Process of Ageing - the role of telomere
What are telomeres? Can they help us live longer? What can we do to protect them?
Why do telomeres matter?
The National Human Genome Research Institute explains, ‘For an organism to grow and function properly, cells must constantly divide to produce new cells to replace old, worn-out cells.’ The Institute goes on to explain that, during cell division, it is essential that the DNA content of all our cells are identical – and that our DNA are located on chromosomes, a key part of the process that ensures DNA is accurately copied during cell divisions.
This means that telomeres protect the two ends of chromosomes i.e. telomeres play a vital role in protecting our genetic make-up. However every time a cell divides the length of telomeres is shortened i.e. a chunk of telomere is chopped off from the chromosome’s end. When a telomere becomes too short, the cell can no longer divide and becomes inactive or "senescent" and therefore dies.
So telomeres are protecting our chromosomes and through this our DNA – but how can we protect our telomeres? As we will see this matters, because it could affect how likely we are to become seriously ill and how long we live.
Can the length of our telomeres affect our health and how long we live?
The link between shorter telomeres and increased illness and shorter life in people was first reported in a study published in The Lancet in 2003. Individuals aged over 60 were recruited and divided into two groups according to the length of the telomeres in their blood cells. Those who had shorter telomeres were found to be more likely to experience heart disease and infectious diseases and to die earlier. Conversely those who had long telomeres at the beginning of the study lived an average of five years more than those with shorter telomeres.
Several other indications that telomere length is a good predictor of longevity have been reported. For example a 2007 study found that, in elderly twins, the twin with shorter telomeres is roughly three times more likely to die first. More recently, in 2014, a systematic review of published research found that telomeres are longer in women than men - and women typically live longer than men.
So there seems to be a clear association between the length of our telomeres and our health and longevity. However, there is some debate as to whether shorter telomeres are causing illness and early death or are simply a useful indicator of vulnerability to illness and early death. Whichever the case it seems to be in our interests to protect the length of our telomeres, as far as possible.
Individual telomere testing is still in its infancy and isn’t available on the NHS. So, for the moment, the focus should probably be on what we can do, based on the research published.
What can we do to protect our telomeres?
The good news is that some research suggests that a healthy lifestyle seems to help here, with two main messages i.e
1. Avoid smoking, obesity, pollution and stress
Studies have suggested these are all associated with shorter telomeres e.g.
A 2005 study in The Lancet found telomeres in the white blood cells of obese women to be shorter than in lean women of the same age.
The researchers calculated this was equivalent to reducing life expectancy by nearly nine years.
The same study also found that the more women smoked the shorter their telomeres were.
While this was a sizeable study, reported in a reputable journal, we should note that a larger and more recent study (published in 2014) reached a different conclusion i.e. that smoking, increased body weight and physical inactivity were associated with short telomere length, but not with telomere length change over the period of the study.
However, if we ask what factors influenced past telomere length a small US study, reported at a conference in 2015, found that when pregnant mothers smoked this appeared to have a knock on effect on the length of telomeres of their babies. More substantial research is needed to confirm this but it might suggest that what happens early in life can make a difference to telomere length.
This small, initial study also correlates with other research suggesting that telomere length is influenced by what happens in the womb, for instance the impact when pregnant mothers are subject to cumulative psychological stress, in a small US study - and a major European study which found, ‘a higher maternal BMI with excessive weight gain during pregnancy resulted in shorter telomere length in the offspring, as observed both at birth and in adult offspring.’
The effect of pollution has also been explored, for instance in a study in 2009. This compared 77 traffic officers exposed to high levels of pollution with 57 office workers, who had lower exposure to pollutants. In this small study the traffic officers had shorter telomeres.
Stress has been identified as another factor leading to shorter telomere length. For example a small scale study of African American boys was published in 2014. It concluded, ‘those who grow up in highly disadvantaged environments have shorter telomeres (at age 9) than boys who grow up in highly advantaged environments.’
In 2014 the Director of the Centre for Ageing, Metabolism and Emotion at the University of California, San Francisco, was interviewed about stress and telomeres, which she had spent the previous ten years researching. She commented, ‘The two biggest factors are chronological ageing and genetics, but stress is now on the map as one of the most consistent predictors of shorter telomere length. When we expose our bodies to years of chronic stress arousal, we see effects that override normal ageing, making our telomeres look like they are from a significantly older person.’
2. Exercise and eat a healthy diet
A 2011 review concluded, ‘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.’
A study of 2284 women in the US, published in 2010, found that eating dietary fibre had a modest but positive effect on telomere length. Conversely, omega 6 fatty acids, found for instance in vegetable oils, had a modest but negative effect on telomere length. As we identify elsewhere on Age Watch we need some Omega 6 in our diets but not too much and it needs to be balanced by Omega 3, found for instance in fatty fish, flaxseed, soy and walnuts.
Interestingly, a study of 608 outpatients with stable coronary heart disease in California, published in 2010, found that a diet containing antioxidant omega-3 fatty acids was associated with reduced rate of telomere shortening. So more omega 3 and less omega 6 may be helpful for telomere length.
Exercise has also been suggested as a factor increasing telomere length, for example in studies of athletes - although a sizeable 2014 study mentioned earlier questions this.
- Telomeres have an important protective role inside our bodies, helping protect our DNA within our chromosomes.
- Shorter telomeres are associated with a greater risk of illness and earlier death ie. faster biological ageing.
- There are two factors affecting the length of our telomeres that we can’t control – ageing and genetics.
- However, we can seek to follow a healthy lifestyle, by not smoking, maintaining a healthy weight, eating a healthy diet (containing dietary fibre and omega 3 in particular) and avoiding pollution and excessive, long term stress.
- Most (although not all) research published so far suggests that a healthy lifestyle helps protect our telomeres, with positive results for our health and how long we are likely to live.
Reviewed and updated by Kayhan Nouri-Aria January 2016. Next review date December 2020.