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The Worst Eating Habits That Weaken Immunity, Say Dietitians

Yes, what you eat can increase or decrease your chances of getting sick.

With new COVID-19 variants upon us, as well as an approaching fall and winter season, building up our immunity is an important place to put our focus. Our immune systems can be impacted by things like how much stress we have, the amount of sleep we get, and especially the food we eat.

When it comes to our immunity, we wanted to make sure we got the best expert advice about how to approach the upcoming season. So we talked with Mary Albus RD, CDN, and Matt Mazzino RD, LD to find out what we should avoid when it comes to maintaining a strong and healthy immune system.

Here are the worst eating habits that can weaken our immunity to know about, and for more advice on building immunity, check out these Proven Ways to Boost Your Immune System.

Consuming too much alcohol


According to Mary Albus, consuming too much alcohol can have a negative effect on our immunity.

"Alcohol can suppress the body's immune response to infection," says Albus, "because with alcohol consumption, it can take the body longer to recognize and respond to a developing infection."

Another way alcohol may weaken our immunity is by altering our absorption of necessary nutrients. Albus says that "alcohol inhibits the absorption of vital nutrients such as vitamin C and zinc, which are important for our immune system function."

Not only can these things affect how easily we become susceptible to something, but they can actually change how our body handles symptoms of illness.

"The effects of too much alcohol consumption can make symptoms last longer and become more severe than they might otherwise," says Albus.

Here are the Secret Side Effects of Drinking Alcohol, Says Expert.

Consuming too much sugar

sugary cereal

Albus also mentions that too much sugar in our diet can weaken our immunity over time.

"Studies have connected regular intake of foods high in added sugar to impaired immune function," says Albus, "and that's because white blood cells, which are the cells involved in fighting infection, are negatively impacted by overconsumption of sugar, which can prevent them from efficiently fighting off infection."

Consuming too much salt


The Dietary Guidelines for Americans state that even though adults should be aiming for about 2,300 milligrams or less of sodium per day, yet American adults are actually averaging about 3,400 milligrams a day. This over-consumption of sodium can have a lasting health impact.

"Following a high-sodium diet that is rich in processed foods can trigger inflammation in the body and increase the risk for chronic disease," says Albus.

Salt is also believed to inhibit some of our body's natural responses if consumed in excess. According to Albus, "salt can suppress anti-inflammatory responses and even alter our gut microbiota, which has a major role in our body's immune function."

High sodium consumption has been linked to worsened existing autoimmune diseases such as Crohn's disease, ulcerative colitis, Celiac disease, and lupus.

RELATED: Popular Foods That Have Way Too Much Salt, According to Experts

Not getting enough fruits and veggies

produce in season

According to Matt Mazzino, we need a good amount of fruits and veggies in our diet to support our immune system.

"Fruits and vegetables contain high amounts of vitamins, minerals, and antioxidants," says Mazzino, "and these compounds are essential to support reactions for your immune system and fight off infection."

Fruits and vegetables also have plenty of soluble fiber, which is actually helpful for our immunity.

"Soluble fiber is food for the bacteria that live within our gut," says Mazzino, "and a healthy microbiome communicates with and supports our immune system so that it can efficiently fight off infections."

A lack of vitamin D

vitamin d supplements

Let's not forget about our vitamins! "Vitamin D is one of the most important nutrients to support a healthy immune system," says Mazzino, "because of its anti-inflammatory properties that are known to enhance the function of immune cells."

If you work from home all day and don't get out into the sunlight as much as you'd like, or if you're in the middle of a rainy season right now, you may want to consider getting vitamin D from a supplement in order to boost your immunity. But be sure to talk to your doctor or a dietitian before making any decisions on supplementation in your diet.

For even more tips on immunity, read these next:

Samantha Boesch
Samantha was born and raised in Orlando, Florida and now works as a writer in Brooklyn, NY. Read more about Samantha