Vitamins - what they do and where you can really get them

They have simple letters like A, C, D or K - and yet our health, performance and even our mood depend on them: Vitamins. Without them, the finely tuned machinery of our body breaks down. Even the smallest deficiencies can favour tiredness, poor concentration or infections, while an optimal supply protects cells, controls energy processes and strengthens the immune system. But where do you really get vitamins from, how do they work - and why are a few multivitamin tablets not enough?

Vitamins are organic compounds that the body cannot produce itself - with the exception of vitamin D and niacin. We therefore have to take them in through our diet. They do not act as direct energy suppliers, but as key substances that enable biochemical processes: from energy metabolism and haematopoiesis to DNA repair.

There are two main groups:

Vitamin A is irreplaceable for vision, skin and mucous membranes. It regulates the growth and differentiation of cells. A deficiency leads to night blindness, skin problems and increased susceptibility to infections.

Strictly speaking, vitamin D is a hormone that the body produces itself under UV-B radiation in the skin. It controls the calcium balance, strengthens bones and muscles, but also regulates immune processes. A deficiency - which is widespread in our part of the world - increases the risk of osteoporosis, infections and even depression.

Vitamin E acts as an antioxidant and protects cell membranes from free radicals. It also supports the immune defence. A deficiency is rare, but can occur with fat malabsorption and leads to muscle weakness and nerve damage.

Vitamin K is crucial for blood clotting and the storage of calcium in the bones. Without vitamin K, the risk of internal bleeding and osteoporosis increases.

Vitamin C is known as an immune system booster, but its role goes far beyond this: it strengthens connective tissue, improves iron absorption and acts as a powerful antioxidant. A deficiency leads to bleeding gums, muscle weakness and increased susceptibility to infections.

The eight B vitamins (B1, B2, B3, B5, B6, B7, B9/folate, B12) act as coenzymes in energy metabolism, haematopoiesis and DNA synthesis.

Vitamins rarely work alone. Vitamin C improves iron absorption, vitamin D and K work together in bone metabolism, B vitamins interlock like cogwheels. These synergies show: A balanced diet is more effective than isolated high-dose supplements.

Both diets can ensure an optimal vitamin supply - with care:

Vitamins are essential for athletes: they regulate energy metabolism, muscle function and regeneration. Vitamin D improves muscle strength, B vitamins optimise energy production and vitamin C speeds up recovery. A deficiency reduces performance, delays healing processes and increases susceptibility to infections.

Vitamins are the silent conductors of your metabolism. The most important source remains a varied diet - fresh, colourful and natural. But this is not always enough: The body's ability to absorb vitamins decreases with age, the need increases in competitive sport and deficiencies can occur with certain illnesses. In such cases, high-quality supplements are more than just an emergency solution - they close gaps that are difficult to cover with food alone. The decisive factor is quality: targeted, sensibly dosed and ideally based on personalised advice.

In the next part of our series, we look at minerals and trace elements. Small substances with a big effect - from oxygen transport and nerve conduction to hormone production. Because sometimes a milligram can make the difference between performance and exhaustion.