Complete Vitamin and Mineral Deficiency Guide

Evidence-based guide to essential vitamins and minerals: deficiency symptoms, food sources, and recommended daily intake.

Medically reviewed by Dr. Sarah Johnson, RD, PhD
Published: December 1, 2025 | Last Updated: December 24, 2025

Vitamin D (Calciferol)

What It Does

Vitamin D helps your body absorb calcium, supports bone health, immune function, and mood regulation. It's often called the "sunshine vitamin" because your skin produces it when exposed to sunlight. Works synergistically with magnesium for optimal bone health.

Deficiency Symptoms
  • Fatigue and tiredness
  • Bone pain and muscle weakness
  • Frequent infections
  • Depression or mood changes
  • Impaired wound healing
Food Sources

Fatty fish (salmon, mackerel, sardines), fortified milk and cereals, egg yolks, mushrooms exposed to UV light.

Recommended Daily Intake

Adults: 600-800 IU (15-20 mcg) | Seniors (70+): 800 IU (20 mcg)

Vitamin B12 (Cobalamin)

What It Does

Essential for red blood cell formation, DNA synthesis, and neurological function. Critical for energy production and brain health.

Deficiency Symptoms
  • Extreme fatigue and weakness
  • Tingling in hands and feet (neuropathy)
  • Memory problems and confusion
  • Pale or jaundiced skin
  • Shortness of breath and dizziness
Food Sources

Meat, fish, poultry, eggs, dairy products, fortified cereals and nutritional yeast (for vegans).

Recommended Daily Intake

Adults: 2.4 mcg | Pregnant women: 2.6 mcg | Breastfeeding: 2.8 mcg

At Risk: Vegans, vegetarians, older adults, and people with digestive disorders (Crohn's, celiac).

Iron

What It Does

Iron is crucial for making hemoglobin, the protein in red blood cells that carries oxygen throughout your body. It also supports immune function and cognitive development.

Deficiency Symptoms (Anemia)
  • Extreme fatigue and weakness
  • Pale skin, nails, and gums
  • Shortness of breath
  • Cold hands and feet
  • Brittle nails and hair loss
  • Unusual cravings (ice, dirt - called pica)
Food Sources

Heme Iron (better absorbed): Red meat, poultry, fish
Non-Heme Iron: Lentils, beans, spinach, fortified cereals, tofu

Tip: Pair non-heme iron with Vitamin C (citrus, tomatoes) to boost absorption. Avoid taking with calcium supplements as they can interfere with absorption.

Recommended Daily Intake

Men: 8 mg | Women (19-50): 18 mg | Pregnant women: 27 mg

At Risk: Menstruating women, pregnant women, vegetarians/vegans, endurance athletes.

Magnesium

What It Does

Involved in over 300 biochemical reactions. Supports muscle and nerve function, blood sugar control, blood pressure regulation, and bone health. Works with Vitamin D and calcium for optimal bone health.

Deficiency Symptoms
  • Muscle cramps and spasms
  • Fatigue and weakness
  • Irregular heartbeat
  • Numbness and tingling
  • Anxiety and irritability
  • Migraines
Food Sources

Dark leafy greens (spinach, kale), nuts and seeds (almonds, pumpkin seeds), whole grains, legumes, dark chocolate, avocados.

Recommended Daily Intake

Men: 400-420 mg | Women: 310-320 mg

Calcium

What It Does

Essential for building and maintaining strong bones and teeth. Also critical for muscle function, nerve transmission, and blood clotting. Requires Vitamin D for proper absorption.

Deficiency Symptoms
  • Weak, brittle bones (osteoporosis)
  • Muscle cramps and spasms
  • Numbness in fingers and toes
  • Abnormal heart rhythms
  • Dental problems
Food Sources

Dairy products (milk, yogurt, cheese), fortified plant milks, sardines with bones, tofu, kale, broccoli.

Recommended Daily Intake

Adults (19-50): 1,000 mg | Women (51+) & Men (71+): 1,200 mg

Zinc

What It Does

Supports immune function, wound healing, DNA synthesis, and cell division. Important for taste and smell.

Deficiency Symptoms
  • Weakened immune system (frequent infections)
  • Hair loss
  • Loss of appetite and taste
  • Slow wound healing
  • Skin rashes
Food Sources

Oysters, red meat, poultry, beans, nuts, whole grains, fortified cereals.

Recommended Daily Intake

Men: 11 mg | Women: 8 mg | Pregnant women: 11 mg

Vitamin C (Ascorbic Acid)

What It Does

Powerful antioxidant that supports immune function, collagen production (skin, tendons, ligaments), and helps absorb iron from plant-based foods. Enhances immune function when combined with zinc.

Deficiency Symptoms
  • Frequent bruising
  • Slow wound healing
  • Bleeding gums and loose teeth
  • Dry, rough skin
  • Fatigue and weakness
  • Scurvy (severe deficiency)
Food Sources

Citrus fruits (oranges, lemons), strawberries, bell peppers, broccoli, Brussels sprouts, tomatoes, kiwi.

Recommended Daily Intake

Men: 90 mg | Women: 75 mg | Smokers: +35 mg

Omega-3 Fatty Acids

What It Does

Essential fats crucial for brain health, heart health, and reducing inflammation. The three main types are ALA, EPA, and DHA.

Deficiency Symptoms
  • Dry, flaky skin
  • Brittle hair and nails
  • Fatigue and poor concentration
  • Joint pain and stiffness
  • Depression and mood swings
Food Sources

EPA & DHA: Fatty fish (salmon, mackerel, sardines, anchovies)
ALA: Flaxseeds, chia seeds, walnuts, hemp seeds

Recommended Daily Intake

Combined EPA & DHA: 250-500 mg | ALA (Men): 1.6 g | ALA (Women): 1.1 g

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