28 November 2012

Genetic testing: better health but buyer beware

Can the genetic tests now being marketed to the consumer supply us with the information we need to make better personal health choices?


When it comes to health, we are inundated with information. Everyone has a voice and an opinion. A lot of it is labelled ‘expert’ and claims to be based on scientific evidence, long experience and the credibility of the brand or an individual. But who can you trust? Will the Tim Noakes low carb diet really work for everyone? Will it work for you? Do you really need to eat all your greens and juice? As we enter an era of personalised medicine – backed by gene analysis – some of the guesswork is being taken out of the equation.

Research is pointing to genetic differences as the basis for individual response to stimuli – food, exercise, stress, medicines, etc. The question is: can the genetic tests now being marketed to the consumer supply us with the information we need to make better personal health choices?

Why it works

The human DNA is 99.9% the same; it’s the 0.1% that makes us unique – it determines how each of us respond to stress and toxins, foods and exercise regimes, and creates a variance in our biological processes like cholesterol regulation, inflammation and insulin sensitivity.  Genetic research also tells us that our genes are responsive. Your genetic makeup may make you susceptible to certain diseases or conditions but whether or not that disease manifests is influenced very emphatically by lifestyle choices, our environment and the food we eat.

Armed with knowledge of our genetics, we can make better decisions, and so can healthcare professionals. It can give us a head start in minimising health risks, addressing existing conditions and altogether avoiding some diseases. However, there are no instant solutions – a holistic approach to health and wellness is essential.

Don’t be blindsided by gene tests

A quick Google search reveals any number of studies suggesting that: if you have a deficient CYP1A2 enzyme, you willmetabolise coffee slowly … and more than a cup or two a day could raise your blood pressure, making you susceptible to a heart attack if you have a certain modification of the APOA5 gene, you are resistant to weight gain; and about 30 gene variations affect the body’s response to exercise.

Really? Well, yes but it’s only a part of the answer, says Dr Daniel Meyersfeld of local molecular biotechnology firmDNAlysis Biotechnology. “Your genes load the gun; your lifestyle pulls the trigger. “If you are going to take a gene test, make sure you understand that what you are testing for is information that will help you understand why your body reacts in certain ways. There is no one-size-fits-all recommendation that will eliminate a risk, nor a test that can with certainty predict what will manifest. It’s your unique gene combination that will affect how you respond to stimuli like nutrition, exercise, medicines, and the like.

“Unlike the claims made by a lot of health products, taking a genetic test is not a quick fix solution; it is an investment in your future health and wellbeing. The inherent risk of disease encoded in your genes stays the same with or without the gene test; but having a gene test gives you knowledge of that risk and therefore empowers you to make the appropriate diet and lifestyle changes to reduce that risk.”

Check validity and utility

In selecting a genetic test you need to consider two elements: validity and utility.

Validity, in simple terms, is about understanding the real risk, or lack thereof, in testing positive (or not) for a certain genetic variation. It’s pointless, for example, to test for a gene variation whose function is unclear and that only a very small percentage of the population possesses. Utility, on the other hand, is about ensuring that if you do test positive for specific genes that there is something you can do about it – i.e., change your diet, exercise differently or take a specific dose of medication.

Consider the following examples:

Detoxification: The lack of a GST-M1 enzyme, which is particularly important in the elimination of toxins from the body, can increase your risk of various cancers, coronary artery disease, atopic asthma, and deficits in lung function. About half the population doesn’t carry this gene. This can be addressed by stimulating the function of related genes in the GST enzyme family by taking a diet rich in antioxidants, minimizing exposure to toxins, and substantially increasing intake of cruciferous and allium vegetables (which stimulate GST enzyme activity). Knowing you don’t have this gene makes a difference – it means cruciferous vegetables and vitamin supplements are not just good for you, they can be life-saving.

Physical fitness/performance: Targeted tests are very useful. If you are interested to learn how your body responds to exercise, the genetic test you take should not be one-dimensional. It should look at gene variations that impact performance (power and endurance) as well as how your body recovers from exercise and propensity for tendon damage. This will tell you the type of exercise and training you will most likely respond well to, and what pre-habilitative work is necessary to prevent injury.

Breast cancer: New clinical gene tests are also revolutionizing risk treatment. There are tests that only look at genes associated with hereditary cancer risk (about 5% of breast cancer) and others that look at variations involved in oestrogen metabolism in women. The latter is aimed at enabling specialists and individuals to make better decisions about taking hormone supplements like oral contraceptives and hormone replacement therapies (HRTs). Studies show that women who use HRTs for five years or more, increase their risk of breast cancer by approximately 35%. The risk is highest for women who do not metabolise oestrogen well. Knowing your risk means the specialist can make smarter decisions about length of treatment, dosages or if HRT alternatives are called for.

Choose wisely

Like any area of great discovery and advance, it will take some time to filter out the noise on genetic testing. As the market for drugs for healthy people continues to expand, the prediction by Sir Richard Sykes of pharmaceutical giant GlaxoSmithKline that “by 2020 most treatment in developed countries will be ‘pre-symptomatic’” looks to be well on its way to realisation.

For more information on DNAlysis Biotechnology and various other products, call (011) 268 0268 or visit or

(Press Release, November 2012) 


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