The What, Why, and How of Genetic Testing

genetic testing.jpg

Genetics is a topic that can be a little confusing and intimidating for people.  My aim here is to help you understand whether genetic testing can be helpful, what it can be helpful for, and what to look for in a genetic test.

What is Genetic Testing, Anyway?

First of all, nutrition-related genetic markers can be broken into two major categories – nutrigenomics and nutrigenetics.

Nutrigenetics is what you probably think of when you imagine genetic testing.  Your DNA gets tested for single-nucleotide polymorphisms (SNPs) that control the way your body functions.  For example, approximately 20% of the population has a version of the gene called TNF-alpha that is closely associated with chronic, low-grade inflammation, obesity, insulin resistance, and altered blood lipids.  In short, metabolic syndrome.  In these individuals, omega-3 fatty acids such as found in olive oil and fatty fish are ESPECIALLY important and helpful. 

In another example, some people have the E4 version of a gene called APOE.  This E4 SNP greatly increases risk of cardiovascular disease and Alzheimer’s Disease, and is highly sensitive to dietary changes.  While saturated fat is not something to worry about for most people, those with the E4 version of the APOE gene DO need to follow a low-saturated fat diet, and they are also highly sensitive to smoking and alcohol. 

It would be pretty good to know either of those examples applies to you, right?  But here’s where it gets pretty amazing.  Remember that nutrigentics addresses how genes change the body’s function.  On the other hand, NUTRIGENOMICS addresses how the environment changes the behavior of genes.  In order to explain that, let’s talk about the Human Genome Project. 

Why the Human Genome Project was a Disappointment

You may recall that the Human Genomic Project was a massive scientific undertaking that took 13 years, thousands of researchers, and billions of dollars of funding.  The goal was to sequence the human genome and the project was completed in 2003.  The project initially made enticing claims that it would lead to breakthroughs in the areas of cancer, heart disease, genetic diseases, diabetes, and mental health disorders.  Unfortunately, none of those promises came to fruition with the completion of the project.  This is because the scientists poorly understood an extremely important detail - epigenetics

It turns out that our environment has a major impact on the way our genes behave.  Imagine your genes forming a giant switch-board.  Environmental factors such as diet, stress, sleep, and exercise are what MOVE THE SWITCHES.  This is mainly accomplished by methylation, the addition or subtraction of a methyl group to DNA.  This turns the gene ‘on’ or ‘off’ or can even act like a dimmer, increasing or decreasing that gene’s action.

So, just knowing your genetic code doesn’t tell the whole story.  Epigenetics and nutrigenomics are the sciences of how environmental cues move our genetic switches.

I don’t mean at all that the Human Genome Project was worthless.  I just mean that our understanding of genetics has evolved – we now know that behavior and environment play much more of a significant role than previously believed.  This is GOOD news for us – your genes aren’t your destiny.  With the right data and plan we can literally hack our DNA. 

With the right data and plan we can literally hack our DNA

As an example of nutrigenomics, consider a compound called sulphoraphane that comes from cruciferous vegetables like broccoli, cabbage, and cauliflower.  Sulphoraphane literally switches on (upregulates) the genes responsible for eliminating toxins from the body.  This reduces cancer risk for everyone, but especially if you have the less active versions of those genes (if you have poor detoxification).  Wouldn’t you like to know if your detoxification genes are under-performers, so that you could know how much sulphoraphane you need to eat to reduce your cancer risk?  It’s pretty cool that you have that option. 

In a sense, the food you eat isn’t simply a compilation of nutrients – it’s information. 

But Watch Out…

Unfortunately, there’s a lot of noise in the genetic testing world.  The most common problem I see is that someone will pay for their 23&Me results.  This gets them a $200 string of meaningless data that they don’t know how to interpret.  So, they pay to put it through a filter such as Genetic Genie.  Unfortunately, they still don’t have something from the filter that gives them clear, actionable data.  So, they come looking for a real person to help them, but already $300 down the road with no results. 

So, yes, genetic testing can be helpful.  But you have to be careful.  There are a few really important things to look for when it comes to genetic testing:

  • The company keeps your genetic data private and secure (note: 23&Me sells your genetic data for research!)
  • They have a reputable scientific panel who can responsibly gauge what genetic SNPs have meaning, and what the true meaning is.  You should be getting on the order of 50 SNPs, not thousands.  There is not data to support clinically relevant recommendations for thousands of different genes, so that is a red flag.
  • Beware the single SNP.  One gene never tells the whole story.  Simply knowing your MTHFR or COMT gene result does NOT tell your whole methylation or clinical story.  Again, look for something on the order of 50 SNPs, not ONE and not THOUSANDS.
  • Watch out for third party interests.  Is the place where you’re getting genetic testing selling your data, or pushing dietary supplements based on the result?  Caution.  Some dietary supplements may be beneficial for some genetic results but selling supplements shouldn’t be a primary, up-front goal of the brand/company.  For example, not everyone with an MTHFR variation needs high-dose methylated B-vitamins.  In fact, that can be dangerous in some cases.  Which leads me to…
  • You should be getting professional counseling with your result.  A trained healthcare professional can help you translate your results into meaningful and effective diet and lifestyle recommendations.  They will consider your whole clinical picture within the context of your genetics.  Otherwise, you’re left with a bunch of meaningless code, or generic guidelines.  Try to work with someone who can incorporate food into your treatment plan.  Remember that food is information for your body!

So, Who Can Benefit?

One way to tell a bad genetic test is if you see promises that it will tell you everything about you and your health.  There are specific genes and SNPs that have good scientific data behind them, and others that don’t.  A good test will only report on the genes that have been shown by research to have a strong effect, and that are actionable with diet and/or lifestyle interventions. 

Fortunately, there is quite a bit that you can reliably know.  Genetic testing can tell you:

  • If you have increased risk of cardiovascular disease, dyslipidemia, inflammation, and obesity – and what to do about it
  • If your body is better adapted for a diet higher or lower in carbohydrates – and how to eat based on that result
  • If you are better adapted for a high or low-fat diet, and what types of fats you should consume
  • If you are a fast or slow metabolizer of caffeine and, thus, whether it is harmful for you
  • If you have robust or poor detoxification mechanisms, which contributes to cancer risk – and how to eat in response to that
  • The type of sports activity you are best suited for, and how to fuel for performance
  • The vitamins and minerals you metabolize less well and, thus, need to increase in your diet.  The most well-known example of this is your MTHFR and COMT genes and how they contribute to your methylation/utilization of the B vitamins folate and B-12. 
  • Your tolerance for dietary sodium
  • Your natural tendencies for cravings and snacks
  • If you have a genetic predisposition for intolerance to gluten and/or lactose/dairy

Where to Begin

Bottom-line, genetic testing is at a point where you can get useful information from it.  However, for good results, it is extremely important to work with a responsible lab and with the help of a trained professional.  I currently use several labs for genetic testing but in my opinion the best panel comes from Nutrigenomix.  You can get a sample test report from their website, or from me.  Some other reputable sources of genetic testing include Genova Labs, Great Plains Laboratories, and Spectracell. 

Who Should Do It

In my opinion, the best candidates for genetic testing are people who:

  • Have a family history of cancer or heart disease, or who have risk factors for them (i.e. obesity, insulin resistance, and/or dyslipidemia)
  • Have tried to improve on their health (lose weight, improve blood lipids, reverse insulin resistance, or decrease inflammation) without success
  • Have an interest in knowing their ideal diet: macronutrients (fats, carbs, and protein), and nutrients (vitamins/minerals) that require increased consumption and/or supplementation.

I hope this article helped to clarify the confusing and somewhat intimidating field of genetic testing.  This testing can fit into a functional medicine framework, but should be combined with your full, unique picture to make helpful, actionable recommendations for diet and lifestyle interventions.  If you have further questions or are interested in getting tested please feel free to contact me for details. 

Best wishes to you, and please feel free to share or comment using the below links.

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This can be accomplished through a combination of increasing probiotics and natural prebiotics, reducing sugar intake, avoiding foods that increase gut permeability and inflammation, and possibly working with a practitioner for further testing, therapeutic diet guidance, and supplement recommendations.

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Candy vs. Your Child - Best Frenemies


This is your child’s brain:


This is your child’s brain on candy:


And yet….we do this every year on Halloween.  Actually, we might even do it every day for the week of Halloween when you count all the school parties and fall festivals.  What’s causing this phenomenon, and what counter-attack can you launch?

Your Kid and Sugar – Best Frenemies

Candy is primarily a concentrated source of sugar – glucose and fructose.  Once it enters your child’s mouth, a primal instinct takes over.  The brain releases a feel-good neurotransmitter called serotonin.  Serotonin makes people feel great – happy and calm (yes, I said that – about kids and candy).  Serotonin is tightly linked to mood.  In fact, a deficit of serotonin is a known cause of depression.  

Anyway, back to your kid.  Life is good – now that their neurons are swimming in feel-good chemicals your kid is super happy.  Until they’re not.  Next thing you know, they’re screaming and throwing a fit – they don’t like the color of their shoes, you won’t let them eat all the candy right now, they want to rip off their costume, whatever. 

What happened?  We were having so much fun trick or treating! 

Well, the unfortunate follow-on to the serotonin high is that it comes back down.  Did I mention that this is a primal response?  We are wired to seek energy-rich foods.  Back when food was scarce, this really helped out our species.  When serotonin goes away, our brain looks for a way to get it boosted again – with more energy-rich foods – like candy.  It looks like this:



Meanwhile, your child’s pancreas.  It noticed that glucose from candy got absorbed into the bloodstream, causing a large increase in your child’s blood sugar – and fueling their tantrums.   The pancreas responds by releasing insulin.  Insulin facilitates the absorption of blood sugar into the body’s cells.  If you’re in luck, your child may then transform from werewolf back into human child.  Unfortunately, the more common result is that your child now feels….like trash – tired, lethargic, and “over it” with this “trick or treating”.  You can carry them home now.



Kids Will Be Kids….

None of this means that your kid shouldn’t be allowed to eat Halloween candy.  Let me just note, though, that the habit of seeking serotonin-boosting foods is pretty addictive.  One of the leading causes of obesity is believed to be the brain’s addiction to the serotonin that comes from energy-dense foods.  Halloween is a special occasion, but you may not want to allow the “roller-coaster of candy emotions” to be a regular occurrence for your kids. 

In fact, high added sugar intake has been linked to the following effects in children (a):

  • Increased LDL cholesterol
  • Increased triglyceriedes
  • Increased diastolic blood pressure
  • Dental carries/cavities
  • Increased fasting blood sugar and insulin levels

Fortunately, there is hope.  A recent study found that when obese children reduced added sugars from 27% to less than 10% of calories, they experienced remarkable reductions in all of these health markers – in only 10 days (a). 

So, don’t feel like you need to keep your kids candy-free on Halloween – but it’s probably not a good idea to let them feast on their stash until Thanksgiving.  Good luck Trick or Treating!

The Diet Myth that Even the Experts Believe

Can I get personal with you for a minute?  I love to eat.  That's why I usually eat all day long - I guess you could call me a 'grazer'.  My snacking habit has always been totally justified in my mind - I've been an 'athlete' of some fashion for the past 18 years, and I've been pregnant and/or breast feeding for nearly 5 years continuously.  I also usually snack on healthy food.  Further, I've always been able to lose weight while still snacking.  And, finally, nutrition 'experts' often recommend snacking!  Need any evidence?

It turns out, I'm not alone with my snacking habit.  Americans have become snack-o-holics.  Americans now snack twice as often as in the 1970s, and consume nearly 1/4 of their energy from snacks (1).  They now eat for at least a 15 hour window, with most of their calories consumed after 6:00 PM (2). 

In fact, snacking is so big that you can subscribe to receive automatic, custom-picked snacks delivered right to your door! 

So, what's the problem?  Well....I'll share a personal experience with you.  The final year of my dietetics program was pretty crazy and I gained a couple (OK, five) pounds.  Yes, I see the irony there.  After graduation I endeavored to lose them with my traditional "5-6 small meals/day" approach.  The results?  Nothing!  No progress.  Hmmmm.....this got me thinking about the evidence in support of intermittent fasting for weight loss.  Studies have shown that fasting periods can be at least as effective for weight loss as a reduced-calorie diet (3). Fortunately, you don't have to go all day without eating.  Just a 12-hour fast has been shown to be effective (4).  This basically just means you don't eat between dinner and breakfast.  In fact, longer periods of fasting can actually be harmful, especially for women (5).

So, could snacking actually not be a great idea?  It turns out, there's quite a bit of evidence that it's not:

  • Obesity is linked to frequent snacking, and snacking increases total energy intake (6, 7
  • The idea that frequent eating increases metabolism and fat loss has been proved false (8, 9)
  • Frequent eating causes elevated blood glucose levels throughout the day (10)
  • Lower meal frequency improves appetite control and satiety (11)

However, other studies have shown weight loss and metabolic benefits with snacking (12).  In total, the research is mixed on the benefits of snacking.  One reason for this fact is that the quality of snacks contributes to their effect (12).  In other words, planning to eat something healthy between meals is usually fine.  Poor planning, then bingeing on any junk sitting around the office/house is another story. 

Now we're faced with a decision - to snack or not?  When faced with a conflict like this I always find it helpful to view it through an 'ancestral lens'.  That just means I consider the way humans have lived and eaten for the vast majority of our existence.  It turns out that hunter/gatherers likely weren't consistently eating 5 to 6 times per day every day.  They experienced more of a 'feast or famine' situation, with periods of surplus food (a successful hunt), and other periods of lack (seeking food) (13).  This implies that an ancestral approach is to eat less snacks.

So, back to my personal dilemma.  I tried my own version of fasting which, literally, just meant not eating between meals, or after dinner.  The exception is after a workout.  Don't laugh - this alone was really hard for me (read: HANGRY).  Until it wasn't.....after a couple of weeks.  My appetite adjusted and, surprisingly, so did those stubborn 5 pounds - they disappeared. 

Now, I'm not saying that snacking is never appropriate.  If you work out at a moderate to high intensity, if you are pregnant or breast feeding (don't judge - my 'baby' is almost weaned and OLD/19 months), if you have a medical condition such as diabetes or a glycogen storage disease, or if you are a child/adolescent, you absolutely should snack!

However, I DO think snacking culture has gotten out of control.  Unfortunately, the deluge of 'health advice' encouraging everyone to snack isn't helping.  

What about you?  Have you bought into the idea that you should snack?  Maybe you snack and it works great for you - that's fine!  However, if you've been struggling with weight loss, or are looking to improve your metabolic health, consider kicking that snack habit.  Make sure you get a full, healthy breakfast, lunch and dinner each day and leave it at that.  A few tips:

  • Fix WHAT you eat first: I DO recommend snacks in most of my meal plans.  This is because switching from a standard American diet to an ancestral diet is change enough.  However, if you already have your diet dialed in and are struggling to meet your goals, you may want to analyze your snacking habit.
  • Control hunger between meals by following an ancestral template when you eat.  Refined carbohydrates and lack of healthy fats causes blood sugar to spike and fall - leaving you starving.
  • Practice mindful eating during meals - eat slowly and enjoy your food (yes I have small children and NO I don't always accomplish this!)
  • Don't take skipping snacks a license to go crazy at meals.
  • If you do snack, make sure it's planned and appropriate, i.e. a post-workout recovery meal.

Try it for four weeks, or take the 4-Week Real Food Challenge if you need support.  I'd love to hear how it goes.  Good luck!