Mousab Kassem Azzawi
2020 / 10 / 1
YOUR HEALTH IN THE AGE OF GENOMICS
Edited by Mousab Kassem Azzawi, MSc, MD, PhD
In this lecture, you will learn about some of the fascinating research that has been done on the human genome, and you will explore the new fields of nutrigenomics and pharmacogenomics. Even more importantly, you will learn that it is possible to turn genes on and off through nutrition and lifestyle change.
Your epigenome is an integral part of your genes that receives signals from the outside of the cell nucleus and responds to these signals. Nutrients and the environment in which you live can influence your epigenome and, ultimately, your health.
Good nutrition and lifestyle choices can have positive and profound impacts on your genes.
The first survey of the entire human genome, called the Human Genome Project, determined that the genome had far fewer genes than were anticipated, but the variation of the genes was far greater than expected—with over three million variations.
Our phenotype—how we look—results from an interaction of our genes and our environment. This interaction occurs through what is called the epigenome.
Human beings have 23 chromosomes, and they occur in pairs. One member of each pair comes from your father, and one comes from your mother.
Our epigenome is the collective history of our life from conception to death, and the composition of this epigenome is the result of the interaction between our genetic determinants—our lineage—and our environment.
According to Randy Jirtle, an authority on the epigenome, certain genes appear more epigenetically sensitive than others, and it is clear in the foetus that these genes are capable of being environmentally marked.
Researchers use a mouse called the Agouti mouse—which is yellow, fat, and has a high risk of cancer, diabetes, and obesity—to study these diseases. If a pregnant Agouti mouse is given nutrients such as zinc and the B vitamins known as folate and B12, the mother mouse produces a completely normal offspring. The baby is thin, brown, and has no risk,´-or-a much lower risk, of cancer, diabetes, and obesity, and the baby mouse lives a long life.
This has profound implications: What we do not only affects our own epigenome, but it also affects the next generation. When a mother eats during pregnancy, she is im-print-ing the foetus with information—called epigenetic tags. There are many conditions that are associated with these tags, including type 2 diabetes, heart disease, autoimmune disease, Alzheimer’s disease, allergies, and even some cancers.
All of these major medical conditions can be influenced by environmental factors. Our chances of developing any´-or-all of these conditions can be increased´-or-decreased by how we live our lives. In other words, your genes are not your destiny-;- you are more than your genes.
Several vitamins, minerals, and phytochemicals—which are chemicals that come from plants—have been shown to affect the epigenome. For example, niacin, zinc, iron, riboflavin, and resveratrol can affect the epigenome.
We take in nutrients all day. The food that we eat is metabolized, and it is absorbed by our small intestine. Eventually, it is broken down, and goes into our bloodstream, then enters the cells of our body. The nutrients, which are the breakdown products of whatever we ate, will certainly interact with the epigenome, and tell this epigenome to turn specific genes on´-or-off, expressing different kinds of proteins.
When genetically identical twins grow up, they do not always have the same diseases. One may have cancer, for example, and the other may not.
In 2008 in the Archives of Internal Medicine, a study was published that looked at a gene called the FTO obesity gene. Researchers studied a population that has this genetic variant to be obese: the Amish people. However, when they evaluated the community, they were not obese. The members of the Amish community were walking over 18,000 steps per day, so the obesity gene was turned off by physical activity.
Numerous studies have shown that there are incredibly strong links between chronic stress and poor health. Stress is a recognized risk factor for several diseases, including diabetes, heart disease, and high blood pressure.
Telomeres are DNA proteins that are essential to cell division. Our cells are dividing all the time, and we change our full body every seven years´-or-so-;- we do not have the same cells we were born with. Without telomeres, we would not be able to make new cells, so we would die. Telomerase is the enzyme involved in this crucial mechanism.
In one study, Dr Elizabeth Blackburn evaluated the relationship between stress and ageing on telomeres and telomerase to determine if stress impacts health by affecting the rate of cellular ageing. She measured the telomere length and the telomerase enzyme in 58 premenopausal women and found that women who had the highest levels of perceived stress had the shortest telomeres. In essence, these high-stress women had a cell age that was 10 years older than their biological age.
An emerging field called nutrigenomics involves the study of the relationship between genes and nutrition.
The ApoE is a type of genotype that is tested routinely in heart patients. We inherit one of these genes from each of our parents. The ApoE has three different types: ApoE2, ApoE3, and ApoE4. Most of us are born with the E3 variant. The E4 variant predicts the highest risk for heart disease and Alzheimer’s disease. Those individuals with the E2 variant do better on a high-fat diet, but those with the E4 variant do better on a low-fat diet.
There is not one diet that fits all because everyone is unique. However, we now have genetic information that is going to start to tell us what kind of nutrition recommendations that we should make.
Nutritionists are being trained in this area because they are getting ready for what is called the nutrigenomics revolution, which would involve physicians making recommendations about what a person should eat and which supplements´-or-drugs to take based on his´-or-her specific genes.
Another area of amazing promise is pharmacogenomics, which involves the study of the interaction between medication and genes. Physicians are already starting to put this information into clinical practice.
Statins are drugs that lower cholesterol, and there is a genetic blood test that can tell you whether you are prone to have a problem with metabolism of statins. When certain people in the population take a statin cholesterol-lowering drug, they get muscle aches, joint aches, and pain. If you are at risk for this problem, then you should try other medications that are not statin therapy.