Helicobacter Pylori and Alzheimer's
The common bacteria, Helicobacter pylori (H. pylori), has recently come into focus as a contributing factor in a variety of human health problems. For example, the physician and scientist Dr. Barry Marshall shared the Nobel Prize for medicine with his colleague Dr. Robin Warren in 2005 for establishing the fact that most cases of stomach ulcers were not caused by stress and worry, as had long been supposed, but rather were due to infection of the stomach lining by H. pylori. In the initial stages of his research, the intrepid Dr. Marshall had actually proved his theory by drinking a flask of the bacteria and later developing ulcers, as he had predicted.
Over the last few years, research has suggested H. pylori infection might also be a risk factor in the development of Alzheimer's Dementia. There are at least two studies showing patients diagnosed with Alzheimer's dementia were more likely to be positive for signs of H pylori infection than people their age without dementia. One study published in the well-regarded Journal of Neurology in 2009 even suggested that in patients diagnosed with Alzheimer's Dementia, eradication of H. pylori can actually improve cognitive function to a significant degree.
How is that a bacteria commonly known to infect the stomach lining could possibly contribute to the development of Alzheimer's and other dementias? Perhaps the most easily explained connection between H. pylori infection and dementia is the fact that this type of infection of the stomach lining is associated with the development of vitamin B12 deficiency. Deficiency of vitamin B12 is known to be a risk factor for the development of Alzheimer's Dementia. Unlike other vitamins, the absorption of vitamin B12 from food requires the presence of a special chaperone protein called intrinsic factor that is produced by special cells in the lining of the stomach. If these cells are damaged by infection or inflammation, then the vitamin is not properly absorbed and the result is deficiency.
Another likely connection between H. pylori infection and Alzheimer's dementia is that atherosclerosis, or "hardening of the arteries," is a risk factor for developing both Alzheimer's and vascular forms of dementias.
It has been suspected that the inflammatory responses generated by infection with H. pylori can increase the risk of atherosclerosis and other vascular abnormalities.
Yet another possible link between H. pylori infection and Alzheimer's is the relationship between H. pylori infection and the development of Diabetes Type II. It has long been known that the likelihood of immunological signs of H pylori infection are higher in patients with diabetes than in those who are not diabetic.
Reports recently made at the Annual Meeting of the Infectious Diseases Society of America, as described in the most recent edition of Clinical Endocrinology News, have helped to further clarify the relationship between H. pylori infection and diabetes. In a study of Latino men over the age of 60, those with H. pylori infection were more than twice as likely to be diagnosed with diabetes. In yet another study, the presence of H. pylori increased hemoglobin A1c levels, which is a marker of high blood sugar, even in individuals who had not yet been diagnosed with diabetes. Diabetes type II, so-called adult onset diabetes, has long been known to be an important risk factor for the development of Alzheimer's and other forms of dementia. Indeed, some studies suggest that diabetes type II can more than double the risk of developing Alzheimer's Dementia.
Is there anything that can be done to prevent or treat H. pylori infection, and thus to reduce the risk of Alzheimer's Dementia, heart disease and diabetes? Thankfully, it is relatively easy to diagnose and treat H. pylori infections. Standard laboratory tests can be performed to detect H. pylori infection, and standard antibiotic treatments can be used to kill the bacteria. Efforts are also being made to produce a vaccine against H. pylori.
Perhaps most encouraging, particularly to those who blanch at the notion of evermore vaccines and antibiotics, are reports suggesting that pro-biotics and dietary components such as yoghurt, buttermilk and other fermented foods may be used to prevent and/or treat H. pylori infection. This latter approach would certainly be the most natural, parsimonious, and inexpensive approach to controlling H. pylori and all of the health problems it helps create.
The prevalence of H. pylori infection in our country is extremely high. Evidence suggests that the likelihood of infection increases with age, and this approaches 85 percent sero-positivity in our elderly. Thus, there is reason to believe that H. pylori infection represents a significant health risk in our country, particularly to our elderly, and that to reduce our burden of H. pylori infection would almost certainly have a dramatic effect on our nation's health. One of the benefits of preventing and treating H. pylori infections would likely be a reduction in the prevalence of Alzheimer's Dementia in our country.