You are What Your Grandmother Ate: How Diet Can Affect Your Genes
We have all heard the saying, “you are what you eat”, but until recently, we had no idea that what your grandparents ate could affect your health, and at a genetic level! Studies show that your grandmother’s childhood nutrition may have influenced your birth weight, or if your grandfather overate between the ages of 9 and 12, you could be more susceptible to diabetes and heart disease.
But how does what you ingest affect your genes and those of your offspring? Diet composition, calorie intake and exposure to chemicals in foods and food packaging can dramatically affect how your genes function. One potential route is through a recently characterized process called “epigenetics”. Epigenetics refers to heritable changes in gene function that are not due to changes in the genetic sequence.
Most people are familiar with the concept that a person’s genes determine their hair color, eye color, body frame etc. Individuals pass genes from generation to generation, and unless an abnormal event causes a mutation, their content is fixed. However, scientists have discovered that DNA and the proteins involved in their packaging contain molecular tags that instruct a gene when to be active or inactive. Your environment—for example, what you eat and breathe—can trigger cellular signals that cause tags to be added or removed, this is one way an organism adjusts to fit a changing world.
During early embryonic development, most of the epigenetic tags from the parents’ DNA are removed. However, some tags are permanent and therefore inherited by subsequent generations. These are “imprinted” on the genes of your offspring. This is how epigenetic tags, and their consequences, can span generations.
Why is this important to health? Epigenetic alterations of gene expression can affect your disease risk, and can affect the development of type II diabetes, obesity, inflammatory disorders, cancer, and neurodegenerative disorders. A good example is the epigenetic silencing of a tumor suppressor gene or the activation of a cell survival gene (or the simultaneous occurrence of both), which can lead to the development of cancer.
How does nutrition fit in? What you eat, how much you eat, and what chemicals you’re exposed to can alter your epigenetic profile. Epigenetic tags are primarily methyl groups (a carbon atom attached to three hydrogen atoms), and your body gets these from sources like B-vitamins, folic acid and choline (found in leafy vegetables, whole grains and liver). Therefore, if you don’t eat enough of these foods, the genes you need for health may not express properly.
Animal studies show that folate or choline deficiency during gestation and right after birth can lead to permanent under-methylation of certain areas of the genome. The same effect occurs in adults, but the change is reversible by a diet full of methyl-donating foods. Also, environmental chemicals such as bisphenol-A (BPA), which is present in food packaging and containers, can affect your epigenetic gene expression. Interestingly, eating a diet with plenty of methyl-rich foods can protect you to some extent from the DNA-altering effects of these chemicals.
Although there isn’t much you can do about your grandparents’ diet, you can make some simple dietary changes, such as eating a diet rich in leafy vegetables, whole grains and liver to improve your epigenetic “profile”, decrease your risk of disease and improve your overall health. If you’re curious, the next time you visit grandma, ask her what she ate for breakfast when she was a child.
Image from Nutrition Science Bites at nutritionsciencebites.wordpress.com.
Reviewed by: Ruthanna Gordon
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