Why do I keep getting sick?
By Vita · fact-checked against NIH ODS
Vita is Vitaminico's AI nutrition coach. The nutrients below are mapped from the Vitaminico check, and every dose is checked against the NIH Office of Dietary Supplements; these pages have not yet been reviewed by our registered dietitians.
Frequent illness usually has everyday causes, but low vitamin D, zinc, iron, or vitamin C can genuinely weaken your immune defenses.
Likely nutrient gaps
These are the nutrients most often worth looking at first for this — not a diagnosis, just where the Vitaminico check starts. Read any one to see what it does, the best foods, and how much is too much.
Vitamin D
15 mcg/dayOne of the most common deficiencies worldwide, especially in winter, darker skin, or little sun exposure. NIH ODS lists vitamin D among the nutrients needed for proper immune function; it supports the immune barrier and antimicrobial defenses, and low levels are associated with more frequent respiratory infections.
Zinc
11 mg/day'Frequent infections' is a recognized clinical sign of zinc deficiency (NIH ODS). Zinc is needed for T cells, NK cells, and other immune defenders, and a shortfall reduces lymphocyte counts and impairs their function. Common in people who eat little meat/seafood.
What to eat
Food first is the safest place to start. Build your plate around a few of these everyday sources of the nutrients above:
- Fatty fish like salmon, sardines, or mackerel, plus eggs and fortified milk, for vitamin D (a little safe midday sun helps too)
- Oysters, beef, or crab for the most absorbable zinc; pumpkin seeds, cashews, and chickpeas for plant sources
- Red meat, liver, lentils, and beans for iron — pair plant iron with a vitamin C food to boost absorption
- Bell peppers, citrus, kiwi, strawberries, and broccoli for vitamin C
- A daily plate that's half colorful vegetables and fruit, plus enough protein (fish, poultry, eggs, legumes) at each meal
- Yogurt or kefir and other fermented foods to support a healthy gut, where much of the immune system lives
How to confirm it (ask your clinician)
Getting sick often is a symptom, not a diagnosis — and the biggest drivers are usually everyday: broken sleep, chronic stress, smoking, and heavy exposure (young kids, daycare, crowded workplaces). Nutrient gaps are only one possible piece. The reliable way to check the nutritional angle is a blood test ordered by a clinician: serum 25(OH)D for vitamin D, and ferritin plus a CBC for iron are the most useful and widely available. Zinc and vitamin C status are harder to measure accurately, so those are usually judged from diet and symptoms. Importantly, if you're not actually deficient, supplementing probably won't reduce how often you get sick (NIH ODS). See a doctor if infections are unusually frequent, severe, or slow to clear, or come with unexplained weight loss or fatigue — that can point to something beyond diet.
Not sure which gap is yours?
The free 2-minute Vitaminico check reads your symptoms across 9 body systems and names your most likely gap — food-first, no pills pushed.
FAQ
Will taking vitamin C or zinc stop me getting colds?
Only if you're genuinely low. NIH's Office of Dietary Supplements is clear that in people who aren't deficient, routine supplements do little to prevent infections. Correcting a real deficiency can help; loading up beyond your needs generally won't, and high-dose zinc taken long-term can actually backfire and cause a copper deficiency.
Which deficiency is most likely if I keep getting sick?
There's no single answer, but vitamin D and zinc are the two most commonly linked to weaker immune defenses, and iron deficiency is very common in menstruating women, vegetarians, and kids. A blood test is the only way to know which, if any, apply to you.
Can food alone fix this?
For most people, a varied diet with enough protein, colorful produce, seafood or lean meat, and some sun covers these nutrients. Food is the best first step. Supplements make sense mainly when a test confirms a gap or your diet clearly can't supply a nutrient (for example, vitamin D in a dark winter).
What if my diet is already good but I'm still always sick?
Then nutrition probably isn't the main issue. Look at sleep, stress, smoking, and exposure first, and talk to a clinician — frequent or severe infections can occasionally signal an underlying condition that needs proper evaluation.
Vitaminico for iPhone
Get your full picture in the app
- A free 2-minute chat with Vita reads your symptoms — no food-logging, no needles
- Your top 3 likely nutrient gaps across the vitamins and minerals that matter
- A food-first plan: what to eat, where to get it, and what to skip
- No signup wall — the full check works the moment you open the app
Free · iPhone · no email to start
Educational, not medical advice. This page does not diagnose a deficiency or any condition. Symptoms can have many causes, nutritional and otherwise — only a clinician and, where needed, a blood test can confirm a real gap. Talk to your doctor before starting any high-dose supplement.