Epigenetics: You Are What Your Grandparents Ate

Why you should care about this relatively new field that shows that your lifestyle choices can affect the development of your grandchildren

Epigenetics generations

We all have heard the saying “you are what you eat.” Or “you are what you smoke or drink.”

The effect of environmental factors, including that of our diets, exercise regime, drinking habits, even stress levels, can severely impact our overall health. That is no secret.

Most people are probably also aware that what you do as a parent, will affect the health of your children. Not only do our own habits affect our children indirectly (through example and secondary exposure), but for pregnant women this influence of lifestyle choices on their children is direct and often clearly apparent.

For example, babies born to women who have excessive weight gain during pregnancy are 3 times more likely to be overweight at age 3. A more dramatic example is fetal alcohol syndrome, where children born to alcoholic mothers have a whole spectrum of possible developmental abnormalities, such as small stature, hearing and vision problems, and lower IQ.

We therefore all know to cut down on alcohol, quit smoking and eat healthy while we are pregnant to prevent those developmental defects in our children. But has anyone ever told you to cut down on the French fries for the sake of your grandchildren?

A relatively new field, called “Epigenetics” tells us that we absolutely should! The term literally means “in addition to genetic sequence.” It generally involves processes altering gene activity but not altering the DNA sequence. Here’s what that means in layman’s terms…

Typically, the traits we inherent from our parents, such as gender, physical appearances and our predisposition to certain diseases, are dependent on our genetics or genes. Most of us contain all the genes necessary to generate every building block to make the human body, as well as those genes needed to keep it functioning properly.

However, different genes are turned on or off as needed. For example, both liver and kidney cells have all the genes needed to make either cell type (liver or kidney). But only genes necessary to produce liver cells will be turned on in the liver, whereas the kidney-specific genes will be turned off.

When the embryo fails to “reset” the epigenetic recipe

To simplify this we can use the analogy of a baker’s pantry stocked with every ingredient you can think of. These ingredients represent the genes. The epigenome, however is the recipe that tells the baker exactly which ingredients and how much are needed to bake his favorite pie.

This epigenetic recipe is mostly “reset or reprogrammed” in the embryo after fertilization and during early development of the future sperm and eggs. But sometimes parts of the epigenetic recipe may escape this reprogramming, and that is when epigenetic inheritance occurs.

A classic example of epigenetic inheritance in humans came from the Dutch famine of 1944. It was noticed that offspring born to women who were pregnant during the famine were smaller (not surprisingly). However, years after the famine was over (it lasted only one winter) and calorie consumption returned to normal, the grandchildren of these individuals who experienced the hunger were also smaller, despite the fact that their parents received a normal diet for most of their lives.

Scientists therefore concluded that the epigenetic template was permanently changed in the eggs of women whose mothers experienced the famine while pregnant. Therefore, the effect could be seen in the grandchildren of the women who experienced the famine firsthand.

Another study looked at the population of a small town in Sweden from the early to late 20th century. A group of pre-pubertal boys (a time when sperm cells are maturing) experienced a “feast” season during the early part of the 20th century. When investigators looked at the grandsons of those boys, they found that they died on average six years earlier than the grandsons of boys who had been exposed to a “famine” season during the same pre-pubertal developmental window.

When the researchers controlled for socioeconomic factors, the difference in lifespan was a staggering 32 years. Similar to the findings from the Dutch famine, granddaughters of women who had experienced a “famine” season before or just after birth were at a significantly increased risk of early death.

One more Swedish study found that grandchildren of men who started smoking at a young age had an increased body mass index.

Your good choices may benefit your grandchildren

These and many other studies demonstrate why we should not only be concerned with the health of our children when we consider our own lifestyle, but also the health of our grandchildren. It isn’t to say that we should start limiting food intake of growing boys or over-feeding pregnant women or newborn girls. But it does make you wonder what other effects diet and environment may have on future generations.

The good news is that these epigenetic modifications can be advantageous, meaning your good choices may have a positive effect on your grandchildren. Furthermore, environmental factors can delete previous epigenetic changes, so that your good choices may in fact cancel out the bad choices of your parents, thereby improving the wellbeing of your own children.

So next time you contemplate an unhealthy lifestyle choice, stop to think about the generations to come.