Diet Minerals May Affect Alzheimers Risk

2013-08-21 09:59
Alzheimer's disease, cell damage, beta-amyloid, iron, copper

Recently, the Physicians Committee for Responsible Medicine developed a set of dietary guidelines aimed to reducing the risk of Alzheimer’s Disease. Two specific minerals in the diet have been linked to cognitive problems, and current studies seem to further confirm this link.

Researchers with UCLA, led by Dr. George Bartzokis, a professor of psychiatry at the Semel Institute for Neuroscience and Human Behavior, studied two areas of the brain known to be damaged by Alzheimer’s disease. The hippocampus, which plays a role in long-term memory and spatial navigation, is typically affected during the early states of the disease, and the thalamus, an area that regulates consciousness and alertness, which is usually not affected until the late stages of Alzheimer’s.

Using brain-imaging techniques, Dr. Bartzokis’ team found that the hippocampus of patients with Alzheimer’s disease has iron accumulation which causes tissue damage. Increased iron was not found in the thalamus.

Myelin, the fatty tissue that coats nerve fibers in the brain, is damaged during the disease process leading to disruption of communication between neurons and cell death. Myelin is produced by cells called oligodendrocytes, which have the highest levels of iron of any other cells in the brain. Although iron is essential for cell function, too much can promote oxidative damage.

Thankfully, we may be able to control this through a preventative diet. "The accumulation of iron in the brain may be influenced by modifying environmental factors, such as how much red meat and iron dietary supplements we consume and, in women, having hysterectomies before menopause," said Dr. Bartzokis.

A separate study, conducted by researchers at the University of Rochester Medical Center, focused on another mineral – copper. Found in red meat, vegetables, dairy products, and pipes that carry drinking water, it has been thought to cause a breakdown in the blood-brain barrier, leading to a buildup of the protein amyloid beta within the brain.

Lead author Rashid Deane studied mice who consumed an equivalent amount of copper that would be in the normal human diet. The mineral caused oxidation which interfered with another protein called lipoprotein receptor-related protein 1 (LRP1) that would normally clear amyloid beta from the brain. Copper also appeared to stimulate neurons to produce more amyloid beta and seemed to encourage it to “clump” together.

"Copper is an essential metal (it helps to make red blood cells and is important to the immune system) and it is clear that these effects are due to exposure over a long period of time," said Deane in a statement. "The key will be striking the right balance between too little and too much copper consumption. Right now we cannot say what the right level will be, but diet may ultimately play an important role in regulating this process."

Neither researcher is suggesting that people take steps to completely eliminate either mineral from their normal diet. Both are essential to life in the proper amounts. However, it should re-emphasize the often-repeated recommendation to avoid over-supplementation with vitamins and minerals and instead focus on an overall healthful diet with plenty of whole, non-processed foods.

Journal References:
Erika P. Raven, Po H. Lu, Todd A. Tishler, Panthea Heydari, George Bartzokis. Increased Iron Levels and Decreased Tissue Integrity in Hippocampus of Alzheimer’s Disease Detected in vivo with Magnetic Resonance Imaging.Journal of Alzheimer's Disease, 2013

Itender Singh, Abhay P. Sagare, Mireia Coma, David Perlmutter, Robert Gelein, Robert D. Bell, Richard J. Deane, Elaine Zhong, Margaret Parisi, Joseph Ciszewski, R. Tristan Kasper, and Rashid Deane. Low levels of copper disrupt brain amyloid-β homeostasis by altering its production and clearance. PNAS, August 19, 2013 DOI:10.1073/pnas.1302212110