When I hear fatalistic reports about how our food is filled with toxins that will instantly cause all forms of disease and tragedy, I often roll my eyes. What is the science behind all these big claims? However, I recently read a review from Drs. Janesick and Blumberg of the University of California Irvine that changed my thinking. Read on for a summary of their thought-provoking research.
Most of us know about the endocrine system- the system in the body that uses hormones to control how our body works. Scientists have long known about the endocrine system, but it wasn’t until the 1990’s that they began to identify chemicals from the environment that disrupt our endocrine system. For instance, diethylstilbestrol (DES) was prescribed to pregnant women to control nausea during pregnancy. However, the world unfortunately learned that DES causes serious birth defects due to the way it interacts with our endocrine system.
A second major realization also occurred in the 1990’s. Doctors and scientists realized that fat is an endocrine organ. It generates hormones and responds to hormones, like other endocrine organs, such as the adrenal glands or ovaries. Taking the next step, scientists realized that fat is also susceptible to chemicals that disrupt the endocrine system. They came up with a special and memorable name for chemicals that interact with our fat: “obesogens.” Obesogens can alter the number of fat cells we have, increase our fat storage, and even control appetite. These sound like some unbelievable, super-villain feats. What is the science behind all these claims?
First, we can look at epidemiological data that certainly shows a change in our BMIs. Seventeen per cent of American children are obese, and about one-third are overweight. Pregnant women weigh more than ever, and birth weight is increasing. Epidemiology studies have shown correlations between exposure to certain obesogens and increased BMI or more Type 2 diabetes mellitus. Second, scientists have tested how certain obesogens affect cells in a test tube. Some obesogens can induce cells to become fat cells in the lab. They have also exposed lab animals to obesogens. Exposing a pregnant mouse to the obesogen “tributyltin” causes developing cells to preferentially become fat cells at the expense of bone cells, an effect which harms the mouse’s children, grandchildren, and even great grandchildren. This means that some obesogens influence the person exposed, while others affect their offspring for generations to come. Scientists believe obesogens affect offspring by changing epigenetics. Epigenetics are changes in gene expression that can be inherited that do not involve changes to the actual gene sequence.
Why does it matter that obesogens lead to more fat cells in offspring? Adults have a relatively stable number of fat cells. If we gain weight, we are generally increasing the size of our fat cells, not increasing the total number of fat cells. Full fat cells release a hormone called leptin that tells us that we’re full. When empty, the fat cells stop releasing leptin, telling us that we’re hungry. The theory goes- if a person has more fat cells, their body is telling them to eat more and more to fill up those fat cells. In this way, exposure to obesogens could cause obesity in future generations, as children are born with more and more fat cells, craving to be filled!
After learning all of this- I immediately wanted to limit my exposure to obesogens. So, what can we do? The options aren’t great: chemicals that disrupt our endocrine system are everywhere. One study even found them hidden in spices! The authors of the review recommend eating organic food and washing fruits and vegetables before eating them. Food additives can also include obesogens: artificial sweeteners, phytoestrogens, preservatives, and added sugar like high fructose corn syrup. Limiting packaging is helpful, too. They also suggest limiting exposure to chemicals in cosmetics like parabens and phthalates. For more details on the science behind this emerging and fascinating area of research, check out the full article here.