COULD KNOW­ING YOUR GENES HELP YOU LOSE WEIGHT?

You are unique. Yes, you re­ally are! What’s good for you isn’t nec­es­sar­ily good for me. Your carb tol­er­ance is my muf­fin top (and it goes far fur­ther than that.) Here’s a new ap­proach to health that starts with you.

Fairlady - - CONTENTS - By Anna Rich

ITwas a mam­moth project. Over the 10 years lead­ing up to the mil­len­nium, sci­en­tists from around the world worked to­gether on the Hu­man Genome Project to iden­tify and se­quence the chem­i­cal com­po­nents of the hu­man genome (the com­plete set of our DNA, in­clud­ing all our genes). Their goal was to iden­tify all 3.3 bil­lion of the base pairs (ade­nine, cy­to­sine, gua­nine and thymine, ab­bre­vi­ated to A, C, G, and T) that com­prise that genome. We said it was mam­moth! The rea­son? The se­quenc­ing of the bases of the DNA mol­e­cule de­ter­mines what con­trols our growth, de­vel­op­ment, func­tion­ing and re­pro­duc­tion. So it’s the key that un­locks (some of) the mys­ter­ies of life, re­ally. And they did it!

Se­quenc­ing the genome means we can see which ge­netic vari­ants

Se­quenc­ing the genome means we can see which ge­netic vari­ants up the risk of dis­eases like di­a­betes and can­cer, and we will also be able to cus­tom-de­sign med­i­ca­tions for some­one’s spe­cific genome.

up the risk of dis­eases like di­a­betes and can­cer, and we will also be able to cus­tom-de­sign med­i­ca­tions for some­one’s spe­cific genome, mak­ing the med­i­ca­tion more ef­fec­tive and po­ten­tially re­duc­ing side ef­fects.

OF COURSE, IT’S NOT THAT SIM­PLE…

We may have se­quenced the genome, but noth­ing is writ­ten in stone: genes re­act to their en­vi­ron­ment – to things like the food we eat, who we in­ter­act with, when and how much we sleep, and how we ex­er­cise. Genes can be turned off and on. If you think of the hu­man life­span as a very long movie, says What is Epi­ge­net­ics? (a great on­line re­source), ‘the cells are the ac­tors and ac­tresses, es­sen­tial units that make up the movie. DNA is the script – in­struc­tions for all the par­tic­i­pants of the movie to per­form their roles. The DNA se­quence is the words in the script, and cer­tain blocks of these words that in­struct key ac­tions or events to take place are the genes. The con­cept of ge­net­ics is like screen­writ­ing. The con­cept of epi­ge­net­ics [bi­o­log­i­cal mech­a­nisms that switch genes on and off] is like di­rect­ing. The script can be the same, but the direc­tor can choose to elim­i­nate or tweak cer­tain scenes or di­a­logue, al­ter­ing the movie for bet­ter or worse’.

IT’S A SNIP!

The way the food we eat in­ter­acts with our genes to af­fect our health is an ex­cit­ing new area of study called nu­trige­nomics, which is a nutri­tional guide to prevent­ing and man­ag­ing dis­eases as­so­ci­ated with obe­sity. A lengthy list of ge­netic vari­ants called ‘snips’ (sin­gle nu­cleo­tide poly­mor­phisms, or SNPs) are as­so­ci­ated with com­mon chronic dis­eases, es­pe­cially in tan­dem with par­tic­u­lar di­ets or foods. ‘We have loads of gene vari­ants, and it’s per­fectly nor­mal,’ Rochez O’Grady ex­plains.

‘You get 50% of your genes from your mum and 50% from your dad, and in that repli­ca­tion process, the amino acid or base pair of­ten dif­fers from the orig­i­nal, and that “spell­ing mis­take” is called an SNP or gene vari­ant. Your DNA is a dou­ble helix strand. Two base pairs con­nect the helix, and there are four let­ters in the DNA ‘al­pha­bet’. So a dif­fer­ent amino acid is the gene vari­ant.’

For ex­am­ple, Dr Ahmed ElSo­hemy, as­so­ciate pro­fes­sor at the Univer­sity of Toronto, and Canada Re­search Chair in Nu­trige­nomics, says a study they pub­lished in the Jour­nal of the Amer­i­can Med­i­cal

As­so­ci­a­tion showed that in some peo­ple, caf­feinated cof­fee in­take low­ered the risk of heart at­tacks. But in oth­ers, the same amount in­creased the risk of heart at­tacks: it came down to whether they had the ‘slow’ or ‘fast’ ver­sion of the gene CYP1A2 (which breaks down caf­feine in the liver).

These find­ings sug­gest that caf­feinated cof­fee in­creases heart dis­ease only in those who have a lim­ited ca­pac­ity to break down caf­feine, says Dr El-So­hemy. And it’s prob­a­bly be­cause those with the ‘fast’ ver­sion of the gene quickly get rid of the caf­feine while pre­serv­ing the an­tiox­i­dants in the cof­fee. He reck­ons ‘it’s these an­tiox­i­dants, not the caf­feine, that might of­fer pro­tec­tion for the heart’. My cof­fee is your poi­son, then. Or your cof­fee is my poi­son. Ev­ery­one re­ally is dif­fer­ent.

In one type of snip, a diet high in pro­tein is linked with greater weight loss, but in some­one with an­other snip, there’s higher weight re­gain! Sim­i­larly, in the pres­ence of one snip, you see less weight loss with a high-fat diet, and some­one with yet an­other snip sees greater weight loss on a low-fat diet. As

Dr El-So­hemy says, ‘This area of re­search ex­plains why some peo­ple can eat a high-fat diet and have no prob­lem with their choles­terol lev­els while oth­ers ex­pe­ri­ence the ex­act op­po­site re­sponse.’

There are also links be­tween spe­cific vi­ta­min and min­eral de­fi­cien­cies and dis­ease – when cer­tain genes are ‘switched on’: low vi­ta­min D is linked with type 2 di­a­betes, and low se­le­nium, with car­dio­vas­cu­lar dis­ease. So that’s where the sci­ence is. But…

CAN ANY­BODY BE TESTED?

Yes, they can – but it’s still ex­tremely ex­pen­sive. Rochez uses ge­netic test­ing in her prac­tice, as do some lo­cal di­eti­cians and health­care prac­ti­tion­ers. No nee­dles nec­es­sary – just a swab from in­side your cheek. The sam­ple is sent to the DNAl­y­sis Biotech­nol­ogy labs to iden­tify the range of genes de­pend­ing on your needs.

‘I usu­ally ask a client about their goals. The foun­da­tion range of tests is DNA Health, which tests for 36 gene vari­ants in­volved in choles­terol me­tab­o­lism and risk for heart dis­ease; bone health and os­teo­poro­sis risk; vi­ta­min B me­tab­o­lism and can­cer risk; in­flam­ma­tion and ox­ida­tive stress, de­tox­i­fi­ca­tion; in­sulin sen­si­tiv­ity and di­a­betes risk; food re­spon­sive­ness in­clud­ing lac­tose in­tol­er­ance, caf­feine pro­cess­ing, salt sen­si­tiv­ity and blood pres­sure.

‘If they’re look­ing for weight loss, I add on DNA Diet, which looks at ge­netic vari­a­tions that im­pact me­tab­o­lism, and ab­sorp­tion and stor­age of fats and carbs. It also iden­ti­fies the genes linked to binge-eat­ing, a sweet tooth, a larger ap­petite or re­duced sati­ety.

Then, I check whether there are oe­stro­gen is­sues, like en­dometrio­sis or poly­cys­tic ovary syn­drome. If there’s a build-up of oe­stro­gen, you have an in­creased risk of breast or ovarian can­cer. I can get enough in­for­ma­tion from those two tests to see if we need oe­stro­gen sup­port, through the DNA Oe­stro­gen test. If you group the tests to­gether, it’s more af­ford­able – it costs about R3 000-R4 000.’

There’s also the DNA Sport test, which looks at in­jury risk, re­cov­ery and ath­letic po­ten­tial.

‘But re­mem­ber, this is about pre­dis­po­si­tion,’ says Rochez. ‘It doesn’t look at what’s go­ing on in the body now. A blood test or a urine test will show you that.’

CAN YOU NUKE A GENE?

Rochez ex­plains that the tests she uses are for low pen­e­trance genes – genes you can in­flu­ence. ‘It doesn’t mean you can change the gene it­self, but you can turn it on (up-reg­u­late) or turn it off (down-reg­u­late). You could have a higher risk of de­vel­op­ing can­cer if you have is­sues with your de­tox­i­fi­ca­tion process. But that doesn’t mean you’re go­ing to get can­cer. We up-reg­u­late those de­tox­i­fi­ca­tion genes with nutri­tion and life­style to lower the risk of can­cer.’

On the other hand, she ex­plains, high pen­e­trance genes aren’t as read­ily in­flu­enced.

‘An ex­am­ple is BRCA, the gene An­gelina Jolie has. The so­lu­tion was a mas­tec­tomy.’

Rochez opens her own re­port, skim­ming through the var­i­ous genes: ‘Here’s TAS1R2, the sweet tooth gene. FTO is about ap­petite and reg­u­la­tion, but that’s just one part of what it af­fects. PPARG, that’s in your in­sulin sen­si­tiv­ity.’ She stops at the GST gene.

‘De­tox­i­fi­ca­tion hap­pens in the liver, in two phases. The GST genes are re­spon­si­ble for the se­cond phase, and you either have it or you don’t. I don’t have it, and this dele­tion is as­so­ci­ated with in­creased risk of lung, lar­ynx and blad­der can­cers as well as basal car­ci­no­mas of the skin.’ Sounds scary. But is there a di­etary in­ter­ven­tion that might help?

‘I have these other two GST genes, so my phase two isn’t ter­ri­ble, but it does mean I have to up-reg­u­late my other GST genes. To aid de­tox­i­fi­ca­tion, I have to eat cru­cif­er­ous veg­eta­bles as the bioac­tive com­po­nent in them, sul­foraphane, up-reg­u­lates your GST.’

She also points out the gene linked to car­bo­hy­drate re­spon­sive­ness.

‘Pota­toes and pasta trig­ger the re­ward cen­tres in your brain. This gene has been linked to other ad­dic­tive be­hav­iour pat­terns too.’

And if you have the MC4R and FTO genes, which are linked to in­creased ap­petite and re­duced sati­ety, you have to make sure you eat plenty of pro­tein, and you shouldn’t skip meals, says Rochez.

NA­TURE & NUR­TURE

The po­ten­tial to im­prove your health by know­ing your genome is ex­cit­ing. But, says Rochez, there are other things be­sides diet that can in­flu­ence these genes, like en­vi­ron­men­tal fac­tors.

‘You also have to find out what’s hap­pen­ing in the body right now. If some­one comes to me with gut is­sues, you have to ad­dress that. You’ve got your kit­bag with all your tools, and ge­netic test­ing is a great ex­tra tool. The more in­for­ma­tion you have, the more you can help.’

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