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.
In 2021, the role of metabolic health for immune strength will only get more important. A staggering 88% of Americans are metabolically unhealthy. That's most of us. As a new year (finally) is upon us, resolving to become more metabolically healthy would pay dividends for immune and overall health. We've compiled current science and expert insights to help understand where the conversation is going.
Let's get to the root of metabolic health.
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."
Years down the road, these roots of metabolic dysfunction (abnormal blood sugar, lipids, and inflammation) can manifest as weight gain, diabetes, hypertension, metabolic syndrome, heart disease, stroke, cognitive loss, weakened immunity, and more. That's a trajectory to avoid.
The metabolic states of America.
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 individuals are metabolically unhealthy too.
Nonetheless, national stats 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 obesity, diabetes, heart disease, 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 death in the U.S. have metabolic health underpinnings: heart disease, cancer, stroke, Alzheimer's disease, diabetes, flu/pneumonia, and kidney disease.
And in 2020, a new leading cause of death unexpectedly shook our world, taking over 350,000 lives in the U.S. alone. I'm referring, of course, to the novel coronavirus.
Metabolic health and immune strength are intertwined.
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 level. Case in point: COVID-19.
The coronavirus pandemic has brought the metabolic health/immunity link to the forefront of scientific research and news headlines across the globe. As Foucher-Urcuyo explains in a recent mindbodygreen podcast, "People who are metabolically unhealthy seem to be more at risk of getting severely ill when they do get infected with the virus."
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.
In a 2020 review 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 publication 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."
Getting metabolic health back on track is one major way to help achieve the resilient and healthier future that Bland describes.
For metabolic (and overall) health, avoid the standard American diet.
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.
The Dietary Guidelines for Americans 2020–2025 are about to drop any day now, but it's time to play catchup. As a nation, we're not meeting the nutrition recommendations from the last couple of decades of guidelines. This is how we stack up:
- Americans are consuming too much sugar and refined grains.
- We are lacking fruits, vegetables, seafood, dairy, and whole grains.
- Of the veggies we do eat, white potatoes (can you say, French fries) represent over 25% of that intake.
- Oversized portions, liberal snacking, and widespread consumption of ultra-processed, convenience foods loaded with sugar, salt, and unhealthy fats are filling us with excess calories that are ironically "empty" (i.e., not good nutrient value).
- Ultra-processed foods account for a whopping 58% of daily calories in Americans.
- Added sugars exceed 10% of daily calories in two-thirds of Americans age 1 and older.
- Nutrient gaps for multiple vitamins and minerals are commonplace.
Simultaneously, food insecurity is widespread in the U.S., and this problem disproportionately and negatively affects BIPOC communities. Overall, this lack of access and the poor-quality diet of our nation is translating into metabolically unhealthy phenotypes like obesity, type 2 diabetes, heart disease, and more.
Focus on plants, slow carbs, and moderation.
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."
Weaving in our current pandemic, Shanahan also identifies an important opportunity: "We should take this whole coronavirus as an opportunity to understand our modern diet is the reason our virus was so scary."
How to gauge improvement: Key biomarkers are metabolic clues.
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.
Here are 10 key biomarkers of metabolic health to know, track, and optimize with the support of your physician:
- Waist circumference: less than 88 cm (35 inches) for women and less than 102 cm (40 inches) for men.
- Blood pressure: systolic less than 120 mmHg and diastolic less than 80 mmHg.
- Fasting blood glucose: less than 100 mg/dL (70 to 80 mg/dL is ideal).
- Hemoglobin A1c (HbA1c): less than 5.7% (lower is better).
- Triglycerides (TG): less than 150 mg/dL (less than 100 mg/dL is ideal).
- Cholesterol: LDL cholesterol less than 100 mg/dL. HDL cholesterol greater than 50 mg/dL for women and greater than 40 mg/dL for men.
- TG:HDL ratio: ideal ratio is 1:1.
- Alanine aminotransferase (ALT): 7 to 55 U/L is normal range (less than 25 U/Lis ideal).
- Uric acid: less than 6 mg/dL for women and less than 7 mg/dL for men.
- High-sensitivity C-reactive protein (hs-CRP): less than 2 mg/dL (less than 1 mg/dL is ideal).
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 fine to track body weight, but don't make it the focus. Family physician Foucher-Urcuyo expounds: "Weight gain is just another symptom of this abnormal process." When the underlying root causes of metabolic dysfunction (blood sugar, lipids, and inflammation) are "treated through nutrition, exercise, and lifestyle, the weight tends to come off. If we only focus on the weight, we miss the forest for the trees."
Call to action: Let's get metabolic health back on track.
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.
When taking charge of metabolic health for immune strength (and all the other health benefits), here's where science says to focus your efforts.
The bottom line.
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.
Whenever possible, it's best to proactively improve metabolic imbalance before chronic diseases develop and begin eroding quality of life. But regardless of where you're at, now is always the best time to improve your health. Incorporating science-backed, personalized lifestyle changes over time is the ideal approach to becoming more metabolically healthy and immune strong, for life.
The mindbodygreen editorial team worked together on the creation of this article, combining their deep expertise honed by years of reporting on health and well-being. It has been thoroughly researched, written, fact-checked, and reviewed by our editors.