Vitamin deficiency: how to spot it and what to do
Feeling tired, weak, or oddly forgetful? Those could be signs of a vitamin deficiency. Not every ache or brain fog means you’re low on vitamins, but knowing the common signals and quick fixes helps you act earlier. This page gives clear, usable steps — how to recognize problems, what tests to ask for, which foods help, and when to talk to a clinician.
Common signs and which vitamin might be behind them
Different vitamins cause different symptoms. Here are the ones I see most often and the clues that point to them.
Vitamin D: persistent tiredness, bone pain or muscle aches, and getting sick more often. Low levels are common if you spend little time outdoors or use strong sunscreen.
Vitamin B12: numbness or tingling in hands/feet, balance problems, memory trouble, or a sore red tongue. Risk goes up with age and for people on some drugs like metformin.
Folate (B9): fatigue, pale skin, and shortness of breath. It matters most in pregnancy or if your diet lacks leafy greens and beans.
Vitamin C: easy bruising, slow wound healing, gum bleeding, and frequent colds. Smokers and people with limited fruit and veg intake are at higher risk.
Other signs worth watching: hair thinning, brittle nails, and frequent infections. They aren’t specific, but they’re a signal to check further.
What to do next: tests, food, and safe supplements
First step: get tested. A basic blood panel can check vitamin D and B12. Doctors can test folate and vitamin C too. Tests tell you whether diet changes will help or if you need supplements.
Boost your diet before jumping to pills. Eat fatty fish, eggs, and fortified milk for vitamin D; lean meats, eggs, and fortified cereals for B12; leafy greens, beans, and citrus for folate and vitamin C. If you’re vegan or have food restrictions, focus on fortified foods or a tailored supplement plan.
Supplements help when levels are low or when diet can’t meet needs. Start with recommended doses and follow up with a retest in 8–12 weeks. Some vitamins need food to absorb well — take vitamin D with a meal that has fat, and take B12 if you have absorption issues or take medications that interfere with it.
Watch for interactions. Blood thinners, antacids, and some diabetes meds can affect vitamin levels. Tell your pharmacist or doctor about all medicines and supplements you use.
When to see a clinician now: sudden numbness, severe weakness, breathing trouble, or very low energy that affects daily life. For mild symptoms, get a blood test and try diet changes first. If you want help choosing a supplement or checking interactions, ask a pharmacist — they can give practical, medicine-specific advice.
Small changes often make a big difference. Fixing a low vitamin can boost energy, mood, and immune strength within weeks. If you’re unsure what to test or try first, start with a simple blood test and a few food swaps — then go from there.
