The promise of personalized nutrition is an exciting one. Rather than buying into the latest one-size-fits-all trend (low-carb! Paleo!), you can now access eating plans tailored to your body’s genetic makeup, gut microbiome, food sensitivities, nutritional deficiencies, and more. One might assume a personalized approach is more likely to produce the results that you are seeking—right? In theory, yes, but unfortunately the actual promise of complete diet personalization is still far from being realized.
With each passing month, more research is being published and our understanding of effective means for personalizing diets grows. Last month a study was published in the journal Cell entitled “Personalized Nutrition by Prediction of Glycemic Responses.” Since then it has been making big waves in the media being touted by some as the diet study that changes everything we know about dieting. While this hyperbolic statement is grossly misleading, the study itself is very interesting, reinforcing things that we already knew about individual diet response and while also shedding light on some new areas. As interesting and useful as this study maybe, it is important to note that this study only looked at individuals’ blood sugar response following meals and throughout the day. This is a good predictor of future health and risk of diabetes, but it is far from a single comprehensive marker of health.
What Does Personalized Nutrition Really Mean?
The Israeli researchers behind this study were intrigued by the fact that when they fed people meals they were not able to predict how each individual’s blood sugar levels would respond. They tried to use carb counting, which is seen as the standard for diet-driven blood sugar control, to predict how people’s blood sugar would change, and that worked okay, but not great. Calorie counting was an even worse, near useless, predictor. What was even more shocking to the researchers was that when different people ate the same meal, their blood sugar levels responded differently, sometimes very differently.
The researchers started digging, quantifying, and classifying differences between individuals in the study in an effort to find out what unique characteristics about different people impacted how their body’s responded to a meal. The researchers collected and assessed more factors than we can discuss in this article, but I have highlighted the three that I think are the most important and useful for you.
Blood Sugar Control: In this study, the speed and magnitude that a person’s blood sugar levels rose in response to a meal was directly related to their body’s ability to process sugar and carbohydrates. There are several factors that physicians and researchers can use to quantify this sugar processing ability and one of the most popular, and reliable, is the Hemoglobin A1c (HbA1c) test.
Hemoglobin is the part of your red blood cells that are responsible for holding onto oxygen molecules as they get transported throughout your bloodstream. As a function of being in the same space in your body (i.e. your blood vessels) sugar molecules can get stuck to your red blood cells; the higher the levels of sugar in your bloodstream, the more sugar molecules are going to be attached to your red blood cells. HbA1c is a measure of the percentage of hemoglobin compounds in your red blood cells have a sugar molecules stuck to them. Since a red blood cell lives for around 90 days, your HbA1c gives you a good long-term measurement of your blood sugar control.
Having a HbA1c of <5.7% is considered good/normal while a HbA1c >6.5% is part of the criteria for a diagnosis of diabetes. In the diet personalization study that we have been discussing, researchers found that a HbA1c of 5.5% was actually the cutpoint for a person having a negative response to a meal. This suggests that we might need to be even more diligent about controlling our blood sugar even if we are in a range that is considered normal. Fortunately HbA1c is a very simple test that most doctors will order without much fuss. Having this test will done arm you with key information about your physiology. If your HbA1c comes in greater than 5.5%, working to reduce your average blood sugar levels would be a prudent goal to take on.
Related: The Truth About How Sugar Really Affects Your Body
You can get started doing this by reducing the overall carbohydrate content of your diet (start with refined and added sugars), increasing your overall activity levels, and losing extraneous body fat.
Digestive Health: The hottest area in nutrition research today is the microbiome. The microbiome refers to the trillions of bacteria cells that reside in our digestive tracts. These bacteria can have a profound impact on different areas of our body’s ranging from immune to and brain function to metabolic health.
In this study specific sub-populations of bacteria were associated with better or worse blood sugar responses to meals. In the latter phases of the study, researchers found that when they put participants on their ideal personalized diets, the sub-populations of bacteria changed for the good, further supporting optimal blood sugar control.
However, you can get proactive with making changes in your gut bacteria without having access to the intricacies of this research study’s proprietary diet customization algorithm. Fermented dairy products like kefir and yogurt are an abundant source of the same bacteria that provide beneficial support in this research study. I have a glass of plain kefir every morning in a ceremonial effort to curate an abundant population of helpful bacteria in my digestive tract. Most research studies also show that high levels of beneficial bacteria are also associated with low levels of unhelpful bacteria. In theory, by constantly augmenting the population of good bacteria in your microbiome, you will be crowding out and evicting the bad ones.
Inflammation: Excessive inflammation is a process that is at the root of nearly all disease processes so it was no surprise to learn that in this study individuals with higher levels of inflammation had a less favorable blood sugar response to their meals. This is not the first study to show a link between inflammation and poor response to diet as there have been numerous studies (including one that I conducted at Pennsylvania State University) which show that people with higher baseline levels of inflammation do not respond as well to heart healthy diets.
Related: How Does Your Diet Contribute to Inflammation?
At a very basic level this suggests that if you have higher levels of inflammation, you may need to be more persistent in your diet and exercise efforts as your body isn’t as eager to change for the good. There are lots of markers of inflammation but the most common blood test you can talk to your physician about getting to measure inflammation in your body is high sensitivity C-reactive protein (hs-CRP). The good news is that reducing C-reactive protein (CRP) levels in your body doesn’t need to be that difficult. Here are three strategies that have been shown to work in reducing CRP:
● Eat more alpha-linolenic acid (ALA): This is the plant-based omega-3 fat found in chia and flax seeds. It is distinctly different from the omega-3 found in oily fish and has been shown to reduce CRP levels.
● Get more sleep: Both short- and long-term sleep deprivation lead to increases in CRP.
● Exercise more regularly: Right after you exercise, you will actually get an increase in CRP but this is a natural response to exercise and it resolves itself very quickly, over the long term, exercise consistently reduces overall CRP levels.
Adapt Yourself to Better Biology
What I found the most interesting about this research study is that it suggests that diet personalization is a moving target. Almost all of the factors that the researchers measured were contextual (e.g. contents of previous meal) or modifiable (e.g. body weight). So unlike the, current pie-in-the-sky promise of gene-based diet personalization which centers on creating a diet based on your personal, yet static, genes, the findings from this study show an appreciation for the ever-changing nature of our bodies. It also provides an optimistic outlook for people who currently have “bad biology.” You can change and modify factors like sleep, the types of bacteria in your digestive tract, your body weight, HbA1c, etc., so that your personal blood sugar biology profile is then structured to work for and not against you.
Normalize Before You Personalize
Everyone is quick to jump at the idea of personalized nutrition but before you can work to personalize your diet, it is important (probably more important) that you normalize your diet. Normalizing your diet or creating a solid nutritional foundation is of the utmost importance as it gives you a solid base to build off of. I have my clients get a lot of blood work done when I first start working with them to measure everything from hormonal profiles to lipid panels to the levels in which their red blood cells are enriched with magnesium and omega-3 fats. Even with all this testing we always work to create a solid nutrition foundation before we get too specific with changes related to their blood work. When we get started in heavy diet personalization I always see this more as fine tuning than the foundation we build their nutrition plan off of.
What is a nutrition foundation? This consists of the nutrition habits that are programmed into your life such as consistently selecting and preparing minimally processed foods to eat throughout the week, drinking ample amounts of water, eating protein at regular intervals during the day to support recovery from exercise and maintain your muscle as the foundation of your healthy body now and as you age. It also includes more behaviorally oriented practices such as eating until satisfied but not stuffed or eating in a slow and deliberate fashion and not in a quick and distracted one.
All of these components are foundational and at some level transcend dietary specifics. Normalize your diet, optimize the bacteria in your digestive tract with fermented foods, and work with your doctor to have some simple blood tests done to fine tune your approach. If you do all these things in a stepwise fashion you will find not just great health but satisfaction and happiness with your diet.
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