Something doesn't add up. Despite the fact that more people claim they exercise regularly and try to take a more health-conscious approach to their lives, the global obesity epidemic continues to worsen each year. It begs the question: What are we missing?
Many obesogens are considered endocrine disruptors that can interfere with the body's hormones.
These disruptions affect processes related to energy intake and expenditure, nutrient metabolism, and adipose tissue (body fat) biology.
Obesogens are found in herbicides and pesticides, as well as many consumer products, including food, personal care items, and plastics.
Obesogens may impact gene expression and cause health issues across generations.
National regulation is limited, so it’s encouraged to reduce exposure on an individual level.
A growing amount of research points to a possible connection with obesogens — a group of chemicals that disrupt the endocrine system and contribute to obesity, type 2 diabetes, and other chronic illnesses. These endocrine disruptors interfere with the body's hormones, and many of them show up in everyday products. These chemicals accumulate in the body over time and have been linked to a variety of health problems. Studying their effects has been challenging due to unclear levels of exposure. However, scientists have found worrisome results in animal models in recent years.
What are obesogens?
Most obesogens are considered endocrine disruptors. Dr. Bruce Blumberg, a developmental biologist and author of "The Obesogen Effect" who coined the term obesogens, told Healthnews in an interview that these substances can interfere with important signaling pathways, such as hormone receptors and transcription factors, in various cells and tissues.
The endocrine system regulates many bodily functions, including growth, development, and metabolism. Disrupting this system has serious consequences for health.
These disruptions affect energy intake and expenditure processes, nutrient metabolism, and adipose tissue biology.
Obesogens may drive fat cell accumulation, leading to chronic metabolic diseasesDr. Blumberg
She explained, adding that there are about 20 different compounds that have been identified as obesogens. These can arise from natural sources, such as heavy metals and particulate matter, or they can be anthropogenic, originating from prescription drugs, insecticides, fungicides, plastics, household chemicals, personal care products, flame retardants, and water or oil repellants.
Additionally, specific food components, including non-nutritive sweeteners, fructose, trans-fats, preservatives, additives, and emulsifiers, also act as obesogens, contributing to weight gain through endocrine and nonendocrine mechanisms. Exposure to these obesogens occurs through various routes, including consumption of contaminated food, inhalation of air pollutants, dermal contact, and ingestion of contaminated water.
How do obesogens affect weight gain?
Dr. Blumberg explained that the way obesogens affect the body depends on the specific chemical and the timing of exposure. Some obesogens mimic the effects of estrogen, leading to overstimulation of estrogen receptors in the body. This leads to an increased risk of breast cancer and other hormonally-driven cancers and excessive weight gain.
Other obesogens interfere with the body's insulin signaling, leading to insulin resistance and an increased risk of type 2 diabetes. They can also interfere with thyroid function. Thyroid hormones play a key role in regulating metabolism, and disruptions in thyroid function lead to weight gain and other metabolic problems such as hypothyroidism.
- Disruption of metabolism. Obesogens interfere with the body's metabolism, altering energy expenditure and nutrient handling. This disruption results in reduced calorie burning, increased fat storage, and a propensity for weight gain.
- Hormonal imbalance. Obesogens that act as endocrine disruptors interfere with the body's normal functioning of hormones. Whether it's in relation to regulating appetite, satiety, or metabolism, they disrupt hormonal signaling, leading to imbalances that affect appetite control and energy regulation, ultimately contributing to weight gain.
- Adipose tissue development. Obesogens impact the development and function of adipose tissue (fat cells). They promote the growth and accumulation of fat cells, leading to an increase in overall body fat mass. This results in weight gain and obesity. Dr. Blumberg explained that the minimum number of fat cells a person will have are being programmed up until puberty — there’s no maximum number. However, once the body programs that minimum number, it defends it, and it is very difficult to fall and stay below it. Hence, it’s so challenging for overweight individuals to keep off the weight they’ve been carrying for decades.
- Insulin resistance. Some obesogens interfere with insulin signaling, leading to insulin resistance. Insulin is a hormone that helps regulate blood sugar levels and facilitates the uptake of glucose by cells for energy. When the body becomes insulin resistant, it leads to elevated blood sugar levels and an increased risk of weight gain and obesity.
- Appetite dysregulation. Obesogens affect the regulation of appetite and satiety signals in the brain, leading to disruptions in hunger and fullness cues. This results in increased food intake and a higher likelihood of overeating, ultimately contributing to weight gain.
Timing of obesogen exposure matters
Dr. Blumberg explained that his research with animal models investigating the impact of a specific obesogen, called tributyltin, that’s found in fungicides, had shown that the damage caused by the exposure was passed down generations, especially when the mother mouse was exposed while pregnant.
Dr. Blumberg and his team administered 50 parts per billion tributyltins because he said that dose had been measured in humans, in the environment, and in organisms that have been accumulated from the environments.
“That obesogen reprograms the fetus to deal with calories differently later in life,” he explained, adding that “a mouse that’s exposed in utero will have a tendency to store more calories as fat later in life even on the normal diet. If you challenge them with a little bit more extra fat, they’ll get obese easily, and they don’t give that weight up easily. If you fast them, the exposed animals resist mobilizing that fat.”
He connected it with what many people experience today — it's easy to gain weight but hard to lose. Based on Dr. Blumberg's research, it wasn't only the exposed animals that exhibited such weight gain issues, but even the third, unexposed generation.
The explanation lies in epigenetic coding. Such exposure to obesogens during early development can lead to lasting epigenetic modifications that may be inherited across multiple generations. This phenomenon is known as transgenerational epigenetic inheritance, which refers to the transmission of effects to subsequent generations not directly exposed to the specific obesogenic agent. Exposure, however, must happen within a specific window of time during development when germ cells are developing, Dr. Blumberg explained.
While such studies in humans haven’t been feasible, Dr. Blumberg and his colleagues hypothesized in a study published in the American Journal of Clinical Nutrition that ”if transgenerational inheritance could be confirmed in humans, then the current obesity pandemic could be partly because of obesogen exposures experienced by our parents, grandparents, or great-grandparents.”
The mechanism actions of inheritance
Dr. Blumberg said that while it's controversial that such things can happen, he and his colleagues have hypothesized that the three-dimensional structure of chromatin in the nucleus may be the central mechanism. "Everything else is secondary, such as DNA methylation or histone methylation," he said.
They are working on publishing a paper in that regard. He explained. “It puts a new contact smack in the middle of the gene that encodes insulin-degrading enzymes lower in expression. We’ve shown that in three separate experiments, in four generations, it’s downregulated.”
We think that it’s very likely that exposure has changed the three-dimensional structure of the DNA protein complex nucleus, called chromatin
He also added that it caused the animals to be slightly hyperinsulinemia — they have too much insulin. This is because they don't break it down well, and as soon as they're challenged with a higher-fat diet, they get very hyperinsulinemic. That makes them hyperleptinemic, also making them leptin-resistant. They do a really good job at storing fat and a very bad job at giving up fat.
Not all animals are impacted equally, though. “In our models, only the males get fat, and only the males are hyperinsulinemic and hyperleptinemic,” he shared, adding that “we don’t know why, but have five years to figure that out.”
Common sources of obesogens
Obesogens appear in many items we come across daily, including pesticides, plastics, and personal care products. Pesticides are used to control pests in agriculture and are found in food and water. Plastics contain chemicals that leach into food and water, particularly when heated. Personal care products, such as cosmetics and fragrances, and even household cleaners and detergents, also contain obesogens. Additionally, printed store receipts also contain chemicals that act as endocrine disruptors.
|Polycarbonate plastic and epoxy resin lining of food and beverage cans.
|The Estrogen mimicking effect contributes to insulin resistance, inflammation, and fat cell formation.
|Used to make plastics more durable and flexible. Toys, medical devices, food packaging, detergents, soaps, shampoo, nail polish, lotions, and perfumes.
|May impair testosterone synthesis contributing to obesity.
|Has anti-androgenic and estrogenic effects and may increase the risk of obesity and insulin resistance.
|Organotins i.e., tributyltin
|Class of industrial compounds used as polyvinyl chloride (PVC) stabilizers, antifouling paints, and pesticides.
|May contribute to an increased risk of obesity and chronic diseases.
|Perfluorooctanoic acid (PFOA)
|Waterproof clothing, nonstick cookware, stain repellent, and microwaveable food items.
|May disrupt fat metabolism.
|Preservatives are found in food such as cereal, beer, candy, shampoo, makeup, shaving, paper products, and medicines.
|May disrupt hormones and cause early puberty in girls.
It can be difficult to avoid exposure to endocrine disruptors, but there are steps that can be taken to reduce exposure.
Can we detox obesogens?
Detoxing is easier said than done. Dr. Blumberg explained that while we can get rid of the chemicals themselves, we can’t get rid of their effects. “The effect of the direct or developmental exposure may lead to epigenetic alterations, and those are much harder to get rid of, if it’s even possible,” he highlighted.
He did, however, emphasize that reducing exposure is indeed possible, but it's a personal responsibility.
How to reduce exposure to obesogens?
Reducing exposure to obesogens can be challenging, but there are several steps we can take to reduce exposure. Dr. Blumberg said that one of the most effective ways is to eat a healthy diet low in highly-processed foods and high in fresh fruits and vegetables. Choosing organic foods also reduces exposure to pesticides and other endocrine-disrupting chemicals.
He also advises drinking clean filtered water. “Make sure you are not exposed to or exposed to the least amount possible of the chemicals that can be endocrine disruptive or obesogens,” he said.
Dr. Blumberg recommends avoiding plastic containers for storage and especially for heating foods because chemicals can leach from plastics into foods. For example, choosing glass or stainless steel containers instead helps minimize exposure. Another way is to opt for glass bottles over plastic when buying water or beverages. Additionally, we should try to minimize phthalates and parabens in personal care products, and Dr. Blumberg recommends watching for the word "fragrance". "It's a catch-all for absolutely anything. They don't have to disclose to anyone what they refer to when displaying 'fragrance,'" he said.
Unfortunately, Dr. Blumberg revealed that not all such obesogens are displayed on a product's ingredient list. However, the Environmental Working Group (EWG) — a nonprofit advocacy organization — maintains a database listing a wide range of consumer products with no or fewer obesogens that are safer for consumer use.
Policy and regulation on endocrine disruptors
Many countries have limited regulations on endocrine disruptors — the United States continues to lag. The European Union has taken a more proactive approach to regulating endocrine disruptors, phasing out or banning several chemicals that have been shown to have hazardous endocrine-disrupting effects.
According to an article published in Environmental Health, at least 72 pesticides approved for outdoor agricultural use in the USA are banned or being phased out in the European Union.
In an effort to address the impact of obesogens and other endocrine-disrupting chemicals, the European Commission took significant steps to assess and minimize exposure in consumer products. In July 2017, they recognized the need to expand regulations beyond plant protection products and biocides, extending them to items such as toys, cosmetics, and food packaging materials.
These regulations, including the Classification, Labeling, and Packaging (CLP) and the Registration, Evaluation, Authorisation, and Restriction of Chemicals (REACH), aim to evaluate and control endocrine disruptors exposure comprehensively. In a recent development on December 19, 2022, the Commission proposed revising the CLP regulation. This revision introduced a dedicated hazard class specifically for endocrine-disrupting chemicals, categorized based on the strength of the evidence supporting their hazardous nature.
In the United States, on the other hand, the Environmental Protection Agency (EPA) has limited authority to regulate endocrine disruptors. Many endocrine disruptors are considered "innocent until proven guilty," meaning they are allowed on the market until proven harmful. However, with a lack of funding for research, conducting a study and finding proof hasn't been feasible.
Although the U.S. Congress passed the Food Quality Protection Act of 1996, an amendment to the Food Drug and Cosmetic Act, it has not been implemented. The Act mandated that the U.S. Environmental Protection Agency test all pesticide chemicals used in food for endocrine disruption.
As of now, the EPA has not fully executed the law, meaning it has not conducted comprehensive testing for endocrine disruption on all pesticide chemicals. Despite the limited number of pesticides that have undergone testing, none have been officially recognized as endocrine disruptors, and consequently, no regulatory actions have been implemented.
Why should we avoid obesogens?
Regulation of endocrine disruptors is limited in many countries, but growing evidence shows their negative health impact across generations. While researchers are taking the initiative to study the effect of obesogens in more depth, Dr. Blumberg admitted it’s a challenging project. “We don’t know how much there is or when exposure happens,” he emphasized, adding that “studies are extremely expensive, take time, and there’s no money to do such studies.”
However, individuals can take steps to reduce their own exposure. By being aware of the sources of obesogens and endocrine-disrupting chemicals, we have the power to take steps to avoid certain products to better protect our health, longevity, and our children’s health.
According to Dr. Blumberg’s opinion, it wouldn’t be worth our time to wait for regulation to occur on a national level. “I don’t think regulation is going to happen to a significant degree,” he said. “I think we will have to do it on a personal level. People need to be educated, and the demand for organic foods and safer plastics will drive the market more than any regulation will.”
- Reproductive Toxicology. Metabolism Disrupting Chemicals and Metabolic Disorders.
- Annual Reviews. Environmental Obesogens: Mechanisms and Controversies.
- The Lancet. Global, regional, and national burden of diabetes from 1990 to 2021, with projections of prevalence to 2050: a systematic analysis for the Global Burden of Disease Study 2021.
- Medicina. Role of Obesogens in the Pathogenesis of Obesity.
- Biochemical Pharmacology. Obesity I: Overview and molecular and biochemical mechanisms.
- Biochemical Pharmacology. Obesity II: Establishing causal links between chemical exposures and obesity.
- Physiological Reviews. Early Developmental Conditioning of Later Health and Disease: Physiology or Pathophysiology?