Vitamins and Minerals - What They Do and Why You Need Them

The Big Difference: Vitamins vs. Minerals

VITAMINS

Fat-Soluble Vitamins (A, D, E, K)

Vitamin A

• What it does: Keeps your vision working in dim light (night vision). Also keeps skin and the linings of your gut, lungs, and urinary tract healthy and intact. Supports immune defense and normal cell growth.
• Food sources: Liver, eggs, dairy, carrots, spinach, orange/yellow vegetables (as beta-carotene, the provitamin).
• Deficiency: Night blindness is the first sign. Severe deficiency can cause total blindness - it is the most common cause of preventable childhood blindness worldwide. It also weakens immunity.
• Robbins & Kumar Basic Pathology, p. 292

Vitamin D

• What it does: Acts like a hormone. Controls how much calcium and phosphate you absorb from food - so it is the master builder of bones and teeth. Also plays a role in cell growth regulation and insulin production.
• Food sources: Sunlight (skin makes it), fatty fish, fortified dairy.
• Deficiency: Causes rickets in children (soft, bent bones) and osteomalacia in adults (bone pain and weakness).
• Harper's Illustrated Biochemistry, p. 624

Vitamin E

• What it does: The body's main fat-soluble antioxidant. It protects cell membranes from damage caused by free radicals - unstable molecules that attack your cells.
• Food sources: Nuts, seeds, vegetable oils, green leafy vegetables.
• Deficiency: Rare in healthy adults, but in animals it causes damage to the germinal epithelium of the testes.
• Guyton and Hall Textbook of Medical Physiology

Vitamin K

• What it does: Makes clotting factors in your blood. Without it, a small cut could become dangerous. Also involved in bone health.
• Food sources: Green leafy vegetables (kale, spinach), also made by gut bacteria.
• Deficiency: Abnormal bleeding.

Water-Soluble Vitamins (B group + Vitamin C)

Vitamin C (Ascorbic acid)

• What it does: Builds and repairs collagen (the protein that holds skin, tendons, and bones together). Acts as an antioxidant. Critically, it helps your gut absorb iron from plant foods - which is why it is often prescribed alongside iron supplements.
• Food sources: Citrus fruits, strawberries, bell peppers, broccoli.
• Deficiency: Scurvy - bleeding gums, poor wound healing, joint pain.
• Harper's Illustrated Biochemistry, p. 607

B Vitamins (B1, B2, B3, B5, B6, B7, B9, B12)

Note: Vitamin B12 is found only in animal products (meat, fish, eggs, dairy). Strict vegetarians and vegans must supplement.

• Kaplan & Sadock's Comprehensive Textbook of Psychiatry

MINERALS

Calcium

• What it does: Builds and maintains bones and teeth (99% of body calcium is in bones). Also essential for muscle contraction, nerve signaling, and blood clotting.
• Food sources: Dairy, dark leafy greens, fortified foods.
• Deficiency: Weak bones, muscle cramps, in children - stunted growth.

Iron

• What it does: Makes hemoglobin - the protein in red blood cells that carries oxygen from your lungs to every cell in your body. Without enough iron, your blood cannot carry enough oxygen.
• Food sources: Red meat, liver, shellfish, beans, leafy greens.
• Deficiency: Iron-deficiency anemia - fatigue, pale skin, shortness of breath. This is the most common nutritional deficiency worldwide.

Iodine

• What it does: The thyroid gland needs iodine to make thyroid hormones, which control your metabolism (how fast the body uses energy).
• Food sources: Iodized salt, seafood, dairy.
• Deficiency: Goiter (enlarged thyroid gland), hypothyroidism, cretinism in babies born to deficient mothers.

Zinc

• What it does: Helps enzymes work, supports immune function, aids wound healing, and is needed for taste and smell.
• Food sources: Meat, shellfish (especially oysters), nuts, seeds.
• Deficiency: Impaired immunity, poor wound healing, loss of taste/smell.

Sodium and Potassium

• What they do: These are the main electrolytes. They maintain fluid balance inside and outside cells, regulate blood pressure, and allow nerves and muscles (including the heart) to fire signals properly.
• Too much sodium: Raises blood pressure (hypertension).
• Food sources: Sodium - table salt; Potassium - bananas, potatoes, beans.

Magnesium

• What it does: Involved in over 300 enzyme reactions. Needed for muscle and nerve function, blood sugar control, and building bones.
• Food sources: Nuts, seeds, whole grains, leafy greens.

Fluoride

• What it does: Protects teeth from decay (dental caries) by strengthening enamel. Present in fluoridated water and toothpaste.
• Basic Medical Biochemistry, p. 616

Key Takeaways

1. Vitamins are organic (carbon-based) helpers - they regulate processes like energy use, immunity, vision, and cell growth.
2. Minerals are inorganic elements - they build structures like bones and teeth, run enzymes, and manage fluids and electrical signals.
3. Fat-soluble vitamins (A, D, E, K) are stored - too little causes deficiency, too much causes toxicity.
4. Water-soluble vitamins (B, C) are not stored - you need to eat them regularly.
5. A varied, balanced diet covering fruits, vegetables, whole grains, lean proteins, and dairy covers the needs of most healthy people, as confirmed by Cleveland Clinic's nutrition guidance.
6. Supplements are useful in specific deficiencies (e.g., iron + vitamin C for anemia, vitamin B12 for vegans, vitamin D in low-sunlight regions) but high-dose "megavitamin" regimens should be avoided unless medically directed.