Now gaining broad credibility among scientists, the study of epigenetics is at the forefront of modern medicine. According to the author, the real upshot of the epigenetic revolution is that it opens the door to what futurists call personalized medicine. For the first time in a trade book, Dr. Pelletier explains in layperson's language the genetic biomarkers that will become the standard reference for measuring which specific lifestyle changes are required to optimize a given individual's health. In the very near future, each person's state-of-the-art genetic and epigenetic profilematched with other precise indicators such as assays of the gut microbiomewill guide their daily health practices.
This short but profound book by a world-renowned pioneer in integrative medicine introduces readers to this exciting new field, and reveals the steps that each of us can take today to change our genetic expression and thereby optimize our health for a lifetime.
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About the Author
Read an Excerpt
NEW REASONS TO HOPE
What We Have Learned about Our Genes
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In May 2013, celebrity actress Angelina Jolie suddenly made headlines — not because she was starring in a new movie but because she had made a drastic medical decision. She announced to the world in a New York Times op-ed that she had undergone a preventive double mastectomy. Her decision to submit to such invasive surgery was, she wrote, the result of genetic tests that indicated she had an 87 percent likelihood of developing breast cancer. Jolie also shared that she had lost both her mother and grandmother to ovarian cancer, which is closely tied to breast cancer. As the mother of six young children, Jolie decided on their behalf "to be proactive and to minimize the risk as much as I could."
Jolie's dramatic story had worldwide impact. The New York Times later reported on how awareness of the breast cancer issue had exploded in Israel as a result of Jolie's announcement. Jolie is of Ashkenazi Jewish descent, and it is known that about half the Ashkenazi women in Israel and the majority of them in the United States are likely to have the same mutation as Jolie. As these susceptible women learned of their increased genetic risk, the Times noted that they face the same crisis that Jolie did before them.
Was the famed actress misguided in making such a drastic choice? Or is preventive mastectomy the only ethical and reasonable medical choice for women with Jolie's mutation? If the answer to the latter question is yes, should insurers cover this procedure for all women with this mutation?
Giving informed answers to questions like these requires a short course in the revolutionary new understanding of human biology that we examine in this book. The discovery early in this century of the significance of epigenetics — and more recently of the genetic role of our body's symbiotic cousin, the gut microbiome — was the tip-off to researchers that something far more complex was going on than had ever been imagined in twentieth-century medicine. Because of these developments, we can now safely say that Angelia Jolie had unwittingly based her decision on a model of genetic determinism that is on the brink of extinction — as you will soon learn.
The End Game for Genetic Determinism
Advances in genetics of the last few decades have been nothing short of astonishing. Scientists can now locate and map (or "sequence") every single gene in the human genome at an increasingly lower cost. The relative ease and precision of today's gene-sequencing technology now makes it commercially feasible to identify the biochemical makeup of every one of the over 20,000 genes in each person's DNA, as well as every other molecular feature of the DNA strand on their inherited genome.
The first effort at comprehensive gene sequencing in 2001, the Human Genome Project, cost about $100 million. Fifteen years later, the cost had dropped to about $500, and continues to fall from there. Impressively, these techniques allow us to zero in on the tiniest molecular units of our DNA, known as base pairs. Geneticists designate these biochemical units by a simple series of four letters. Sequencing techniques allow them to locate those genes that carry potentially harmful mutations — rogue base pairs whose letters are out of proper order. These unique variations in a standard base pair are also known as gene variants.
Is there a practical import for your health? Yes, indeed there is, because gene variants can often be correlated with some degree of risk for a specific disease. Such a statistical association of a variant with a particular disease makes you vulnerable to it; only rarely is it a certainty. The new science of epigenetics shows that many other crucial influences are at work in creating disease conditions in the body that may or may not activate this genetic predisposition. Plus, some variants can actually be beneficial adaptations — though again, rarely.
Because advances in gene-sequencing now make it easy to locate variants, a giant new industry for gene mapping is beginning to have wide influence in clinical medicine. And while it is a wonderful gift to become aware of our inherited genetic traits and possible disease vulnerabilities, putting such information in the wrong hands can also be dangerous and misleading.
According to the National Institutes of Health, the genetic testing industry will grow to about $20 billion by 2020. Most of these billions will be spent on promises to predict your risk of major diseases. But what the public doesn't know is that such genetic tests can predict with certainty only a few percent of all known diseases. All other cases of disease occurrence depend at least in part on factors outside your inherited genome, most notably your lifestyle and your particular life conditions.
Nevertheless, because of the persistence of the mechanistic paradigm of genetics inherited from the last two centuries, massive resources are being spent on predicting genetic diseases and matching drugs to such conditions. This can be a blessing to those millions of Americans who suffer from the inexorable expression of one of roughly 5,000 rare genetic diseases that afflict about ten percent of the population. But what about the vast majority of us who don't have such defective genes? An even greater blessing would be to refocus genetic research on optimizing the expression of our good genes! This book reveals the state-of-the-art of this more expansive and proactive approach to human biology.
The difficult case of Angelina Jolie illustrates the transitional state of the genetics industry, as we wait for clinical practice to catch up with the new biology. Jolie has a well-understood mutation in genes known as BRCA1 and BRCA2, which work as tumor suppressors. This relatively common mutation can make these genes incapable of performing their important function, giving women with these variants a high risk of both breast and ovarian cancer.
Brace yourself, because what follows is a graphic description of the aggressive intervention necessitated by Jolie's decision. Once she knew her test results, Ms. Jolie opted for a complex form of preventive surgery that requires three consecutive operations over several months. First, she underwent a procedure designed to spare the nipple and surrounding areola. Next, surgeons removed all the breast tissue while saving the skin that contains the breasts. In a third procedure, her breasts were reconstructed with implants. This procedure only targeted her breasts because, as she wrote, "my risk of breast cancer is higher than my risk of ovarian cancer." Jolie still has to face a decision about preventive surgery on her ovaries as well — yet another drastic and expensive intervention.
The Better Choice: Change Your Gene Expression
Without a doubt, Jolie faced a big risk for breast cancer and made a tough decision. But we can only wonder to what extent she was made aware of the valid alternative approaches for women who face this dilemma, even within the old paradigm of medicine. For example, a far less invasive approach would have been to take tamoxifen, an estrogen-blocking drug. Or, she could have opted for preventive medical monitoring in an effort to catch breast cancer early. The best approach of all would have been to combine these two treatments with what we in California call a "reframe"— that is, to simply leave behind the outmoded concept of genetic determinism and embrace the science of epigenetic modification. This would entail that she consciously change her patterns of gene expression in ways that compensate for her inherited BRCA1 and BRCA2 mutation. We now know that the most powerful option for Jolie — or anyone with a known genetic predisposition to any disease — is to change their environment and their lifestyle in the ways we will discuss in future chapters. Such an approach can reduce or may even eliminate every type of inherited genetic risk, with the exception of those rare genetic diseases that are virtually irreversible.
And you and I can go even further with this new understanding: We can engage in practices that optimize gene expression for a lifetime of sustained wellness.
We sometimes designate this new approach to human biology by the term epigenesis, which conveys the sense that our genes and DNA are dynamic and fluid in their expression. Evidence for epigenesis is now very well-established in the leading medical journals. Hundreds of studies show that our genes are responsive to the biochemical and energetic environment we create in and around our cells through our daily choices. As a result, a thrilling new picture is emerging: the discovery that our biology is consciously modifiable. Scientists are discovering that our bodies — and our gene expressions — quickly adapt to new conditions, and they are also learning that these adaptations can be traced to specific biomarkers (covered in the next chapter) that you and I can target to boost our health prospects. The general academic discipline concerned with this approach is systems biology, and its clinical application has been called functional medicine.
Yet, the mind-sets of many geneticists and doctors are out of step with these newly discovered realities, too often because of biases in favor of the old paradigm based on previous training — or sadly, because they are driven by the momentum of commercial considerations. As a result, today's biomedical science is riddled by at least two very divergent approaches. Genetic researchers and medical clinicians are diverging into two general types:
The mechanistic approach: Those who focus on using whole-genome mapping to identify mutations that have a probability of resulting in disease, with the aim of developing drugs or surgical procedures that either treat these genetic predispositions preventively or after the associated genetic disease appears.
The systems approach: Those who search for modifiable biomarkers — including gene variants, epigenetic modifiers, and biomic markers in the gut — and who use this information to design a set of lifestyle and environmental changes that create measurable health improvements in the targeted biomarkers.
Clearly, the first approach above is of course the one chosen by Ms. Jolie. This reductionistic understanding of the genome has given rise to a host of companies that exploit the fear that our genes dictate our destiny. Again, it is true that inheriting certain gene variants guarantees you will get a rare disease; but the overemphasis on that isolated fact has gone so far that, as we'll see, government regulators have had to step in powerfully to protect the public.
This lesson especially applies to all of us concerned with optimal health, especially if we work in the healthcare industry. All of us will need to modify our business practices and our health practices in light of the research that conclusively proves that our genes respond — or more specifically our epigenome and our gut biome respond — to how we interact with ourselves, with each other, and with our world.
Introducing the New Science of Epigenetics
We've noted that when the map of the human genome was first revealed, it was believed that geneticists would soon be able to make solid predictions about which diseases each of us would get as we age. But the immediate aftermath of the mapping of the human genome has led in a radically different direction as we begin to understand the human epigenome. We now know that environmental and psychosocial factors as well as lifestyle choices play the largest part in how our epigenome functions, which in turn determines the expression of the genes that govern our health and longevity.
Epigenomics, the new scientific discipline of research into the epigenome, is the study of the chemical tags that park themselves on the genome that literally control the activities of our genes. In a sense, these markers appear "above" the genes — and is thus signified by the Greek prefix "epi," which means "above" or "upon." It is almost as if there are two languages being "spoken" by our DNA: the original "script" of our genome, and a secondary and more powerful linguistic control system that sits on top of each gene. This system determines, more than 95 percent of the time, whether, when, and how much a given gene (or some other portion of the DNA strand) is permitted to express itself as it does its routine work of "coding" for a myriad of biochemical activities in the cell.
The analogy of a theatrical script helps illustrate how epigenetic regulation works. Perhaps you have seen different movie versions of William Shakespeare's Hamlet — for example, those featuring Richard Burton (1964), Kenneth Branagh (1996), or more recently Benedict Cumberbatch (2015). These films differ greatly from one another, but of course the words on the page in Shakespeare's underlying script never change. Shakespeare's original theatrical script can be compared to our genetic code, and the differing performances of Hamlet are analogous to the function of epigenetic regulation. Once we inherit our unique genome, how it appears "on the printed page" remains stable throughout our lives; what is critical is our expression of these "lines" of the DNA script in and by the way we live our lives. In that sense, we are like actors who are "directing" the "performance" of our genetic script in ways that are unique to us, but in a manner that is also conditioned by the "theatrical set" — our immediate environment.
Allow me to extend the metaphor a bit more. If we could read our epigenome, it would look like a director's "notes" that we have written above the lines or in the margins of our genetic "screenplay"; this "shooting script" provides the epigenetic modifications that are made possible by our directorial choices. In essence, we direct our biological lives in the same sense that a movie director determines the expression of the underlying script by the actors (not to mention set designers, lighting and camera crew, etc.).
Bear in mind, however, that the variations in gene expression that make up our epigenome do not govern every biological trait or function. Certain physical characteristics, such as eye color or height, are one hundred percent predetermined by the inherited genes. This characteristic of gene expression is known as gene penetrance. For example, in identical twins, the penetrance of their genes for physical appearance is one hundred percent guaranteed. Plus, as noted, gene mutations that program for certain rare diseases also have this level of predictability — they can't be modified epigenetically. But again, complete penetrance is the exception, and not the rule — as we will soon observe in living color when we examine the genetic studies of identical twins.
Penetrant genes make up only about five percent of the human genome. In all other cases, genes for thousands of functions must be either activated, suppressed, or modified by epigenetic mechanisms. That's the bottom line for this discussion, but there's one more feature of the epigenome to ponder later on. The epigenetic alterations that you may acquire don't just change your biology during your lifetime; some of these modifications can be passed on to future generations that follow you. This surprising phenomenon is known as transgenerational epigenetic inheritance.
If I may use yet another analogy, we can compare epigenetic regulation to switching on or off a light in your bedroom. Much like our genetic code, the light switch on your wall and the light bulbs and their fixtures that are connected by wires to this switch are a stable presence — they are the infrastructure that always remains in place. But you are the determining factor in this simple equation. You must decide whether or not you want the light to shine, or whether this light should be turned up or down in intensity.
Our growth from the time of our conception and our daily health practices and habits — along with the routine moment-to-moment shifts in the functions of the tissues and organs of our bodies through a variety of biochemical pathways — all these factors constitute a galaxy of biological changes that determine our well-being in this life. All of these elements are orchestrated by the biochemical switches that constitute the epigenomic superstructure that sits on top of our inherited genetic infrastructure. Specific chemical reactions are able to switch the relevant parts of our genome on and off or up and down at strategic times and locations on a given gene or on the vast regions of the DNA strand that were once known as "junk DNA." Epigenomics is the study of the biochemistry that regulates those switches — for humans as well as for all organisms.(Continues…)
Excerpted from "Change Your Genes, Change Your Life"
Copyright © 2019 Kenneth R. Pelletier.
Excerpted by permission of Origin Press.
All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.
Excerpts are provided by Dial-A-Book Inc. solely for the personal use of visitors to this web site.
Table of Contents
Foreword Dr. Andrew Weil xxi
Chapter 1 New Reasons to Hope
What We've Learned about Genes 13
Chapter 2 Keys to Wellness
Biomarkers That Govern Your Health 39
Chapter 3 Epigenesis
Seven Pathways to Optimal Health 63
Chapter 4 Nutrigenomics
Your Genes and Biome Express What You Eat 91
Chapter 5 Mind Matters
Turn Off Genetic Vulnerabilities by Reducing Stress 135
Chapter 6 The Era of Personalized Medicine
What the Future Holds 169
A Selection of Sources Consulted 195