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Graphic of a strand of DNAFeature
The DNA diet
Can a Genetic test help you
make healthier eating choices?
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By Bill Redekop
Summer 2018

There are DNA tests for everything these days.

Companies perform direct-to-consumer genetic testing for "risk" genes like breast cancer, Alzheimer's and cardiovascular disease.

But there's also DNA testing for things like an individualized diet, depression, obesity, slumber type (whether you're a night owl or early morning person, and how to adjust your behaviour), weight loss, ancestry, genetic disorders in prospective parents, paternity cases, optimal exercise for your body type, and your body's ability to process prescription medicines.

You just mail in some spit and one of the new DNA companies spits back the results: your DNA sequence and what it's supposed to mean.

Consumer genomics has exploded, particularly in the United States, with company names like Orig3n, 23andMe (on television ads), DNAFit.com, Exploragen, and Genelex.

But it's difficult for a consumer to ascertain whether a company is selling legitimate DNA information or snake oil. In one publicized case, a DNA company told a person he was susceptible to obesity while another said he wasn't.

So it's reassuring that the Wellness Institute at Seven Oaks Hospital has done legwork for consumers and partnered with DNA profiling firm, Nutrigenomix.

Casie Nishi, Executive Director of the Wellness Institute, says the science emerging around this type of genomics, which is called nutrigenomics, meshes well with the organization's mandate as a medical fitness facility specializing in exercise and education for clients managing chronic disease.

"We did a lot of research," says Nishi. "We partnered with Nutrigenomix (based out of the University of Toronto) because we really believe in their evidence. Our physician team reviewed all the evidence and found (Nutrigenomix) to be the best practice."

The partnership with Nutrigenomix is not a diagnostic service - it won't tell you whether you have the gene marker for certain cancers or cardiovascular diseases. What it does do is personalize nutrition recommendations according to your genetic makeup. It helps to develop an eating plan to fit a person's DNA to optimize health outcomes.

Photo of a woman holding a salad in her lap

A simple example is caffeine. Health Canada says three to four cups of coffee (up to 400 mg of caffeine.) per day is safe but that's a generalized figure.

What does your DNA say?

The CYP1A2 gene (they are all labeled like computer passwords with a mix of letters and numbers) metabolizes caffeine in the liver. If you have a GA or AA variant of the gene, it means you break down caffeine at a much slower rate than normal.

A slower metabolism for caffeine puts you at greater risk of high blood pressure and heart attacks. Therefore, you should limit your intake to one or two cups a day (200mg of caffeine).

The program has only been running for about half a year and has had just 30 participants as of mid-May. One of those is Winnipegger Monalisa Abas.

Abas took a DNA test for a couple of reasons. Health is her primary concern but she's also a biochemistry student in university.

"I'm very interested because of my choice of studies in school but also because I wanted to be more aware of myself. (Nutrigenomix) is not just providing an opinion about my health. It's genetic, it's pure, it's your blueprint, what you're made of."

She also hopes to provide an example to her father, who tends to join Monalisa in her interests.

"If he sees me succeeding in something, he feels motivated to do that, too. Like, if I exercise, he also feels motivated."

So if she's eating right for her body type and genetic makeup, it may rub off on him.

"I'm very much like my dad physically and health-wise. So I did it to inspire my dad. I want him to stick around as long as he can," she says.

The program doesn't specifically target weight loss but that's been one of first results from personalizing her dietary recommendations. Abas has only been on her new diet for a little more than a month and has lost 15 pounds.

Nutrigenomix says its profiling can help with weight loss but it doesn't promote it above other features. However, others on genetically prescribed diets have also witnessed weight loss. The Globe and Mail reported one woman lost 42 pounds in six weeks. A study in Consumer Reports stated that 73 per cent of participants on a diet plan tailored to their genes lost weight after 300 days, versus 32 per cent on a general weight-loss diet. The people on the genetic diet with elevated blood sugar were also twice as likely to drop into a healthy range. (No word on whether they were able to keep the weight off.)

Photos of Registered dietitian Jennifer Gashinski and program participant Patti Simko.
Registered dietitian Jennifer Gashinski (left) and program participant Patti Simko.

Abas, 21, didn't take the program to try to lose weight but it has been one of the collateral benefits. "I got that weight loss from healthy eating. I'm changing things that are suitable for my genetics," she says.

She's increased her consumption of vegetables, of course, and has eliminated a lot of foods from her diet, like red meats. She eats fish three times a week and at least two eggs a day for the different mix of vitamins and minerals.

Abas also changed the way she exercises. The DNA report said she was "ultra" when it comes to power and strength. "I have a high ability to build muscle. So I've changed my exercising to include more weightlifting, but not crazy weightlifting. It's not all cardio, cardio, cardio anymore."

Her DNA sequence told her she has an elevated sensitivity to salt and therefore an elevated risk of high blood pressure.

"When I eat salty food, which I do a lot because I really like salty food, I notice my fingers get really, really big. That's my body retaining water," she says.

It also told her she had an elevated risk for lactose intolerance. It's something she's suspected for some time. (This does not mean she is lactose intolerant, as the test is not diagnostic, but that her genes indicate she has an elevated risk for it, and may even already have it.) So she is limiting dairy products.

Sample of a Nutrigenomix report

The test also told her she has an elevated risk for deficiency in vitamins A and D if her intake of these vitamins is low. Vitamin A is broken down by the enzyme BCMO1. People with the GG variant of BCMO1, like Abas, have difficulty converting beta-carotene (vitamin A in plant form). So she has started taking multivitamins to supplement her diet to ensure she meets the recommended daily intake.

As part of the program, a dietitian at the Wellness Institute went over her results and recommended dietary strategies specific to her DNA.

Patti Simko is another participant. Not knowing she was predisposed to heart disease, she suffered a massive heart attack when she was 50, even though she exercised regularly and had good eating habits. She's using Nutrigenomix as part of a preventive plan for future heart disease.

It took five weeks for her saliva to be processed. She then spent an hour with the dietitian going over the 45-page report that showed how her body processed various vitamins and minerals.

Like Abas, she is among the one-in-five people who don't process beta-carotene into the active form of vitamin A very well. Vitamin A is important for things like vision, immune system and reproduction.

"This made sense to me because my eyesight has changed rapidly over the past five years," Simko says.

She also learned she needs to eat protein with every meal to keep up her iron level. She now does that, along with several other tweaks to her diet, and has noticed big changes.

"I feel I have a lot more energy," she says.

She rates her experience with the program very positively. "I understand more about my body and the role that certain foods have on my overall health."

Nutrigenomix will also tell a person their variant of the gene APOA2, which produces the protein that has an important role in how your body utilizes different kinds of fat. Depending on your gene variant you may have an increased risk of obesity with a higher saturated fat diet. You're lucky if you've got the TT or TC variant of the gene, which is considered a typical risk. But people with the CC variant of the gene are more susceptible to obesity and should especially ensure they keep their saturated fat to less than 10 per cent of their intake along with the rest of the population.

Nutrigenomix is a University of Toronto start-up biotechnology company that works with health-care professionals and their clients to provide sound genomic sequencing. Founded in 2012, it tests 45 different genes, and is currently in 22 countries, according to its website, with DNA reports translated into seven languages.

Jennifer Gashinski, the Wellness Institute dietitian who consults with clients and helps to translate the test results in a meaningful way so clients can improve their eating habits, says people take the DNA test for a variety of reasons.

Photo of fatty foods

Some people are healthy like Abas and want to stay that way, while others like Simko have been diagnosed with a chronic illness and want to prevent a recurrence. There are those who are curious and others who are interested in its possibilities for weight loss.

While some participants aren't surprised by their DNA results, like Abas with her sensitivity to salt, others are very surprised.

"It's a lot about what's going on inside that you can't feel," says Gashinski.

The clincher is whether people will listen to what their DNA tells them. People know they should eat their veggies and cut out snacking, but what do they do about it? If they don't listen to their doctor, will they listen to their DNA and a dietitian?

From Gashinski's experience so far, the DNA profiling does seem to give added weight to dietary prescriptions. Perhaps it's like one of those road signs that show your speed as you approach a construction zone. People tend to adjust their driving speed to get to the prescribed speed limit when confronted with their individual speed.

"People who take the DNA test appear to be more motivated to make changes in their lifestyle," says Gashinski. "You're finding out how your genes respond to various nutrients. Some studies show that really helps people make changes when they know they're related to genetic makeup."

If you've ever visited a dietitian, you know that a personal consultation can have a very lasting influence, compared with advice you see on TV, or in a magazine like this one, or even from a physician. Dietitians are trusted experts in nutrition. Now imagine if that dietitian has your genetic code. That's another major tool for the dietitian to tailor a dietary program for you.

Says Executive Director Nishi: "The way we see it at Wellness is that it's one more tool that can support your motivation and help build importance because those are the two cornerstones of behavioural change."

The DNA test "only motivated me more," says Abas. "It's not the reason I lost weight. The reason I lost weight is because of the choices I'm making. The test just gave me knowledge to make my choices."

DNA tests aren't cheap. The cost for the Nutrigenomix program is $500, including the hour-long follow-up with a dietitian. That's a break even fee for the Wellness Institute, after the company's share, covering its overhead and the cost of the dietitian, Nishi says.

Coverage from private health insurance policies varies. Some people may be able to get much or all of their costs covered by a combination of health insurance and/or a health savings account. But that's rare. More commonly private insurance plans may cover 80 per cent of the dietitian's cost, which is $155 of the $500 total.

Of course, people searching for less expensive options for nutrition advice can check out one of the healthy eating programs available at the Wellness Institute or one of the other health centres in the city. And, of course, there is also Eating Well with Canada's Food Guide, which offers broad guidelines for healthy eating.

In any case, Nishi believes DNA testing is here to stay, and will play an increasingly larger role in health management in the future. "I think this area is growing. There is a growing interest in genetics and how it impacts our health," she says.

Participants like Abas vouch for it.

"It's expensive, so that sucks," says Abas of the Nutrigenomix program, "but it's so cool to have your genetics broken down so that you can actually see what you're at risk for based on how you were built as a person."

Bill Redekop is a Winnipeg writer.