Our guest contributor Dr Neil Lamb continues his fortnighty Shareable Science Blog. Neil is the Vice President for Educational Outreach at the HudsonAlpha Institute for Biotechnology and Shareable Science will explore how genetics is relevant to people in their everyday lives. 

We’ve already talked about how the traditional Thanksgiving dinner is a masterpiece of genetics, so no judgement from us if you pack on a few pounds over the holidays. That said, between all the celebrations and the eventual resolutions you’ll make going into the new year, it’s possible that at some point you’ll start to worry less about the genetics of a great meal and more about the genetics of weight loss.

In the last few years, a number of consumer-facing companies have started promoting diets based on genetic profiles. There’s even some science to back those claims up, but it might not be as definitive as you think.

What do we really know about genetics and weight? Let’s explore.

 

Do genetics make you more likely to be skinny or obese?

The latest research suggests your natural weight state could be inherited through genetics. A study published in January 2019 associates multiple gene locations both with obesity and healthy thinness, meaning changes at those locations could make you predisposed to a heavier or lighter natural weight.

The study posits something many of you might have guessed from personal experience: Some people have an easier task maintaining their weight based on their genetics alone.

As always, it’s important to note the genetics are not deterministic here. Diet, exercise and environment still play huge roles in determining weight. However, we do now have specific evidence showing genetics can predispose you to a certain build.

 

Can genetics help you pick a diet?

This is the million dollar question. These days, it might even be a billion dollar question. While new evidence emerges all the time, the most comprehensive studies to date do not support the idea that a genetic test can help you pick a more effective diet.

That’s a reversal of previous research.

In 2010, a small study found that four specific genes could help determine which diet would work best for you. For example, in theory, the test would tell you whether you’d be better off with a low-fat diet or a low-carb diet. The study showed that participants on what was determined to be a genetically-appropriate diet lost more than 5% of their total body weight over the course of a year, as compared to participants that were not on their alleged genetically-appropriate diet. The second group lost a little over 2% of their body weight over the course of the study.

However, scientists revisited the study with a much more comprehensive research project. The follow-up study determined no link between genetic profiles and weight loss on specific diets. The Scientific American quoted the author of the study as saying, “We didn’t even come close. This didn’t work.”

Of course, in a field that changes as often as genetics, we’re always one study away from a new viewpoint. As for right now, the evidence does not support that a simple test can point you to a genetically superior diet.

If you want to learn more about this part, I dedicated an entire Biotech 201 lecture to the topic, which you can watch here.

 

Where can we expect the next breakthroughs?

It’s always possible that we do find a few genes that point to more effective diets for individuals. However, it’s also worth noting there are a few other weight-related areas where we could see a breakthrough in genetics.

For starters, we could come to understand the metabolism itself better, which might allow us to learn ways to “game the system,” so to speak.

However, one of the most promising areas for potential advancement is in the gut. We’ve talked about the microbiome before, and the collection of bacteria and microorganisms that inhabit the human body are a hot topic in science currently. For example, in an earlier Shareable Science explaining how gut bacteria were successfully manipulated to treat autism, we also discussed all the advancements being made linking the microbiome to health outcomes. The microbiome has been linked to everything from schizophrenia to Alzheimer’s disease. Now research has started to link the microbiome to weight loss.

As for what specific elements of the microbiome could contribute to weight loss, researchers at the Mayo Clinic conducted a study and found that patients with an abundance of bacteria to break down carbohydrates had a harder time losing weight. The study would suggest that analyzing the microbiome on the front end of making a diet plan could allow you to more successfully recommend cases where a low-carb diet would make a big difference.

The study was small, and there’s a lot of work to do sorting out specifics before we can definitively assign diets based on the microbiome. However, the field is certainly moving in that direction.

Additionally, there’s growing interest in how the gut microbiome could be shifted or modified to extract fewer calories from our food or even send our brains a signal of “fullness” to help people with their diets. The field of probiotics and prebiotics are still in their infancy, but one paper, which combined the findings of dozens of studies, concluded:

[D]ietary agents for the modulation of the gut microbiome are essential tools in the treatment of obesity and can lead to significant decreases in BMI [or Body Mass Index], weight and fat mass. Further studies are needed to identify the ideal dose and duration of supplementation and to assess the durability of this effect.

All told, it’s a promising direction for research to be heading

 

Ditching Misconceptions

This is going to serve you well no matter what aspect of weight management you’re dealing with—stay skeptical and vigilant. Anyone claiming to have an easy answer probably doesn’t have any answer at all. As of this writing, we don’t have any definitive way for genetics or the microbiome to guide diet. That’s not to say people aren’t working on it! It’s just not reality yet.

Of course, the old stand-bys, moderation, a balanced diet and regular exercise, remain the most dependable way to maintain a healthy relationship with your scale. Those things can definitely be a challenge over the holidays (I have a particular weakness for iced sugar cookies, eggnog and fudge), but at least we know where to aim.

 

The HudsonAlpha Institute for Biotechnology is a nonprofit institute in Huntsville, AL dedicated to developing and applying scientific advances to health, agriculture, learning, and commercialization. The state-of-the-art facilities co-locate nonprofit scientific researchers with entrepreneurs and educators. HudsonAlpha has become a leader in genetics and genomics research and biotech education and fosters more than 40 diverse biotech companies on campus. To learn more, visit hudsonalpha.org.