Vitamins and minerals in sports nutrition

October 25, 2025Michal Jetelina

Vitamins and minerals are micronutrients essential for the proper functioning of the body .
They are not a source of energy, but they allow the body to use energy from food effectively - in the production of ATP , regeneration , immune response and muscle contraction .

Sports stress increases their need for several reasons:

  • accelerated metabolism (higher need for coenzymes from B vitamins),

  • increased sweat and urine losses,

  • greater formation of free radicals (higher need for antioxidants),

  • faster cell turnover and more intensive tissue regeneration.

Even mild, so-called subclinical micronutrient deficiency can reduce performance, slow down recovery, and limit adaptation to training, even if laboratory values ​​remain normal.

Vitamins – basic overview and their role

Vitamin Main functions Increased need/Risk Typical sources
B-complex Coenzymes in the conversion of carbohydrates, fats and proteins into ATP The need increases by 10–20% during training Whole grains, legumes, meat
C and E Antioxidants, cell protection Excessive supplementation may dampen adaptive signals Fruits, vegetables, nuts
D and K Bone metabolism, immunity, muscle strength Deficiency common in winter; ideal vitamin D levels 75–100 nmol/l Sun, fish, eggs, leafy greens
AND Epithelial regeneration, immunity, vision Excess (retinol) can be toxic Liver, butter, carotenoids

Minerals and electrolytes

Minerals play a vital role in muscle contraction, nerve impulse transmission, fluid balance, and bone structure.

Typical electrolyte losses through sweat

Mineral Typical loss / 1 l of sweat Importance in performance
Sodium (Na) 400 – 1,800 mg The main electrolyte, the most lost
Potassium (K) 120 – 400 mg Maintains balance between cells and plasma
Calcium (Ca) 20 – 100 mg Less important under load
Magnesium (Mg) 5 – 40 mg Enzyme activator, losses are low


Electrolyte replenishment during exercise

  • within 60 minutes: water is usually enough,

  • 60-90 minutes: 300-800 mg Na/l,

  • with heavy sweating or in heat: 1,000–1,500 mg Na/l.

During long-term exercise, it is also necessary to supplement sodium - too much water with a low sodium content can lead to plasma dilution (hyponatremia).

Magnesium and potassium – when to supplement

Losses of magnesium and potassium are small compared to sodium – typically 120–400 mg K/l and 5–40 mg Mg/l of sweat.
For most athletes, their needs are reliably covered by their regular diet.
Only during prolonged exercise in the heat (over 3 hours) can approximately 200–300 mg K/l and 10–50 mg Mg/l be added to drinks.
The performance benefit is limited; after exercise, it is advisable to replenish these minerals naturally (e.g. banana, potatoes, legumes, nuts, seeds).

Trace elements

Element Main functions Risk of shortage/surplus Typical sources
Iron (Fe) Oxygen transport (hemoglobin, myoglobin) Deficiency → decreased VO₂max; ferritin < 30 µg/l Red meat, legumes
Zinc (Zn) Regeneration, immunity, enzymes Excess > 40 mg/day → limited copper absorption Meat, seeds
Selenium (Se) Antioxidant system Toxicity > 400 µg/day Brazil nuts, fish
Copper (Cu) Iron and collagen metabolism Excess → liver damage Seafood, nuts
Iodine (I) Thyroid hormones, metabolism Deficiency → hypothyroidism Seaweed, iodized salt

High intake of one mineral can reduce the absorption of another – for example, iron ↔ calcium or zinc ↔ copper.
A balanced diet is the best prevention of imbalance.

Supplementation – when does it make sense?

Add-on type When does it make sense? Note
Multivitamin Low energy intake, vegan diet, high stress Does not bring performance effect with adequate diet
Ionic drink Performance > 60 min, hot, high sweating 300–800 mg Na/l + 20–30 g carbohydrates/100 ml
Vitamin D / Iron / Zinc In case of proven deficit Targeted based on blood tests, for vitamin D even in winter
Antioxidants (C, E) Only in deficit Excess dampens adaptive signals
K, Mg At a power of > 3 h in a hot environment 200–300 mg K/l + 10–50 mg Mg/l in drink; limited benefit for performance, normal diet after exercise will cover needs


Risk of excess

Fat-soluble vitamins (A, D, E, K) and some trace elements (iron, selenium) accumulate in the body and can be toxic if consumed in excess over a long period of time.
Recommended doses should not be exceeded without professional supervision.

"Food first" – the basic principle

A varied diet provides not only vitamins and minerals, but also other bioactive substances (polyphenols, flavonoids, carotenoids) that act synergistically and support adaptation to training.
Supplements cannot replace this comprehensive effect.

The basic principle of sports nutrition remains the same:

First quality food, then supplements.

Summary

  • The need for micronutrients increases with the volume and intensity of training.

  • During exercise, it makes sense to mainly replenish sodium and fluids.

  • Losses of potassium and magnesium are small; a normal diet is usually sufficient.

  • Supplementation of individual vitamins or minerals only makes sense in cases of deficiency.

  • Excessive doses of antioxidants can inhibit adaptation processes.

  • The basis is a varied and balanced diet – the "food first principle".

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