The Secret Code

For a long time we've just had to put up with the fact that many diseases are genetic. But Yael Joffe has been doing some ground-breaking research unlocking the secrets to a longer and healthier life. And yes, diet can influence your fate.

By Robyn Daly

A raid on Yael Joffe's cupboards reveals some startling secrets. There, plain as daylight is a can of baked beans. The last item besides, perhaps, a McDonald¹s takeaway that you'd expect to find in a nutri-genomist¹s cupboard. Yael is a nutritional geneticist, or a genetic nutritionalist, or whatever you want to call her to describe the combination of genetics and nutrition that¹s her highly specialised field of research. "It's so new there isn't really a name for me," says Yael. She started her career as a dietician but soon got bored with just foodstuff. Convinced there¹s more to health than good eating, she added a genetics degree to her CV. Then she met Ruth DeBusk, a US dietician and a geneticist who believes longevity is not just in your genes. DeBusk was a pioneer and Yael soon joined her. "Oh, I didn't invent anything," chuckles Yael. She has a ready sense of humour and a bright, energetic attitude to what could be a very heavy field of science. It shows in her book, co-authored with Dr DeBusk, It's Not Just Your Genes (available on amazon.com), which is surprisingly readable, even quite funny at times as it dispels the myth that you¹re born with a genetic fate and that's it.

Apparently our genetic make-up isn't a life or death sentence. It's not, this is what you¹ve been given and you have no choice. Some genes will impact on your life and, together with your lifestyle choices it may lead to a disease, cancer for instance, but there's no one cancer gene.

There are exceptions, such as cystic fibrosis and familial hypocholestrolemia (FH). In breast cancer, about five per cent of them, there is likely one gene that¹s the cause. But in 95 per cent of breast cancers it¹s a combination of genetics and lifestyle. If someone dies from breast cancer at a young age, there's a chance they have the BRCA1 or BRCA2 gene. If they were in their 60's, then it's more a lifestyle-inheritance combination.

The Big Killers

So let's talk about the things that really kill people: heart disease, diabetes, obesity, cancer. These diseases kill the majority of South Africans (apart from crime no genetics in that). There's that ready laugh again. It's a combination of our genes and our lifestyle: diet, exercise, smoking, pollution, stress and those sorts of things. The two interact our whole lives. So genes show our potential rather than defining whether or not we¹ll get the disease. The type of food we eat, the exercise we do and the way we live our lives can change how our genes behave and if they will go on to express themselves as cancer or diabetes. So if you have a gene that has a potential for cancer - POTENTIAL - and you smoke a packet of cigarettes a day, don't exercise or eat fruit and vegetables, the chance of the cancer potential coming out of that gene is high. Whereas if you do everything right there's a good chance the gene will never express itself. We can control how our genes behave by our choices. It transpires we have a set of genes that manages toxin processing. ³When we smoke a cigarette or sit in the traffic surrounded by carbon-monoxide fumes or if we're eating all the burned parts of the braai that aren¹t good, toxins are going into our bodies. We process them to get them out of our system. If you have a set of genes that make you a really good metaboliser, it means those toxins come into your body and get out very quickly. If you¹re not a good metaboliser, it means the nasties hang around inside you for a long time giving them ample opportunity to cause damage.

Different genes for different scenes

So genetics is a lot more than blue eyes and brown hair. "There's a set of genes that will just metabolise smoke particles or another set that will just process food toxins," says Yael. We have more or less 25000 genes. But one gene can do a number of jobs. There's even a gene that can tell you whether you¹re a better endurance runner or should go to the gym for power training. Yael is a marathon runner, so we know which one she got. That same gene can also tell us whether or not you¹re susceptible to high blood pressure. There's not one gene that makes a person fat, there are probably 300 to 1000 genes that are involved in processes that cause over-weight. You need to understand all of them and how they interact with the environment to be able to say what makesone person put on weight and the other not. Understanding the differences between us is most useful.

Into the future

Genetic testing is the future. Yael paints a picture of what she jokingly calls 'designer nutrition'. We can confidently test about 20 genes now, but in 10 or 15 years we¹ll be able to do all 25000. We'll have our DNA tested and when we go to the doctor or dietician we'll have a card with a chip on it and all the information will be there.

There was a time when there was no such thing as a cholesterol test. So your doctor knew there was a family history of heart disease but didn¹t know what to measure. Now you wouldn¹t think twice about having a cholesterol or blood pressure test. It¹s all about information doctors and dieticians are always looking for more.

Now, back to those baked beans in the kitchen cupboard. "They're actually very good for you," Yael laughs. All the goodness is packed in the tin. She confesses that she also likes the occasional McDonald¹s milkshake. So while the rest of us sweat it out over little slips at the drive-through, knowledge has set Yael free.

Myths and Legends

Myth: Fresh veggies are always more nutritious.

Truth: Frozen vegetables have about 10 per cent more vitamins than fresh veggies. Unless you pick fresh and eat vegetables quickly, light and oxygen destroys vitamins.

Myth: Whole milk has the highest calcium content.

Truth: Skim milk has more calcium than full-cream milk. The fat is taken out so there¹s more space for the calcium.

Myth: Fat is bad for you.

Truth: Bad fat is bad for you (fried food, butter and heavy cholesterolstuff). Olives, olive oil, avocado, canola oil - those are good for you. This whole concept of fat free, fat free, fat free your body needs fat. It's really about the type of fat, not how much.

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