In 1918, during the influenza pandemic, nurses and female doctors worked under extreme conditions on the front lines of public health—often with only the most basic means: hygiene, nutrition, and fluid intake. This quiet, practical science demonstrated what modern research can now precisely substantiate: everyday choices at the table influence how well our immune system responds. From this legacy of pioneering caregivers, the path leads directly to a question for high performers: How do we orchestrate nutrition so that immune cells operate more efficiently, faster, and more resiliently?

The immune system is a connected defense network made up of cells, signaling molecules, and barriers. Central components include innate immunityrapid, non-specific defense by phagocytes and natural killer cells, adaptive immunitytargeted response by T and B cells with memory, and mucosal immunityprotection at mucous membranes, especially in the gut. Nutrition acts here like a conductor: vitamins, polyphenols, and fiber modulate signaling pathways, energy availability, and the composition of the gut microbiotatotality of gut bacteria that train immune responses. Problematic influences include excessive sugar, trans fats, and dehydration, which can ramp up inflammatory programs or slow down immune cells. The goal is a dietary profile that minimizes oxidative stress, cuts inflammatory bridges, and strengthens communication between the gut and the immune system—for more energy, lower susceptibility to infections, and faster recovery.

Insufficient consumption of fruits and vegetables not only misses out on vitamins but also on pectin—a fiber fraction that positively influences blood sugar and blood fat profiles and is linked to effects on immune regulation ^[1]. Leafy green vegetables provide key micronutrients such as vitamins C, E, and folate, as well as magnesium and secondary plant substances that support defense cells and help prevent infections ^[2]. Conversely, a high consumption of fructose can shift the balance of the T cell response, drive pro-inflammatory Th1 and Th17 programs, and thus promote chronic inflammation ^[3]. Dehydration also weakens defense mechanisms: In animal models, combined food and water restriction impaired infection control by reducing the phagocytic activity of macrophages ^[4]. Trans fats, on the other hand, amplify IL-1 signaling pathways and promote a senescent-like inflammatory cell profile—a breeding ground for metabolic disorders ^[5]. Positively, fermented foods provide live cultures that can strengthen gut barriers and modulate immune responses ^[6][7]. Green tea and its metabolites support the activation of dendritic cells—key players between innate and adaptive immunity—through antioxidant and immunomodulatory effects ^[8].

Several lines of evidence paint a consistent picture. Reviews on fruit and vegetable intake emphasize the role of pectin and fiber: they alter the digestion of starch, nourish the gut microbiota, and are associated with positive effects on blood sugar, blood fats, weight control, and immune-related parameters—a plausible mechanism for why plant-rich diets delay chronic diseases and support healthy aging ^[1]. Additionally, a comprehensive overview shows that a balanced spectrum of micronutrients and bioactive plant compounds—including a variety of leafy greens—can activate immune cells, modulate signaling pathways, and help prevent infections; the practical essence: diversity and nutrient density matter ^[2]. On the risk side, experimental research describes how high fructose intake shifts T cell programs through mTORC1 and oxidative stress pathways, thereby promoting inflammatory bowel diseases—a mechanistic piece that explains the clinical observation of pro-inflammatory effects of excessive sugar ^[3]. At the same time, it has been shown that trans fats, particularly elaidic acid, amplify IL-1 signals and induce a pro-inflammatory senescence signature—a signaling pathway that can exacerbate metabolic and vascular diseases ^[5]. On the intervention side, fermented dairy products provide a natural, everyday option: starter cultures reach the gut in high concentrations and show immunomodulatory potentials; in a controlled study, fresh yogurt increased adaptive markers such as IgM and naïve CD4 T cells, while both yogurt types improved innate phagocytosis—indicating that live cultures particularly stimulate the specific immune response ^[6][7]. Lastly, research on green tea metabolites underscores that the gut transforms polyphenols into active compounds that activate plasmacytoid dendritic cells, thereby strengthening the bridge to antibody formation—relevant for infection resilience and vaccine response ^[8].

- Eat garlic daily: 1–2 cloves raw or lightly crushed and briefly heated to activate allicin precursors. This way, you utilize sulfur-containing compounds with antimicrobial and immunomodulating effects ^[9].
- Incorporate fermented foods: 1 serving of fresh yogurt, kefir, or a small bowl of sauerkraut per day. Live cultures support the gut barrier and adaptive defense; fresh yogurt showed benefits in IgM and T cell markers ^[6][7].
- Increase leafy green vegetables: A large handful of spinach, arugula, or Swiss chard daily. Combine with some oil for better absorption of fat-soluble vitamins. This strengthens antioxidant capacity and cell functions ^[2].
- Drink green tea: 2–3 cups over the day. The catechin metabolites can activate dendritic cells and thus support the antibody response ^[8].
- Avoid immune suppressors: Reduce added fructose and sugar excess from soft drinks and sweets to prevent pro-inflammatory T cell shifts ^[3].
- Hydrate strategically: 30–35 ml of water per kg of body weight as a guideline. Adequate fluid stabilizes immune functions; dehydration weakens phagocytosis ^[4].
- Eliminate trans fats: Check labels (hydrogenated fats) and avoid fried industrial foods. This way, you can prevent IL-1-driven inflammation loops ^[5].

The next evolutionary step in immunonutrition connects personalized microbiome profiles with targeted phytonutrients—precise, practical, and measurable. We can expect new data on polyphenol metabolites, postbiotic effects, and smart timing of nutrients that further bridge prevention, performance, and longevity.