Why zinc might be very important for preventing Alzheimer's disease
Alzheimer's and Parkinson's disease are both neurological disorders that are linked to the way proteins that clump in the brain. Now researchers at University of Wisconsin-Madison understand more about why zinc may be so important for preventing the diseases.
One of the hallmarks of Alzheimer's and Parkinson's disease is that proteins lose their shape, stop working and them form clumps.
Shape is important for proper cellular function. Proteins lose their shape when they're exposed to stress like high temperature and chemicals, the researchers explain.
The researchers for the new study found a shortage of zinc is another type of cellular stress that causes proteins to become defective.
For their study, published online in the Journal of Biological Chemistry, Colin MacDiarmid and David Eide looked at what happens to yeast that is a fungus when there is an excess or deficiency of zinc. Yeast cells and human cells share many similarities.
They discovered the gene Tsa1 creates "protein chaperones" that stop protein clumping when zinc is in short supply, which in turn prevents cell death. Tsa1 was already known to reduce levels of oxidants when zinc levels are low.
MacDiarmid says, " Tas1 is really a two-part protein. It can get rid of dangerous reactive oxygen species that damage proteins, but it also has this totally distinct chaperone function that protects proteins from aggregating. We found that the chaperone function was the more important of the two."
He goes on to explain we need zinc and Tas1 in the cells or they will die.
"If you don't have zinc, and you don't have Tsa1, the proteins will glom together into big aggregations that are either toxic by themselves, or toxic because the proteins are not doing what they are supposed to do"
There is still more research to be done to understand the role of zinc in preventing Alzheimer's disease and other brain disorders. MacDiarmid warns eating a diet that is high in whole grains and low in meat could lead to zinc deficiency.
Foods that are high in zinc include oysters, calf's liver, crimini and shitake mushrooms and spinach. Zinc is also essential for keeping our immune system intact, balancing blood sugar and maintaining metabolism.
The medical implications of the study aren't entirely clear, but the researchers plan to continue their studies to find out how zinc deficiency might contribute to Alzheimer's and Parkinson's disease.
Journal of Biological Chemistry
"Peroxiredoxin chaperone activity is critical for protein homeostasis in zinc-deficient yeast"
Colin W. MacDiarmid, et al.
September 10, 2013