7 Sneaky Things That Can Weaken Your Immune System

Our immune systems are crucial for keeping us healthy, since they help protect us from outside "invaders" such as bacteria, viruses, toxins and more. The topic of immunity has become especially relevant during the COVID-19 pandemic. Though having a strong immune system alone isn't enough to avoid the coronavirus (social distancing, masking up, regular hand-washing and getting the vaccine are all still the best ways to protect yourself), supporting your immune system is still important—especially as cold and flu season approaches.

We can help support our immune systems by eating a nutritious diet, getting enough sleep and staying away from people who are sick. But it turns out there are certain things that can also weaken our immune systems. Here are seven things to avoid if you want to keep your immune system in tip-top shape.

7 Things That Can Weaken Your Immune System

1. Not Eating Enough Fiber

According to research, 95% of Americans don't eat enough fiber each day. Eating fiber is important for so many reasons—it can help you lose weight, ward off chronic disease, lower inflammation and even improve your gut health. We know that gut health plays a role in immunity, so eating enough fiber every day (that's 25 grams for women and 31 grams for men) can help support your immune system.

2. Not Eating the Right Nutrients

Vitamins A, C and D, as well as zinc, are all important vitamins and minerals for supporting your immune system. Probiotics and prebiotics, which add to and support the good bacteria in your gut, help support immunity too. You can score vitamin A from foods like shrimp, salmon, eggs, leafy greens, carrots and sweet potatoes. Vitamin C can be found in citrus fruits, bell peppers, tomatoes and broccoli. Vitamin D is tougher to get through food sources, but can be found in vitamin D-fortified milks, UV-fortified mushrooms, egg yolks and salmon. You can also score some free vitamin D from spending a few minutes in the sun each day (just make sure to wear sunscreen). Zinc can be found in foods such as oysters, beef, chickpeas and yogurt. Get probiotics from fermented foods like yogurt, kimchi and sauerkraut. Prebiotics, which feed those good bugs in the gut, come from fiber-rich foods like fruits, veggies, whole grains and legumes.

3. Drinking Alcohol

Sorry to be the bearer of bad news, but booze can negatively impact your immune system. In fact, doctors say it's the worst thing for immunity since it's dehydrating and can cause inflammation. So if you're trying to support your immune system, stick to mocktails or cut back to the occasional glass of wine or cocktail. Staying hydrated is another great way to support your immune system, so be sure to drink plenty of water as well. (Need some more motivation? Here's what happens to your body when you stop drinking.)

4. Smoking

You probably already know that smoking cigarettes isn't good for you, but it turns out that it can actually make your body less successful at fighting off illnesses. According to the Centers for Disease Control and Prevention, "Smoking is [also] known to compromise the equilibrium, or balance, of the immune system. This increases the risk for several immune and autoimmune disorders (conditions caused when the immune system mistakenly attacks the body's healthy cells and tissues). New evidence finds that smoking is a cause of rheumatoid arthritis, an autoimmune disease in which the immune system attacks the joints and causes swelling and pain."

Not to mention, smoking can increase your risk of COVID-19 complications. A recent study published in the journal Thorax found that, compared to nonsmokers, smokers were 80% more likely to be admitted to a hospital and significantly more likely to die from COVID-19 after being infected.

Want to quit smoking? The Mayo Clinic has a helpful smoking cessation plan that may help you toss your cigs for good.

5. Not Getting Enough Sleep

Getting enough shut-eye is important to help our bodies rest, recover and fight off illness. According to the National Sleep Foundation, "Consistent sleep strengthens the immune system, allowing for balanced and effective immune function. Lack of sleep, on the other hand, can throw off the immune system. Evidence indicates that in both the short- and long-term, sleep deprivation can make you sick."

Most adults need 7 to 9 hours of sleep per night. Thankfully, there are plenty of things you can do to improve your sleep cycle (and immune system). Eating a sleep-promoting diet, avoiding these habits and trying these expert-backed sleep tips can all help you log some zzz's.

6. Not Getting Enough Exercise

A study published in the Journal of Sport and Health Science found that obesity and inactivity can weaken your immune system. Additionally, the study found that living an active, healthy lifestyle can improve your immune system's surveillance activity (or immune cells looking for pathogens in the bloodstream). Don't know where to start? These are the best exercises for your health, according to a Harvard doctor.

7. Not Spending Enough Time Outside

Spending time outdoors won't just help you get some immune-supporting vitamin D from the sun—it can also help you fight off stress, which multiple studies have linked to lowered immune function. While some stress in life is inevitable (ugh, work deadlines to meet and bills to pay), chronic stress can hurt your health. Try to keep stress to a minimum by eating foods that help with stress, exercising regularly, meditating, buying some soothing essential oils, trying these science-backed stress-relieving tips and/or talking to a licensed therapist.