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Alzheimer's Disease and the Role of Vitamin B12

  • Synopsis: Published: 2010-10-19 (Revised/Updated 2012-09-21) - Risk of developing Alzheimers disease may be connected to levels of Vitamin B12 -

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A recent study of 271 Finns, published in the journal Neurology, shows that the risk of developing Alzheimer's disease may be connected to levels of Vitamin B12.

The study found that those people who had the highest levels of B12 were the least likely to develop the disease. So what's the connection between B12 and Alzheimer's, and should anyone at risk be taking B12 supplements to combat this

Vitamin B12 deficiency is known to raise the levels of homocysteine in the blood, and scientists know that this can increase the risk of heart attack, stroke and dementia. B vitamins have therefore been linked with dementias, including Alzheimer's, for many years. Because increasing B12 levels can lower homocysteine levels, it seems that this could possible stop dementia developing.

A recent study showed that brain shrinkage was slowed down in people who took high doses of B12. As brain shrinkage has been associated with Alzheimer's, it is another reason to suspect a link between B12 and Alzheimer's.

Most people get their B12 from meat and fish, but it is also found in smaller quantities in eggs and dairy products. Additionally, many products aimed at vegetarians and vegans are fortified with B12, most typically breakfast cereals. So who exactly is at risk

Many people think that it is only vegans and vegetarians that are at risk of B12 deficiency, but research shows that this just isn't the case. It is true vegans and vegetarians are at particular risk, especially those that don't take B12 supplements or eat B12-fortified foods, but there are a range of other people that are at risk. The biggest of these groups is elderly people.

One of the reasons that elderly people are at risk is because people tend to produce less stomach acid as they get older. As B12 is bound to animal proteins in the food you eat, stomach acid is needed to split the B12 from the protein. So with low stomach acid, you won't be able to absorb enough of the B12 that's present in the food.

Another group of people that is likely to be B12-deficient are people who have had gastric surgery for weight loss, or those who have had part of their stomachs removed. This people will have lost the cells that produce stomach acid, and therefore won't be absorbing B12.

So how common is Vitamin B12 deficiency? The simple answer is that it is much more common than most people think.

  • Researchers at Tufts University, who analyzed data from the Framingham Offspring Study, found that nearly 40% of participants between the ages of 26 and 83 had B12 plasma levels in the low-normal range. This is a level at which some people begin experiencing neurological symptoms.
  • Many smaller studies have reported that B12 deficiency among seniors to be in the 12-20% range.
  • In a recent study, 40% of hospitalized elderly patients were found to have low or borderline B12 levels.
  • Of long-term vegans who don't supplement their diets with adequate amounts of B12, 80% show signs of deficiency.
  • For long-term vegetarians, the figure is 50%.

So is the answer just to take B12 supplements? For many people, taking an oral supplement isn't the answer, because due to lack of sufficient stomach acid and other issues, they just won't be able to absorb the oral B12. For these people, the best solution is to ask their doctor for B12 injections.

Before you start taking any supplements, whether oral, sublingual, patches or injections, it's a good idea to get tested to see whether you are deficient or not. Most doctors check B12 status via a serum test, but this test often gives false positive or false negative results. It is therefore suggested that this test is done in conjunction with a Methylmalonic Acid (MMA) test. An elevated level of MMA means a deficiency of B12. The most accurate of these tests is the urinary MMA/creatinine ratio test, which was developed in 1985. This test doesn't produce false positives or false negatives - you can ask your doctor for this test.

Related Information:

  1. Nutrient Mix for Alzheimer's Patients Shows Promise for Improving Memory
  2. Slowing the Progression of Alzheimer's Disease
  3. Alzheimer's Discovery Could Bring Early Diagnosis, Treatment Closer

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