Tuesday 16 January 2018

Shape Up: DNA does not have to be your destiny

Library image. Photo: Getty Images
Library image. Photo: Getty Images

Damien Maher

The first principle in Jack Canfield's book, 'The Success Principles', is that we should all take 100pc responsibility for the position we find ourselves in today. However, if health statistics are anything to go by then clearly the majority of the population has a lot to learn -- heart disease, cancer and diabetes continue to escalate while obesity levels hit record numbers.

When it comes to weight loss, it is quite common for people to point the finger of blame away from themselves. Often they'll use a label or an ailment in order to absolve themselves from future responsibility for initiating change. So could DNA be the cause of your weight gain?

There are many people who blame weight gain on their genetics but your DNA is not your destiny. Professor Brendan Loftus, from UCD, recently mapped the complete genetic code of an Irish person for the first time and -- guess what -- his research didn't reveal an Irish person's propensity to drink alcohol or to gain weight.


Dr Ruth Loos and other obesity researchers at the Medical Research Council's Epidemiology Unit in Cambridge discovered that having an active lifestyle could go a long way to countering a person's genetic inheritance.

The findings concluded that the concept that obesity runs in families and is unavoidable is a myth and that even those who are genetically at a higher risk of obesity can improve their health by taking some form of daily physical exercise.

Your genes are like a gun but your environment is the trigger that will activate the genes that increase your risk of obesity.

Research into genetics and DNA is not new. In 1986, 'The Lancet' published papers showing that if a pregnant woman ate poorly, her child would be at significantly higher than average risk for cardiovascular disease as an adult. This inspired Dr Lars Olov Bygren, of Karolinska Institute in Stockholm, to continue research on whether that effect could start even before pregnancy.

Dr Bygren wondered whether parents' experiences early in their lives could somehow change the traits they passed to their offspring.

Charles Darwin's theory taught us that evolutionary changes take place over many generations and through millions of years but Dr Bygren's research suggested that the effects of the environment, like near death from starvation, could leave an imprint on the genetic material in eggs and sperm. These genetic imprints can short-circuit evolution and pass along new traits in a single generation.

Dr Bygren's research showed that children who went from normal eating to gluttony in a single season produced sons and grandsons who died an average of six years earlier than other grandsons who had not undergone such a change. Once Dr Bygren and his team controlled for certain socio-economic variations, the difference in longevity jumped to an astonishing 32 years.

In 2000, Randy Jirtle, a professor of radiation oncology at Duke University in the US, started a ground-breaking genetic experiment where they used pairs of fat yellow mice, known to scientists as agouti mice. These mice were so called because they carried a particular gene, the agouti gene, that made the rodents ravenous and more prone to cancer and diabetes.

Prof Jirtle wanted to see if they could change the genetic legacy of these mice. When agouti mice mate, their offspring look identical to their parents -- yellow, plump and susceptible to a life-shortening disease.

The offspring in Prof Jirtle's experiment looked different. The young mice were slender, brown in colour and they did not display their parents' susceptibility to cancer and diabetes. They lived to a ripe old age.

The researchers did not alter the DNA of the agouti mice. The only change the researchers made was to change the mother's diet. Just before conception, Prof Jirtle fed the test group of mother mice a diet rich in methyl donors that would attach to a gene and turn it off.

Methyl donors are commonly found in foods like onions, garlic, beets and food supplements often given to pregnant women.

The mother mice would pass on the agouti gene to their children intact, but thanks to their methyl donor-rich pregnancy diet, the methyl donors attaching to the gene acted like a chemical switch to diminish the gene's harmful affects.

The 25,000 genes identified in the Human Genome Project are regarded as an instruction book for the human body but genes themselves need instructions for what to do, and where and when to do it.

These instructions are not found in the DNA but in an array of chemical markers and switches known as the epigenome, which can switch on or off the expression of a particular gene.


Prof Jirtle showed, like Dr Bygren, that epigenomes are sensitive to cues from the environment. Researchers are finding that an extra bit of a vitamin, a brief exposure to a toxin, even an added dose of mothering can alter the epigenome and, therefore, alter our DNA in ways that affect an individual's body and brain for life.

So what you eat or smoke today could affect the health and behaviour of your children and grandchildren.

Your DNA is not your destiny. In our gym, I find that the harder people train, the cleaner they eat, and so the cleaner their genes become. They have the attitude, belief, courage and determination to change their lifestyles.

A gym is a place where people get out what they put in and the discipline and dedication learned in changing your body can be transferred into any area of your life.

Your background and your circumstances may have influenced who you are but you are responsible for who you become.

Take care of your body and the addition of fresh vegetables and a quality multi-vitamin can help provide you with the methyl donors to switch off genes that can be affecting your health, especially if you are considering raising a family.

Give your children a bigger chance, as it is much easier to raise a child into good health habits than to rehab an adult.


Irish Independent

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