Your Metabolic Health & Immune Strength Aren't Just Linked — They're Intertwined

For obvious reasons (pandemic), immunity is on the brain. As COVID-19 research adds to our scientific understanding of immunology in real-time, an important fact has clearly emerged: Your metabolic health and immune system aren't just linked. They are intertwined.

When you hear the term "metabolically unhealthy," what comes to mind? Perhaps obesity and diseases like diabetes or heart disease. You wouldn't be wrong. But, you can have none of those conditions, feel OK, and even be lean, and still be metabolically unhealthy. As family physician Cate Shanahan, M.D., explains on the mindbodygreen podcast, "A person who is seemingly healthy can have an undiagnosed metabolic problem."

So, what are the roots of metabolic health? Family physician Julie Foucher-Urcuyo, M.D., M.S., provides the answer: "Metabolic dysfunction is any abnormal regulation of blood sugar, lipids, or a chronic state of inflammation that leads to disease later on."

National data reveal how widespread this problem is: Only 12% of American adults are metabolically healthy. That's the subgroup to be in. Research demonstrates that this minority is more likely to be young, female, educated, never-smokers, and physically active.

They also tend to have a lower body mass index (BMI). But don't judge a book by its cover. A BMI in the normal/healthy weight range (18.5 to 24.9) is no guarantee of metabolic health. As it turns out, 20% of lean individuals1 are metabolically unhealthy too. 

Nonetheless, national stats2 reveal a sobering reality: The overwhelming majority (over 70%) of U.S. adults are now overweight or obese. Furthermore, 14 to 20% of our children are obese, setting them up for a future of chronic disease and reduced quality of life. These statistics represent overall averages. If we look closer, we see that the metabolic health burden is worse in BIPOC communities. 

There are significantly higher rates of obesity3, diabetes4, heart disease5, and stroke (to name a few) in Black and Hispanic individuals than in those who are White. Awareness of these inequities must be woven into the fabric of personalized preventive and treatment approaches by health care practitioners, as well as public health strategies.

With the poor metabolic state of America, it's no wonder that seven of the top 10 causes of death6 in the U.S. have metabolic health underpinnings: heart disease, cancer, stroke, Alzheimer's disease, diabetes, flu/pneumonia, and kidney disease.

It turns out that your immune system acts as a sensor of your metabolic state. In other words, immunity is not simply linked to metabolic health; they're intertwined at the physiological level7. Case in point: COVID-19.

In a 2020 review8 published in Endocrinology, physicians from the NIH explain that "endocrine-immune-vascular interactions" shape the clinical outcomes of COVID-19. Patients with metabolic syndrome are at increased risk of worse coronavirus severity and death. Poor metabolic health elicits hyperinflammation, immune dysregulation, and vascular dysfunction, a dangerous combination that's been repeatedly documented in COVID-19 patients.

Another 2020 publication9 exploring metabolic health and the coronavirus pandemic argues that, in addition to hygiene and social-distancing practices, beneficial health and lifestyle behaviors should be leveraged to improve COVID-19 outcomes. Blood sugar and blood pressure control are stressed, and the researchers also emphasize a healthy diet, hydration, moderate alcohol consumption, smoking cessation, physical activity, stress management, and adequate sleep.

And what about after this pandemic? Jeffrey Bland, Ph.D., the father of functional medicine, shares his vision: "There will be a world after COVID-19, and I'd like us to start thinking about immunity in new ways so that we can all start working now toward making that world a more resilient and healthier place in which to live and prosper."

The standard American diet, aka SAD, really is sad when it comes to metabolic health consequences. The SAD is high in carbohydrates and refined and processed foods while deficient in plant-based nutrition. It's excessive in food quantity and lacking in quality.

When it comes to improving nutrition, don't get lost in the details. Instead, focus on the good, colorful stuff: fruits, vegetables, whole grains, legumes, nuts, seeds, healthy fats (especially omega-3s), and high-quality protein. 

In discussing the American diet with mindbodygreen, pediatrician and former FDA commissioner David A. Kessler, M.D., strongly recommends a plant-based (or plant-heavy) diet where veggies are the focus. Kessler also gets granular about carbs. 

He explains that the SAD is providing us with an "endless flood of glucose we're pouring into our bodies." Instead of "fast carbs" like starch and sugars from refined and processed sources that digest rapidly and spike our blood glucose and insulin, Kessler is a proponent of "slow carbs," or complex carbs (i.e., carbs that nature makes, like vegetables, legumes, and whole grains). 

Simplifying the nutrition prescription even further, the goal is to focus on nutrient-dense and whole foods. As Kessler notes, "If it doesn't look like food, we have a problem."

Lastly, moderation is the glue that holds any healthy dietary approach together. As Cate Shanahan, M.D., explains, "There's no carte blanche with any of the three macros. Anything consumed in excess has to be stored as body fat." 

Through nutrition, exercise, and other approaches, if you're ready to hone your metabolic health, how can you gauge improvement? A waist circumference measurement, blood pressure reading, and specific labs are the best physiological clues. Most of the relevant blood tests are included in a standard comprehensive metabolic panel (CMP) and lipid panel. 

You'll notice that weight is missing from this list. As pediatric endocrinologist Robert Lustig, M.D., explains, "your waist circumference is very important, more important than your weight." That's because your waist size reflects abdominal and visceral fat, which increase risk for metabolically driven diseases.

It's become mundane to discuss obesity and cardiometabolic disease in our nation. But, the wide-reaching and deleterious effects of these two epidemics on our current public health and the well-being of future generations practically beg for renewed attention. 

As preventive medicine specialist David Katz, M.D., warns, "All those slow-burning chronic diseases that affect you over time can kill you tomorrow." The COVID-19 pandemic has tragically underscored this fact. The upside that Katz shares in a recent mindbodygreen podcast episode is that, "There's never been a better time to have the 'Let's get healthy, America' conversation."

So, let's get healthy, America. This is a mindbodygreen call to action. We're talking about taking control of metabolic health in a science-backed, personalized, and holistic way. We're not talking about judging a person's health by their exterior. Furthermore, dramatic weight loss, chronic or quick-fix dieting, and society's irrelevant goal of "thinness" (all potentially dangerous gateways to disordered eating) should be deleted from health vocabularies.

When small lifestyle changes are attainable, evidence-based, and individualized, the result is sustainable (and enjoyable) health and wellness. Health care practitioners have the ability to partner with patients to champion meaningful, personalized changes for their metabolic health, immunity, and more. Empathy should guide those health journeys, and social inequities must not be ignored. 

The name of the game is immune strength, which is driven by metabolic health. Whether you're carrying some extra weight or are lean, metabolic dysfunction can exist. That is why seven out of eight Americans are metabolically unhealthy. We're in this together, so let's tackle this together.