If every cell has the same DNA, how do some become neurons and others red blood cells? How do some produce smooth muscle and others fat? What makes cells differentiate is a process called epigenetics.
Carlos Aschoff, a molecular geneticist and medical adviser at DB Diagnósticos, likes to compare the process to an orchestra. “When we go to a concert, there’s a conductor and many musicians with their instruments, and the conductor is the one who decides when each instrument comes in, when it drops out, whether they all come in at once. He’s the one providing that regulation. That’s what epigenetics means,” he explains.
Through a series of mechanisms, certain genes either are or are not read by each cell, so some are expressed while others stay silent, without manifesting the trait they represent. “Genes have the function of encoding enzymes, hormones, transporters and receptors. So epigenetics is when, because of what we’re exposed to, our metabolism produces and releases chemical molecules that interact with our genes and change those genes’ ability to be expressed.”
Genetics versus environment
Beyond cell differentiation, science has found that epigenetics also comes into play in connection with some of our lifestyle habits. That’s because certain substances can trigger some of the mechanisms that keep these genes from being read.
To understand this better, it helps first to know some of these mechanisms:
Methylation: occurs when a methyl group binds to a specific DNA sequence, preventing it from being read. This process only happens where a cytosine is immediately followed by a guanine;
Histone modification: when the proteins that help package DNA are acetylated, methylated or phosphorylated, which changes which parts will be unpacked and read inside the cell;
Noncoding RNAs: RNA molecules transcribed from DNA but not translated into proteins, so they do not lead to expression of the gene they correspond to.
As it turns out, science has shown that much of what we consume may be linked to these mechanisms. “The nutrients or supplements we ingest that have the capacity to bring about epigenetic changes,” emphasizes nutritionist Annete Marum, a specialist in nutritional genomics, coordinator of a graduate program in nutrition and precision medicine, and a partner of Biotec Dermocosméticos.
Of course, this action is not entirely clear-cut — after all, the body has 37 trillion cells and DNA has about 20,000 genes. “It’s extremely complex for us to say which activities or which routines we should adopt that improve or worsen expression, or that will produce a better or worse response,” Aschoff cautions.
It is not yet possible to say whether specific habits can or cannot activate specific genes. Precision medicine, however, can tell that some specific nutrients may work, but it is still difficult to bring this into the doctor’s office. “When we assess this in cells, the change happens within a few hours. Usually, when we’re talking about intake of a nutrient, studies report an assessment at roughly 10 to 12 weeks. However, it’s important to say that this type of analysis isn’t assessed in standard lab tests,” Marum notes.
So why does it matter to know more about epigenetics?
Today, epigenetics can already be used in specific situations. “I believe it will still take a long time for epigenetic testing to become more widely available, but we already have epigenetic tests when we’re carrying out specific clinical investigations for neurodevelopmental disorders, for pathophysiological and diagnostic investigation of certain types of cancer, and for assessing methylation regions involved in the genesis of a specific cancer, such as colorectal cancer,” Aschoff lists.
“Epigenetic tests will not replace routine tests. They will add to them and provide more molecular information that will help physicians, alongside routine tests, understand this individuality and be more precise,” Marum predicts.
Another piece of good news from epigenetic research is that the changes involved can be reversed, although it is not known to what extent. “What we know is that in somatic cells the epigenetic process is reversible — it exists and it’s possible. But how far it can reverse years and years, that information doesn’t exist in the scientific literature,” the specialist says.
General advice on healthy lifestyle habits remains important in the clinic, and not only because of epigenetics. “Lifestyle changes generally have multiple impacts. They will have impacts on epigenetics, yes, but also on other areas of our lives that end up producing a benefit,” Aschoff emphasizes.
