Personalized Nutrition: Taking Diet Science to the Next Level

Dietitians have long used the “individualized” approach to tailor their recommendations. Now another method is gaining ground — the “personalized” plan, which uses emerging technologies to incorporate data gathered from each patient. What’s the difference, and what should you know before you embark on one path or the other?

Personalized vs. Individualized

Dietitians don’t just look at what you’re eating. They look at your social interactions, your environment, values, skills, demographics, biometric data like blood work and weight, preferences and goals to create an individualized eating plan. Why does this matter? Take your environment: If your dietitian doesn’t know that you have no access to a kitchen, or perhaps live far from any grocery store, your plan might not take those factors into account. That could make it harder for you to achieve your goals.

A “personalized” plan takes those components and adds genetic testing and other biological measures to fine-tune your approach, using molecular-level assessments, DNA and data about your microbiome.

Future of Nutrition

The future of nutrition lies in genetics. Right now it’s not possible to prove that eating or avoiding a particular food will affect your health in a specific way. But one day, perhaps soon, genetic and other testing might tell you exactly that.

One way technology is changing nutrition is through machine learning, which uses mathematical operations to analyze data about large numbers of people and arrive at predictions useful to an individual. Let’s say you have metabolic syndrome, a cluster of conditions that can raise your risk of stroke, heart disease and type 2 diabetes — this kind of analysis suggests that people who eat a Mediterranean diet could be less likely to have metabolic syndrome.

Dietitians do this now in observational studies; new technologies are making it possible to examine the genetic variables of people who have the syndrome. An even newer field — “precision nutrition” — has the potential to categorize whole populations based on shared biomarkers.

Sounds like science fiction, right? That’s because we’re not there yet — scientists are still figuring out how to evaluate individual results relative to a broader population and vice versa.

For example, studies have shown that folate intake has a big effect on brain development during pregnancy, and that vitamin B12 metabolism plays a role in obesity. But do such studies prove that those nutrients conclusively caused the changes observed in individuals? There’s not yet enough evidence to say. But the potential is enormous, making this an exciting time in nutrition science.

Before You Begin

As often happens with new technology, the business model is ahead of the research. Many internet sites offer genetic testing that can tell you things like whether you are prone to inflammationor don’t metabolize a particular vitamin or nutrient well. But what is the relevance of that information to you? This information comes at a cost — you can find genetic testing for as little as $199, while microbiome tests can run from $100 to $1,000.

Some things to consider before you proceed:

• Is the test you’re about to purchase reliable and relevant to your goals?
• Is the test evidence-based? Has it been evaluated by scientific studies?
• Is the test invasive? For example, some require stool samples — are you comfortable handling that kind of material?
• What will the test maker do with your data? How will it be safe-guarded?
• For genetic testing, how might your results affect family members? Will you share that data with them?
• What will this cost? Will your insurance pay for it?

Double-Check Information

Another question to ask is, is information available on the test itself?

Let’s say your goal is combatting obesity — do the test makers offer data on their results? If yes, does that information suggest it will make a difference in obesity, specifically? Is there enough data to say? You want to be as sure as possible that changing your diet based on testing will actually affect the condition you are trying to manage.

In a world where new tools are being developed all the time — yet only a limited number of genetic variants have been studied so far — you can improve your outcome by working with a registered dietitian who knows the data and can say, yes, this test is appropriate for you. If you let the internet stand in for your provider — and who hasn’t googled medical information? — you could inadvertently cut out essential nutrients and end up with a deficiency.

Measuring Success

The science of personalized nutrition is not yet advanced enough to say definitively that a particular diet can prevent a specific disease. In the absence of data that can be extrapolated, your best measure is to stay in touch with your goals. Did you lose weight? Did your cholesterol go down? Even when it’s not possible to say why a change occurred, having specific, measurable goals will give you an idea of whether an approach is effective for you.

From the limited studies done so far, individualized plans seem about as effective as those that include genetic and microbiome information — although the “personal” part of personalization makes that hard to study. Someone who’s more analytical might strongly respond to looking at data from their genes and microbiome; for others a traditional approach gives them all the information they really want.

It All Comes Down to You

No matter which approach you choose — individualized or personalized — you still have to be ready to do the work to make changes in your diet. If you don’t follow the recommendations, whatever path you choose, you won’t see any difference.

The good news is, either approach can help you and your dietitian create an eating plan that works for you as part of your lifestyle, whatever that might be.