What Are The Functions Of Vitamin B12?

What Are The Functions Of Vitamin B12?

From bowel problems to fatigue, there is a multitude of symptoms of a vitamin B12 deficiency. We’ll show you why the vitamin is so important and how to get it.

After a good night’s sleep, you should feel rested and start the day fresh. Still can’t concentrate and would like to have a little nap at lunchtime? Anyone who constantly feels weak and unable to concentrate may suffer from a vitamin B12 deficiency. Vitamin B12 is also called the feel-good vitamin, so a deficiency should be remedied quickly.

Why do we need vitamin B12?

b12 vitamin
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Vitamin B12 is involved in the metabolism of carbon, fat, and protein. It is important for cell division and blood formation. The vitamin is needed to make red blood cells and to bind iron into the blood cells. It is also involved in building the nerve cells in the spinal cord and building DNA. The vitamin is necessary to keep folic acid active.

We can take vitamins with the water-soluble vitamin through food. It is absorbed via the mucous membrane cells in the intestine and from there carried to the liver. It is stored here for several years.

Vitamin B12 is produced by bacteria and blue-green algae and is mainly found in fish, meat, and milk. In plant-based products, it occurs only in small amounts after bacterial fermentation has occurred, such as in sauerkraut.

What causes a deficiency?

b12 deficiency
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Since the vitamin is stored in the liver for a long time, a deficiency only shows up after years. Older people in particular are therefore affected by a deficiency. The cause can be a diet poor in vitamin B12 (e.g. a vegan or vegetarian diet) or gastritis / gastric mucosal inflammation. In addition, intestinal disorders or medication can prevent absorption. Common symptoms of a vitamin B12 deficiency are:


Frequent migraines

Hair loss



Eye problems

Loss of memory and concentration

Sensory disorders

If you often feel weak or have other symptoms, it makes sense to have your blood values checked by a family doctor. The methylmalonic acid test (MMA test) can be used to determine whether there is a vitamin B12 deficiency; if there is a deficiency, the MMA level in the blood and urine rises. If a deficiency is found, the diet will be changed after consultation with the doctor: Foods containing vitamin B12 are more often on the menu or even on dietary supplements.

How much vitamin B12 should I consume?

b12 vitamin
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Children up to 15: The reference values vary depending on age from 0.5 to 4 µg per day.

From the age of 15: 4 µg should be consumed per day.

Pregnant women: You need 4.5 µg per day.

Breastfeeding: Women who breastfeed have an increased requirement of 5.5 µg per day.

Which foods provide us with the vitamin?

vitamin b12 foods
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We can only get vitamin B12 from food and almost exclusively from meat and animal products. We have listed some good suppliers:

Fish and marine animals: Oysters, herring, mussels, and herring are good sources of vitamin B12 and should be on your shopping list.

Dairy products: Whether camembert, cream cheese, or Edam – the daily cheese still can provide us with vitamin B12.

Meat: Pork, beef, and veal also contain vitamin. Chicken contains a little less.

Vegan/vegetarian foods: Sauerkraut, Shiitake mushrooms, and seaweed contain fluctuating vitamin B12 values. However, the proportion is so low that at least dairy products should also be consumed.

Is it possible to overdose?

b12 vitamins in spoon
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The intake of too much vitamin B12 is practically impossible through natural foods. The intestines only absorb as much vitamin B12 as is actually needed. Any excess is simply excreted.

However, this only applies to natural products. An overdose can occur if too much vitamin B12 is absorbed through supplements. Therefore, they should only be taken on the recommendation of a doctor.

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