Is Your Immune System Confused?

Note: this article was written in March 2020, early in the COVID-19 pandemic. Public health guidance has changed since then; please follow current recommendations from your healthcare provider and public health authorities.

We are getting flooded with information right now about what to do in the time of COVID-19, much of it (rightly so) focused on reducing the spread of the coronavirus. You've heard it already, but here it is again:

• Wash your hands
• Try not to touch your face
• Avoid close contact with others
• Practice social distancing and avoid large groups
• Sneeze into a tissue and throw it away

But what else can we do to support a resilient immune system? Today, we talk about regulatory T cells.

Regulatory T cells, in scientific terms

Regulatory T cells (Tregs) are specific immune cells responsible for immune homeostasis (balance), particularly in the face of chronic inflammation and infection. Research has shown that inducing Treg cells in coronavirus infections protects against more serious forms of disease (1).* Treg cells also appear able to lower the cytokine (inflammatory chemical) storm (2) that contributes to disease severity.

*This research involved a different coronavirus strain, so applying it here is an extrapolation—but, I think, a reasonable one.

How can we support our regulatory T cells?

Sleep

Treg cells show inhibitory activity linked to our circadian rhythm, and sleep deprivation disrupts this normal rhythm (3). Sleep apnea can also significantly decrease Treg cell presence, relative to severity (4). Beyond Tregs, there is increasing evidence that acute and chronic sleep deprivation harms the immune system (5), so sleep should be a top priority for staying healthy.

Takeaway: give yourself the opportunity to get eight hours of sleep a night.

Exercise

Crowded exercise classes and busy gyms may not be the best idea right now, but that doesn't mean you should stop exercising. Both acute exercise and a regular weekly routine exert anti-inflammatory effects mediated in part by increased mobilization of Treg cells (6).

Takeaway: exercise at home. Many trainers and physical therapists offer virtual sessions.

Gut health

I often ask my patients, “Is your gut working for you or against you?” This can relate to inflammation or infection, but what I find most interesting through the lens of Treg cells is a set of compounds called short-chain fatty acids.

The three major short-chain fatty acids—butyrate, acetate and propionate—are produced when gut bacteria ferment soluble fiber from foods such as fruits and vegetables. They are important signaling molecules involved in Treg cell differentiation (7), weight regulation (8), blood sugar regulation (9), allergies (10) and even hunger (11). A diet high in fiber has been shown to increase short-chain fatty acid levels.

Takeaway: fill half your plate with vegetables (potatoes and corn don't count), eat a variety of colors daily, and favor vegetables that grow above ground.

Stress hormone

We can't avoid stress entirely, nor would we want to—living with too little stress hormone, as in Addison's disease, is miserable. But dysfunctionally high cortisol isn't good either. Beyond contributing to high blood pressure, anxiety and sleep problems, excess stress hormone also reduces Treg cells (12).

Takeaway: practice a stress management technique. Easier said than done, I know. I like guided meditation apps; my current favorites are Waking Up (paid) and Insight Timer (free).

Of course, regulatory T cell biology is much more nuanced than this—our bodies are beautifully and frustratingly complex. But it helps show why these simple (not necessarily easy) habits have broad effects on our health, supporting mood, immune resilience, metabolism and energy.