I remember when I first heard about “epigenetics,” the study of the biological mechanisms that turn genes on and off. I was just starting the two years of science classes I had to complete before applying to graduate school for nutrition — classes I had avoided during my undergrad years studying journalism. When it came time to select a topic for a biology-class group project, I chose the intersection of diet, environment and genetics.
The research papers I started reading led me straight to epigenetics, and I was fascinated by the idea that the genes we inherit from our parents are not necessarily our destiny. That’s not because the genes themselves are likely to change in our lifetime, but because what happens within us and around us — nutrition, physical activity, stress, social connections, exposure to chemicals — can alter how those genes are “expressed.” In other words, whether they are turned on or turned off. If your genome is your body’s hardware, then your epigenome is its software.
If this topic intrigues you, you don’t need to power through a pile of research papers to learn more. In the new book “You Are What Your Grandparents Ate: What You Need to Know About Nutrition, Experience, Epigenetics & the Origins of Chronic Disease,” Toronto journalist and author Judith Finlayson has done that work for you. The book’s title refers to the fact that nutrition — as well as other lifestyle and environmental factors — can alter gene expression in ways that affect the risk of chronic disease two generations down the line. How is this possible? Because the egg you developed from was created in your mother’s ovaries while she was still a fetus in your grandmother’s womb.
A deeper understanding of health
Finlayson lays out the twists and turns in the history of epigenetics, beginning with the dismissal of early pioneers like British epidemiologist David Barker and Swedish physician Lars Olov Bygren in the 1980s and 1990s. The author also describes the gradual acceptance in the 2000s of the idea that adult chronic diseases may originate in the womb, and practical applications of the ever-evolving research on epigenetics (aka actions you can take to help shape your own epigenetic programming).
Finlayson said when she started reading Barker’s work, it was hard to wrap her head around the premise that nutrition during pregnancy could impact the probability that babies would develop chronic diseases as adults. “We’re so conditioned to believe that heart disease is a consequence of our lifestyle — that was a whole other way of looking at things.” She was already familiar with social determinants of health — the idea that conditions where we live, learn, work and play affect our health — but when she read about the link Barker found between poverty and heart disease, everything clicked.
“The more adverse childhood experiences you have, the greater likelihood that you’ll develop a chronic disease,” she said. “We have a health crisis now, and throwing money at medical care isn’t the answer.” Not everyone has access to nutritious foods, or lives in neighborhoods they can safely walk in. The book’s epilogue offers a compelling summary of how the current problem of income disparity may be altering life expectancy. “It’s more than an individual thing,” she said. “Within the context of what we know about social determinants of health, it’s a broader social problem.”
Critical windows: puberty and preconception
What surprised Finlayson most was Bygren’s discovery that men with grandfathers who had access to an abundance of food in the years right before puberty thanks to a bountiful harvest died six years sooner than men whose grandfathers experienced famine right before puberty. “Now we’re beginning to see through epigenetics that that’s because sperm cells are forming at that time,” she said.
The book provides abundant information about actions we can take throughout our life spans to encourage beneficial shifts in gene expression, including paying attention to nutrition during critical windows like the 1,000 days between conception and a child’s second birthday. The first eight weeks after conception are perhaps the most critical part of that window, but many women don’t have optimal preconception nutrition for a variety of reasons, including unplanned pregnancies and lack of support from the health-care system. This means as a society we’re missing a significant opportunity to improve the health of the next two generations.
Beyond personal responsibility
Western society is enamored with the cult of personal responsibility when it comes to health, but “focusing on health” is hard when your life is hard. It’s important to understand that we as individuals are not solely responsible for our health. That said, the idea that the foundation of your future health was laid before your parents were born, and further influenced by your experiences as a small child as well as by societal factors — none of which you had any control over — could be a bit depressing. “We’re conditioned to want simple solutions to complex problems,” Finlayson said.
Yet there is room for optimism. “This could easily be a story of hopelessness, or of hope. I vote for hope. No matter what hand you were dealt with your genetic ‘hardware’ or your epigenetic ‘software,’ you can improve on your hand. You can positively affect gene expression — we don’t know how much impact you can have, but you can have impact by avoiding environmental toxins, eating nutritious food and getting regular exercise. It’s one step at a time,” she said. “But this isn’t just another tale of personal responsibility like those we are so often told. There are serious inequalities in our society that impact health, and not everyone is able to go solo. If you can, do, and be thankful for your privilege.”