The Human Genome Project was an ambitious plan to completely map out all the DNA found on our 23 pairs of chromosomes. It was first proposed in 1984 with a hope that once we completed it, we would have all the information about our genes and would gain the understanding of how our DNA affects our health. The largest collaborative biological project in history began in 1990 and after 13 years and around a billion dollars spent, finally completed their work in 2003. I remember when I was a student at UC Berkeley in the Molecular and Cellular Biology department in the late 90´s, there was a lot of excitement about the upcoming completion of this project. There was optimism that we would finally have the answers to many diseases including cancer and congenital illnesses.
And, we learned a lot from this project. Much of the new research in medicine and diseases have been driven from this. As an interesting aside, only 15 years later, you can sequence an entire human genome in 1-2 days for less than $5000 – a staggering stat that shows the progress of technology in such a short time.
However, as is the case often in science, the more we learn, the more we realize that we don´t know. Life is supremely complicated. We thought that once we knew the secret of our genome, we would know everything we needed about genetics. Two new areas of research show us that there is still much more to learn – epigenetics and the microbiome. I will talk about the first this week and the second will wait for a later time.
The first area is the concept of epigenetics. This is a fascinating area of much new research. To oversimplify, epigenetics is the study of how we turn on or off certain genes. This process is necessary for our cells to specialize. Every cell in our body starts from a single cell zygote formed when a sperm fuses with an egg. However, as this cell divides and grows – cells need to specialize – some will become skin cells, others muscle tissue, still others neurons in our brain. Each cell still has all the same DNA, but it is which genes that are turned on or off that determine what type of cell it will become. This process is controlled by epigenetic changes where certain parts of our DNA become accessible and other parts become closed off.
But, cell specialization is only one part of this equation. We are learning that many illnesses can be caused by these epigenetic changes including cancer, asthma, autoimmune diseases like rheumatoid arthritis and lupus, and even mental illness. Also, there is growing research that our nutritional status, vitamin levels, and exposure to toxins in the environment can have a dramatic effect on our epigenetics and can contribute to health or disease. And lastly, the most staggering implication is that these changes can be passed on to our children and grandchildren. When we eat healthier and do things that help us, it appears to have benefits for our future generations and when we are exposed to chemicals or have nutritional deficiencies, this can negatively affect future generations.
Epigenetics also helps explain why identical twins, who have 100% identical genetics, begin to have differences shortly after birth. One may have an illness and the other not, even with the same genes and similar upbringings. Over time, however, their epigenetic maps(what genes are turned on and off) become almost as different as two unrelated individuals. This epigenetic pattern can have almost as much to do with our health, vitality, and disease risk as our genes themselves.
This research is still very new. We knew virtually nothing about this until recently and we still have a lot to learn. And more and more epigenetic studies are showing a mechanism for how making healthier choices in food and lifestyle can improve our overall well-being and lower our risk for disease. Smoking, drugs, and environmental pollution exposure have the opposite effects. And again, these changes can affect our children and grandchildren, so these things are even more important if a woman is pregnant or if a man or woman wants to have children later in life.
For now, it seems to validate what we have known for a while – eating healthier, staying physically active, avoiding drugs and toxic exposures, getting adequate sleep, and being emotionally content, all are important for our overall health and preventing disease. We just did not know that these things can actually affect our DNA and can even help or hurt the next 3-4 generations. For now, here are a few takeaways to help without epigenetic profiles to keep our disease risk down and stay as healthy as possible for us and our descendants:
- Limit exposures to toxic chemicals that can negatively affect our epigenetics:
- Heavy metals such as cadmium, arsenic, nickel, chromium, methylmercury have been shown to negatively affect epigenetics
- Air pollutants such as particulate matter, black carbon, benzene can also negatively affect our DNA
- Endocrine disruptors such as bisphenol A (BPA – found in some plastics), persistent organic pollutants, dioxin and certain industrial chemicals (trichloroethylene, dichloroacetic acid, trichloroacetic acid) have been shown to be problematic
- Stop smoking
- Chemicals in tobacco smoke have been linked with negative epigenetic changes
- Consume more antioxidants and phytonutrients found in a plant-based diet
- Cruciferous vegetables like broccoli, cabbage, kale, etc have show positive epigenetic effects
- Spinach, garlic, brazil nuts, kidney beans, and soy products contain methionine which has shown to be protective
- Leafy green vegetables, peas, beans, and sunflower seeds contain natural folic acid which seems to be helpful. Vitamin supplements of folic acid or fortified grains have shown mixed benefit, but can possibly be unhealthy for some individuals based on genetics.
- Red wine and Green Tea are beverages with beneficial antioxidants which can help protect our DNA
- Some small studies in animals have shown some promise with a Ketogenic type diet – low carb, higher fat, moderate protein. The benefit may also come with supplements that provide ketones from outside the body – especially on mental processes.
The field of epigenetics is really in its infancy at this point. It will be exciting to see what happens in the next few decades and new therapies are already starting to be proposed and tested based on the concept. It also is showing us that just because we know our genes (and there are many ways now to test your genetics), we don’t have the whole picture based on this. It is also important which genes are turned on and off. And that is determined more by our environment than we ever knew before. And, as I stated at the beginning, the Microbiome map (the different bacteria we have living in our digestive tract and around our body) can be equally important for health and disease as our genes and our epigenetics. We will focus on that in the next article.