Fuel Immunity First: How to Use Nutrition to Stay Ahead of Infection

(This is the first in a series on this topic with Dr Swiner.)

When it comes to preventing infections, building a strong immune system is the most important and effective first line of defense, and nutrition plays a crucial role in that process. Infection preventionists and other infection control personnel should understand this, not only for themselves and their families but also for their patients. While many people believe they are getting enough nutrients from their diet, the reality is that modern eating habits often fall short of delivering the essential vitamins and minerals our bodies need to perform optimally. That’s where strategic supplementation can make a significant difference.

In a conversation with C. Nicole Swiner, MD, author of The Healthy Kidney Handbook: A Comprehensive Guide to Manage Hypertension, Control Stress, and Prevent Renal Failure, Kidney Disease, and More; and How to Avoid the Superwoman Complex: 12 Ways to Balance Mind, Body & Spirit, Infection Control Today^® (ICT^®) examined what vitamins help with preventing or mitigating infections.

“We saw a lot of data, especially during the COVID-19 pandemic, on increasing your vitamin D intake because not only does it help improve your bone density, energy levels, and mood, but it also helps your body have the energy to keep going,” Swiner, who is also a medical adviser and spokesperson for Black Girl Vitamins, told ICT. “It can also help decrease cortisol levels, as well as the extra adrenaline, which is good when you want to get up and go, fight, or flight. However, elevated adrenaline isn't so good for stress levels. So, the better you can keep your cortisol and stress levels by including all the good nutrients and vitamins in your diet, the less likely you are to get sick.”

Vitamins like A, C, D, and E, along with minerals such as zinc, are powerhouses for immune support. These nutrients help regulate inflammation, strengthen cell membranes, and boost the activity of white blood cells that fight off bacteria and viruses. Vitamin D, in particular, has emerged as a key player in both immunity and overall health. Known for its role in bone strength and mood regulation, vitamin D also activates the body’s immune responses, especially those tied to respiratory health.

Swiner explains that during the COVID-19 pandemic, research showed that individuals with adequate vitamin D levels had stronger immune resilience, faster recovery, and lower inflammation levels. It was not just about reducing risk; it was about reducing severity and duration when illness did occur. Vitamin D also plays a part in lowering stress-related hormones like cortisol, which, when elevated, can suppress the immune system and increase vulnerability to infection.

However, the benefits of vitamins extend beyond simply avoiding colds and influenza. Regular intake of immune-supporting nutrients helps regulate stress, stabilize energy, and keep our internal defense systems ready. This is especially important during seasonal illness spikes or in high-stress environments, such as health care facilities, schools, or crowded urban areas.

While a balanced diet is the foundation, as Swiner said, supplementation ensures you do not leave your immune system exposed.