As a physician and Nobel laureate, Tu Youyou made a name for herself worldwide with the discovery of artemisinin – not because she invented a miracle cure, but because she meticulously searched for what was lacking in the immune system and the body to combat infections. This attitude – systematically identifying deficiencies and addressing them – is also a game changer in the everyday lives of high performers. Recognizing nutrient deficiencies early activates the silent reserves of the immune system: greater resilience, better recovery, and prolonged performance.

The immune system is not a single organ, but a network of cells, signaling molecules, and barriers that requires a constant supply of raw materials. Nutrient deficiency does not necessarily mean underweight; it refers to deficits in micronutrients that disrupt biochemical switches. Omega-3 fatty acids, vitamin B12, and magnesium are particularly relevant. Omega-3 fatty acids such as EPA/DHAlong-chain omega-3 fatty acids from marine sources modulate inflammation signals. Vitamin B12cofactor for DNA synthesis and methylation; essential for blood formation and nerve function regulates cell division and the maturation of immune cells. Magnesiummineral and cofactor in hundreds of enzyme reactions; regulates immune cell activation acts like a key switch for immune responses. General truths also apply: alcohol inhibits the absorption and utilization of many nutrients and weakens barriers such as the intestinal wall. Therefore, those seeking high performance need not only quality calories but also nutrient precision – with a laboratory perspective on bottlenecks.

Inadequate magnesium supply is associated with impaired immune defense: reduced phagocytosis, weaker natural killer cell function, and altered cytokine release – all processes that determine viral defense and inflammation resolution ^[1]. Chronic magnesium deficits promote baseline inflammation and oxidative stress, which increases the risk of age-associated diseases; animal models show impaired cellular immunity and antibody synthesis ^[2]. With omega-3, evidence in clinical contexts shows: adequate intake can dampen hyperinflammation, reduce infection complications, and shorten recovery phases – strong indications that inflammation regulation is a central lever for immune robustness ^[3]. Vitamin B12 deficiency is common in vegetarian/vegan diets and is associated with risks for neuro-, vascular, immune, and inflammatory disorders ^[4]; deficiency states often correlate with altered blood cell profiles ^[5]. When B12 is supplemented in pernicious anemia, T and B cell markers normalize, and NK activity improves – a direct indication of immunological recovery through nutrient correction ^[6]. Excessive alcohol worsens the situation: it disrupts the absorption of essential nutrients, increases gut permeability, and contributes to immune dysfunction ^{[7] [8]}.

Two lines of evidence stand out. First: Omega-3 fatty acids in clinical studies. A meta-analysis of randomized controlled trials with intensive care patients showed that omega-3 significantly reduces the excessive inflammatory response (lower TNF-α, IL-1, IL-6, procalcitonin), decreases the risk of secondary infections and sepsis, reduces the length of ICU stay, and lowers 28-day mortality ^[3]. While this is a high-risk cohort, the mechanism – better inflammation resolution – is relevant for everyday immunity. Second: Magnesium as an immune regulator. Reviews report that low magnesium levels are associated with immunosuppression, reduced phagocytosis, and decreased NK function, while magnesium influences the activation, proliferation, and differentiation of immune cells and modulates NF-κB signaling ^[1]. Additionally, the literature review shows that magnesium deficits increase baseline inflammation and oxidative stress and weaken cellular and humoral immune responses; sufficient intake stabilizes these processes, while over-supply should be avoided ^[2]. Parallelly, human research on vitamin B12 points to an often underestimated gap in individuals with plant-based diets. The deficiency is widespread ^[4] and corresponds to altered immune markers in observations ^[5]; in pernicious anemia, substitution restores T, B, and NK parameters, underscoring the causal role of B12 in immunological signaling pathways ^[6]. Together, a clear picture emerges: targeted correction of specific nutrient deficiencies measurably strengthens immune function – from the signaling level to clinically relevant outcomes.

- Precisely integrate omega-3: Consume fatty sea fish (e.g., salmon, mackerel, sardines) 2–3 times a week or use a high-quality algae oil (EPA/DHA). Aim for a regular intake that supports inflammation resolution. Particularly during periods of high stress or after infections, a consistent supply is advisable, as studies show a reduction in pro-inflammatory markers and complications ^[3].
- Ensure vitamin B12 status: In vegetarian/vegan diets, test holo-transcobalamin and methylmalonic acid every 6–12 months; immediately supplement if a deficiency is found. Background: Plant-based, unfortified foods do not provide B12; deficiency is common and also affects performance-oriented young adults ^[4]. Data show altered blood and immune markers in untreated deficiency ^[5]; therapeutic B12 supplementation improves T, B, and NK cell parameters in pernicious anemia patients – a strong signal for immune relevance ^[6].
- Smartly replenish magnesium: Incorporate magnesium-rich foods into your daily diet, such as pumpkin seeds, almonds, cocoa, oats, beans, and leafy green vegetables. In cases of high training load, sleep issues, cramps, or frequent infections, check serum magnesium levels and possibly erythrocyte magnesium with your doctor to devise a suitable supplementation strategy. Magnesium supports the activation and function of key immune cells; deficiencies weaken viral defense and promote chronic inflammation ^{[1] [2]}.
- Consciously limit alcohol: On training-intensive days and during recovery phases, abstain from or significantly reduce alcohol intake. This keeps nutrient absorption (e.g., B vitamins, zinc, iron) intact and stabilizes the gut barrier – both crucial for strong immune responses ^{[7] [8]}.
- Establish periodic monitoring: Conduct a lab check once a year focusing on B12 status markers, magnesium, and hs-CRP. With increased stress or a plant-based diet, check every six months. Translate results into concrete dietary and supplementation plans and reevaluate after 8–12 weeks to measurably improve immune performance.

Your immune system performs only as well as its nutrient supply. Specifically close the gaps – establish omega-3, reliably check and replenish B12, ensure magnesium, reduce alcohol – and test the success in the lab. Start this week with an omega-3 plan, a B12 check, and a magnesium-rich shopping list.