Epidemics of the 21st Century

By Dr. Daniel A. Kinderlehrer MD


I’ve been a doctor for over 40 years and I’ve witnessed many changes, including epidemic rises in multiple medical conditions. I’m not talking about the present pandemic, nor am I referring to the opioid crisis, another devastating epidemic that has taken the lives of over 500,000 Americans. I’m talking about chronic conditions that cause a slow burn and sometimes kill.

Lyme disease is but one example. But think how things have changed since the beginning of the previous century: heart disease was barely on the radar in 1900, but for over 50 years it has been the number one cause of death in the U.S. (1) A whopping 69% of Americans are now overweight, with 36.5% obese, (2) directly contributing to the skyrocketing incidence of adult-onset diabetes mellitus. (3) When I was in training in the 1970s, I never saw a patient with AODM who was under 40 years old; now it is being diagnosed in children.

And then there are the dramatic increases in autism spectrum disorder, (4) attention deficit hyperactivity disorder (ADHD), (5) autoimmune conditions, 6 some types of cancer (7), and food allergies. (8) Twenty-five years ago, when I had a large environmental medicine practice, most of my patients with food sensitivities reacted to one or more of a half dozen foods: milk, corn, eggs, wheat, citrus, or sugar/yeast. It was easy to put patients on an elimination diet: fish, lamb, vegetables, legumes, potatoes, and rice. Now people react to avocados, rice, lettuce, and anything under the sun.

And, of course, there’s the rise in mental health disorders. Even before the Covid pandemic, the World Health Organization predicted that depression would become the leading cause of death globally.9 According to the CDC, in 2019 19% of Americans suffered from depression in the U.S., and seven percent were moderately to severely affected.10 Among adults, suicidal ideation is increasing; suicide has become the second leading cause of death in children and adolescents ages 13 to 19—and the leading cause of death among 13 year-olds. 11 (Among all Americans, it is the tenth leading cause of death. (11)

There are a host of factors that determine the how, where and why illness occurs. These include genetic proclivity, lifestyle, trauma, diet, exposures to microbes and toxins. But here is what is further catapulting these seemingly disparate epidemics: a change in the human condition that we now understand as epigenetics.

While it takes millennia of natural selection to change our genes, specific proteins that turn genes on and off can alter gene expression in a single generation. Epigenetics explains how a change in the expression of genes can be passed from one generation to the next without actually changing the DNA. There are literally thousands of conditions that can cause epigenetic changes.

Nutrient deficiencies, exacerbated by soil depletion, can activate epigenetic changes that result in neurological issues from mood and behavioral disorders to cognitive dysfunction, and these problems are passed on to subsequent generations.(12),(13) Epigenetics helps explain why the skyrocketing sugar intake in our diets is causing obesity. (14),(15)

Chemical exposures also have epigenetic consequences. Over the past century, we have been exposed to hundreds of thousands of chemicals that are new to human existence. Pesticides, insecticides, herbicides, and other chemicals all have the potential to modify epigenetic activity. (16) Countless agents now ubiquitous in daily life, from air pollution to air fresheners and fabric softeners can negatively impact overall health. (17),(18)

But it is not only diet, nutrition, and exposure to toxic chemicals that have changed in the past century. Another factor that has undergone a radical transformation is the social milieu. The social sphere, which used to revolve around communities, has devolved to extended families, then to nuclear families, then single-parent families, and now, tragically at times, to homeless families or solitude. 

It is no longer routine for people to go next door to be held by grandma, or move in with aunts and uncles when going home gets rough; in essence, the safe shelter has disappeared. This lack of safety is compounded for survivors of childhood trauma, who often develop epigenetic abnormalities and thus pass the trauma on to their offspring. (19)

That’s right—PTSD can be inherited. A review paper by Rachel Yehuda and Amy Lehrner on intergenerational transmission of trauma and the role of epigenetic mechanisms states, “There is now converging evidence supporting the idea that offspring are affected by parental trauma exposures occurring before their birth, and possibly even prior to their conception. On the simplest level, the concept of intergenerational trauma acknowledges that exposure to extremely adverse events impacts individuals to such a great extent that their offspring find themselves grappling with their parents’ posttraumatic state.” (20) PTSD is not only a psychological disorder, it triggers increasing dysregulation of an individual’s neurobiology. (21)  

Other social factors also have an enormous impact on health and well-being. Social isolation is a major risk factor for depression. (22) The chronic stresses of poverty, racism, homophobia, and misogyny not only make for a bad day, but they also act on our biochemical pathways impacting immune, hormonal, and neurological function. (23) The long-term release of the stress hormone cortisol and of proteins called cytokines (which regulate the body’s immune system response) can cause even more damage. These biochemical messengers, in turn, can result in epigenetic changes that are passed on to future generations. (24) 

Epigenetic transmission means that both physical and emotional traumas are cumulative over generations. Newborns are not born with a clean slate. And these alterations in epigenetics are manifesting in a tsunami that is destabilizing individuals’ core regulatory systems. Increasingly, people respond as if they have continuous PTSD—their nervous and immune systems going haywire at both real and imagined threats, with all the downstream consequences evident in an increasingly sick population. 

This brings us back to PANS, which I have been discussing in the past few articles. I think we are witnessing an epidemic of autoimmune reactivity to multiple agents in the environment—like foods, viruses, bacteria, and mold. We are clearly seeing it with SARS-CoV-2. When autoimmune reactivity results in neuroinflammation, it results in cognitive dysfunction, PANS, and a panoply of mental health disorders—for generations to come.

We need to become more cognizant of the cumulative stresses that result in combined mental and physical issues and address them at their core.

About the Author

Daniel Kinderlehrer, MD, is a nationally recognized physician with expertise in the fields of nutrition, allergy, environmental medicine, Lyme disease, and the healing of mind-body-spirit as a unified whole. He recently released a new book Recovery from Lyme Disease, The Integrative Medicine Guide to Diagnosing and Treating Tick-Borne Illness. The book discusses his integrative approach and offers the most up-to-date and comprehensive plan available for treating and beating this disease.


  1. https://pubmed.ncbi.nlm.nih.gov/24811552/
  2. https://www.healthline.com/health/obesity-facts#1.-More-than-one-third-of-adults-in-the-United-States-are-obese.
  3. https://www.cdc.gov/mmwr/volumes/67/wr/mm6712a2.htm
  4. https://www.statista.com/statistics/676354/autism-rate-among-children-select-countries-worldwide/
  5. https://chadd.org/adhd-weekly/is-there-an-increase-in-adhd/
  6. https://www.immunology.org/news/report-reveals-the-rising-rates-autoimmune-conditions
  7. https://www.forbes.com/sites/williamhaseltine/2020/12/09/cancer-rates-are-on-the-rise-in-adolescents-and-young-adults-new-study-shows/?sh=5d56188c3b7b
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  10. https://www.cdc.gov/nchs/products/databriefs/db379.htm
  11. https://webappa.cdc.gov/sasweb/ncipc/leadcause.html
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  18.  https://www.scientificamerican.com/article/greener-laundry/ 
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