The vitamin atlas

Vitamin A supports vision, immunity and cell differentiation. Preformed vitamin A differs from beta-carotene in form and risk.

Food sources include liver, dairy and carotenoid-rich vegetables. Preformed vitamin A and plant precursors differ in metabolism and excess risk.

Thiamin supports energy metabolism and cell function. Stores are limited, requiring ongoing dietary supply; it is not a stimulant.

Pork, whole grains, legumes and fortified foods can provide thiamin; refining and processing affect content.

Riboflavin forms FAD and FMN cofactors in energy and fat metabolism. An essential role does not establish extra-dose energy benefits.

Dairy, eggs, meats and fortified grains are common sources. Riboflavin supports energy metabolism, but extra intake does not necessarily increase vitality.

Niacin connects to NAD/NADP metabolism. Nicotinic acid, nicotinamide, NR and NMN are not interchangeable products at equal doses.

Meat, fish, poultry and fortified grains can provide niacin. Forms differ, as do risks at higher intakes.

Pantothenic acid helps make coenzyme A for fatty-acid and other metabolic processes and is widely distributed in foods.

Pantothenic acid occurs widely in animal and plant foods and contributes to coenzyme A. Supplement benefits in healthy people require specific evaluation.

B6 supports many enzyme reactions, including amino-acid metabolism. Water solubility does not imply unlimited safety; add exposures across products.

Fish, poultry, potatoes and some fruit provide B6. Excess supplemental intake can cause nerve injury, so total sources matter.

Biotin participates in fat, glucose and amino-acid metabolism. Its essential role alone does not establish hair or skin benefits in healthy people.

Eggs, fish, meat, seeds and some vegetables provide biotin. High supplemental doses can interfere with certain laboratory tests.

Folate supports one-carbon metabolism and DNA synthesis. Food folates, folic acid and 5-MTHF differ; compare label equivalents carefully.

Folate occurs in leafy greens and legumes. The form and amount in fortified foods or supplements should be specified.

B12 supports nerves, red blood cells and DNA. Both methylcobalamin and cyanocobalamin can be used by the body; “methylated” alone does not prove superiority.

B12 comes mainly from animal foods and fortified foods. Intake and absorption are separate issues; people eating fully plant-based diets need reliable sources.

Vitamin C supports collagen synthesis, antioxidant activity and non-haem iron absorption. Adequacy differs from high-dose “immune boosting.”

Citrus, kiwi and peppers provide vitamin C. It supports normal tissue function, while specific disease-prevention claims require their own evidence.

Vitamin D supports calcium absorption and bone mineralization. 25(OH)D commonly assesses status; interpretation depends on assay and individual context.

Sun exposure, certain fish and fortified foods contribute. Status depends on individual, environment and diet; prolonged excessive intake can cause harm.

Alpha-tocopherol meets human vitamin E requirements and supports antioxidant defence. Antioxidant activity is not evidence of preventing every chronic disease.

Vegetable oils, nuts and seeds provide vitamin E. Forms differ, and high-dose supplements may increase risks for some people.

Vitamin K supports clotting proteins and other functions; K1 and K2 forms differ. Warfarin users need coordinated medicine and dietary management.

Leafy greens are important sources. People using anticoagulants such as warfarin should discuss changes in vitamin K intake with their clinician.

A, D, E and K are fat-soluble; the eight B vitamins and C are water-soluble. This classification helps learning, but storage, elimination and safety require nutrient-specific assessment.