Deficiency: how to spot common nutrient gaps and what to do
Feeling unusually tired, weak, or forgetful? Those are classic signs that something in your diet or meds might be missing. Nutrient deficiencies are common, often sneaky, and usually fixable once you know what to look for. This page gives clear, practical steps to recognize the most common deficiencies, how they’re tested, and safe treatment basics you can discuss with your clinician.
Common deficiencies and the signs to watch for
Iron: look for persistent fatigue, breathlessness with small effort, pale skin, or restless legs. A simple blood panel—CBC and ferritin—is the first step. Ferritin below about 30 ng/mL is often used as a sign of low iron stores, though doctors interpret results with context.
Vitamin B12: low B12 can cause tiredness, numbness or tingling in hands and feet, and memory problems. Serum B12 under ~200 pg/mL is suspicious; checking methylmalonic acid (MMA) helps confirm deficiency.
Vitamin D: many people are low, especially in winter or if they avoid sun. Low vitamin D can mean bone pain, muscle aches, or general low energy. Labs measure 25(OH)D—levels below 20 ng/mL are commonly called deficient, 20–30 ng/mL is often considered insufficient.
Other gaps to know: long-term medications can cause deficiencies—metformin is linked to B12 drops, proton pump inhibitors can reduce B12 absorption, and some antibiotics or anticonvulsants may affect vitamin K or vitamin D. Statins can lower CoQ10 for some people, which may be linked to muscle soreness.
Testing, treatment, and staying safe
Start with targeted tests: CBC for anemia, ferritin and iron studies for iron, serum B12 and MMA for B12, and 25(OH)D for vitamin D. Don’t rely on symptoms alone—blood tests give clear direction.
Treatment usually means dietary changes plus supplements when needed. For iron, eating lean red meat, beans, and vitamin C with meals helps. For B12, animal foods or a B12 supplement work; vegans often need supplements or injections. For vitamin D, moderate sun exposure and supplements can raise levels. Typical treatment plans vary, so follow your provider’s dose and timeline.
Watch for interactions and side effects. Iron can upset the stomach and interfere with some meds; take it apart from certain antibiotics and thyroid medicine. High-dose vitamin D needs monitoring—too much can cause calcium issues. Always tell your doctor about prescription and OTC meds before starting supplements.
If symptoms are sudden, severe, or getting worse—like significant numbness, breathlessness, chest pain, or fainting—seek medical care right away. For routine low-level symptoms, a primary care visit and simple blood tests are the fastest way to get clear answers and a safe plan.
Want specific help? Look for a healthcare provider who orders the right labs, explains results in plain language, and helps you pick safe supplements or diet changes. Fixing a deficiency can often bring big improvements in energy, mood, and daily function—so it’s worth checking.
