3 reasons why I’m not testing my biological age with telomeres.
The limitations you should know before buying a telomere test.
Last week I spoke at Longevity 2020 and my talk was on the topic of biohacking for longevity, with the theme of my talk centred on answering the question, “Do you know how you’re aging?”
Being a biotechnology geek, I’m all about utilizing the latest tech to quantify and optimize my biology.
During my talk, I had a slide on three popular ways of measuring one’s biological age:
- Epigenetics
- IgG glycosylation pattern
- Telomeres
Of course, you can’t talk about aging without mentioning telomeres.
After all, telomere attrition is one of the nine processes involved in aging, as defined by Lopez-Otis et al in the 2013 Cell publication, “The Hallmarks of Aging”.
Telomeres protect cells from DNA mutations, senescence and death by serving their function as chromosome end-caps, protecting the integrity of our genes.
As our cells divide, our telomeres get shorter. When humans are first conceived, the typical length of telomeres is 15,000 bases. By the time a baby is born, its telomeres have already shortened to 10,000 bases. Over the course of life, our cells continue dividing to support growth, repair injuries, fight off diseases, with telomeres continuing to shorten until they get too short and the cell loses its ability to function.
Considering human cells can only divide for a certain amount of time (the Hayflick limit), it’s been estimated that if you had great genetics and lead an ultra healthy lifestyle, your telomere shortening rate would allow for a maximum lifespan of 125 years of age.
So what we’re seeing now is companies offering telomere testing services to determine your biological age based on the length of your telomeres.
Logically, this sounds like a great idea.
Unfortunately, there are several major issues with the current approach which in my opinion makes telomere testing potentially a “fun” test to do, but not very useful or reliable.
So, let’s talk about telomere testing.
There are a lot different companies out there offering to test your telomeres and provide your biological age.
Here are some examples of tests available on the market today:
Read below for the three reasons why I’m not rushing to take a telomere test any time soon.
1. Consumer test accuracy is low.
All of these tests require a blood sample.
How this sample is processed as part of testing, makes a huge difference to the accuracy of the result.
Personally, I’m not a big fan of using a telomere length measurement to measure my biological age because of the inaccuracy of the available tests.
There are two main blood sample processing methods for consumer telomere tests:
- Polymerase chain reaction (PCR) — a popular method because it’s the cheapest way to do the testing.
SpectraCell and TeloYears both use PCR.
PCR is a widely used method to take a very small sample of DNA and amplify it to a large enough amount to study in detail, by making millions of copies of the DNA.
The issue with PCR is that it is very difficult to control the input variables to ensure accuracy of the test result.
For example, just by slightly altering the temperature or salt concentrations, you can get a very different outcome. When dealing with blood samples, it’s quite difficult to ensure that every blood sample has the exact same kind of concentration of salt and other required factors. So processing blood samples with PCR makes for quite the unreliable way of testing.
Knowing how the test is actually done can help manage expectations and how much stock you put into the test outcome.
2. Fluorescence in situ hybridization (FISH) is arguably the best available way of testing telomere length.
Life Length and RepeatDx use this approach.
With FISH, a fluorescent DNA probe gets bound to the telomeres, which really increases the accuracy of the test.
But, it’s still not 100% accurate.
Terminal Restriction Fragment (TRF) is a better and more accurate testing method is which is considered the “gold standard” for telomere measurement.
With this method the telomeres are essentially “chopped off” and run on an electrophoresis gel, where you can actually see them distributed from small to big. It’s great because you’re not just measuring a signal, you’re actually seeing the telomere length distributions. When you take two different cells that are from different ages, you can actually see clearly that one has a longer distribution of telomeres than the other.
So, the TRF technique is more accurate, but the issue is it’s still qualitative not quantitative, meaning that you can make observations, but the conclusions of those observations (ie inferring biological age from translating telomere measurements) may change depending on who is interpreting the data. There is no pre-determined degree of certainty.
Unfortunately, although TRF is the more accurate methodology for telomere analysis, this technique is used only for research purposes as it is not a scalable technology and limited to research laboratories.
2. Most tests measure average telomere length.
Most tests on the market today will estimate your biological age based on the average length of telomeres found within your blood sample. The issue is that doesn’t tell you how short the shortest telomeres are in your sample and how many of these short telomeres you have.
Life Length comes out as the winner in this category, because in addition to measuring the average telomere length, they’ll measure the percent of telomeres that are critically short.
This is a stronger indicator of the state of your lifespan than simply looking at the average average telomere length.
3. Random blood samples provide inconsistent results.
This is one of the biggest issues with telomere testing and ties in closely to the previous point about average length.
What these tests do is take a small sample of your blood and then test the average length of telomeres found in those cells.
The issue is that you’re going to have varying cell distribution throughout your body. So one of the big problems with measuring telomere length is that it’s random. Even an elderly person will have long telomeres in some of their cells, or even some of the cells with short telomeres are still going to have some chromosomes with long telomeres in it.
Something you can try to do is send in several samples and see what type of results you get. And if you’re extra diligent, consider sending in different samples under different names for anonymity.
That’s why most tests always report on the average length because the distribution is very wide. See the previous point on why that’s not good.
BONUS: Cost.
You know the drill. As usual, you get what you pay for.
Telomere testing costs are in the range of $100–300 and the more accurate the test, the more expensive it is.
Something to consider though is that even the most expensive test will still have limitations in accuracy.
Concluding thoughts
If you are still overcome with curiosity and have some extra funds lying around for telomere testing, consider these three points:
- Type of testing method used makes a difference in accuracy. Many anti-aging clinics will have one test brand/company that they’ll recommend. Choose your telomere test provider wisely.
- Prioritize tests that look beyond the average telomere length and measure the percent of telomeres that are critically short in your blood sample.
- Consider testing several times, using different names for anonymity, to get a better sense of the telomere variation across different cells in separate blood samples.
