Genes are only one element in the equation of the body, Kate Hodal learns from David Ewing Duncan.
As with all good experiments, his started with a fish.
Well, two fish, to be exact. For the halibut and swordfish that journalist David Ewing Duncan ate for lunch, and then dinner, were to provide him with some clues regarding his genetic make-up.
Writing about mercury levels in fish for a magazine – a toxin that can cause severe brain damage – he discovered a curious quirk.
In the same way that some people have blue eyes, or others have a high risk of heart attack, Duncan had a gene that helped protect him from dangerous levels of mercury in the blood. So when the tall, white and generally healthy 50-year-old discovered his blood-mercury levels had tripled overnight due to his fishy meals, his body expelled the unwanted chemical. His discovery got him thinking about all the other things his genes possibly could – or couldn’t – do. Nearly ten years and thousands of blood tests, body scans and brain scans later, he has written a book to describe the tale, called Experimental Man.
“Besides having the insanity gene in my DNA, I’m not sure why I did it,” laughs the award-winning America-based journalist and self-proclaimed medical guinea pig. “I was just curious, I guess: the more tests that I took I realised how different and unique I am from you or anyone else, and that that uniqueness can dictate what can happen to me in the future in terms of disease. It can even explain some of my present behaviour and state of my physical being.”
Duncan started off by convincing genetic-testing companies to use him as a guinea pig. As the science of it all is still in its early days, he compared it to “using a clunky old mobile phone: it works, but it’s still a prototype – plus it’s really expensive”.
The most commonly-known genetic testing on the market these days is the DNA paternity test, or those that help determine a genetic proclivity to a life-altering disease such as Hutchinson’s.
But Duncan’s battery of tests analysed both genetically-related diseases and genes that affect personality, intelligence, physical and mental abilities.
Through these tests – some of which cost upwards of €150,000 (or £90,000) – Duncan extended his family tree by tracking down a long-lost cousin whose gene pool had diverged from his own 600 years earlier.
Brain scans showed neural activity that explained why he had grown up to be a writer and not a taxi driver. A full body scan illuminated bumps on his kidney. One test highlighted his body’s tendency to accumulate wet earwax.
Despite the incredible breadth of information that these scans provide, however, they are but the tip of the iceberg in understanding what’s happening in your body, says Duncan.
“The genes are really only one element of this whole equation, even though they get a lot of attention,” he says.
“One of the most important factors is the interaction of environment on our genetics, as our genes evolve over time to both take advantage of, and
protect us from, the environment.”
Duncan grew up in Kansas near a toxic waste dump, a fact which partially explains why he tested positive for 165 out of 320 possible chemical toxins. It’s a high number but it’s not that uncommon, he says.
“We’ve added a lot of toxins and pollutants into our environment and one of the fascinating things for me was to look at whether we’re equipped genetically with an ability to get rid of those toxins or neutralise them,” he says.
“We know there are people who get ill more than others, so are there some that are more sensitive to dioxins or pesticides too? Genes are not a static indicator but a blueprint as to what might happen to us.”
It’s this ‘linkage’, as he calls it, between environment and genetics that is a subject of fascination for Duncan, who says he will devote his next book to what could become the future of healthcare.
“Instead of lumping people together by age and sex to figure out what treatment or medicine to give them, we could start looking at their genetic make-up and treat them that way,” he muses.
“That would radically change healthcare by altering the way we regulate chemicals and look at drug design.”
In Duncan’s thirst for knowledge, it wasn’t just his own health that he tested: he had his parents and daughter involved too. Interested in seeing what genes carried forward and which didn’t, Duncan was surprised to learn that, despite his parents’ great bill of health, plus a history of ancestors that lived well into their 80s and 90s, he had received the short end of the stick when it came to the genetic make-up bag.
“My parents gave me the worst possible set of genes they possibly could,” Duncan laughs. “While they carry a lot of risk factors in their genes, they themselves are fairly low-risk. It’s the combination of their genes together that gave me the higher risk that I now have.”
But, as they say, like father like son – Duncan has also managed to pass on a bad gene to his daughter, that of a higher risk of breast cancer, a fact which he calls “horrifying”.
“It’s awful to think that you’ve given something to your child that may make them die but, then, that’s nature!” he says. “But to actually know that is not easy – and, as genetic testing gets more accessible, I expect people will have to grapple with that.”
Medical techies and even techno nerds, like Kevin Kelly, co-founder of techie magazine Wired and a paying customer of genetic testing himself, have lauded Duncan’s account as “news from the year 2029” that will “inspire the millions that will follow [Duncan] in the great quest for truly personalised medicine”.
But others, including Duncan’s regular GP, have flouted these tests as an expensive lesson in following common healthcare and medical sense.
That’s because just what he can do to prevent a heart attack, now that he knows he’s at high risk of one, is to keep his weight stable, say the geneticists – and his GP. “It’s true that a lot of what the genetics testing tells you is common sense: not gaining weight is a good idea to make sure that you stay stable and fit,” Duncan says. “A lot of people ask me, ‘Why do we need a fancy genetic test to let us know the obvious?’ But if we were already acting on the obvious, already making the changes we needed to make, then most of us wouldn’t have to wait for the tests to convince ourselves to change.”
Those interested in taking some of their own tests can do so from Duncan’s website, www.experimentalman.com, which has more details about his book, the experiments, and a link to web-based tests that can measure the age of your brain.
Duncan advises to take these tests with a pinch of salt, as such experimentation means that you can find out a lot you may not understand all at once.
As for Duncan, “I’m just glad to have discovered some of the secrets of time and to be able to understand myself a bit better.” Not bad for a human guinea pig.
* Experimental Man: What One Man’s Body Reveals About His Future, Your Health And Our Toxic World by David Ewing Duncan is published by Wiley, priced £17.99.