Vitamin D and B12 Deficiency Overview
Know about vitamin D & vitamin B12 deficiency, signs, symptoms, diagnosis and tips to manage and prevent the deficiencies.
Written by Dr. Vasanthasree Nair
Reviewed by Dr. Rohinipriyanka Pondugula MBBS
Last updated on 3rd Aug, 2025
Introduction
Vitamins D and B12 are essential nutrients that play crucial roles in keeping our bodies healthy. However, deficiencies in these vitamins are common and can lead to various health problems if left untreated. If you’ve been feeling unusually tired, weak, or experiencing unexplained aches, you might be dealing with a deficiency.
This article will help you understand the causes, symptoms, and ways to manage vitamin D and B12 deficiencies, so you can take the right steps toward better health.
What Are Vitamin D and B12?
Vitamin D: The Sunshine Vitamin
Vitamin D is a fat-soluble vitamin that helps your body absorb calcium, keeping your bones strong. It also supports your immune system, muscles, and mood. Our bodies produce vitamin D when our skin is exposed to sunlight, but we can also get it from certain foods and supplements.
Vitamin B12: The Energy Booster
Vitamin B12 (cobalamin) is a water-soluble vitamin that helps in red blood cell formation, nerve function, and DNA synthesis. Since our bodies can’t produce B12, we must get it from animal-based foods or supplements.
Consult Top Nutritionists
Common Causes of Deficiency
Why Does Vitamin D Deficiency Happen?
Limited Sun Exposure – Spending too much time indoors, wearing sunscreen all the time, or living in regions with little sunlight can reduce vitamin D production.
Dietary Insufficiency – Few foods naturally contain vitamin D (fatty fish, egg yolks, fortified milk).
Dark Skin – Melanin reduces the skin’s ability to produce vitamin D from sunlight.
Digestive Disorders – Conditions like Crohn’s disease or celiac disease can impair absorption.
Obesity – Vitamin D gets stored in fat, making it less available for the body.
Why Does Vitamin B12 Deficiency Occur?
Vitamin B12 deficiency may happen for the following reasons:
Poor Diet – Vegans and vegetarians may not get enough B12 since it’s mostly found in animal products.
Digestive Issues – Conditions like pernicious anaemia, gastritis, or gut surgeries can hinder absorption.
Medications – Long-term use of acid-reducing drugs (like PPIs) or metformin can lower B12 levels.
Age – Older adults produce less stomach acid, which is needed to absorb B12.
Signs and Symptoms to Watch For
Vitamin D Deficiency Symptoms include:
Fatigue and weakness
Bone pain or frequent fractures
Muscle cramps or aches
Mood changes like depression, anxiety
Slow wound healing
Hair loss
Vitamin B12 Deficiency Symptoms:
Extreme tiredness and weakness
Numbness or tingling in hands/feet due to nerve damage
Memory problems or confusion
Pale or yellowish skin due to anaemia
Balance issues
Mouth ulcers or a sore tongue
If you experience these symptoms, it’s best to get tested.
How Are These Deficiencies Diagnosed?
A simple blood test can check your vitamin D and B12 levels. If you suspect a deficiency, you can:
- Book a test through Apollo 24|7 for a quick and easy check-up.
- Consult a doctor to interpret results and recommend supplements if needed.
Managing and Preventing Deficiencies
Boosting Vitamin D Levels
1. Sunlight Exposure – Spend 10-30 minutes in the sun (without sunscreen) a few times a week.
2. Eat Vitamin D-Rich Foods – Fatty fish (salmon, mackerel), egg yolks, fortified milk, and mushrooms.
3. Supplements – If levels are very low, your doctor may prescribe vitamin D3 supplements.
Increasing Vitamin B12 Intake
1. Dietary Sources – Meat, fish, eggs, dairy, and fortified cereals.
2. Supplements – B12 tablets, sublingual drops, or injections (for severe deficiency).
3. Fortified Foods – Plant-based milk and cereals for vegans/vegetarians.
Lifestyle Tips
Exercise regularly – Helps with bone strength and circulation.
Limit alcohol – Excessive drinking can worsen deficiencies.
Manage gut health – Probiotics may help with nutrient absorption.
When to See a Doctor
If you have persistent symptoms or fall into high-risk groups (vegans, the elderly, people with digestive disorders), consult a doctor. They may recommend:
Regular blood tests to monitor levels.
Personalised supplementation to correct deficiencies safely.
Final Thoughts
Vitamin D and B12 deficiencies are common but often overlooked. The good news? They’re easily manageable with the right diet, sunlight, and supplements if needed. Listen to your body—if you feel something’s off, don’t ignore it. A simple test can make a big difference in your energy, mood, and overall health.
Consult Top Specialists
Consult Top Nutritionists
Dr Sumanth R
General Physician
2 Years • MBBS
Bengaluru
PRESTIGE SHANTHINIKETAN - SOCIETY CLINIC, Bengaluru
Dr. Sasikamalam
General Practitioner
1 Years • MBBS
COIMBATORE
Apollo Sugar Clinic Coimbatore, COIMBATORE
Mrs Sneha P V
Nutritionist
10 Years • Master of science in Food and Nutrition
Bengaluru
Apollo Clinic, Sarjapur Road, Bengaluru
Dr. Bhukya Pavan Kalyan
General Physician
5 Years • MBBS DNB Paediatrics
Bengaluru
PRESTIGE SHANTHINIKETAN - SOCIETY CLINIC, Bengaluru
Dt. Ila Sharma
Clinical Nutritionist
18 Years • Master in food & Nutrition
Gurugram
VIPUL GREENS - SOCIETY CLINIC, Gurugram
Consult Top Specialists
Dr Sumanth R
General Physician
2 Years • MBBS
Bengaluru
PRESTIGE SHANTHINIKETAN - SOCIETY CLINIC, Bengaluru
Dr. Sasikamalam
General Practitioner
1 Years • MBBS
COIMBATORE
Apollo Sugar Clinic Coimbatore, COIMBATORE
Mrs Sneha P V
Nutritionist
10 Years • Master of science in Food and Nutrition
Bengaluru
Apollo Clinic, Sarjapur Road, Bengaluru
Dr. Bhukya Pavan Kalyan
General Physician
5 Years • MBBS DNB Paediatrics
Bengaluru
PRESTIGE SHANTHINIKETAN - SOCIETY CLINIC, Bengaluru
Dt. Ila Sharma
Clinical Nutritionist
18 Years • Master in food & Nutrition
Gurugram
VIPUL GREENS - SOCIETY CLINIC, Gurugram
