Vitamins and Minerals Explained: What They Do and Who Actually Needs Supplements

BioMedic Africa Editorial Desk Published 29 August 2026 · Last updated 29 August 2026 · Editorial policy

The two kinds of vitamin

Fat-soluble vitamins — A, D, E and K — are stored in the body. They are absorbed with dietary fat and can accumulate to harmful levels, which is why they carry upper limits.

Water-soluble vitamins — the B group and vitamin C — are largely excreted when intake exceeds need. This limits toxicity but means regular intake matters more.

What each of the main vitamins does

A short functional summary is enough for most decisions.

• Vitamin A — vision, immune function, skin. Deficiency remains a cause of childhood blindness in parts of the region
• Vitamin D — calcium absorption, bone, immune function. Made in skin from sunlight
• Vitamin E — antioxidant in cell membranes
• Vitamin K — blood clotting and bone metabolism
• B vitamins — energy metabolism, nerve function, red blood cell formation
• Vitamin C — collagen synthesis, immune function, iron absorption from plant foods

The minerals that matter most

Calcium and magnesium are needed in larger amounts; iron, zinc, iodine and selenium in trace quantities. Their availability from food is affected by what else is on the plate — phytates in unrefined cereals reduce iron and zinc absorption, while vitamin C improves iron uptake.

This interaction matters in diets built on maize, sorghum and millet, where absolute mineral content may look adequate while absorption is not.

Which deficiencies are actually common in Africa

Four stand out in the published nutrition literature for the region: iron deficiency anaemia, particularly in women of reproductive age and young children; vitamin A deficiency in children; iodine deficiency where salt is not iodised; and zinc insufficiency in cereal-based diets.

Vitamin D deficiency is increasingly documented in urban populations despite abundant sunshine, because indoor work and covering clothing reduce exposure and deeper skin pigmentation requires longer exposure for the same synthesis.

Food sources across the region

Regional diets contain excellent sources when they are included. Dark leafy greens supply folate, calcium and vitamin A precursors. Small whole fish such as omena and dagaa supply calcium and vitamin D. Groundnuts, beans and pumpkin seeds supply zinc and magnesium. Guava, baobab, mango and citrus supply vitamin C.

The pattern in nutrition transition — refined staples displacing legumes and vegetables — is what creates gaps, and it is also what reverses them.

When a supplement is the right answer

Supplement where food genuinely cannot reach: folic acid before conception, vitamin B12 on a plant-based diet or with metformin use, vitamin D with limited exposure, iron in confirmed deficiency, and zinc in acute childhood diarrhoea under health guidance.

Outside those situations, a varied diet does the work more cheaply and with less risk of exceeding upper limits.

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