The process of making a new cell in your body starts by copying the map of how to build that cell, which is contained in a package of DNA strands called a chromosome. The chromosome divides in two, giving a new set of instructions to the new cell. At the end of the chromosome is something called a telomere, which is a bit like the hard bit at the end of a shoelace. This becomes shorter with each cell copy, until it is too short and the DNA is no longer protected. This initiates rapid ageing because cells stop dividing, and hence being replaced.

Meanwhile, there is an enzyme called telomorase, which can lengthen the telomere. The more telomorase activity, the slower the ageing process. For example, there’s one bacteria called tetrahymena thermophile that has super-active telomorase so its telomeres never shorten and it lives forever.

The length of your telomeres is a very good predictor of your healthy lifespan. Also, people who have cardiovascular disease, arthritis or vascular dementia tend to have shorter telomerase; and shorter telomeres predicts risk of cancer and cardiovascular disease death. The higher the level of inflammatory markers, the shorter one’s telomeres. At this point in time there’s a fair bit of ‘chicken or egg’ – do the diseases cause shortening telomeres, or are shortening telomeres resulting in the disease? But, a critical issue in ageing is what lengthens or shortens telomeres, and what promotes telomorase?

I attended a lecture by Professor Elizabeth Blackburn from the University of California, who won a Nobel prize for her part in discovering all this. She updated me on all the things that lengthen or shorten telomeres, many of which we can control over.

• Reduce your stress – many studies have found that people in prolonged stress situations, such as caring for a sick child or parent with dementia, lessens telomorase activity and telomere length. So do childhood traumas, chronic depression and cynicism. Those with ‘hostile’ cynicism, which sounds a bit like those people who ‘hate’ complementary medicine, have shorter telomeres. Conversely, there are some good studies that show that meditation is associated with longer telomeres.

• Sleep well: the better you sleep, the longer your telomeres. As far as longevity is concerned, seven hours seems to be optimal.

• Exercise: the more you exercise, and the less stress you have, the longer your telomeres. In one study, those with post traumatic stress disorder who exercised didn’t have the usual telomere shortening.

• Don’t smoke and stay slim: obesity and smoking are both associated with shorter telomere length.

• Up your omega-3 and vitamin D: the higher your intake of omega-3 fish oils, the longer your telomeres. A study last year gave people either linoleic acid, DHA or EPA, and found that DHA and EPA, which are the more potent forms of omega-3 found in fish oil, reduced telomere shortening. Two studies also found that the higher your blood level of vitamin D, the longer your telomeres; but another failed to find this, so the jury is still out. Both omega-3 and vitamin D are found in oily fish.

“Those with ‘hostile’ cynicism, which sounds a bit like those people who ‘hate’ complementary medicine, have shorter telomeres”

The lower your homocysteine level and the higher your B12 and folate blood levels, the longer your telomeres are likely to be. These vitamins are well known to lower homocysteine – and the older you get the more B12 you need as absorption can get a lot worse.

The more anti-inflammatory foods a person eats (as measured by the Dietary Inflammation Index) the longer are their telomeres, the latest research shows.

In addition, multivitamin-takers have longer telomeres.

When I first came into this field the predominant concept was that you needed enough nutrients for enzymes to work, but now it’s clear that optimizing your intake of nutrients not only turns on and off the right genes, but may actually lengthen your healthy life by allowing more cell divisions to occur before your telomeres fray at the edges.

If you want to find out how long your telomeres are www.regeneruslabs.com can do this for you. I had mine done and I have the average telomere length of someone half my age. Validation indeed for a healthy, wholefood diet and daily supplements.

For details on these studies visit patrickholford.com/telomeres.