What is ageing? I am afraid it is not a simple answer at all, but I am going to try and explain it as simply as possible. There are huge complexities at play, so here goes.
Regardless of cell type, ageing is a combination of things that ultimately leads to the loss of cellular function, eventually ending, not in cell death, but cell senescence. Senescent cells are cells that no longer function properly, but they do not die. This is a problem. These senescent cells send inflammatory, distress signals to neighbouring cells, which then interrupts their function and leads them down a potentially similar path. As we progress through life our senescent cell percentage increases and does so quite rapidly in the later decades of life. Senescent cells have been described as ‘Zombie’ like. They do not function normally, but yet they will not die, and they send inflammatory distress signals to their neighbours, that result in their loss of function. They sound pretty Zombie like to me.
Loss of cellular function that occurs on a large scale within the organs and tissues of the body can lead to disease or signs of ageing, if you believe there is much of a distinction. Loss of cell function can lead to dysregulation of cell division, as is the case in many cancers. It may interrupt important protein synthesis, further worsening the loss of functionality. Certainly, you do not want this to be occurring on a wide scale in the cells of your immunity. These specialised cells are amazing at defending our body, but when they experience a loss of normal function, they can soon start using that specialist skill to attack the body’s cells, leading to further loss of function in other tissues.
This ageing process eventually comes to us all, but there are factors at play that can result in this process occurring prematurely.
Let’s begin with genetics. Our genes supply the blueprints for the 20,000 proteins that our bodies make. To date, there are many genes that have now been found to be important to the ageing process, some offering protection and other propagating a faster decline.
To offer a good example, the TERT gene codes for a section of an enzyme called telomerase. Telomerase’s role is to keep our telomeres, the ends of our chromosomes (the larger unit of bundled up DNA) longer. Every time our cells divide our chromosomes shorten and eventually the telomeres unravel, and protection of the DNA is lost. These cells then lose normal function and becomes a dreaded senescent cell.
Luckily, we have telomerase, which helps to keep the telomere’s longer for longer. Some people have genetic variations in the TERT gene that means that their telomerase enzyme may not work as effectively. This potentially could accelerate the ageing processes. Luckily, this is just a tiny part of the picture, with many other genes, and probably many more unknown ones, playing a part. Genetic testing is becoming more widely available and cost effective and these variations can be discovered and counteracted earlier with good lifestyle applications. For example, supplementing with vitamins D, E and omega 3 fatty acids, was shown to increase telomerase activity to normal levels in people with unfavourable variations in their TERT gene.
Every month we discover more and more genes that play a role in the ageing of our body. However, extremely interesting is that we are yet to find a gene that codes for us to age. There are genes that promote premature ageing processes and those that promote longevity, but these are just outcomes of their function. There is no gene that leads the ageing process. This is pretty exciting for those seeking the fountain of youth.
OK, so that’s genetics. Let us now move onto epigenetics. Epigenetics is the area of science that deals with gene expression. Like a dimmer switch, genes can be turned up to produce more of the protein that it codes for. Or, it can be turned down, to produce less of the protein.
The genes can also be switched on full time or off completely. The study of this regulation of gene expression is called epigenetics. This is the system that keeps genes relevant to your eye function switched off in your liver. It is also why your brain does not grow teeth.
Every single cell in the body, apart from red blood cells, contain the same genetic material, but it is the epigenetic system that really controls the gene expression. Wonderfully, we can actually now measure biological age by measuring this epigenetic landscape, referred to in science as measuring methylation. As we age our methylation patterns alter. To describe it in simply, the more methylation on our DNA, the higher the biological age.
Negative lifestyle behaviours, such as smoking, chemical exposure, pollution exposure, excessive UV exposure, lack of nutrients, excessive physical activity and excessive alcohol or drugs can all leave their mark on this epigenetic landscape and result in higher levels of methylation and therefore a higher biological age.
Positive lifestyle behaviours, such as consuming a highly nutritional intake of food, regular moderate exercise and minimising stress, have all been shown to slow down this methylation process. This is why lifestyle plays a huge role in your anti-ageing strategies.
The next big player in ageing to mention is mTOR. mTor is a complex protein in the body, one that which is increasingly linked to ageing processes as science progresses. mTor has a central role in maintaining normal cell function and homeostasis as well as regulating cellular growth and proliferation. mTor is essential in early growth and development, but high levels of this protein in adulthood can be problematic. Dysregulation of mTor has been shown to promote ageing processes in the body, including an increase in methylation. Dysregulation of mTor is also associated with metabolic diseases, including diabetes, neurodegeneration and cancer. mTor has even been nicknamed by many as the engine of ageing.
mTor is overstimulated by the consumption of food, particularly those foods rich in amino acids, Leucine and methionine. These aminos are both abundant in animal proteins. This includes eggs, fish, dairy, meats and poultry, anything from an animal. We now live in a world of plenty and many of us make the most of this with eating habits being quite constant throughout the day. The biggest mTor activators, animal products, are now much more affordable and accessible. Most humans really enjoy them too, leading to animal protein presence in every meal. This results in much more mTor activation and therefore, a lot of proliferation within the tissues. So, why is this a bad thing? Well when proliferation occurs, a process called autophagy does not. To put is simply, autophagy is a positive process of recycling tired and worn out cells with damaged DNA or loss of function. It is thought essential for keeping the aging process at bay. During autophagy, DNA is given chance to repair, making sure that the subsequent daughter cells will not be passed on mutated genes or genetic issues. At times of proliferation, from excessive mTor activation, autophagy cannot occur and instead these tired old dysfunctional cells proliferate passing on their potentially damaged DNA. This could contribute to both disease and ageing processes. Reducing the volume of food and the high levels of animal proteins is a great way to ensure mTor behaves normally within the body. This is why intermittent fasting and plant based diets label themselves as anti-ageing.
Finally, in pursuit of what ageing is, we need to visit a process in the body named oxidative stress. This is an umbrella term that describes the accumulation of toxins in the cells of the body. Actually, every time we make a molecule of energy, and we make a lot, we make a free radical toxin. This is part of normal cellular metabolism, and we have many enzymes within our cells that neutralise them. If these free radical toxins are not neutralised, then they accumulate and begin to disrupt cellular function. As you can imagine we make a lot of energy every day. Therefore, we make a lot of free radicals on a daily basis, plenty to be keeping our neutralising enzymes busy. Stress, both physical and mental, leads to higher energy creation and therefore a higher toxin count. Too make things more challenging, the way we live promotes further free radical toxin production. Exposures to radiation, the sun’s UV rays, pesticides sprayed onto our food, chemicals in our skin & self-care products, chemicals in our cleaning products, pollution, many medications and heavy metals, like mercury will all result in more free radial toxins and increased cellular dysfunction. This is thought to be one of the reasons that diseases are occurring in younger individuals than before, and cases of diseases, like cancer continue to rise, despite scientific advancement. Each passing decade our average exposure to these environmental factors increases.
Genetically, we are all very different, which results in different neutralising enzyme ability. Some of us have better functioning enzymes for neutralising these toxins than others. Those that have genetic variations that cause a reduction in their function will need to consume a higher number of antioxidants from their food, to support this detoxification process. These external antioxidants, often found in vegetables and plants, will act in the same way as the enzymes and neutralise free radical toxins. Both the enzymes and external antioxidants prevent accumulating toxins within the cell and therefore help to keep the ageing, oxidative stress at bay. Dietary antioxidants include the vitamins A, C and E, as well as glutathione, co enzyme Q10 and alpha lipoic acid. So, diet is vital in preserving normal cellular function. Selenium and zinc are not antioxidants, but they activate them within the body, and support neutralisation reactions.
If oxidative stress is allowed to occur over a long period of time, it will lead to the deregulation of methylation in the epigenetic system, loss of cell function and will promote senescence, eventually. The biological age of the cell will advance, neighbouring cells will become involved and the cycle goes on.
By understanding what ageing is, science is allowing us to really look at how these processes can be prevented. No one wants to age, and many of us would not want to live forever. Ageing and disease are not dissimilar, in fact I believe they are one, in many cases. Ageing is a disease and disease is ageing. Therefore, if we can get to grips with keeping cellular ageing processes slow, we can hopefully keep disease progression slow, or prevent it in the first place. Exploring the science of ageing will help in the world of preventative medicine.
Dr Michael Barnish