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How diet influences gene expression
The genetic information contains the complex code that controls the development of a living being. This code is contained in a structure known as DNA and is read in the form of genes. The human genome contains 20,000 to 25,000 genes that code for proteins that participate in a wide variety of cellular functions. In order to keep the genomic information intact, there are several mechanisms that are in charge of checking for errors that could potentially cause a mistaken genetic sequence, ending up in a not very nice outcome.
However, there are several factors that naturally cause changes, or mutations, in the genetic code. These factors can either act directly on to the DNA chain, such as errors that occur while the DNA is being copied when cells replicate, and environmental factors like UV rays or some toxic chemicals.
Epigenetic changes: What are they exactly?
There are other ways to alter the expression of a gene, which do not involve mutations, but subtle changes to the mechanisms that guard the DNA.
Researchers have focused in several mechanisms that can promote epigenetic changes, but one of the most studied is the effect of our diet in the induction of such modifications. Yes, just as you read: What you eat can affect the expression of one or several genes. It is hard to believe right? Because genes are supposed to be well kept in the nucleus of each cell. How would a burger or a broccoli floret could reach such a well-guarded site in your cells?
Food switches genes on and off
In general, all the food we ingest is modified in the gastrointestinal tract in order for it to be absorbed by the cells of the small intestine, transported through the blood stream and metabolized by the cells.
Certain food components, when metabolized, produce a specific chemical group known as methyl group.
Once DNA methylation, as this process is called, happens, it stays throughout the life of the individual.
Where can we find methyl groups?
Certain foods are better as methyl group donors than others. Vitamins and minerals, such as vitamin B12 and B6, and methionine and folic acid, are important in the chemical synthesis of methyl groups.
Other substances like betaine, present in wheat, spinach and beets, resveratrol, present in red wine, and genistein, an antioxidant present in soy, also participate in the production of methyl groups.