In the 21st century, we all are aware that what we eat influences our health.
In the last decade we are beginning to learn that what we eat also influences the health of our children.
Something as simple as the food you eat can change yours and your children’s epigenome.
What is the “Epigenome”?
Our cells execute distinct patterns of gene expression that control how are bodies function and our health.
While we are unable to change our actually genes, we can change how those genes are expressed.
Changes in how our genes are “programmed” or expressed without changing our actual genome is termed epigenetics.
The epigenetic programming of gene expression is somewhat dynamic in response to environmental exposures — especially during fetal development and early in life (1).
The epigenome is the expression or cellular phenotype, caused by mechanisms separate and independent from changes to the underlying DNA sequence.
Our epigenome is equally important as our genome as it orchestrates the development and maintenance of an organism by a set of chemical reactions that switch parts of the genome off and on at strategic times and locations (2). In essence, our epigenome is the expression of our genetic material.
Researchers over the past decade have shown that our genome dynamically interacts with the environment through “chemical switches” that regulate gene expression, our epigenome, receive cues from stress, diet, behavior, toxins and other factors (2).
The field of epigenetics has revolutionized the field of genetics.
As we will see in this post, our environmental factors significantly impact our genetic expression, our phenotypes, and even the genetic expression of our offspring.
Nutrition and the Epigenome
It is almost superfluous to mention that what we eat plays a significant role in our health as we are living in the middle of a “nutrition and lifestyle” derived obesity epidemic. Researchers have clearly shown that nutrition plays a role in disease, and have recently begun to demonstrate that the mechanisms behind the influence of nutrition on disease can and do occur at the level of the “epigenome”.
What we eat has the ability to impact our genetic expression, our epigenome, through a process known as methylation. Methylation is the process of the addition or substitution of a methyl group to a substrate, atom, or group.
Methylation can occur in various places throughout the body but here we are focused on DNA methylation, is a epigenetic signaling tool that cells use to lock genes in the “off” position. The process of DNA methylation is a critical part in normal development of an organism (humans included).
Furthermore, DNA methylation can serve to stably alter genetic expression such that cells can “record their history” or remember past experiences. This process of methylation could almost be argued as “mini-evolution” within a single organism and is a vital component to controlling gene expression (3)
Many of the foods we eat are rich in methyl donating groups and have the ability to rapidly alter gene expression including methionine, folic acid, vitamin B12, vitamin B6, choline, betaine, and a handful of others (4,5). See Table 1 for dietary sources of these compounds.
|Methionine||Chicken Breast, Beef, Liver, Salmon, Eggs, Cashews, Walnuts, Almonds|
|Folate (folic acid)||Liver, Seaweed, Lentils, Spinach, Egg Yolks, Broccoli,|
|Vitamin B12||Liver, salmon, trout, tuna, beef, milk, eggs, “fortified” cereals|
|Vitamin B6||Liver, Tuna, Salmon, Chicken, Potatoes, Banana, Beef|
|Choline||Egg yolks, Liver, Shrimp, Pistachios, Salmon, Bacon|
|Betaine||Lamb, Beets, Spinach, Quinoa, Kamut|
The foods we eat can and do affect DNA methylation and subsequently our epigenome. In the last decade researchers have shown how powerful the results nutritional DNA methylation are in genetic expression and the subsequent phenotypes of organisms.
There are a few landmark papers that one must discuss when addressing the impact nutrition has on DNA methylation and our epigenome. I will post links to several papers but there is one in particular I want to point out.
Perhaps, the landmark study in examining the role nutrition plays in our epigenetics involves examining the role of methyl supplements play in epigenetic variation and DNA methylation in offspring of mice. The paper is titled “Maternal Methyl Supplements in Mice Affect Epigenetic Variation and DNA Methylation of Offspring” In short, succinct terms, Agouti mice, were fed one of three diets during pregnancy: control, mid-range methyl supplement, and high methyl supplement. Table 2 shows the mid-range and high methyl supplement diet breakdown.
I don’t want to get too technical with the results as it takes some time to make sense of but the take home message is crystal clear. The researchers found significant differences in DNA methylation and epigenetic phenotypes based upon the amount of methyl supplementation in the diet during pregnancy.
The difference in epigenetic phenotypes was apparent as the offspring from the high methyl diet group had darker coats and were skinnier than the offspring of the control and mid-range methyl group. Here are two pictures (c/o University of Utah ) to illustrate this point.
The discussion section of this paper is articulate and straight-forward and I highly recommend reading through it. Although this study was conducted in mice, the concept and process of DNA methylation and the subsequent epigenetic changes in progeny are virtually identical in humans (the authors of this paper address this issue in the last sentence of the article).
The author’s discuss the implications of their findings in regards to the role of nutrition and epigenetics in humans.
“Epigenetic variation affecting health and life span could contribute significantly to individual variation in longevity, as seems to be the case in experimental animals with identical genetic and environmental backgrounds. Similarly, epigenetic variation could account for a significant portion of the health and life span variation seen in humans, although parsing these influences from other variables in humans would be a daunting task without guidance from well-defined examples in animal systems. The epigenetic variations that affect adult health and life span are probably established during embryonic and fetal development.”
Furthermore, the author’s continue one to address the role of epigenetics in disease stating, “Many human diseases may have significant epigenetic components. Epigenetics plays an important role in many cancers that appear late in life and may have roots in epigenetic inheritance or epigenetic variation established in early development. Insufficient methylation of many parts of the genome can lead to disease in humans, and, in mice, lowered survival”.
The point I am attempting to make is this. What we eat directly affects our DNA through epigenetic modifications. This process alters our genetic expression.
These changes are not limited to one’s self, they can and are passed onto your children.
Additional Papers on Nutrition and Epigenetics