3 Foods That Negatively Impact Your Immune System

Jessica Bippen, MS, RD, looks closer at the foods and drinks that can negatively impact your immune system, and provides alternatives for unhealthy dietary habits. Optimizing your immune system goes beyond eating well and loading up on supplements. (Though yes, these are still important and highly recommended!) But if you find yourself coming down with frequent colds, you may need to take a step back and address your daily dietary habits. Instead of focusing on adding more things into your daily routine, it may be more beneficial to kick some habits to the curb. Keep reading to find out how sugar, alcohol, and caffeine can all compromise immune health.

3 Foods that Negatively Impact Your Immune System

When it comes to supporting your immune system, you may want to consider quitting excess sugar, alcohol, and caffeine. Your mid-day sweet tooth, all-day coffee fix, and heavy evening pour may be sabotaging your immunity. When you ditch these immune-suppressing habits, your body can begin to function at an optimal level. Think of it as eliminating the roadblocks to a healthy immune system. Woman adding raspberries to a sugar filled cake

1. Sugar

This culprit likely isn’t a surprise since excess sugar compromises your overall health. In terms of immune function, it takes its toll in several ways. Research shows that consuming added sugar in the form of sugar-sweetened drinks suppresses the function of immune cells for up to five hours. This short-term effect turns into bigger issues when you constantly consume sugar throughout the day—namely an increase of inflammation in the body, which suppresses the immune system even more. In addition, sugar can disrupt the good bacteria in your gut. Not having the proper balance of bacteria in your intestinal tract can lead to numerous health issues and affect how well your immune system functions. After all, over 70 percent of your immune cells are formed in the gut!

Nutritionist Tip

Just because sugar is a food that can negatively impact your immune system, it doesn’t mean you have to swear it off completely. However, there are countless benefits from reducing your overall sugar intake. That being said, if you’re feeling like you’re coming down with a cold or just looking to boost your immune system for a period of time, consider cutting out added sugar. Look for alternative ways to satisfy your sweet tooth. For instance, try a Medjool date stuffed with almond butter, or simply grab fresh fruit. Person pouring red wine in glass at home to take the edge off, but is a bad dietary habit that can negatively impact the immune system

2. Alcohol

Has your weekly happy hour turned into a nightly ritual? If so, you may need to put the breaks on your alcohol consumption. Your body views alcohol as a toxin. Once alcohol breaks down in the body, the metabolite acetaldehyde may impair your ability to attack and break down bacteria and viruses, thus putting you at higher risk for infection. In addition, heavy drinking can occasionally take the place of consuming nutrient-dense foods. Even if you’re eating, food choices that accompany imbibing are typically aren’t the most nutritious. This undernutrition can lead to a weakened immune system, making it harder to fight off infection. If that isn’t enough, studies show that consuming alcoholic drinks messes with your sleep cycle and interferes with your ability to get a good night’s sleep. And we all know that sleep is essential for immune function!

Nutritionist Tip

It’s important to address why you’re drinking in the first place. Are you trying to take the edge off? Is it just a bad habit? Once you gain clarity, it’s easier to make a change. Challenge yourself to go a week without drinking and make a fun mocktail instead. This makes the transition easier since you’re keeping the ritual of winding down with a non-alcoholic drink, rather than just forgoing it completely. Other good options include fruit-infused sparkling water, kombucha, or a bedtime latte.

Woman pouring highly caffeinated cold brew over ice3. Caffeine

For starters, the energy boost you get from caffeine isn’t for everyone. Coffee affects people differently, as each person metabolizes caffeine at different rates. You may find that your body doesn’t handle caffeine well, and in turn, it exacerbates stress and increases cortisol levels. It can also affect your sleep quality. Simply put, drinking coffee to make up for sleep deprivation and stress can lead to a vicious cycle of poor-quality sleep. Elevated stress and decreased sleep quality can drastically affect your immune function. When you’re stressed, your body’s ability to fight off illness can significantly weaken. This happens because your body increases its production of corticosteroid, which in turn suppresses the effectiveness of the immune system. When you’re sleeping, your body has time to recover and repair. This is also the time when your immune system releases proteins called cytokines that are needed when you have an infection, inflammation, or when you’re under stress. Not getting adequate sleep causes your body to underproduce these cytokines and reduces the cells needed to fight infections.

Nutritionist Tip

While coffee and caffeinated drinks do have their benefits, some people do better without them. It can be hard to know how caffeine affects you without taking a break from it for a little while. Try replacing your daily coffee with herbal tea, chicory (which has a similar taste to coffee), or an almond milk steamer to provide latte vibes. If you can’t imagine going cold turkey, try limiting yourself to only one cup per day. You can also switch to matcha, which allows you to get a more balanced boost without a heavy crash.

The Bottom line

When it comes to optimizing your immune system, it’s worth taking a look at your daily dietary habits. Reducing or eliminating your sugar, alcohol, and caffeine consumption—especially when you need an extra immune boost—may give you an edge in fighting off potential illness. This doesn’t mean you can’t enjoy eating your favorite chocolate chip cookie, or sipping on a glass of red wine or caffeinated beverage of choice. You totally can! Just keep in mind like most things in health and wellness, moderation is key.
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