The Role of B12 in Dementia

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Are “senior moments” an inevitable part of aging? For 1 in 9 Americans over the age of 65, those moments will progress to Alzheimer’s disease. Surprisingly, for a significant portion of that population, their cognitive issues may actually be the result of a simple vitamin deficiency, and treating it in its early stages could halt or even reverse dementia. Such a discovery should be on the front page of every newspaper and a top priority for every physician to monitor closely in elderly patients. Unfortunately, it isn’t.

B12 is essential for the functioning of brain and nerve cells. Nerves are protected by myelin sheaths, which ensures proper impulse transmission, and B12 is necessary for the synthesis and maintenance of myelin. It also plays a critical part in a biochemical reaction in the brain which is responsible for the synthesis of neurotransmitters responsible for mood and cognitive function: dopamine, serotonin, and norepinephrine. B12 is a necessary part of another process that prevents brain-damaging levels of the amino acid homocysteine from accumulating.

Because of its importance in brain function, researchers have long suspected a link between B12 and dementia. In 2005, a study of 19 elderly patients with low serum levels of B12 as well as dementia confirmed those suspicions. After a year of B12 supplementation, 12 of the patients showed significant improvement in dementia symptoms. Their conclusion: Many cases of dementia may actually be B12 deficiency, and therefore fully reversible.

The symptoms of B12 deficiency have been known for 100 years. Yet, it is the rare physician who takes the preemptive step to monitor B12 levels in patients, even though 40% of the population over 60 is estimated to be deficient and 40% of the total population falls into the low-normal range. A disease affecting such a significant portion of the population would be considered a pandemic, yet, B12 deficiency continues to fly under the radar much of the time.

Our bodies cannot manufacture B12, so it has to be supplied through food. It occurs naturally and in abundance in meat, fish, eggs, and dairy products, and synthetic versions fortify most grains and cereals. So why are so many people lacking this critically important vitamin?

There are several factors. Essential to the absorption of B12 is stomach acid. As we age, stomach acid decreases naturally, putting seniors at a disadvantage. Worsening the situation are acid-blocking medications known as proton pump inhibitors (PPIs), which are prescribed with abandon for conditions such as ulcers, gastritis, and acid reflux. Those with certain health conditions that affect absorption, such as Crohn’s disease, Celiac disease, or intestinal parasites, as well as some genetic disorders, are also likely to become deficient. As animal products are the primary source of B12, strict vegans frequently have insufficient levels of B12 as well.

Signs of deficiency begin gradually, over months or even years, and often before blood tests raise alarm. Symptoms vary widely between individuals and include fatigue, yellowish skin, shortness of breath, headaches, loss of balance, depression, irritability, tingling in extremities, poor muscle coordination, personality changes, inflamed tongue, incontinence, memory loss, paranoia, delusions, and changes in taste and smell. The disparity in symptoms often leads to a misdiagnosis.

To further confuse the issue, blood tests which detect serum levels of B12 may be misleading; by the time levels reflect the deficiency, damage may have already been done. Tests measuring methylmalonic acid and homocysteine are more accurate indicators of B12 status, as levels of both increase as B12 decreases.

Supplementation of B12 can be given orally, sublingually, through a nasal spray, or by injection. In patients whose deficiency is caused by malabsorption, injection is the quickest and most efficient way to increase levels.

When detected in the early stages, symptoms of B12 deficiency, including cognitive and nervous system impairments, can generally be completely reversed. However, if deficiency is allowed to continue unchecked for a length of time, damage to the brain and nerves may be permanent. While monitoring patients for appropriate nutrient levels should be a part of routine care by physicians, patient education is imperative in order to prevent an overlooked or misdiagnosed condition. To that end, be sure to ask your doctor about your B12 levels and what you can be doing in terms of diet and lifestyle to ensure robust health as you age.

Sources:
J Geriatric Psychiatry Neirology 2005 Mar. 18 www.ncbi.nlm.nih.gov/m/pubmed/15681626/

Michelle Schwake
Michelle is a married mother of two from the Midwest, with a passion for teaching others how to live a healthier life. She believes everyone should have accurate knowledge about the specific roles that diet and lifestyle play in one's health, and use that knowledge to become their own healthcare advocate.