A good immune system functions like a modern airport: smooth operations, quick checks, clear security lines. Oxidative stress is the chaos in the terminal – it disrupts signals, slows down processes, and allows intruders to slip through. Antioxidants are the first responders that restore order. When used wisely, they reduce the risk that the next cold even takes off.

Antioxidants are molecules that neutralize reactive oxygen species (ROS)aggressive oxygen compounds that damage cells and enhance inflammation. During infections, ROS production increases; beneficial for defense, but harmful in excess. This is where vitamin C, vitamin E, polyphenols from citrus fruits, and sulfur compounds like allicinreactive sulfur-containing compound from fresh garlic come into play: they stabilize cell membranes, protect immune cells, and modulate inflammation. Importantly, food not only provides individual vitamins but also a network of bioactives that collectively support innate immunityrapid initial defense, e.g., phagocytes, natural killer cells and adaptive immunityspecialized defense by T and B cells. For high performers, this means: fewer sick days, more stable energy, better recovery.

Vitamin C is actively accumulated in immune cells and supports the functions of phagocytes and T cells; a deficiency weakens defense, while adequate intake stabilizes immune performance ^[1]. Intervention studies show that vitamin C and zinc shorten the duration of respiratory infections; particularly benefiting those under high stress or with low baseline levels ^[2], whereas for well-nourished populations, high-dose supplements do not reliably reduce incidence ^[3]. Citrus juices provide not only vitamin C but also folate and polyphenols like hesperidin and naringin, which lower inflammation markers and support barrier function; in human studies, orange juice reduced postprandial inflammation and C-reactive protein ^[4]. Vitamin E improves the immune response in older adults and reduced the rate of colds in nursing homes – relevant because immune function naturally declines with age ^[5]. Garlic and its allicin have antioxidant and immunostimulatory effects, enhancing cellular defense mechanisms and potentially impacting susceptibility to infections ^[6][7]. Opponents of these effects include a diet low in fruits and vegetables, which lowers the antioxidant reserve ^[8], and chronically high alcohol consumption, which weakens central defense mechanisms of the airways ^[9].

Several lines of evidence show that diet measurably influences immune defense against colds. Randomized intervention studies with vitamin C consistently document: Under stress or low levels, supplementation shortens respiratory infections, while in well-nourished, healthy populations, prevention through high additional doses is limited; biologically plausible because vitamin C secures the redox stability of immune cells and supports functions like chemotaxis and natural killer cell activity ^[2][3]. Complementarily, research on citrus juices clarifies that the food matrix effect matters: In addition to vitamin C, they provide folate and polyphenols (e.g., hesperidin), which in human studies lowered inflammation markers like CRP and dampened postprandial inflammation – a realistic, practical signal that inflammation-related performance decline can be mitigated ^[4]. In older individuals, whose immune response physiologically declines, a placebo-controlled annual study with 200 IU of vitamin E daily showed a lower incidence of colds; the data support the targeted use of a fat-soluble antioxidant in a risk group ^[5]. Additionally, experimental and nutritional data on garlic suggest that allicin has immunostimulatory effects and buffers oxidative stress; the relevance lies in the everyday integration of a food with multifactorial defense effects ^[6][7].

- Start your day with a vitamin C source: 1 orange or 2 kiwis for breakfast, plus a handful of strawberries as a snack. This fills the vitamin C stores of immune cells and supports phagocyte and T cell functions ^[1][2][3].
- Smartly incorporate citrus juices: 150–200 ml of freshly squeezed orange juice with a main meal, especially if it's richer in fat. You benefit from vitamin C, folate, and polyphenols like hesperidin, which can lower inflammation markers ^[4].
- Utilize vitamin E from foods: daily a small handful of almonds (about 25–30 g) or 1 tablespoon of sunflower seeds in your muesli/salad. This supports the immune response, especially relevant in older age ^[5].
- Use garlic 4–5 times a week: finely chop 1–2 fresh cloves, let sit for 10 minutes (to promote allicin formation), then add to dressings, dips, or at the end of cooking. This way, you benefit from the antioxidant and immunostimulatory effects ^[6][7].
- Maintain a broad base of antioxidants: plan for "5 colors" of vegetables/fruits each day to avoid gaps in natural antioxidant supply; food instead of pills is a more robust approach for most ^[8][3].
- Manage alcohol consciously: schedule alcohol-free evenings on training or intensive workdays. This protects the mechanical and cellular defense lines of the airways ^[9].

Antioxidants are not a hype but a precise tool: more vitamin C-rich fruits, nuts/seeds for vitamin E, regular garlic, and wisely incorporated citrus juice measurably strengthen your defense. At the same time, reduce peaks in alcohol consumption and fill your plates with color. Implement one of these measures today – your future, energetic self will thank you.