Natural Remedies A-Z
Vitamin B12 |
Vitamin B12 is a nutrient that has been the focus of a great deal of debate in recent years. Most of this has been surrounding this nutrient and vegetarians. Since the Western diet is drenched in animal products, vitamin B12 deficiency is scarce. There is an exception amongst elderly people - this will be discussed later. This nutrient is found in high levels in animal products such as meat and milk. Vegetarians, especially vegans have been at ‘potential’ risk of deficiency. But it now appears there are viable sources for such people.
Actions within the body
Within the body B12 has vital roles in the formation of red blood cells. It is partly responsible for their formation, and maintains their proper growth. This nutrient also has a maintenance role for various leukocytes, thus supporting immunity. There is an ability to generally support the body during degenerative diseases, and in some cases aid in their prevention, particularly where the nervous system is concerned.
This is a particularly complex one when it comes to post digestion absorption. The acidic environment of the stomach unlocks this nutrient from food. It then binds to a substance called intrinsic factor (IF) which is released by parietal cells in the wall of the stomach. This complex of IF and B12 moves from the stomach to the ileum where certain receptors recognise it and absorb it by means of phagocytosis. Once through, the vitamin binds to a transport protein called transcobalamin II (TCII), which takes it off to the liver. Within the liver there is a B12 storage pool, which can store enough of this nutrient to last for anything up to 3 years. Coupled with this actual area of storage, there is the fact that this nutrient is not easily excreted via the urine - despite the fact it is a water soluble vitamin.
Food sources
It is undoubtedly true that the highest levels of B12 are found in animal produce. The highest source being lambs liver. Eggs, fish, cheese, and meat are also very rich sources. There are however some very rich vegetarian sources of this nutrient, although how bioavailable this is has been the focus of much debate. B12 is produced by specific micro-organisms. Foods such as mushrooms, some green leafy vegetables, fermented foods such as tempeh, and various seaweeds have a reasonably high B12 content, and this is due to the presence of these micro-organisms. In some manufacturing facilities that have extremely high levels of contamination control, these micro-organisms were completely destroyed and the B12 levels that were being claimed in the products nutritional information had completely vanished. As a result, many facilities have begun to artificially reintroduce these organisms into produce so as to maintain, and in many cases, increase the B12 content. These foods certainly are beneficial to vegetarians, and their B12 profile. While it is true that these foods will not provide the same levels of this nutrient as a diet that contains animal produce, because of the body’s ability to store B12, they will be sufficient to prevent actual deficiency.
It is interesting to note that there is a real irony with this vitamin. The Human body actually does synthesise it within the colon. Unfortunately, the site for B12 absorption is much higher up in the gut, so this all goes to waste.
Deficiency signs
Prolonged deficiency of vitamin B12 will manifest in two distinct conditions that seriously threaten the life of the individual. The first of these conditions is Megaloblastic anaemia. This is essentially caused by a breakdown in activity of various enzymes that effect a new blood cells ability to use iron in its structure. This fault can then be transferred via DNA to further generations of blood cells. The symptoms of this are essentially the same as iron deficiency anaemia - weakness, fatigue, depression. The end cause is too essentially the same as iron deficiency anaemia - the red blood cells lose their ability to carry oxygen tissues. This can be turned around very quickly however, via intravenous injection of B12.
The second major pathological state associated with B12 deficiency is subacute combined degeneration which is a neuropathy. In the early stages this can present itself as reduced memory, apathy, moodiness, paranoia, and personality changes. This condition involves progressive degeneration of the myelin sheath that surrounds cells within the nervous system and the brain. As the condition progressive, this degeneration leads to reduced sensations and balance in the lower extremities, parasthesia (tingling skin), loss of sensory and mental acuity, vision impairment and both urinary and fecal incontinence. If this is allowed to continue, the end result is irreversible paralysis, brain damage and finally death.
Apart from dietary lack of this nutrient, there is another factor that can lead to deficiency of B12. AS has been discussed earlier, B12 absorption requires the presence of a substance called intrinsic factor. In turn intrinsic factor requires set levels of hydrochloric acid (HCL) within the stomach. The production of this acid declines with advancing age. Therefore the elderly commonly display signs of vitamin B12 deficinecy to varying degrees.
Therapeutic applications
Atherosclerosis prevention
Vitamin B12 is what is known as a methyl donor. As such, it is involved in the metabolism of homocysteine. Homocysteine plays a role in the progression of atherosclerosis, and elevated levels of this can be a major risk factor for having a heart attack.
AIDS
Patients with AIDS often have a drop in serum B12, and also experience a significant degree of neurological symptoms. This maybe due to reduced nutrient absorption, or a side effect of medication. Reduced B12 can further increase nuerological symptoms, as well as further impingement of immune function. Supplemental, or even intravenous B12 can help to at least slow these problems down.
Mental decline in the Elderly
It is clear that a significant number of cases of reduced cognitive function in the elderly is greatly linked to poor nutritional status. Many factors such as reduced apetite, narrow range of foods consumed, and reduced ability to absorb nutrients can contribute to this overall poor nutritional status. As has been previously discussed, B12 is reliant on intrinsic factor to be absobed, and the production of this decreases with advancing age. This can have serious repercussions upon the functioning of the brain and nervous system. Daily supplementation of B12, preferably in a liquid format, can be of great help in such circumstances. However, more serious pathologies MUST be ruled out. Never treat blind!!!!!
Dosage
In a normal (whatever that means) healthy individual, a daily intake of around 2 microgrammes per day is required. This low amount is due to the body’s ability to store B12 in the liver. However, in individuals that are in a deficiency state will need a dosage of around 2,000 microgrammes for a period of about one month, then drop down to a daily dosage of around 1,000 microgrammes for at least 3 months. After this, the lower daily dosage is sufficient as the liver will have a considerable amount in storage. A dosage of around 1,000 microgrammes is suitable for the clinical applications mentioned above also.