While traditional genetics describes the way the DNA sequences in our genes are passed from one generation to the next, epigenetics describes passing on the way the genes are expressed and used. Epigenetics is additional information layered on top of the sequence of letters (strings of molecules called A, C, G, and T) that make up DNA.
How does epigenetics work? The epigenome is a series of chemical modifications that occur on DNA or specific amino acids in histone proteins that DNA is wrapped around. These act as markers or tags (like post-it notes) which tell genes whether they should be active or inactive.
There are two main types of epigenetic modification:
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DNA methylation (and demethylation): DNA methylation is the addition or removal (demethylation) of a methyl (CH3) group to the 'C' (cytosine) molecules of DNA, often modifying the function of the genes and affecting gene expression. Generally, more DNA methylation of a gene results in the gene being switched off.
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Histone modifications: Other tags can be added to proteins called histones that are closely associated with DNA. Histones can be modified either by acetylation or methylation. These are chemical processes that add either an acetyl or methyl group respectively to the amino acid lysine that is located in the histone. Acetylation promotes gene activation, whereas deacetylation is associated with gene repression. Methylation is associated with both gene activation and repression.
Note: This is not a complete list of types of epigenetic modification, but these are the main ones, and it's beyond the scope of this newsletter to cover all known epigenetic processes.
How is epigenetics related to my health?
Everything is epigenetics - what you eat, where you live, who you interact with, when and how much you sleep, how you exercise. Even aging can eventually cause chemical modifications around the genes that will turn those genes on or off over time.
Perhaps it helps to view epigenetics as the reason that it's so important to do all the right things in terms of our lifestyle and to live in a healthy environment. They are all influencing our epigenome, and we need to do what we can to keep it (ourselves) healthy. For example, consuming plant flavones (eating your broccoli) has been linked to a reduction in cancer - now we know that the intermediate step involves changes in DNA methylation, i.e., epigenetic changes.
Epigenetics is reversible. If we could map every single cause and effect of the different combinations of genes being turned on or off, and if we could reverse the gene's state to keep the good while eliminating the bad, then we could theoretically prevent or cure diseases, slow aging, stop obesity, and much more.
That's a big "if" and it may be more helpful to think in terms of how our lifestyle and environment in the broadest sense may be affecting us epigenetically. A wide variety of illnesses, behaviours, and other health indicators already have some level of evidence linking them with epigenetic mechanisms, including most types of cancers, cognitive dysfunction, and respiratory, cardiovascular, reproductive, autoimmune, and neurobehavioural illnesses. Known or suspected drivers behind epigenetic processes include many agents, including heavy metals, pesticides, diesel exhaust, tobacco smoke, polycyclic aromatic hydrocarbons, hormones, radioactivity, viruses, bacteria, and basic nutrients.
Epigenetic influence of foods and supplements
While epigenetics is relatively new, and more study is still necessary, there are several links between foods and supplements and epigenetic health. In addition to the link between flavones and reduction in cancer mentioned above,
- polyphenols (found in fruits, vegetables, olives and chocolate) have been shown to effectively promote resilience against stress and in reducing depression by modulating inflammatory responses, and synaptic plasticity in the brains of those with depression.
- grape-derived compounds may epigenetically promote resilience against depression.
- blueberries are extremely high in antioxidants, and it is believed that this can epigenetically reduce DNA damage, protecting people against cancer, and possibly even slowing aging.
- B vitamins have the potential to epigenetically protect against harmful pollution. Air pollution has been shown to disturb DNA methylation profiles, which could worsen inflammatory and oxidative responses.
The good news is that we have a lot of control over many of the environmental factors that affect our epigenome. Knowing the adverse epigenetic effects of making the wrong choices gives us another reason to do our best to make wise choices and decisions.
