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Nutrition Science

Bioavailability

How much of a nutrient actually enters your bloodstream — the difference between what a food label says and what your body receives.

— Definition

Bioavailability is the proportion of a nutrient that is absorbed from food and becomes available for physiological use. A food can be nutritionally rich on paper but poorly bioavailable in practice.

— In Detail

Factors affecting bioavailability: (1) Food matrix — nutrients in whole foods are often less bioavailable than in processed forms, but also more stable; (2) Synergistic compounds — Vitamin C dramatically increases iron bioavailability; piperine increases curcumin 2,000%; fat increases fat-soluble vitamins (A, D, E, K); (3) Antinutrients — phytic acid, oxalic acid, tannins, and trypsin inhibitors all reduce mineral and protein bioavailability; (4) Preparation methods — cooking, soaking, fermenting, sprouting all modify bioavailability; (5) Gut health — inflamed or damaged gut wall absorbs less of everything; (6) Competition — high calcium intake reduces iron absorption; high iron reduces zinc; (7) Physiological state — pregnancy, iron deficiency, and gut pH all alter absorption rates.

— Why It Matters

Traditional food preparation methods — soaking, fermenting, cooking in iron vessels, pairing with acidic ingredients (tamarind, lemon, amla) — are bioavailability optimisation techniques developed over thousands of years of empirical practice. Modern nutrition science is documenting the mechanisms behind these practices, not inventing them.

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