It is a beautiful thing remembering when we were kids and how we were celebrating birthdays until we came of age till this point in life. Now, watching our once upon a time agile parents grow old is very saddening. Ageing as we all know is one of the world's ancient deadliest diseases. It has brought about more sorrow than joy because it is a gradual process and there is nothing that can be done to stop it. I look at the development of every human as a projectile, when it reaches it max point, it then begins to decends until we die. Although, so many research has been undergoing for years in order to stop aging, which has led researchers to various knowledge on the reason why aging occurs. But still, ageing remains inevitable and we will all grow old and die.

Biochemically, ageing is a gradually deteriorating process which occurs in the cell, that leads to decrease in efficiency of the mechanism responsible for controlling the body functions. Ageing is associated with increase in various diseases such as high blood pressure, dementia, reduction in body mass and muscle, loss of ability to taste, reduced respiratory function, heart related diseases and loss of vision and hearing. Various theories about ageing has been propounded over the years which are free radical, DNA damage, telomere, wear and tear, mitochondria, immunological, endocrine etc.

Free radicals are molecules with unpaired electron such as superoxide ion, hydrogen peroxide and hydroxyl radical which are capable of causing oxidative damage. Although, free radicals are not only produced in the body, they are also taking into the body through the food we eat, air we breathe, water we drink and through smoking. The continuous accumulation of the oxidative damage caused by free radicals over a long period of time, results into ageing. Although, many research has been made to affirm the theory but, no significant result has been made. One of the research which was carried out by Kakkar R. *et. al*., (1996), showed that the administration of vitamin E on ageing drosophila through their diet is said to increase their life span. This was based on the idea that, antioxidant inhibits oxidative damages in cell. However, another research which was carried out by Arking (1998), showed that there were no clear evidence to affirm that free radicals inhibitors such as antioxidants extends the life span in mammals because the results were complex and was not easy to interpret.

The hypothesis advocates that if a DNA is damaged and is not repaired or completely repaired quickly by DNA polymerase or other repair mechanism as they are produce, will lead to accumulation of this damaged DNA, then incorrect genes, messenger RNA and protein will be produced which will cause impairment and reduction in gene expression or cell death, contributing towards ageing. It has been researched that the ability to attain longevity is directly proportional to the ability of damaged DNA to get repaired. But the ability of this damaged DNA to get repaired has been hindered due to progression of ageing.

Telomeres are buffer located at the end of every chromosome which function is to protect the chromosome from undergoing fusion with nearby chromosome. As humans, our cells undergoes division all through life. Every time cells undergoes division, the telomere gets reduced in length and when they get too short to perform their function, it leads reduction in cell activities, cell death and aging of the body. This theory is evident in cancer cells where the very high activity of telomerase the enzyme responsible for preventing shortening of telomere is abundant, thereby preventing the death of cancer cells and promoting the proliferation of these cells.

Since the mitochondria is the energy production house of the body, it has been researched that the mitochondria is capable of producing reactive oxygen species (ROS) such as peroxide, hydroxyl radicals, superoxide due to escape of electron from the electron transport chain. This reactive oxygen species then causes damages to the mitochondria DNA and protein which in turn leads to deterioration of cell activities, death and in turn ageing.

Just as the sole of our shoes undergoes wear and tear as a result of friction and continuous usage, the wear and tear theory proposes that parts of the body also undergoes wearing and tearing due to repeated usage and other factors such as diseases, toxins, radiation etc

This theory implicates the immune system to be the cause of ageing. As we all know, the function of the immune system is to protect the body against diseases pathogen and harmful foreign substances. But as we grow older, the activities of the immune system begins to decrease giving way for various sickness and diseases to attack the body as we see in older people. It is also said that the immune system is programme to be on the decline after reaching it max at puberty stage in every human.

Endocrine theory

This theory proposes that the decrease in activity of the hypothalamus - pituitary gland - endocrine system which is responsible for the regulation of the body's metabolism and other processes through the secretion of hormones is responsible for ageing process. This theory was backed by a research carried out by Powers et. al., (2006). In the research, the pituitary gland of lab mice were removed using hypophysectomy, and it was discovered that mice without pituitary hormone had extended life span compared to the control. This gave birth to the theory that the pituitary gland produces pituitary hormone alongside an unknown hormone that contributes towards ageing process.

Natural ways to slowdown the process of ageing

In view of the above theories and research which is yet to solve ageing process, it is advisable for us to watch the kinds of diet and activities we do, as this may contribute directly or indirectly towards ageing. Lets discuss ways by which we can slow down this process naturally

• Diet : Looking at ancient people, they have higher life span compared to people of nowadays. This is as a result of their nutritional diet, they eat more of natural foods and not junks. Since we already know the negative effects caused by free radicals, eating foods that are rich in anti oxidants cannot be emphasized enough. Vegetables, protein, red whine, fruits such as berries and watermelon are very effective in slowing down the process of ageing because of the presence of antioxidants in them. Inflammatory foods such as junk foods should be avoided because of their negative effects which directly or indirectly accelerates ageing process. Foods such as whole grain contains fibre, carbohydrate, protein and essential fatty acid that helps in reducing cholesterol levels in the body should be consumed more. On the other hand, wines, vegetables and fruits are good source of flavoniods, carotenoid and vitamins that helps in preventing cellular damages caused by the activities of free radicals.

• Exercise : Various research has been carried out and they support the motion that regular exercise helps attenuate the process of ageing. From the molecular view in a research carried out by Cash et. al., (2013), it was concluded that moderate exercise helps in the repair of damaged DNA. Damaged DNA contributes to ageing as discussed above in DNA damage hypothesis.

Nutritional requirement for the aged

The aged are refered to people who have attained the age of 60 and above. Not all kinds of food is healthy to the aged, so extra effort has to be made to help them stay healthy as discussed bellow

• Fats: The presence of fat should be greatly reduced in diets of the aged. Reduction of fats in their diet helps reduce calorie intake and reduction of heart related disease such as atherosclerosis. Only fats that contains essential fatty acids and fat soluble vitamins should be included in their diet. Good source of these type of fat are olive oil and canola oil.

• Calories : The intake of calories needs to be reduced due to the decrease in cells metabolism and decrease in muscular activities. Although, individuals varies but the calorie intake required daily for the aged should not be more than 1,600 kcal.

• Fibre : Fibres are well known for the prevention of colon cancer and aid easy emptying of the bowel. It also helps in binding to blood cholesterol and carries it out of the body, thereby preventing heart related diseases such as atherosclerosis.

• Vitamin and minerals : The defiency of vitamins and minerals is noticeable in the aged people. Extra efforts has to be made to provide them with essential vitamins such as Vitamin C, E and B. Minerals such as iron and calcium are relatively low in aged people which results in fatigue. Fresh fruits and vegetables should be mostly eaten by the aged as they contain most of the essential vitamins and minerals.

• Carbohydrate : Complex carbohydrates should mostly be taken by the aged people. Carbonated drinks should be avoided as they contain very high amount of sugar that may result in pile and hyperglycaemia.

• Protein : The need for essential amino acid is same for the young and aged people. Aged people should avoid beef and egg as their source of protein because egg yolk is rich in cholesterol, while beef contains essential nucleic acid which when metabolize, results in the accumulation of uric acids in joints that causes arthritis. Plants protein should be the source of protein for the aged because they contain biomolecules capable of preventing and minimizing diseases associated with ageing.

  Conclusion

  From all the discussed theories above, it is clearly seen that the process of ageing does not involve an individual process but a multiple complex process. Regulating our diet and regularly exercising will help reduce the process of ageing, making us active and young even at old age.

  References

  • _{Mc Auley M.T., Guimera A.M., Hodgson D., Mcdonald N., Mooney K.M., Morgan A.E., Proctor C.J., (2017). Modelling the molecular mechanisms of aging. Biosci Rep. 28; 37(1). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5322748/}

  • _{Cash, S. W., Beresford, S. A. A., Vaughan, T. L., Heagerty, P. J., Bernstein, L., White, E., & Neuhouser, M. L. (2014). Recent physical activity in relation to DNA damage and repair using the comet assay. Journal of Physical Activity & Health, 11(4), 770–776. http://doi.org/10.1123/jpah.2012-0278}

  • _{Rebelo-Marques, A., De Sousa Lages, A., Andrade, R., Ribeiro, C. F., Mota-Pinto, A., Carrilho, F., & Espregueira-Mendes, J. (2018). Aging Hallmarks: The Benefits of Physical Exercise. Frontiers in Endocrinology, 9, 258. http://doi.org/10.3389/fendo.2018.00258}

  • _{Powers R.W., Harrison D.E., Flurkey K., (2006). Pituitary removal in adult mice increases life span. Mech Ageing Dev.127(8):658-9. https://www.ncbi.nlm.nih.gov/m/pubmed/16643985/#}

  • _{Jin, K. (2010). Modern Biological Theories of Aging. Aging and Disease, 1(2), 72–74. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2995895/#b2-ad-1-2-72}

  • _{Park, D. C., & Yeo, S. G. (2013). Aging. Korean Journal of Audiology, 17(2), 39–44. http://doi.org/10.7874/kja.2013.17.2.39}