Last week I mentioned new research findings, which indicate that certain B vitamins, namely folic acid, vitamin B12 and possibly also vitamin B6, may be implicated in the development and progression of Alzheimer’s Disease. These B vitamins appear to lower the levels of a chemical compound called homocysteine in the body. High homocysteine levels in the blood are known to be associated with risk of heart disease and now there also appears to be a link between homocysteine and mental deterioration.
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Strange findings
This potential link between B vitamins and Alzheimer’s Disease reminded me of a short article I read in The Lancet late last year. In this article, Dr David Spence, an expert on homocysteine, recounted his own experience with vitamin B12 deficiency. Dr Spence had his folic acid and vitamin B12 levels monitored when he developed neurological problems. He also had his blood homocysteine levels checked.
The results of these tests showed that Dr Spence had supposedly normal folic acid and vitamin B12 levels, but that his blood homocysteine levels were dangerously high. Dr Spence decided to take oral supplements of folic acid and vitamin B12 to try and lower his homocysteine levels. When he went for follow-up tests, he found to his consternation that the levels of vitamin B12 in his blood had not increased despite the supplement he was taking. Dr Spence concluded that he was not absorbing the vitamin B12 in the supplement he was taking by mouth.
Malabsorption of B12
Vitamin B12 is a rather problematic vitamin. On the one hand it is very important to ensure that we don’t develop megaloblastic or pernicious anaemia, nerve deterioration and now it seems, possibly also Alzheimer’s Disease.
On the other hand, vitamin B12 is only found in foods derived from animals, such as meat, fish, eggs, and to a lesser extent in milk and dairy products. Anyone eating a totally vegetarian or vegan diet, therefore, may become deficient in B12. Additionally, vitamin B12 requires the so-called “intrinsic factor” which is found in the digestive tract, plus adequate levels of stomach acid and pepsin enzyme for proper absorption. Before researchers discovered this “intrinsic factor” a vitamin B12 deficiency was often fatal. Nowadays there are tests to discover if patients lack this “intrinsic factor” and doctors can prescribe it together with vitamin B12 supplements to treat pernicious anaemia. However, low levels of stomach acid and pepsin enzyme occur frequently in older people who lose their ability to manufacture sufficient acid and pepsin.
A new absorption factor
Recent research has uncovered another factor called “Transcobalamin II” which is
necessary for transporting vitamin B12 from the digestive tract to the liver and into the cells. There is evidence that some people develop antibodies against transcobalamin II which makes it ineffective and other people have a hereditary deficiency of this transport factor. Such individuals will therefore not be able to transport the vitamin B12 they absorb and will consequently also develop a vitamin B12 deficiency.
A bigger problem than suspected
Dr Spence pointed out that up to 40% of older patients have a vitamin B12 deficiency. This could be due to lack of vitamin B12 in the diet, lack of “intrinsic factor”, stomach acid and pepsin enzyme for absorption, and/or lack of transcobalamin II for transport. The vitamin B12 picture is, therefore, much more complex than was originally suspected, and it is quite possible that there are many people, particularly older individuals, who suffer from B12 deficiency.
We know that a lack of vitamin B12 causes homocysteine levels to rise, which can result in an increased risk of heart disease, and possibly of Alzheimer’s Disease. But it is not always easy to replenish vitamin B12 levels in the human body, if the patient suffers from malabsorption due to a lack of intrinsic factor, stomach acid or pepsin enzyme, and/or deficient B12 transport.
Possible solutions
If you suspect that you may have a vitamin B12 deficiency (lack of meat, fish, and eggs in your diet) or develop symptoms that point to such a deficiency (tiredness, lack of energy, depression, pale or yellowish tinge to the skin, neurological symptoms), then it may be a good idea to ask your doctor to test your vitamin B12 blood levels. If the results are lower than the normal range, then you need to take a vitamin B12 supplement and increase your intake of food that are rich in this vitamin (red meat, organ meats, especially liver, fish, eggs, particularly the yolk, milk and cheese).
Go for regular checkups and if your vitamin B12 blood levels don’t increase with supplementation and additional intake via the diet, then ask your doctor about these two important factors - the intrinsic factor and transcobalamin II, as well as possible lack of stomach acid and/or pepsin enzyme.
If oral supplements and replacement of missing digestive factors does not help, then you may have to have vitamin B12 injections to improve your B12 levels and prevent megaloblastic anaemia, nerve degeneration, increased risk of heart disease and mental deterioration.
Make quite sure that you do not develop a vitamin B12 deficiency and if you suspect such a deficiency, take the necessary steps to remedy this problem - your physical and mental health may depend upon it!
f you have any diet queries, post a question or message on The Message Board. I am here to assist you with your Diet and Food Choices, so let’s interact. - (Dr I V van Heerden, DietDoc)
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