Our nutrition occupies a great deal of our time day to day. We are constantly eating to fuel our bodies with enough calories to achieve our goals for the day. But our diets can do more than just offer us calories. Can food change your genes and affect the health of your skin?
Nutrition from foods we eat can negatively or positively affect our overall health depending upon the type of food and the nutrients within each food. Yet not much is known about how our diet affects our overall skin nutrition and health. Looking closely at the way different foods impact the way our cells function is a major area of research. One particular way foods may affect our skin cells is through the modulation of our genes through processes collectively called nutritional epigenetics.
What Is Epigenetics?
DNA is the structure that contains our genes or hereditary material. Each person has their own very specific DNA, similar to the way fingerprints are specific and no two people have the same. At one time, scientists thought that our DNA was the only factor that determined who we are. However, scientists have uncovered several ways that our body modifies the expression of our DNA. Different foods have been shown to impact the way we use our DNA - creating even more diversity in different people with different nutrition. There are 3 major ways our bodies can change DNA directly: methylation, chromatin modification, and noncoding RNAs.
- Methylation adds methyl groups to DNA to turn genes off and demethylation removes the methyl groups to turn genes on.
- Chromatin is the large package that contains the DNA in each and every cell in the body. DNA is like a string that winds around proteins called histones that fit tightly together to create chromatin. Modifying histones by adding bulky groups makes the package easier to open, making DNA more accessible to be read and translated. But if the groups are removed from histones, they can come together and fit perfectly into their chromatin structure, making DNA less accessible.
- Noncoding RNAs are small pieces of modified DNA that can cover up and hide parts of DNA to turn genes off or make genes more visible, turning them on.
These changes in DNA expression are collectively called epigenetics. When and which genes get turned on or off is still an area of research. How foods, drinks, vitamins, and minerals affect our DNA is also still being studied. But we know our internal genetic programming, nutrition, and other environmental factors can play a role in epigenetics. Some foods have already been shown to affect our DNA through epigenetics.
Vitamin D is a very important vitamin involved in balancing the calcium levels in our body. Recently, research has shown that vitamin D is also very important for our immune system to work properly. In skin cells, vitamin D has been shown to activate an important protein that combats microorganisms like bacteria called cathelicidin. Vitamin D also activates immune cells within the skin, which has a tag known as CD14. It does this by making the genes for cathelicidin and CD14 more accessible through epigenetics. So vitamin D applied directly to the skin or activated by the sun, stimulated the skin’s natural immune system to be ready for foreign microorganisms. Many studies have shown that vitamin D affects the immune system in ways other than epigenetics as well.
Folate, vitamin B12, and choline
There are some vitamins that are known to help in the process of turning genes on and off by adding things to DNA. Folate (folic acid), vitamin B12, and choline are just some of these vitamins. These three vitamins have been shown to affect genes involved in eczema development. Although the results from various studies have been mixed on whether folate, vitamin B12, and choline have a positive or negative effect on eczema, there is little doubt that they impact our genes by silencing and activating genes through DNA methylation.
Polyphenols in Green Tea, Soy Beans & Other Foods
Polyphenols are compounds found in all sorts of foods like green tea and soybeans. Recent research has found that these substances are beneficial in various parts of our bodies. Some polyphenols, including flavanols, garcinol, and curcumin have been found to inhibit DNMT1, an enzyme that turns off genes by adding methyl groups to DNA. By inhibiting DNMT1, polyphenols prevent methylation of DNA and turns genes on, allowing them to be read and translated into their designated proteins.
Many polyphenols, like resveratrol in grapes, nuts, and chocolate have been shown to activate a group of enzymes known as sirtuins. These enzymes make DNA less accessible which silences DNA. One specific sirtuin, SIRT1, has been shown to promote the expression of filaggrin, a protein involved in maintaining skin integrity. In up to 50% of patients with significant eczema, the genes that make filaggrin are defective. One study found that SIRT1 was low in eczema lesions of mice and when the mice were created with an absence of SIRT1, they ended up developing eczema lesions. This tells us that when polyphenols activate SIRT1, they are promoting our skin integrity.
EGCG in green tea
The major polyphenol in green tea, epigallocatechin-3-gallate (EGCG), has been shown to have anti-cancer effects. One way in which EGCG does this is through the reactivation of genes that are shut off by skin cancer, specifically p21 and p16. Both p21 and p16 are important proteins that help prevent and combat cancer. EGCG reduced the DNA silencing (by reducing DNA methylation) of the genes that make these proteins, thereby turning the genes back on, allowing the proteins to be made. EGCG has also been shown to inhibit the enzyme DNMT1.[11,12] DNMT1 is an important enzyme in DNA methylation and acts to silence DNA. This means that EGCG in green tea shuts off the off switch, which means it turns genes on.
Genistein in soy beans
Genistein, a polyphenol found in soybeans, has also been found in different studies to inhibit DNMT1 in cancer cells and reactivate genes like p16 important in cancer prevention. While these studies looked at esophageal and prostate cancer cells, genistein may have similar functions for skin cells but more research needs to be done. Another study looked at human eye melanoma cells outside of the body. The researchers looked at genistein’s effects on these melanoma cells from the eye. The study found that genistein inhibited the melanoma cells using a noncoding RNA, miRNA-27a. Along with genistein, miRNA-27a has been shown in various studies to inhibit the growth of different cancers throughout the body.[15,16]
Foods and Your Genes
Although the question of whether foods can change gene expression has some early answers, there is still much to learn. How much of any one food we need to eat or drink to see the positive effects stills needs to be determined before we stock up on vitamin supplements, tea, or soybeans. Some studies have shown effects on the body with amounts of food that is impossible to consume in one day! How so many other foods in our diets impact our overall skin health remains to be seen and research is ongoing to find out. We can say our genes are definitely affected by what we eat.