Genetics is amazing. It tells us so much about humanity and it’s a minefield of information. Admittedly, it’s a minefield that has only just been touched upon, but scientists argue that genetics is the answer to everything – so does that include diet and fitness? Companies like DNAFit say yes. They argue that the results of a DNA test will allow you to develop a personal gene-based diet and fitness plan that works for you – and that brings a whole new meaning to the term ‘tailor-made’. It may sound like a futuristic way to develop a fitness plan, and the possibilities are nothing if not intriguing, but there are some questions of the efficacy of these tests. So can they really help you improve your diet and fitness? And are they worth the money?
What They Do
At a very basic level, our genes dictate everything. Like a computer code written into us before we’re even born, our genes influence everything we do in life and how we respond to different external stimuli – and that, of course, includes how we respond to different foods and exercises. It makes sense, then, that a DNA test could tell us what foods are best for us to eat and which exercises will have the best results. Companies like DNAFit are now branching out from working with only professional athletes to providing home-testing kits and the results can provide information about your sensitivity to carbohydrates, salt, saturated fats, lactose, and gluten. You can find out about your specific requirements when it comes to anti-oxidants and vitamins, and your ability to process things like caffeine and alcohol. Not only that, but you can discover which sports suit you best – endurance sports or power sports? These tests even claim to tell you how likely you are to injure yourself during training and how long it will take you to recover[1].
The term ‘designer babies’ has been bandied around for some years now, and refers to babies whose genetic make-up has been selected or altered. This could be to eradicate a disease or defect, or it could be to ensure that particular genes are present. The idea has been discussed in science for many years and in science fiction, the concept has been around for much, much longer. The issue, however, is extremely controversial and as science races to meet science-fiction, the debate is becoming a serious one.
Pre-Implantation Genetic Diagnosis
Actually, the concept of ‘designer babies’ is not that far-fetched and already, doctors and scientists use some form of gene-selection during in-vitro fertilization (IVF) treatments. Pre-implantation genetic diagnosis, or PGD, refers to the practice of screening IVF embryos both for disease and for gender selection. Using this process, scientists can remove the defective mitochondria (the ‘powerhouse’ of cells) from an embryo and replace it with healthy mitochondria from a donor egg, and in this way they can effectively ‘design’ babies without certain diseases. Of course, the process doesn’t work for all diseases, and they can actually use this process for non-medical preferences too, such as the gender of the resulting child. Both forms of PGD are currently legal in the US, although the American Congress of Obstetricians and Gynecologists frowns upon the latter use, arguing that by allowing parents to choose the gender of their child, we run the risk of increasing sex discrimination[1].
DNA Editing
There is more to come though. Dr. Tony Perry of the University of Bath in the UK was one of the first scientists to clone mice and pigs, and he claims that more in-depth DNA editing is on its way. It won’t be long, he says, until we can pick and choose which parts of our baby’s DNA that we want to cut out and potentially replace with new pieces of gene-code[2]. In fact, it’s already begun. Earlier this year, scientists in China took discarded IVF embryos and began experiments to correct the abnormal gene that causes the blood disorder beta thalassemia[3]. Even though these embryos were due to be destroyed, the experiments incited much controversy. Whilst few would argue against potential disease eradication, this technique could be used to alter healthy genes too and the real question is how far would be too far?
‘Nature vs. Nurture’, the debate that has been with us for years, has reared its head again. So, the question on everybody’s lips is “can our environment be blamed for obesity or are some people really born to be fat?” David Geffen, of UCLA, recently published findings that suggest the latter (Red Orbit, 2013). After a two-year study, Geffen concluded that obesity is less about what you put in your mouth and more about your DNA, meaning that maybe your genes really are making you fat. But is he right?
Genetics
In 2007, New Scientist reported a University of Oxford study which showed that around half of the 39,000 people tested had a defective FTO gene (Roxanne Khamsi, 2007). This defect made them 30% more likely to be obese. Moreover, 16% of those tested were found to have a double defect, or the defective gene twice, leading to a massive 70% chance of developing obesity. These are startling statistics, especially given the high regularity of the defective gene. What’s more, this study isn’t alone in supporting nature’s side of the debate.
Timothy Frayling of the University of Exeter examined further research, when he declared that the link between obesity and genetics is stronger than we might think (Timothy Frayling, 2012). Frayling looked into adiposity rates in twins (the rate in which they store fat) and found an extraordinarily high correlation. Similarly, he compared BMI levels of adoptive children to both their adoptive and their biological parents. The biological association was significantly stronger than the adoptive one, suggesting that nurture has less to do with obesity than nature. In fact, Frayling concluded that around 60-70% of weight gain is related genetics rather than environment. With findings like these, it is easy to blame nature for your spare tyre.
