteins; as well as through inhibiting aromatases as the P450 family members.⁶ The toxicants may change nuclear receptor signaling pathways in preadipocytes, which would result in altered adipocyte differentiation and a tendency toward excess weight.⁶

Bisphenol A (BPA) is a chemical found in numerous household products, including hard plastic water bottles, plastic dishes, plastic cutlery, food packaging, canned food, paper sales receipts, and more. There are different classes of bisphenols with the most common one being bisphenol-A (BPA). Classes of bisphenols, BPS and BPF, which have replaced BPA in many BPA products, can have similar adverse health effects.⁷ BPA is considered an obesogen because BPA exposure is linked with an increased risk of developing obesity. Studies clearly demonstrate that BPA promotes adipogenesis, cholesterol and glucose dysregulation, and adipose tissue inflammation, which contribute to obesity.⁸

Phthalates are a class of chemicals present in many consumer products. They are in products such as toys, vinyl flooring, mattress covers, vinyl shower curtains, detergents, and plastic food packaging such as storage containers and plastic food wrap. Phthalates are in personal care products such as nail polish, hairsprays, aftershave lotions, soaps, shampoos, and perfumes.  Phthalates are also found in plastic beverage bottles such as water and soda bottles.⁷ Studies suggest that phthalates have significant effects on the development of obesity, especially prenatal exposure at low doses. Several proposed mechanisms of action include activation of peroxisome proliferator-activated receptors (PPARs), antithyroid effects, and epigenetic modulation. PPARs serve as metabolic sensors for lipophilic hormones, fatty acids, and fatty acid metabolites, which control adipocyte proliferation and differentiation.⁹

Polybrominated diphenyl ethers (PBDEs) are a class of chemicals that are added to products as flame retardants. They are in furniture, wire insulation, rugs, draperies, upholstery, plastic cabinets for televisions, personal computers, and small appliances. They get into the air, water, and soil and can leak from products that contain them. They accumulate up the food chain; food is the main source of exposure along with air pollution.⁷ PBDEs contribute toadipogenesis and alter insulin metabolism, which are factors in developing obesity.¹⁰

Polyfluoroalkyl chemicals (PFCs) are man-made chemicals that have been used in non-stick cookware, water-repellent clothing, stain-resistant fabrics and carpets, cosmetics, firefighting foams, and products that resist grease, water, and oil. They are called ‘forever chemicals’ because they do not break down in the environment. In addition to being in products, they can accumulate up the food chain through air, soil, and water.⁷ PFC can contribute to obesity as shown through studies looking at adults. Higher blood PFC levels are associated with increases in weight and hip girth over time.¹¹ The timing of exposure seems to be significant as childhood PFC concentrations were associated with higher adolescent body mass index and waist circumference.^11.

Organochlorine (OC) pesticides is the umbrella group for several pesticides, including DDT, eldrin, lindane, aldrin, chlordane, and heptaclor to name a few. They are and were used to treat pests and termites and used in agriculture on crops. Some of these are no longer in use in the US due to their adverse health effects but are still in our soil and water and used in other countries. We are exposed through air, water, and food.⁷ Organochlorine pesticides are linked to metabolic syndrome and insulin resistance, which both contribute to obesity.¹²    

Polychlorinated biphenyls (PCBs) are a group of chemicals that were used in manufacturing and in hundreds of industrial and commercial products. Although they were banned in 1979, they are in the soil and water and accumulate up the food chain. Meat, dairy, and farmed fish are a common way people are exposed to PCBS.⁷ One study showed that PCB exposure, even in low doses, is linked to excess adiposity, dyslipidemia, and insulin resistance among study participants without diabetes. The mechanism appears to be through PCBs’ influence on insulin and creating insulin resistance.¹³

Case Example

A 65-year-old female came to see me three years ago for help with her weight. She was motivated and ready to make some lifestyle changes as she admitted her diet was not great and she was sedentary. At the initial visit, her vitals were consistent with obesity and hypertension.  Height is 5’5” and weight is 220 lbs., which is a BMI of 36.60. This meets the criteria for obesity. Her blood pressure was 150/80. She had hyperlipidemia and was on atorvastatin 20 mg. She takes a fish oil and vitamin D3 daily (2,000 IU). She is fatigued and gets winded easily. She sleeps well and last year had a sleep study, which was normal. She is managed by a cardiologist and recent cardiac testing was all normal. Her blood work from a month prior showed normal CBC, TSH 1.2, CMP normal except her fasting glucose was 102, HgA1C 5.4%, Vitamin D 54, and B12 897. Her lipids were not controlled, which is when her cardiologist increased the dose of her statin medication from 10 mg to 20 mg. She wants to lose weight and improve her health. She hates to exercise and knows this is an obstacle for her. She has tried several weight loss programs in the past, which did not help her lose weight or keep weight off. She has met with nutritionists and life coaches, and she has even tried counseling and hypnotherapy but could not keep her weight off consistently. She is looking for a wholistic approach.

Her environmental intake was significant for childhood and adolescent pesticide exposure. She grew up on an agricultural farm in Iowa. She currently uses regular conventional cleaning and personal care products. She eats non-organic meats and dairy and some farmed fish. She cooks with non-stick cook pans, uses plastic wrap on her foods, and stores food in plastic containers. She drinks bottled water that she buys in bulk from the store. She has a diet coke every day and does not exercise. Based on her exposure intake she clearly had exposure to organochlorine (OC) pesticides years prior, living on the farm in Iowa. She also has daily low dose exposure to BPA, phthalates, and PCBS. She declined toxicant testing and said she just wanted to focus on treatment.

Her plan began with educating her on avoidance of environmental obesogens, which included the following:

• Use cosmetics, lotions, and shampoos that are free of parabens or phthalates.
• Avoid using cleaning products with solvents and fragrances.
• Store and heat food in glass not plastic.
• Get rid of non-stick cooking pans.
• Stop buying plastic water bottles and instead install reverse osmosis filtration under the sink and use RO water for drinking and cooking.
• Buy in bulk to decrease plastic packaging.
• Store food in glass jars when you get it home.
• Carry groceries in cloth bags and reuse them instead of plastic bags.

She agreed to go home and make changes in the products and plastics she uses in her home. Next, we addressed her diet and implemented a diet plan that would either eliminate toxicants in food or have her eat foods designed to help the liver metabolize hormones and toxicants.

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