Picture: Sergey Nivens/123RF
Picture: Sergey Nivens/123RF

One quick swab against the inside of your cheek could open the door to new health information that medical practitioners say will help individual patients understand how their genes relate to illness.

Home DNA testing has already gained in popularity for other purposes: in exchange for a couple of hundred rands and a saliva sample, consumers can receive important information about their origins and ancestors. Websites like Ancestry.co.uk provide results that include ethnicity estimates and the option of seeing who else you’re matched with from customers on its database (distant cousins).

But SA consumers are fast realising that family history isn’t the only potential upside to DNA testing. Companies in SA and abroad say DNA tests can help consumers personalise medicine.

Tests that are more extensive — and usually cost more than ancestry checks — can tell a user about the illnesses they may be predisposed to suffer from.

DNA tests can also determine how people respond to certain drugs and how those drugs are metabolised in the body.

This means medical practitioners will have greater power to determine accurately the correct drugs and dosages for patients, based on their DNA.

The SA Medical Research Council recently launched its Genomics Centre in Cape Town, where individual genome sequencing will be conducted to help scientists better understand how a particular patient’s genes relate to illness.

And direct-to-consumer DNA kits have gone mainstream with DNAlysis, a firm that offers tests meant to provide information about diet, sport, skin, mind and oestrogen levels.

Its diet test, for example, looks for gene variations that affect the metabolism, absorption and storage of fats and carbohydrates. Coupled with information about eating behaviour, it can help someone get to grips with an eating plan.

The skin test determines skin condition, including firmness and elasticity. During a consultation, lifestyle, nutrition and other changes to reduce visible signs of ageing will be recommended.

The company’s health test by itself costs R1,885, but a combination of any two nutrigenomics tests comes to R3,355. Prices exclude a consultation fee.

Daniel Meyersfeld, who has a PhD in molecular biology, established DNAlysis Biotechnology in 2007. He says it was difficult to sell DNA tests in the early days, but it is easier now as costs have come down and people generally understand DNA better.

DNAlysis asks its customers to select a health-care practitioner, who will facilitate the test process and discuss results. A DNA kit is then sent to the customer. It includes a sealed tube with a swab that is used to rub against the inside of the cheek. The kit is later collected by a courier company, and within two to four weeks the results are shared and discussed in detail with the client.

DNAlysis has partnered with Nordic Laboratories and has expanded to more than 30 foreign markets. The company has completed over 100,000 tests, about half of which were done in SA.

"Our emphasis on the education and training of health-care practitioners and the push to have genetics included as part of a broader clinical investigation is what resonates with our clientele," says Meyersfeld.

Poobalan Pillay, a sports physician based in Tongaat, KwaZulu-Natal, says no two people have the same genetic make-up. Why should they then be treated the same, he asks.

"Our genes determine who we are, from the more obvious characteristics we see when we look at each other (phenotype), to the less obvious differences, such as risks for certain diseases and our response to various medications.

"Personalised medicine gives doctors the tools to highlight these differences and use them as a basis for making precise treatment decisions," he says.

Pillay says DNA tests such as those offered by DNAlysis and others investigate inflammation, insulin resistance, bone health, cholesterol and food responsiveness, which makes this a test that could be done first.

People need be assured that their genes are not their destiny, Pillay says. "Having one, or multiple, genetic variants may increase risk, but many health concerns can be reversed or avoided by assessing risk factors and implementing recommended diet and lifestyle measures."

Pillay has incorporated DNAlysis testing at his practice and the reports have helped him manage patients better. The DNA sport test examines areas affecting training responsiveness and sports performance, such as soft-tissue remodelling, oxidative stress, glycogenolysis (how glycogen is broken down to glucose), mitochondrial biogenesis (the way mitochondrial mass is increased in cells), muscle-building capacity and muscle-fibre type, he says.

"These reports provide another weapon in health practitioners’ armoury against disease."

Should users of home DNA kits worry about compromising their privacy? DNAlysis says it keeps customers’ DNA for a few months on the chance that they may opt for additional testing, but after that it is destroyed.

"We have strict confidentiality protocols; we share results with nobody other than the referring doctor," says Meyersfeld.

How a DNA test made me rethink my diet

After a diet test with DNAlysis, I have changed the way I eat. An analysis of my genes revealed that I need to follow a low-carb diet, and that my body is less responsive to mobilising fat from my cells (I require higher amounts of physical activity to burn fat).

I’ve subsequently cut out refined carbs (bread, pasta, pizza) and saturated fats (animal fats and certain kinds of cheeses, for example). I now eat lean cuts of meat, more vegetables, opt for whole-wheat options and cook in olive oil. I focus on the good carbs like sweet potato, corn, beans and chickpeas, and include more omega-3 in my diet from fish, as suggested by my dietitian.

I also discovered other interesting things: salt doesn’t seem to affect me, I pick up on bitter tastes, I can drink a fair amount of coffee a day, I’m not lactose intolerant, and I have a particular CAT gene, which is cancer preventative. That said, it was the list of potential diseases that my body is susceptible to that has kept me motivated to eat better.

*The writer was offered a free diet and health DNA test from DNAlysis