Over the past century, researchers’ understanding of genetics has undergone a profound transformation.
Genes, the regions of DNA largely responsible for our physical characteristics, were considered immutable under the original model of genetics pioneered by biologist Gregor Mendel in 1865. That is, genes were thought to be largely unaffected by a person’s environment.
The emergence of the field of epigenetics in 1942 shattered this idea.
Epigenetics refers to changes in gene expression that occur without changes in the DNA sequence. Some epigenetic changes are an aspect of cell function, such as those associated with aging.
However, environmental factors also affect the functions of genes, that is, people’s behavior affects their genetics. For example, identical twins develop from a single fertilized egg and, as a result, share the same genetic makeup. However, as twins get older, their appearance may differ depending on different environmental factors. One twin may eat a healthy, balanced diet while the other eats an unhealthy diet, causing differences in the expression of genes involved in obesity, which helps the former twin have a lower body fat percentage.
People don’t have much control over some of these factors, like air quality. But other factors are more within a person’s control: physical activity, smoking, stress, drug use, and exposure to pollution from plastics, pesticides, and the burning of fossil fuels, including car exhaust.
Another factor is nutrition, which gave rise to the subfield of nutritional epigenetics. This discipline relates to the concepts of “you are what you eat” and “you are what your grandmother ate.” In short, nutritional epigenetics is the study of how your diet and the diet of your parents and grandparents affect your genes. Because the dietary choices a person makes today affect the genetics of their future children, epigenetics can provide motivation to make better nutritional choices.
We both work in the field of epigenetics. The other explores how diet and lifestyle choices can help people stay healthy. Our research team is comprised of fathers, so our work in this area builds on our already intimate familiarity with the transformative power of parenting.
A story of famine
The roots of nutritional epigenetics research can be traced back to a poignant episode in history: the Dutch Hunger Winter in the final stages of World War II.
During the Nazi occupation of the Netherlands, the population was forced to live on rations of 400 to 800 kilocalories per day, a far cry from the typical 2,000 kilocalorie diet used as standard by the Food and Drug Administration. As a result, approximately 20,000 people died and 4.5 million were malnourished.
Studies have found that famine causes epigenetic changes in a gene called IGF2, which is involved in growth and development. These changes suppressed muscle growth in both the children and grandchildren of pregnant women who endured the famine. For subsequent generations, this pressure has led to increased risks of obesity, heart disease, diabetes and low birth weight.
These findings marked a pivotal moment in epigenetics research and clearly demonstrated that environmental factors such as famine can lead to epigenetic changes in offspring that can have serious effects on their health.
The role of the mother’s diet
Until this groundbreaking study, most researchers believed that epigenetic changes could not be passed on from one generation to the next. Rather, researchers reasoned that epigenetic changes might occur during early life exposures such as pregnancy, an extremely sensitive period of development. Therefore, the first nutritional epigenetics research focused on dietary intake during pregnancy.
Findings from the Dutch Hunger Winter were later supported by animal studies; This allows researchers to control how animals are raised, which can help control background variables. Another advantage for researchers is that the mice and sheep used in these studies reproduce faster than humans, allowing faster results. In addition, researchers are able to precisely control the animals’ diets throughout their entire lives, allowing certain aspects of the diet to be manipulated and studied. Together, these factors allow researchers to better investigate epigenetic changes in animals than in humans.
In one study, researchers exposed pregnant female mice to a commonly used antifungal drug called vinclozolin. In response to this exposure, the first generation born showed a decreased ability to produce sperm, leading to increased male infertility. Critically, these effects, like the famine, were passed on to subsequent generations.
While these studies were tremendous in shaping nutritional epigenetics, they neglected other developmental periods and completely ignored the role of fathers in the epigenetic inheritance of their offspring. However, a more recent study in sheep showed that paternal diet supplemented with the amino acid methionine fed from birth to weaning affected the growth and reproductive characteristics of the next three generations. Methionine is an essential amino acid involved in DNA methylation, an example of epigenetic change.
Healthy choices for future generations
These studies underscore the lasting impact of parents’ diets on their children and grandchildren. Because the dietary choices parents make impact their children’s diets, they also serve as a powerful motivator for parents and current parents to make healthier dietary choices.
Consulting with a nutritionist, such as a registered dietitian, can provide evidence-based recommendations for making practical dietary changes for individuals and families.
There are still many unknowns about how diet influences and influences our genes. What research into nutritional epigenetics is beginning to show is a strong and compelling reason to consider making lifestyle changes.
There are many things researchers already know about the Western Diet that many Americans eat. The Western Diet is high in saturated fats, sodium, and added sugar, but low in fiber; It’s no surprise that Western diets are associated with negative health outcomes such as obesity, type 2 diabetes, cardiovascular disease and some cancers.
A good place to start is to eat more whole, unprocessed foods, especially fruits, vegetables and whole grains, and less processed or convenience foods (including fast food, chips, cookies and candy, ready-to-cook meals, frozen pizzas). canned soups and sugary drinks.
The health benefits of these dietary changes are well known and are described in the 2020-2025 Dietary Guidelines for Americans and by the American Heart Association.
Many people find it difficult to embrace lifestyle change, especially when it comes to food. Motivation is an important factor for making these changes. Luckily, this is where family and friends can help; They have a profound impact on lifestyle decisions.
But at the broader societal level, food security—meaning people’s ability to access and afford healthy food—must be a critical priority for governments, food producers and distributors, and nonprofit groups. Food insecurity is associated with epigenetic changes that have been linked to negative health outcomes such as diabetes, obesity, and depression.
With relatively simple lifestyle changes, people can significantly and measurably influence the genes of their children and grandchildren. So when you reject a bag of chips and choose fruit or veg instead, keep this in mind: It’s not just for you, it’s for future generations too.
This article is republished from The Conversation, an independent, nonprofit news organization providing facts and analysis to help you understand our complex world.
Written by: Nathaniel Johnson, University of North Dakota; Hasan Hatib, University of Wisconsin-Madisonand Thomas D. Crenshaw, University of Wisconsin-Madison.
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Nathaniel Johnson receives funding from the United States Department of Agriculture and the National Institutes of Health. He has previously received funding through the National Science Foundation, the National Beef Association and the North Dakota Beef Check.
Hasan Khatib receives fund no. From USDA National Institute of Food and Agriculture 2023-67015-39527
Thomas D Crenshaw receives funding from the Hatch Multistate Research Formula Funds; USDA/Natl. Institute of Food and Agriculture; DHHS, PHS, National Institutes of Health.