Sometimes too much of a good thing isn’t so great.

 

Maintaining a strong immune system is essential for overall wellness since it acts as our body’s first line of defense against infections and illnesses. There are some factors that are out of our control when it comes to keeping illness at bay (if you have a child in childcare, you know what we are talking about). However, many of our lifestyle and dietary choices can have a profound impact on how our bodies combat illness or infection. But sometimes, some things that we perceive as “healthy” may inadvertently harm our immune function. 

In this article, we will uncover some “good” things that could be bad for your immune health, according to experts, to help you know what to do and what not to do to help keep your body healthy.

Why Immune Health Is Important

Immune health gets a lot of buzz these days, and for good reason. It is essential for maintaining overall well-being and quality of life. A robust immune system acts as your body’s first line of defense against harmful pathogens, including viruses and bacteria.¹ When your immune system functions optimally, it helps reduce the risk of illnesses and may help reduce the duration of colds.²

When you have a weak immune system, your body becomes more susceptible to infections and diseases. This diminished ability to fight off pathogens can result in more frequent illnesses, longer recovery times and an increased risk of more severe health complications. Common signs of a weakened immune system include recurrent colds, chronic fatigue and slow healing of wounds.³

Suardi C, Cazzaniga E, Graci S, Dongo D, Palestini P. Link between Viral Infections, Immune System, Inflammation and Diet. Int J Environ Res Public Health. 2021 Mar 2;18(5):2455. doi: 10.3390/ijerph18052455.

While factors like nutrition and lifestyle choices can impact immune health, other factors—like underlying conditions such as autoimmune disorders—may further compromise immune function. Additionally, age is a significant factor: As people grow older, their immune response tends to weaken, making them more vulnerable to infections.⁴ Furthermore, chronic stress can affect the body’s ability to regulate immune responses.

6 “Good” Things That Could Be Bad for Your Immune Health

Some things that sound good for you may be not-so-great for your immune health. We asked some registered dietitians to share some surprising “good” things that could be bad for your immune health. Here is what they said. 

1. Over Consuming Zinc 

Zinc is a popular supplement that people take when they feel under the weather, gaining even more popularity when data showed that zinc supplementations may have a positive impact on COVID infection outcomes.⁶ But don’t think that taking mountains of zinc supplements will always work wonders for your health.

“Taking excessive zinc supplements can impair the absorption of iron and copper,” shared Lisa Andrews, M.Ed., RD, LD, a registered dietitian in Cincinnati, OH. Copper plays a critical role in maintaining a healthy immune system, as it is essential for the development and function of immune cells, particularly neutrophils and lymphocytes, which are vital for the body’s defense against infections.⁷

Liu Y, Zhu J, Xu L, Wang B, Lin W, Luo Y. Copper regulation of immune response and potential implications for treating orthopedic disorders. Front Mol Biosci. 2022 Dec 5;9:1065265. doi: 10.3389/fmolb.2022.1065265.

Andrews advised obtaining zinc naturally in your diet through whole grains, nuts, seeds, beans, lentils, poultry and fortified cereal. She also suggests that you “talk to your doctor or dietitian before taking a zinc supplement.”

2. Eating a Low-Fat Diet

“Eating a diet low in fat may seem like a good thing, but you will be missing out on the healthy fats which are vital for immune function and overall health,” per Michelle Rauch, M.Sc., RDN, registered dietitian nutritionist for The Actors Fund.

“Healthy fats include unsaturated fats such as those found in olive oil, avocado and certain nuts and polyunsaturated fats such as those found in fatty fishes (think: salmon and sardines), chia seeds and walnuts. Two types of polyunsaturated fats—omega-3 and omega-6 fatty acids—are important for immunity,” she added. 

Rauch explained that omega-3 and omega-6 fatty acids are essential for the production of eicosanoids. These important molecules play a role in the immune response by telling your body how to respond to situations including (but not limited to) injuries or infections.⁸

3. Cleaning Too Much

Maintaining good hygiene is essential for preventing illness, but excessive cleanliness can paradoxically undermine immune health. Constantly sanitizing our environments and bodies can limit our exposure to a variety of microorganisms that our immune system needs to learn from. This concept is part of the “hygiene hypothesis,” which suggests that a lack of early childhood exposure to infectious agents, symbiotic microorganisms and parasites increases susceptibility to allergic diseases and autoimmune disorders. When we shield ourselves from these organisms, our immune system may become less effective and more prone to overreacting to harmless substances, resulting in allergies or other immune-related conditions. Data continues to emerge regarding this notion.⁹

But this doesn’t mean that you should skip basic hygienic steps, like washing your hands. Hand hygiene plays the most important role in infection control activities.⁹ But excessive use of antibacterial soaps for a long duration is not recommended, according to some (not all) experts. 

4. Excessive Exercise 

While regular physical activity is essential for maintaining a robust immune system, excessive exercise can have the opposite effect. When individuals engage in high-intensity workouts or prolonged training without adequate recovery, the body may experience heightened levels of stress hormones, such as cortisol. Elevated cortisol can inhibit the functioning of immune cells, making the body more susceptible to infections and illnesses.¹⁰ Additionally, overtraining can lead to fatigue, particularly in athletes, which can further compromise their immune response.¹¹

Furthermore, excessive exercise can also be linked to inflammation and disrupt the balance of beneficial gut bacteria that are crucial for healthy immune function.¹² A weakened gut microbiome can impair the body’s ability to fend off pathogens, increasing the risk of gastrointestinal issues and other infections.¹³ Therefore, it is vital for individuals engaging in strenuous exercise to prioritize rest and recovery, ensuring they maintain an optimal balance that supports their immune health rather than undermining it.

5. Drinking Alcohol—Including Red Wine

Drinking wine, particularly red wine, is often touted for its potential health benefits, including the presence of antioxidants like resveratrol, which is believed to contribute to heart health and possibly extend lifespan.¹⁴

However, while moderate consumption might have some benefits, excessive or frequent drinking of alcohol of any kind can have negative effects on immune health. Alcohol, including wine, can impair the body’s immune response, making it more susceptible to infections and diseases. Regular consumption can lead to the weakening of the immune system, as it affects the production of immune cells and alters the gut microbiome, which is crucial for a balanced immune response.¹⁵ Thus, the potential health benefits of wine should be carefully weighed against its risks, particularly for those concerned about maintaining a robust immune function.

6. Only Relying on Supplements for Nutrients

Relying solely on supplements for immune health can be detrimental for several reasons. While supplements can provide essential vitamins and minerals, they often lack the complex array of beneficial plant compounds found in whole foods. These compounds—including flavonoids, polyphenols and antioxidants—play a vital role in supporting immune function by enhancing the body’s ability to fight off infections and reducing inflammation.¹⁶¹⁷ Additionally, whole foods offer a diverse range of nutrients that work synergistically, promoting better absorption and utilization within the body. Neglecting a balanced diet rich in fruits, vegetables, whole grains and lean proteins means missing out on these critical components that contribute to optimal immune health.

For instance, consider those who rely heavily on vitamin C supplements to meet their needs while neglecting their intake of citrus fruits, such as oranges and grapefruits. While vitamin C is important for immune function, these fruits also contain hesperidin, a powerful flavonoid that offers additional health benefits, like reducing inflammation and providing antioxidant protection.¹⁸ By choosing supplements over whole foods, you may inadvertently miss out on certain compounds, like hesperidin, which may offer protective properties and other synergistic nutrients found in foods, ultimately compromising overall immune health.