A new study suggests a common baking spice may hold promise for delaying or mitigating the effects of Alzheimer’s disease.
Despite years of research and investigation, no cure has been found for Alzheimer’s disease, the most common form of progressive dementia.
However, two compounds found in cinnamon — cinnamaldehyde and epicatechin — may be effective in fighting the disease.
Graduate student Roshni George and Donald Graves, Ph.D., scientists at University of California – Santa Barbara, have published the results of their study in the online edition of the Journal of Alzheimer’s Disease.
George and Graves believe they have proof that the compounds can prevent the development of the filamentous “tangles” found in the brain cells that characterize Alzheimer’s.
Another factor to be considered is a protein called tau which is responsible for the assembly of microtubules in a cell influencing the structure of the neurons, as well as their function.
“The problem with tau in Alzheimer’s is that it starts aggregating,” said George. When the protein does not bind properly to the microtubules that form the cell’s structure, it has a tendency to clump together, she explained, forming insoluble fibers in the neuron.
“The older we get the more susceptible we are to these twists and tangles, and Alzheimer’s patients develop them more often and in larger amounts.
Researchers say the use of cinnamaldehyde, the compound responsible for the bright, sweet smell of cinnamon, has proven effective in preventing the tau knots.
By protecting tau from oxidative stress, the compound, an oil, could inhibit the protein’s aggregation.
To do this, cinnamaldehyde binds to two residues of an amino acid called cysteine on the tau protein. The cysteine residues are vulnerable to modifications, a factor that contributes to the development of Alzheimer’s.
Graves gives the example of sunburn as a form of oxidative damage. “If you wore a hat, you could protect your face and head from the oxidation. In a sense this cinnamaldehyde is like a cap.”
While it can protect the tau protein by binding to its vulnerable cysteine residues, it can also come off, Graves added, which can ensure the proper functioning of the protein.
Experts have known that oxidative stress is a major factor to consider in the health of cells in general.
Through normal cellular processes, free radical-generating substances like peroxides are formed, but antioxidants in the cell work to neutralize them and prevent oxidation. Under some conditions, however, the scales are tipped, with increased production of peroxides and free radicals, and decreased amounts of antioxidants, leading to oxidative stress.
Epicatechin, which is also present in other foods, such as blueberries, chocolate, and red wine, has proven to be a powerful antioxidant.
Not only does it quench the burn of oxidation, it is actually activated by oxidation so the compound can interact with the cysteines on the tau protein in a way similar to the protective action of cinnamaldehyde.
“Cell membranes that are oxidized also produce reactive derivatives, such as [the organic compound] acrolein, that can damage the cysteines,” said George. “Epicatechin also sequesters those byproducts.”
Oxidative damage is known to influence several disease states.
Studies indicate that there is a high correlation between Type 2 diabetes and the incidence of Alzheimer’s disease. The elevated glucose levels typical of diabetes lead to the overproduction of reactive oxygen species, resulting in oxidative stress, which is a common factor in both diabetes and Alzheimer’s disease.
Other research has shown cinnamon’s beneficial effects in managing blood glucose and other problems associated with diabetes.
“Since tau is vulnerable to oxidative stress, this study then asks whether Alzheimer’s disease could benefit from cinnamon, especially looking at the potential of small compounds,” said George.
Although this research shows promise, Graves said, they are “still a long way from knowing whether this will work in human beings.” The researchers caution against ingesting more than the typical amounts of cinnamon already used in cooking.
Nevertheless, the potential for cinnamon and its compounds to impede Alzheimer’s would be a significant step forward in an effort to control the disease.
As a major risk factor for the disease is age, the population shift of aging baby boomers threatens to overwhelm the U.S. health care system. According to the Alzheimer’s Association, in 2013, Alzheimer’s disease will cost the nation $203 billion.
“Wouldn’t it be interesting if a small molecule from a spice could help?” Graves said.