PART THREE: SLOWING BIOLOGICAL AGEING
Each human cell normally contains 23 pairs of chromosomes, ie. a total of 46. One chromosome in each pair is inherited from the mother, and the other from the father. The 23rd pair, the sex chromosome, determines your gender.
Females have two copies of the X chromosome, one from each parent, while males have one X chromosome from their mother, and one Y chromosome from their father. It is the father who determines the sex of his child.
Chromosomes allow the parent to pass his or her genetic material on to their descendants. Eggs or sperm cells have half of the parent organism’s genetic material, ensuring that mother and father each contribute half of their genes. It is the ‘shuffling’ of genes at the point of conception that make up your genome, accounting for the fact that siblings may be very different. You have approximately 24,000 genes.
Telomeres – a measurement of ageing
A telomere is a string of repetitive DNA which protects the chromosome from damage. When chromosomes divide to make copies, the telomere ensures that all of the important genetic material is also copied.
Each time a chromosome divides, the end of the telomere shortens fractionally and when it comes to the end, the cell dies. These are called ‘senescent cells’. For this reason, many scientists believe that the length of your telomeres may be a good indicator of biological ageing and mortality risk.
Although senescent cells can no longer divide, they may remain and are injurious to health as they secrete toxic molecules that damage neighbouring cells and trigger chronic inflammation. Although the immune system does clear senescent cells away, this process gets less effective as we get older and the senescent cells accumulate.
Research reported in Nature last year (February 2015) showed that mice that were genetically modified to respond to a drug that killed off senescent cells lived healthier for longer – over 20% longer and tumour growth was reduced. This killer process, when it happens naturally, is called apoptosis. We know that some nutrients like Omega 3 and curcumin do encourage apoptosis.
Lifestyle factors that influence telomere length
A report (3) by M. Shammas of the Cancer Institute in Boston states that:
‘The rate of telomere shortening can be either increased or decreased by specific lifestyle factors. Better choice of diet and activities has great potential to reduce the rate of telomere shortening or at least prevent excessive telomere attrition, leading to delayed onset of age-associated diseases and increased lifespan.’
Negative lifestyle factors included smoking, unhealthy diet and obesity – all reducing telomere length. Interestingly, one study showed that traffic police officers who were exposed to air pollution had shorter telomeres than their equivalent office workers.
In another study, women exposed to stress in their daily life also had shorter telomere lengths than their equivalent cohort.
How? Stress is associated with release of glucocorticoid hormones by the adrenal gland. These hormones have been shown to reduce the levels of antioxidant proteins and may therefore result in increased oxidative damage to DNA and thence to accelerated telomere shortening.
The research shows positive correlation for telomere length with increased intake of fibre, Omega 3 fatty acid, a diet rich in anti-oxidants including vitamins C, E and beta carotene, and healthy fats derived from nuts, avocado and fish.
The research strongly indicates that a relatively calorie-restricted diet is also a route to slower telomere shortening. This is almost certainly because calorie restriction equates to lower oxidative stress in the mitochondria.
We all know that exercise is good for you. Researchers Jiang and Song have shown that the frequency and duration of exercise is also positively correlated to less damage to DNA and longer telomeres (4). Other studies show that telomeres of athletes are longer than non-athletes, again due to lower oxidative stress.
The Shammas report concludes that:
‘Older people with shorter telomeres have three and eight times increased risk to die from heart and infectious diseases, respectively. Rate of telomere shortening is therefore critical to an individual’s health and pace of aging.’
Of course shortened telomeres are only markers of ageing and oxidative stress. The key is to take action that delays that shortening.
THE CONCLUSIONS FROM THIS 3-PART SERIES
Putting together the evidence from all three parts of this series Building Healthy Cells,we can summarise:
- Health is determined at the level of your cells
- Cells are renewed frequently – some as frequently as every day or every few weeks
- Your nutritional intake is the source material for building new cells
- Nutrients that protect and build healthy cell walls include Omega 3, vitamin E, carotenoids, vitamin C, vitamin D3 and polyphenols
- Nutrients that protect your mitochondria include CoQ10 and anti-oxidants like vitamins C, E, the polyphenols like curcumin and the catechins in green tea, plus the carotenoids like beta carotene, lycopene and lutein.
- Nutrients that help the DNA repair mechanism include selenium, zinc and lutein
- Evidence from telomere research shows that all the above nutrients are important in slowing ageing, plus lifestyle factors like exercise and reducing stress. These will be the subject of future articles.
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1. Mayne, S. T. Beta-carotene, carotenoids, and disease prevention in humans. FASEB J. 10, 690–701 (1996).
2. Seo, Y. R., Kelley, M. R. & Smith, M. L. Selenomethionine regulation of p53 by a ref1-dependent redox mechanism. Proc. Natl. Acad. Sci. U. S. A. 99, 14548–53 (2002).
3. Shammas, M. A. Telomeres, lifestyle, cancer, and aging. Curr. Opin. Clin. Nutr. Metab. Care 14, 28–34 (2011).
4. Jiang, H. et al. Proteins induced by telomere dysfunction and DNA damage represent biomarkers of human aging and disease. Proc. Natl. Acad. Sci. U. S. A. 105, 11299–304 (2008).
5. COQ10 review – https://umm.edu/health/medical/altmed/supplement/coenzyme-q10