Dear EarthTalk: Is there a connection between Mad Cow Disease and Alzheimer?s?
-- Jon Luongo, Brooklyn, NY
Despite limited evidence, some researchers fear that just such a connection might exist.

Mad Cow Disease: Long Before 1993
In his 2004 book, Brain Trust, biochemist Colm Kelleher argues that Mad Cow Disease (also known as Bovine Spongiform Encephalopathy, or BSE) has actually been in North American cattle since long before 1993 when the first case was publicly ?discovered? in a beef cow in Canada?s Alberta province.

According to Kelleher?s research, undocumented cases date back at least a quarter century and may have tainted many a steak and hamburger already consumed. Further, Kelleher speculates that the infectious ?prion? proteins that cause Mad Cow Disease and its brain-wasting human variant, Creutzfeldt-Jakob Disease (CJD), could be a factor in the substantial increase in cases of Alzheimer?s disease in recent years.

Common Symptoms Between Mad Cow Disease and Alzheimer?s
Some other research bears out Kelleher?s claims; though blaming all of the increase in Alzheimer?s on rampant prions might be pushing it. Dr. Michael Greger, Director of Public Health and Animal Agriculture at the Humane Society of the United States, cites several studies detailing that as much as 12 percent of all senile dementia or Alzheimer?s cases diagnosed in North America these days may actually be cases of CJD.

?It would seem CJD is seriously underdiagnosed at present,? says Greger. He goes on to describe how the symptoms and pathology of both Alzheimer?s and CJD overlap.

Also, he points to epidemiological evidence suggesting that people eating red meat more than four times a week for prolonged periods have a three times higher chance of suffering dementia than long-time vegetarians.

?We don?t know exactly what?s happening to the rate of CJD in this country, in part because CJD is not an official illness,? says Greger, explaining that the U.S. Centers for Disease Control (CDC) does not actively monitor incidences of the disease. He adds that several clusters of CJD outbreaks have been reported across the continent in recent years and stresses that more studies need to be done to determine just how many of the five million North Americans with Alzheimer?s-like symptoms might actually have CJD.

Negative Health Effects of Red Meat
Regardless, nutritionists hardly need more evidence about the potentially negative health effects of eating red meat. For starters, the saturated animal fat in red meat contributes to heart disease and atherosclerosis. Recent research also shows that frequent red meat eaters face twice the risk of colon cancer as those who indulge less often. Red meat is also thought to increase the risks of rheumatoid arthritis and endometriosis.

Meanwhile, according to the American Dietetic Association, vegetarian diets can significantly reduce the risk of heart disease, colon cancer, osteoporosis, diabetes, kidney disease, hypertension, obesity, and other debilitating medical conditions. While red meat is a key source of protein and vitamin B12 in North American diets, nutritionists explain that properly planned meat-free diets easily provide these important nutrients while keeping you healthier in the long run.