So many people lament about the same set of non-communicable diseases but blame it on different causes, that it all becomes just not very credible any more.
The suite of problems is almost always the same: dramatic increase of obesity, diabetes, cancers, Parkinson's and Alzheimer's, immune system gone berserk, birth defects, infertility, autism, and so on.
The dizzying array of claims bombards us from different sides every day: endocrine disrupting chemicals and other environmental contaminants; too sterile environment (not enough good gut microbes); wrong chemicals in your food (as in too much sugar, saturated fats); modern lifestyle (as in you are a couch potato); GMOs (and the weird proteins these plants produce); heavy metals (lead and mercury); not enough natural chemicals – nutrients – in the food grown with intense agricultural methods, stress, pesticides, pharmaceuticals, antibiotics in meats and dairy products, etc. The only disasters not on that list are climate change and the population explosion. These two don't cause diabetes.
The common link in all these non-communicable disease epidemics seems to be gene expression. Frighteningly few people understand what it is, but once you get it, you can nicely fit the puzzle pieces together.
Epigenetics is the new buzz for science and health. It is about a suite of natural molecular tools that decide when and which genes in our DNA can be turned on and off. Epigenetic mechanisms regulate the interaction between a hormone and a gene expression.
Your DNA – the code that you get from each of your parents when you are just one cell - is the blueprint you get for making proteins. That is all you get. Somehow from that one cell you grow heart tissue, eye tissues, bone cells, and so on, each with wildly different characteristics. And every subsequent cell in your body as you live out your life carries that very same DNA. Be it a cell in the skin of your toe, your liver, or your brain.
In each organ that DNA is used trillions of times per second as the genes provide you with the proteins you need at the right time and place. That is absolutely vital to health, and to making you who you are, from your sex to your sexuality.
What makes this possible is that different genes of the DNA are turned on and off in different cells. That process is under the control of hormones.
For example, a hormone can stimulate a cell to make a protein that tells your cells it is time to eat, or a protein that protects you from tumors, or a protein that makes you happy. Liver works with enzymes, which are proteins made though gene expression. New blood cells are built with different proteins made thanks to gene expression.
The interaction between hormones and genes is controlled by epigenetic tools. There are a few mechanisms.
Some serve as a lock. Like a lock on an electrical switch, that prevents you from flipping the switch and turning on the light. A part of genes in the cell that constitutes your tooth is supposed to be quiet because a tooth is not supposed to make dopamine, for example. How do you make sure that part is not turned on? There is a lock stuck on that part of the gene.
There are molecular locks to prevent genes from being turned on at the wrong time or in the wrong tissue. One common ‘molecular lock’ is called methylation. A small molecule, called a methyl group, attaches itself to the gene in a way that prevents a hormone from reaching the switch. So the gene can’t be turned on and the protein it would mistakenly make isn’t made.
Another epigenetic mechanism – called histone modification – is coiling up the unused part of the DNA for example in your tooth enamel so it does not start functioning like the cell in your testicles. Hormones simply can't get to the promoter sites (the triggers) on the DNA. (Note that your cell has almost 2 meters of DNA if it were completely unwound. But normally in the cell it is wrapped around a histone, and then it is only 0.1 of a mm)
Conversely, activating the exact right spot of your gene at exactly the necessary time is of vital importance.
The whole machinery is extraordinarily intricate and fine-tuned. There are so many chemical signals – hormones – that are sent out for our physiology to function on daily basis, that our blood would literally clog up with them if they did not evolve to be effective in infinitely small doses. Doses like parts per trillion: the equivalent of one drop of syrup in 24 Olympic swimming pools.
Check fragments of videos that illustrate some of the processes in real time.
Science is learning a lot right now about how the life you live can affect epigenetics and gene expression. Stress, natural chemicals in food (nutrients), alien proteins, such as the ones in genetically modified plants, chemicals secreted (or not) by the complex microbiome of our bodies, environmental contaminants – such as endocrine disrupting chemicals or heavy metals - can, and do, alter gene expression.
The important thing is that once you realize this, you understand how very different environmental factors can be contributing to the same diseases.
Of course, there are many natural things that influence gene expression. Ultraviolet light from the sun makes your skin produce melanin and you tan, for example.
The problem starts being serious when we realize that we surrounded ourselves with new, man made chemicals (or heavy metals like mercury and lead, that we have extracted from beneath the surface of the earth in unusually high quantities) that influence our gene expression but we have never before in our evolutionary history had to adapt to them. That adaption, if it were at all possible, would take many generations. Meanwhile, the biological disturbances affecting us, and our ecosystems, may exacerbate and reinforce each other. Take pesticides or biocides for example: the may act directly in our bodies as endocrine disrupters, and/or weakening certain strains of symbiotic bacteria in in our microbiome, which in turn leads also to adverse health effects.
Hopefully, this burgeoning field of research in epigenetics will help answer a myriad of today’s mysteries of health deterioration.
Meanwhile, I invite you to take a look at this National Geographic video that examines the biology of homosexuality: How could one identical twin be gay and the other straight?