No such thing as 'bad genes'

For more years than I care to count I have been coaching runners and encouraging non-runners to take up the sport as a physical activity.

It's generally accepted that being physically active is good and will reduce health risks in later life, but there's more to it than that.

I also came to learn over the years that once someone takes up running on a regular basis (let's say 3-4 days per week), then it is not very long before they realise that it would be so much easier if they could just lose some excess pounds.

So, their next question (after how often should I run, and how far) often tends to be... what should I eat?

When I hear those four simple words I know that this particular person's life is about to take a huge change for the better.

I am extra happy to see women take up running. Not only do they start asking what to eat, how much to eat, and so on for themselves, but because they are responsible for the shopping and cooking for the entire family their newfound knowledge of a healthier diet starts getting applied to everyone in their household.

In response to their built-in mothering instinct they begin to buy healthier, better quality foodstuffs, fewer sugary snacks and even start working on banning soft drinks in the house.

When you think about it, it's pretty insidious stuff this running business. And the positive effects are further-reaching than you would ever believe.

In 2000, a professor and a post-doctoral student at Duke University, in the US, designed a ground-breaking genetic experiment that was stunningly simple.

They began with pairs of fat, yellow mice, known as agouti mice because they carry a particular agouti gene that makes this breed fat and prone to cancer and diabetes. The scientists wanted to see if they could improve the negative genetic destiny of these mice.

Typically, most offspring of these agouti mice are identical to their parents. Every bit as yellow, fat as butterballs, and at high risk of life-shortening diseases. The majority of offspring after this experiment, however, looked little like their parents. They were much slimmer, mousy brown and lived to a right old (mouse) age with no susceptibility to cancer and diabetes.

Yet, this amazing experiment did only one very simple thing; it changed the mother's diet.

From shortly before conception until giving birth, the mothers were fed a diet rich in methyl donors, common molecules found in such foods as onions, garlic and beets.

After being consumed by the mothers, these methyl donors worked their way into the developing embryos' chromosomes and onto the critical agouti gene.

The mothers still passed this gene on to their offspring, but due to their methyl-rich diet, the gene now came with a chemical switch that dimmed its negative consequences.

Our human DNA (all 25,000 genes identified in the Human Genome Project) are now recognised as the instruction manual for the human body. But every one of those genes needs instructions on what to do, and where and when to do it. Those instructions are not in the DNA, but on it, in chemical switches and markers known collectively as the epigenome.

Acting like software code, these switches and markers help switch on or off the expression of particular genes.

Researchers are finding that extra vitamins, or a brief exposure to a toxin, can alter the software of our epigenome in ways that affect an individual's body and brain for life.

And even more far-reaching surprise is that these epigenetic signals can be passed from one generation to the next.

It's well known that the environment in a mother's womb can alter the development of the foetus. Growing evidence now supports the belief that the epigenetic changes caused by one's diet or behaviour can echo far into the future.

Put simply, and this is not science fiction, what you eat or smoke today could affect the health and behaviour of your great-grandchildren.

To date, many of us accepted the idea that our DNA was our destiny; that we inherited particular body shapes, personalities and susceptibility to diseases from our parents.

Some scholars have even contended that the genetic code we inherit pre-determined our intelligence, perhaps even our propensity to crime and violence.

These notions now appear outdated. Everything we do (all that we smoke or eat or how often we run) can affect our own gene expression and that of future generations. We can no longer lament to being limited by our genes or have inherited "bad genes".

It finally looks as if we might actually have a large degree of control over them.

Scientists have lately discovered that the epigenome can change in response to the environment throughout an individual's lifetime.

In other words, not only can how we live affect the genes of our offspring, it can also affect our own genes right now.

According to one scientist at McGill University in Montreal, "People used to think that once your epigenetic code was laid down in early development, that was it for life, but life is changing all the time, and the epigenetic code that controls your DNA is turning out to be the mechanism through which we can change along with it."

Put simply, epigenetics tell us that even the littlest thing we do in our life can have an effect of great magnitude.

Beginners' challenge

This week four beginners have emailed me stating their intention to take up the challenge of training for next year's half marathon by following the schedule published last week.

Good luck to each of you, keep in touch and let me know how it goes.

If there are others, feel free to drop me an email.

Perhaps we might have an article later on new runners training for the 2009 event. Enjoy your running.

johnwalsh42195@yahoo.it