New Delhi: A creeping lack of energy that shows up as yawns at the desk, afternoon crashes, or that persistent “I can’t focus” fog is easy to blame on long hours and bad coffee. Sometimes it is just burnout. Often, though, simple nutrient shortfalls — iron, vitamin B12 or vitamin D — are the stealthy culprits behind fatigue in otherwise healthy young adults, especially those working long indoor hours or living stressful, irregular lives. Early recognition matters because these deficiencies are common, treatable, and leave fingerprints that clinicians can test for.
Dr Sandeep Reddy Koppula, HOD – Internal Medicine, Arete Hospitals, decoded this for TV9 English.
Iron: the classic energy thief
Iron is essential for making haemoglobin and ferrying oxygen to muscles and the brain. In women of reproductive age and people with restricted diets, iron deficiency (with or without anaemia) is a leading cause of unexplained tiredness. Symptoms range from subtle — persistent tiredness, poor exercise tolerance, difficulty concentrating — to classic signs such as breathlessness, pallor, restless legs, or unusual cravings. Ferritin (a measure of stored iron) is the practical screening test; cutoffs are context-dependent, but values below ~30 µg/L often indicate depleted stores in otherwise healthy adults, while lower thresholds apply when inflammation is present. Treatment is straightforward: dietary changes, oral iron replacement, and, in selected cases, intravenous iron. Public-health data show iron deficiency remains widespread among young women globally.
Vitamin B12: the quiet neuro-and-blood problem
Vitamin B12 deficiency can cause fatigue through anaemia, but also through neurological effects that include numbness, balance problems, and cognitive sluggishness that may be described as “brain fog.” Risk rises with restrictive diets (strict vegetarianism/veganism), after bariatric surgery, with long-term use of acid-suppressing drugs, or in autoimmune pernicious anaemia. Serum B12 screening is the first step; when results sit in a borderline zone, methylmalonic acid (MMA) or homocysteine testing helps confirm deficiency. Timely treatment — high-dose oral B12 or intramuscular injections depending on cause — usually reverses haematological problems; neurological recovery is better the earlier therapy is started.
Vitamin D: more than bones
Vitamin D deficiency is surprisingly common among indoor workers, shift workers and people who avoid sun exposure. Low 25-hydroxyvitamin D levels may present as fatigue, muscle aches, and low mood, and can worsen recovery after exercise. Definitions vary: many groups flag levels under 20 ng/mL as deficient, while others use higher cutoffs to define insufficiency. Risk clusters — long commutes indoors, work-from-home routines, heavy sunscreen use, and darker skin tones — make vitamin D a likely suspect in fatigued young professionals. Simple blood testing (25-OH vitamin D) followed by tailored supplementation and sensible sunlight exposure is the usual pathway.
How clinicians separate the signals from the noise
Doctors look for patterns: timing of fatigue, menstrual losses, diet, medications (especially PPIs), weight changes, and neurological symptoms. Basic blood work often resolves the question: a complete blood count and ferritin for iron status, serum B12 for cobalamin, and 25-OH vitamin D for vitamin D stores. Interpreting ferritin needs care when inflammation is present, and borderline B12 levels are common — clinical context and confirmatory tests matter.
Practical, low-friction steps for busy people
Begin with lifestyle checks: ensure iron-rich meals (lean red meat, lentils, dark leafy greens with vitamin C), maintain regular sleep, manage stress, and get modest daily sunlight when feasible. If symptoms persist despite these measures — or if risk factors exist (heavy menstrual bleeding, strict vegan diet, long-term acid blockers, or chronic medical conditions) — ask a clinician for targeted testing. Many deficiencies respond quickly to treatment; monitoring assures improvement and guards against over-supplementation.
When to escalate
Seek urgent review for worrying signs: chest pain, fainting, rapidly worsening weakness, new numbness or walking difficulty, or very low haemoglobin. For most people with isolated fatigue and abnormal labs, staged outpatient management with follow-up testing and lifestyle counselling will do the job. Fatigue is common. So are treatable deficiencies. For a young professional who can’t shake the tiredness, a short panel of blood tests and a focused conversation with a clinician often turns chronic exhaustion into a simple fix — and saves months of missed focus, energy and quality of life.