What Is Epigenetics?

To understand epigenetics, it’s useful to get a grasp on the role they play on the body. A great analogy of this we found on Mind Body Microbiome, is that epigenetics is similar to an orchestra playing music. While your genes would be the musical notes, epigenetics represent the conductor and musicians deciding how fast or loud to play, which instruments to use and which not. Epigenetics is the study of heritable changes in gene expression, that doesn’t affect the underlying DNA sequence – rather it affects the way that your cells read the genes. This can change the behaviour of cells, which in turn affects body tissue and organs. The difference between genetics and epigenetics is that genetics focuses on how DNA sequences lead to changes in cells, while epigenetics focuses on how DNA is regulated to achieve those changes in cells.

What Causes Epigenetic Change?

Epigenetic change is a natural occurrence that can be influenced by several factors such as age, environment, lifestyle and disease. These changes can be beneficial to us, making us more resilient to illness, or damaging by cause diseases like cancer, depending on how a gene is expressed or mutated. It is because of these factors and changes, scientists are investigating the role of epigenetic in a variety of human disorders and diseases such as various cancers, mental disorders, age-related diseases and immune disorders. These epigenetic changes may also have an effect on later generations, some studies have found that prenatal and early post natal environmental factors can influence the adult risk of developing obesity, chronic diseases and behavioural disorders. 

The former examples of influential factors (age, environment etc.), cause a process called DNA methylation. This is one of the most broadly studied epigenetic modifications that occurs by the addition of a substance called a methyl group to DNA, often modifying the function of the genes and affecting gene expression. This process signals to cells to inappropriately switch a gene ‘on’ or ‘off’. This can have a massive impact on the body if that particular gene was, for example, one responsible for tumour suppressing in cancer cells and was switched ‘off’.

 OfImpact Of Obesity On Epigenetics

Most of us are aware that obesity increases the risk of type 2 diabetes, high blood pressure and cardiovascular diseases, but studies have suggested that a higher BMI can cause DNA methylation, the most commonly studied epigenetic mark, which can make us more susceptible to cancers and neurodegenerative disorders. Fortunately, research has found that diet and exercise interventions for weight loss can reverse these epigenetic changes.

To fight the obesity epidemic, you’ll likely know that it’s important to maintain a healthy lifestyle with not just our diet, but our physical activity levels too. Research has looked into why some people are happy to exercise daily, and some people are content with a much more sedentary lifestyle. One study investigated if they deleted a gene responsible for DNA methylation that regulates a certain type of neurone in the hypothalamus in mice, whether this would affect energy balance and food intake. What they found was that instead of significantly changing the eating habits of the mice compared to normal mice, it made them lazier. The normal mice chose to run on their wheel twice as much as the experimental mice. If you’re someone who doesn’t enjoy exercise or finds it difficult to motivate themselves to be active, you may breathe a sigh of relief thinking that you are predisposed to feel this way. However, an individual’s predisposition to exercise is a changeable characteristic that can be affected by epigenetics. So with a little push to start exercise, eventually you will start to enjoy and become more motivated to exercise more regularly due to epigenetic change.

Examples Of Epigenetic Influence

In another research study of rats, a behavioural study was conducted on the power of maternal love. The quality of maternal care would affect the offspring’s behaviour, with rats that were groomed frequently as babies being more able to cope with stressful situations later in life, compared to those who received little contact.

A human example of powerful epigenetic change took place at the end of World War 2. A famine was experienced in the Netherlands due to Nazi blockade for over 6 months. The famine was so severe that 22,000 people died of malnutrition and the population consistently had around 580 calories of food per day. In the decades following, the offspring of those affected by the famine were being born significantly underweight despite being well fed. The famine had essentially marked the DNA of descendants.

A ‘one-off’ trauma was also shown to affect children if the trauma had affected a pregnant mother in the later stages of pregnancy. After the 9/11 attacks in America, it was estimated that more than half a million people suffered with post-traumatic stress from just witnessing the attacks. Just short of 2000 of those were pregnant women. Mothers who gave birth shortly afterwards were much more likely to give birth to infants who experienced very unusually high reactions to stimuli such as loud noises, unfamiliar people or new food. There are currently studies ongoing to determine if PTSD can be essentially passed down to children.

Epigenetic Reprogramming

Some scientists believe that it is epigenetic information loss, rather than loss of genetic information that leads to mutations, and is a main cause for our cells to age, meaning that we age faster and increase are likelihood of disease. Epigenetic reprogramming, infecting mice with reprogramming genes lead to the reversal of cell ageing by specific enzymes which remove the right methyl tags on DNA. This also allows cells to survive and grow like a newborns cells. At the moment, how the enzymes know which tags to remove and which to keep to allow this age reversal is unknown, but if scientists could find this reason out, and replicate the process in humans, then we could potentially reverse the process of ageing, and reduce the risk and the occurrence of all age related disease.

Epigenetics is a complex field that needs more research to gather the true potential of how much it can tell us about what factors we need to implement into our lives, and what we should avoid doing to prevent the risk of disease and disorder at a genetic level. For now though, if we focus on leading a good lifestyle, with a healthy diet with limited sugars and carbohydrates, regular exercise with a mixture of strength and cardiovascular training, and a global effort to improve the air we breathe, we can limit the negative epigenetic changes and reduce the likelihood of disease in ourselves, and future generations.