Vitamin B12 1000 mcg, 100 capsules

Vitamin B12 in seinen besten Formen Methylcobalamin und Adenosylcobalamin

These are the forms in which vitamin B12 occurs in food and is used by the body. Cyanocobalamin, a synthetic form of vitamin B12 that does not occur in nature, is used in many other products.
This product is specifically aimed at people who prefer a neutral‑tasting and unsweetened B12 capsule dietary supplement. If desired, the capsule can be opened to sprinkle the powder under the tongue. However, this is not necessary. It is also effective to take the whole capsule, preferably on an empty stomach.

Benefits of biologically active B12

Under oxidative stress, supplementation with a reduced form of vitamin B12 (such as methylcobalamin) can be more advantageous than using an oxidised form (such as cyanocobalamin). Studies also suggest that vitamin B12 levels rise more after taking biologically active vitamin B12 than after taking cyanocobalamin. More vitamin B12 is stored in the liver, while 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 called R‑proteins or transcobalamin I) that occur in saliva and the mucus of the oesophagus and stomach. In the duodenum, the proteases of the pancreas (digestive enzymes produced there) cleave vitamin B12 from the R‑proteins and link it to the “intrinsic factor” (IF), a specialised protein produced in the stomach that is required for vitamin B12 absorption. In the terminal section of the ileum, vitamin B12 is taken up into the enterocytes (intestinal cells) by active transport after it has bound to specific receptors, provided the vitamin is bound to IF. Within the enterocytes IF is degraded, and the released vitamin B12 binds to the transport proteins transcobalamin I and II. This complex is then released into the blood plasma.

Utilisation of vitamin B12 by the body

20–25 % 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 for reuse or excretion). Methylcobalamin is primarily needed in the blood plasma, cytoplasm and cerebrospinal fluid, while adenosylcobalamin is used in tissues and in the mitochondria.

As methylcobalamin (in the cytoplasm), vitamin B12 acts as a cofactor for the conversion of homocysteine to methionine by the enzyme methionine synthase (see figure 2). Methylcobalamin donates its methyl group to homocysteine, while the remaining cobalamin receives a new methyl group from 5‑methyltetrahydrofolate. The cycle then begins again. This process is also called (re‑)methylation. The main use of methionine is in the production of S‑adenosylmethionine (SAMe), the main methyl donor 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 required for the normal functions of the brain and nerves and therefore has a positive effect on memory, concentration and mood. Vitamin B12 also affects the activation of certain immune cells and thus normal immune function, 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 cellular energy metabolism. Thus vitamin B12 contributes to energy levels and can help reduce fatigue.

Active and passive absorption

Dietary absorption of vitamin B12 is very efficient, but the absorption rate decreases rapidly as vitamin B12 intake is increased, because receptor saturation occurs. With an intake of a few micrograms of vitamin B12 the absorption rate is between 25 and 65 %, whereas at 25 µg it is only 5 %. If absorption is not IF‑dependent, it occurs via passive diffusion* (along the entire gastrointestinal tract). However, this type of absorption is inefficient. If IF is absent, only 1 % of vitamin B12 is absorbed. In addition, vitamin B12 that is not bound to IF is broken down more quickly by proteolytic enzymes and gut bacteria. Therefore normal production and function of IF is very important for active vitamin B12 uptake.

In certain situations it may be necessary to use a high‑dose vitamin B12 preparation (with a dose of 500–2000 µg) for additional support. A considerable part of this can be absorbed via passive diffusion, thereby particularly ensuring an adequate supply of B12. It is advisable to use vitamin B12 together with folate and other B vitamins or a comprehensive multivitamin preparation.

Nutritional properties

• Vitamin B12 contributes to normal energy metabolism and has a function in cell division.
• Vitamin B12 contributes to the normal function 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 normal formation of red blood cells and, like folic acid, contributes to the normal function of the immune system.

Nutritional declaration

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

Ingredients

Anti‑caking agent (rice fibres), plant‑based capsule (pullulan, from fermented cassava starch), adenosylcobalamin, methylcobalamin.

Directions for use

Take 1–2 capsules per day with water between meals. The capsule can also be opened and the powder sprinkled under the tongue.

Note

This product contains no folate or vitamin B6, so using a multivitamin that includes folate and B6 in combination with this B12 product is possible.

Storage instructions

Store in a cool, dry place protected from light (do not refrigerate).

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.