Vitamin B12 2000 mcg, 100 lozenges

Vitamin B12 in its best forms: methylcobalamin and adenosylcobalamin

These are the forms in which vitamin B12 is found in food and utilised by the body. Cyanocobalamin, a synthetic form of vitamin B12 that does not occur naturally, is used in many other products.

Benefits of biologically active B12

In cases of oxidative stress, supplementation with a reduced form of vitamin B12 (such as methylcobalamin) may be more beneficial than using an oxidised form (such as cyanocobalamin). Studies also suggest that vitamin B12 levels rise more significantly after taking biologically active vitamin B12 than after taking cyanocobalamin. More vitamin B12 is stored in the liver, whilst less is excreted in the urine (longer half-life). For this reason, bioavailability is higher.

Absorption of vitamin B12

The absorption of vitamin B12 from food is a complex process. In the stomach, vitamin B12 is separated from dietary proteins and temporarily bound to transport proteins (also known as R-proteins or transcobalamin I), which are present in saliva and the mucus of the oesophagus and stomach. In the duodenum, proteases from the pancreas (digestive enzymes produced there) break down the vitamin B12 from the R-proteins and bind it to the ‘intrinsic factor’ (IF), a specialised protein produced in the stomach which is essential for the absorption of vitamin B12. In the final section of the ileum, vitamin B12 is taken up into the enterocytes (intestinal cells) via active transport after it has bound to specific receptors, provided that the vitamin is bound to IF. Within the enterocytes, IF is broken down, whereby the released vitamin B12 is bound to the transport proteins transcobalamin I and II. This complex is then released into the blood plasma.

The body’s utilisation of vitamin B12

20–25 per cent of the vitamin B12 present in the blood is bound to transcobalamin II. Only the vitamin B12 bound to this protein is taken up by the body’s cells. Transcobalamin II releases vitamin B12 in the cell’s lysosome and converts it into methyl- or adenosylcobalamin (lysosomes are vesicles in the cytoplasm that break down certain substances in order to reuse or excrete them). Methylcobalamin is particularly essential in blood plasma, the cytoplasm and cerebrospinal fluid, whilst adenosylcobalamin is required in tissues and mitochondria.

As methylcobalamin (in the cytoplasm), vitamin B12 acts as a cofactor in the conversion of homocysteine to methionine by the enzyme methionine synthase (see Figure 2). Methylcobalamin donates its methyl group to homocysteine, whilst the remaining cobalamin receives a new methyl group from 5-methyltetrahydrofolate. And then the cycle begins again. This process is also known as (re)methylation. In the case of methionine, its main function is the production of S-adenosylmethionine (SAMe), the most important methyl donor, which is involved in the synthesis of DNA, RNA, myelin, phospholipids, proteins and neurotransmitters such as serotonin and dopamine. In this way, methylcobalamin can contribute to normal cell division and the formation of red blood cells . It is also essential for the normal functioning of the brain and nerves and therefore has a positive effect on memory, concentration and mood. Vitamin B12 also influences the activation of certain immune cells and thus the normal function of the immune system, as it is involved in DNA and protein synthesis.

Vitamin B12 is present as adenosylcobalamin (in the mitochondria) and is involved in the conversion of methylmalonyl-CoA to succinyl-CoA (see Figure 2). Succinyl-CoA plays a role in the citric acid cycle, a series of biochemical reactions that ensure energy metabolism at the cellular level . Vitamin B12 thus contributes to energy levels and can help alleviate fatigue.

Active and passive absorption

The absorption of vitamin B12 from food is very efficient, but the absorption rate decreases rapidly as the intake of vitamin B12 increases, as receptor saturation occurs. With an intake of a few micrograms of vitamin B12, the absorption rate is between 25 and 65 per cent; at 25 mcg, however, it is only 5 per cent. If absorption is not bound to IF, it occurs via passive diffusion (along the entire gastrointestinal tract). However, this method of absorption is not very effective. In the absence of IF, only 1 per cent of vitamin B12 is absorbed. Furthermore, vitamin B12 that is not bound to IF is broken down more rapidly by protein-splitting enzymes and intestinal bacteria. Therefore, normal production and function of IF are very important for the active absorption of vitamin B12.

In certain situations, it may be necessary to use a high-dose vitamin B12 supplement (with a dose of 500–2000 mcg) for additional support. A significant proportion of this can be absorbed via passive diffusion, thereby ensuring an adequate supply of B12 in particular. It is advisable to take vitamin B12 together with folate and other B vitamins or a comprehensive multivitamin supplement

Nutritional properties

• Vitamin B12 contributes to normal energy metabolism and plays a role in cell division.
• Vitamin B12 contributes to the normal functioning of the nervous system and to normal psychological function.
• Vitamin B12 and folic acid contribute to normal homocysteine metabolism and help reduce tiredness and fatigue.
• Vitamin B12 contributes to the normal formation of red blood cells and, together with folic acid, contributes to the normal function of the immune system.

Nutrition declaration

*Reference value according to Regulation (EU) No 1169/2011

Ingredients

Sweeteners (mannitol and xylitol), firming agent (hydroxypropyl cellulose), anti-caking agent (magnesium salts of fatty acids), cherry flavouring, acidity regulator (citric acid), methylcobalamin, adenosylcobalamin.

Recommended intake

Allow 1 lozenge per day to dissolve under the tongue. Do not exceed the stated recommended daily intake. Contains sweeteners. May have a laxative effect if consumed in excess. Note

Note

This product does not contain folate or vitamin B6, so it is possible to take a multivitamin containing folate and vitamin B6 in combination with this B12 product.

Storage instructions

Store in a cool, dry place away from light (not in the fridge).

Legal information

Do not exceed the recommended daily intake. Food supplements are not a substitute for a balanced and varied diet and a healthy lifestyle. Keep out of reach of young children.