In their book “Kinderernährung – Expertenwissen für den Alltag” (German only), Swiss nutrition experts Dr George Marx and Andrea Mathis give a comprehensive overview of the wide-ranging and often controversial topic of child nutrition. We translated a selection of their insights and publish their findings on this blog to make them available to a wider audience. Please find the links to further posts of this series at the end of this contribution.

Vitamins are vital for life and are involved in various metabolic processes in the body. Vitamins are known as essential nutritional components; i.e., our body cannot produce them itself. We answer the most important questions about vitamin intake in children.


Vitamins have various functions in the conversion, composition and breakdown of nutrients for energy production and are involved in cell growth, vision, bone metabolism and blood clotting. They have an antioxidant effect.

They are categorized into fat-soluble and water-soluble vitamins:

  • Fat-soluble vitamins: These are the vitamins A, D, E and K. Fat-soluble vitamins are stored in fat tissue. An excessively high intake can result in an overdose, which in turn can have serious adverse effects.
  • Water-soluble vitamins: These are the vitamins B1, B2, B6, B12 and C, folic acid, niacin, pantothenic acid and biotin. The water-soluble vitamins are eliminated by the kidneys. An overdose is virtually impossible.


The average daily requirement depends on age and gender. A varied, balanced diet covers the vitamin requirement (with the exception of vitamin D).

Photo: Nadja Lenherr

It’s very clear that vitamins are important. Without them, serious signs of deficiency can develop. So does this mean: The more vitamins, the better?

Many studies prove: Even if additional vitamins are taken, for example, in the form of tablets or powders, a person is not healthier as a result. Certain vitamins can even be harmful if too much is taken, for example, vitamins A, D, E and K. These are known as fat-soluble vitamins which are stored in the fat tissue and liver.

Do organic products have more vitamins?

Putting an organic product in the shopping basket immediately makes a person feel a little better. Yet this feeling cannot be scientifically substantiated: Cucumbers and turnips from the organic rack do not contain more vitamins than regular supermarket vegetables. This was shown by a meta-study by the British Food Standards Agency from 2009.

Even the stubborn suspicion that everything was better in the past and that vegetables would have had more vitamins and minerals 50 years ago than today has been refuted. But: Organic products at least contain fewer harmful substances. The level of pesticide contamination of organically cultivated produce is about 100 times lower than that of regular food.

Where are there more vitamins? In vegetables from the farmer’s market or in the “summer vegetables” package from the freezer?

Those who are fans of freezers actually make healthier purchases in general, unless the vegetables go directly from one’s own garden to the table, in which case they can compete with frozen foods. However, if broccoli or carrots are stored for several days in the market stall, on the supermarket shelf and then at home, they lose a considerable amount of vitamins. For example, the vitamin C content of spinach goes to nearly zero. Even locally grown fruit contain their full nutritional value almost only in summer and early autumn. Conversely, spinach, when frozen at minus 18 °C, still has 85% of its original vitamin C content after four months. Since the vegetables are flash-frozen shortly after harvest and packaged in opaque, air-tight bags, the nutrients are better preserved.

Is lettuce high in vitamins and fiber?

Lettuce is considered to be synonymous with a healthy diet and immediately makes one feel good. But wrongly so: Lettuce is one of the most overvalued foods. Lettuce is more than 95% water and has low nutritional value, little fiber, and few vitamins. Vitamins should be obtained in the form of vegetables and fruits.

Is it true that lemons contain the most vitamin C?

They are not exactly low in vitamin C, but the honor goes to other fruits. Lemons contain about 52 mg ascorbic acid (per 100 g). Even broccoli, with over 115 mg per 100 g, is far superior to lemons in terms of vitamin C content. Kiwi, with 71 g per 100 g, is also rich in vitamin C.

Can I use vitamin pills to protect my child from diseases?

Our body needs vitamins and minerals, but not from a jar. They do not work like original vitamins in foods. It is not yet known why this is the case. An apple alone contains about 1,000 substances – presumably the body needs an interaction of various substances.

The products in capsules and powders can even be harmful. Supplementation is recommended only for deficiencies which have actually been proven and then in a targeted manner with the missing substance. However, this should be discussed with the doctor or nutrition specialist.


Please feel free to download this tasty, healthy and easy-to-prepare recipe which will soon be a favorite of your children!

Please check out the other posts of our series here:


Dr. med. George Marx, Andrea Mathis, BSc in Nutrition and Dietetics
Kinderernährung – Expertenwissen für den Alltag

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