7 simple ways to optimize your immune system

You may have only a vague concept of DNA and cells. Yet as a “genetic engineer” of sorts, you have the power to help determine, on a daily basis, which of thousands of your genes are turned off or on based on your own choices and behavior. Each healthy act can help switch on youth-promoting genes and switch off genes that cause you to age.

Science tells us that when you are under the age of six, your genes determine what happens in terms of your health. But by the time you are 55, a greater share of your health is determined by your choices, which dictate which of your genes are on and which are off. So while your genetic component at birth certainly has some influence on your ultimate health and longevity, life outcomes are much more about engineering via your behaviors, choices, and decisions than they are about genes.

How to self-engineer your immune system

We cannot know for certain how quickly new medical advances will happen, what the costs will be, or how accessible these treatments and/or diagnostics will be. (For example, you probably won’t be able to go to a walk-in clinic for a cancer-curing patch in the foreseeable future.)

That’s why we advocate for your own preventive behaviors. Because one thing is certain: A higher functioning defense system will be your best protection against cancer and other forms of aggressive disease.

That’s not to say that you can prevent or treat every serious condition by behavior alone—but you will certainly stack the odds in your favor if you do. Here’s what we recommend:

Hunker down in the produce section

The absence of various micronutrients in your diet can decrease your immune function. So it's good to diversify your portfolio of leafy greens (like kale and spinach), cruciferous vegetables (like broccoli and cauliflower), berries, and citrus fruits.

Aim to really get a variety. This will help improve the chances that all of your micronutrients—such as vitamins A, B, C, D, as well as minerals like zinc and selenium—are being covered.

Eat (the right) protein

Protein is key, since it’s a building block of antibodies that are integral to your immune function. Salmon’s healthy fats are good for the brain and whole body. You can also get protein from cooked beans and legumes and lean white meats, like chicken or turkey. As much as possible, stay away from red meat and processed meats.

Make smart cuts

For improved immune function and to help prevent cancer, it’s best to limit added sugar, added syrups, and simple carbohydrates. But even better, eliminate processed foods and swap in whole foods like fresh vegetables, fruits, whole grains, and lean proteins.

Move, move, move

Get your motor revved. One study that examined older adults found that physical activity was associated with a hearty production of protective T cells.

Note here: Don’t overexercise. Overexercising (running, biking, or otherwise training continuously for more than two hours) causes inflammation and depresses your immune system.

Don’t overmedicate

Medication is one of our most important social advances. We have significantly lengthened the human life span with our ability to treat, cure, and prevent disease. That said, overmedicating can be counterproductive, as it has the potential to mess with your immune function (overriding it, in effect).

Though we can’t give guidelines for this because every person’s case is unique, we do recommend that you discuss your medication and supplementation regimen with all of your doctors. This also goes for any over-the-counter medications and supplements you take regularly.

Get your vaccines

Stay up to date, and get an annual flu shot. The flu increases overall inflammation, and research suggests that getting an annual flu shot decreases the risk of heart attack, stroke, and heart-related death, probably by decreasing the inflammation that accompanies the flu and the plaque breakage that inflammation causes.

The COVID vaccine must be added to prevent heart attacks, strokes, memory loss, and kidney disease that may result from COVID inflammation. Getting great sleep for several days prior to a flu shot may help boost the flu shot’s success in protecting you from the influenza virus.

Take time for you

One of the major threats to your immune system is chronic stress. The cascade of hormonal responses it causes weakens your immune function over time. Chronic stress can lead to a buildup of cytokines, which, while fighting infection, can also hurt your own cells in the process. And yet, in some circles, “self-care” is an eight-letter four-letter word.

People pooh-pooh the idea of self-care because, they say either (a) they don’t have time or (b) they’re too tough. (“I don’t need no stinking self-care.”)

And we get it. It’s our nature to put others before ourselves. But as the Cleveland Clinic’s great gynecologist Linda Bradley, MD, says, “You can’t pour from an empty cup!”

Think of it this way: If you don’t take time to care for yourself, you won’t be around long enough to be with the people you really want to help and be with anyway.

There’s no such thing as total stress relief. (After all, stress is simply a byproduct of living a fulfilling and challenging life.) But there are ways to self-engineer the effects that negative and chronic stress can have on your body. These include meditating, practicing deep breathing, maintaining positive social connections, and getting at least 6.5 hours of quality sleep every night.

Excerpted and adapted from the book The Great Age Reboot, by Michael F. Roizen, MD with Peter Linneman, Ph.D. and Albert Ratner. Copyright © 2022 by Michael F. Roizen, MD. Reprinted by permission from National Geographic.