Keeping your immune system strong is one of the most important things you can do right now, as the COVID-19 pandemic continues. But boosting your immunity via what you eat is a two-step process; it’s about choosing foods that help support your body's immune function AND ditching dietary habits that can weaken immunity. Here are some habits to be mindful of as you work on boosting your body’s defenses.
Drinking too much alcohol
A glass of wine here and there is fine. But excessive alcohol consumption, even short-term, can alter your immune system in ways you might not realize.
In a paper published in the journal Alcohol Research, researchers note that there’s been a long-observed relationship between excessive alcohol intake and a weakened immune response.
The effect includes an increased susceptibility to pneumonia, and a greater likelihood of developing acute respiratory stress syndromes (ARDS)—factors that could potentially impact COVID-19 outcomes. Other outcomes observed involve an increased risk of sepsis, a higher incidence of postoperative complications, poor wound healing, and a slower and less complete recovery from infections.
If you find yourself drinking too much, cut back to a moderate amount of no more than one drink per day for women or two for men. And if you think you may need help regarding alcohol, there are several ways to seek professional services from home, including counseling via the Substance Abuse and Mental Health Services Administration national helpline: 1-800-662-HELP.
Going overboard with salt
You may associate excess sodium with problems like fluid retention and high blood pressure. But a new study from the University Hospital of Bonn conducted in both humans and mice concludes that too much salt may lead to immune deficiencies. Researchers found that when the kidneys excrete excess sodium, a domino effect occurs that reduces the body’s ability to fight bacterial infections.
According to the CDC, more than 70% of Americans’ sodium consumption comes from processed foods. That’s why the best way to curb your intake is to limit highly processed products, like canned soup and frozen pizza. Check the mg of sodium per serving on Nutrition Facts labels.
Consuming excess sugar
Cutting back on excess added sugar is a smart idea for a number of reasons, including good mental health. It’s also beneficial for immune support.
A study published in The American Journal of Clinical Nutrition found that after an overnight fast, humans fed 100 grams of sugar experienced a reduction in the ability of immune cells to engulf bacteria. The greatest effects were found between one and two hours later, but lingered for up to five hours.
This doesn’t mean you have to nix sugar completely, but avoiding an ongoing surplus or short-term overindulgence is a worthwhile goal. The American Heart Association recommends limiting added sugar—the kind added to foods by you or a manufacturer—to no more than six teaspoons worth per day for women, and nine for men. One teaspoon equals four grams of added sugar, so that’s 24 and 36 grams of added sugar respectively for women and men daily.
Overdoing caffeine intake
Coffee and tea are health-protective, due to their high levels of antioxidants linked to anti-inflammation. However, too much caffeine can interfere with sleep, and that result can increase inflammation and compromise immunity.
To best support immune function, ditch caffeinated drinks with no nutrients made with sugar or artificial sweeteners, like soda and energy drinks. When you do enjoy coffee and tea, be sure to cut off your caffeine intake at least six hours before bedtime to prevent sleep interference.
Skimping on fiber
Fiber supports good digestive health and helps to shift the makeup of gut bacteria in ways that enhance both immunity and mood. Research shows that a higher intake of dietary fiber and prebiotics supports healthier immune function, including protection against viruses. Adequate fiber also promotes more and better sleep. Yet just 5% of Americans consume the recommended daily goal of at least 25 grams per day for women and 38 grams for men.
The best way to upgrade your fiber intake is to eat more whole foods, including vegetables, fruit, whole grains, pulses (beans, lentils, peas, chickpeas) nuts, and seeds. Trade lower-fiber processed foods for fiber-rich unprocessed fare.
Other ideas include swapping sugary cereal for oatmeal topped with fruit and nuts, exchange white rice for brown or wild. Replace fiberless meat with beans or lentils, traditional pasta for pulse pasta, and exchange packaged snacks, like cookies and chips, with combos of fruit and nuts or veggies with hummus or guacamole.
Not eating enough green veggies
Aiming for seven cups of a wide array of produce daily provides numerous health benefits, but green veggies may be particularly helpful for immunity. These plants provide key nutrients known to help immune function, including vitamins A and C, plus folate. Greens also offer bioactive compounds that release a chemical signal that optimizes immunity in the gut, the location of 70-80% of immune cells.
For the most benefit, zero in specifically on green veggies in the cruciferous family, which include kale, collards, broccoli, bok choy, cabbage, and Brussels sprouts. Incorporate at least three cups per week—either raw, like kale salad, vinegary slaw, and fresh broccoli florets with dip, or steamed, sautéed, oven roasted, and stir-fried versions.