Is it possible to ward off Alzheimer’s disease, Parkinson’s disease, and other forms of cognitive decline? According to a growing body of research on the effects of curcumin, the answer may be “yes.” This remarkable compound is a natural anti-inflammatory which has been used in medicine going back thousands of years. More recently, biologists have investigated curcumin for its numerous bioactive effects, ranging from controlling inflammation to reducing cell death. Because of the range of different physiological targets, curcumin is promising for an array of different diseases. What’s more, curcumin offers the prospect of treating these diseases in a natural way that carries few side effects. Thanks to curcumin’s impact on inflammation, immune cells, and the body’s response to stress, patients today have the chance to get ahead of their illnesses.
Controlling Inflammation to Prevent Neurodegeneration
Neurodegeneration has many causes, but over the long term, oxidative stress is one of the most significant which curcumin can address. Oxidative stress is a kind of chronic cellular damage which occurs when highly reactive byproducts of normal metabolic processes—or environmental effects which are damaging to cells—are let loose inside of cells. These byproducts, called reactive oxygen species (ROS), cause damage to cellular machinery and DNA by blocking the action of other biological molecules necessary to sustain cellular life.
Oxidative stress has been implicated in Parkinson’s disease, Alzheimer’s disease, and other types of cognitive impairment via its relationship with inflammation. Because it damages the cell, oxidative stress causes inflammation, which is linked to neuronal damage and cognitive impairment. Thus, reducing the quantity of ROS is a reliable way of reducing inflammation and potentially reducing cognitive symptoms. Curcumin is especially effective at “scavenging” these reactive oxygen species, which prevents them from causing damage to cells. Informally, molecules like curcumin which are effective at removing ROS from circulation are called anti-oxidants.
In a review conducted by Dr. Ramassamy at the University of Laval in Quebec, curcumin was identified as a particularly effective anti-oxidant capable of staving off neuronal death compared to other organic molecules of its type. Furthermore, the review states that curcumin’s ability to modulate the gene expression of immune cells—thereby altering their ability to generate inflammation—leads them to be a deeply worthwhile area for future research into alternative Parkinson’s disease and Alzheimer’s disease treatments. The researchers emphasized the potential of curcumin to reduce inflammation in Parkinson’s disease in particular. If curcumin can reduce the level of oxidative stress in the areas of the brain associated with motor control, patients might retain more functionality even as the disease progresses. The rationale for curcumin’s usage in Parkinson’s disease could also apply to general brain health, however; inflammation in the brain is disadvantageous for patients, meaning that even if patients don’t have Parkinson’s they can potentially benefit from supplements that reduce the passive level of inflammation.
However, there is a catch when it comes to reducing inflammation in the brain via curcumin’s immune regulatory actions. If curcumin acts on the genes of immune cells, it means that the changes which curcumin induces will be delayed; the immune cells will need time to adjust their cellular machinery to reflect the changes which the chemical caused to their genes. In other words, patients won’t get instant relief. This also means that patients who are currently suffering from memory deficits or cognitive issues may have to take curcumin for a sustained period of time before they realize any benefits. But, this delayed and indirect mechanism to reduce inflammation is only one of curcumin’s anti-inflammatory effects on cells.
Controlling inflammation directly at the source is another beneficial effect of curcumin. One study found that a single injection of curcumin into rat brains heavily inhibited tumor necrosis factor alpha (TNFa) secretion from neurons. TNFa is a chemical message secreted by dead or dying cells that prompts inflammation upon its reception by other cells. Inhibiting TNFa is important because the inflammation it causes in the brain is linked to neurological deficits. In the rats, curcuminoid administration mitigates the neurological deficits induced by the researchers, even when those deficits were induced by brain damage intended to mimic a traumatic brain injury. As a result of their investigation, the researchers hypothesized that curcumin is capable of slowing the onset of Parkinson’s disease via its inhibition of TNFa in the regions of the brain associated with voluntary motor control. If the same inhibition of TNFa could be applied to the regions of the brain associated with memory recall, it might also be an effective therapy for Alzheimer’s disease. Aside from Alzheimer’s disease and Parkinson’s disease, the relationship between mild cognitive impairment and TNFa is still unclear, but it’s highly likely that increased TNFa activity exacerbates cognitive impairment.
Curcumin May Slow Alzheimer’s Disease
While the anti-inflammatory benefits of curcumin are promising for patients experiencing neurological conditions and cognitive decline, a study conducted in 2007 on mouse models of Alzheimer’s disease suggests that curcumin’s benefits go beyond merely reducing inflammation. Led by Dr. Garcia-Alloza at the Massachusetts General Hospital’s Department of Neurology, the study aimed to examine whether there was any interaction between intravenously administered curcumin and beta-amyloid plaques. In Alzheimer’s disease, these beta-amyloid plaques are thought to be responsible for the cognitive impairment and neuronal malfunctions which result in inflammation.
At the start of their experiment, the researchers examined the brains of all of the mice, counting the number of beta-amyloid plaques in each cubic millimeter of each mouse’s brain tissue and estimating the size of the plaques. Next, the researchers injected the treatment mice with curcumin dissolved in saline and injected the control mice with saline alone. Both groups of mice were engineered to develop Alzheimer’s such that they could be used to study the disease.
Over the course of seven days, the injected curcumin slowly became visible on the researchers’ detection apparatus, which gathered fluorescent light emitted from the molecules. They theorize that the trafficking of curcumin from the injection site and into the brain tissue of the mice was extremely slow, which would explain the lag between injection and detection. Upon examination of the mice brains, the researchers found that curcuminoid had bound itself to nearly all of the beta-amyloid plaques, and, more importantly, that those plaques were 30% smaller than in the control mice. Additionally, the control mice developed an average of 6 new identifiable plaques per cubic millimeter of brain tissue over the course of the experiment. In contrast, the mice treated with curcumin developed 4 new plaques per cubic millimeter of tissue, and researchers identified an average of 21 fewer plaques per cubic millimeter of tissue than they had at the start of the experiment. In other words, the curcumin had shrunk existing plaques, prevented new plaques from forming, and even caused existing plaques to be dissolved.
Whether these impressive effects could extend to humans with Alzheimer’s disease remains to be seen. Nonetheless, the researchers present a compelling account of curcumin’s benefits for brain health. While it isn’t reasonable for patients to expect the exact results experienced by the mice, patients who supplement their diet with curcumin may have a meaningful edge when it comes to defending against Alzheimer’s disease and cognitive decline.
Stay The Course with Curcumin to Derive Benefits
Based on the strength of animal studies, researchers are now recommending further investigations into curcumin to support brain health in those who are aging. In a recently published editorial, a multi-national group of researchers has lauded curcumin as one of the most promising brain health supplements to protect against inflammation and cognitive impairment. Likewise, the authors are optimistic about curcumin’s potential in the treatment of Parkinson’s disease and other inflammation-related disorders. The authors cautioned, however, that in the context of Alzheimer’s disease, curcumin treatments “appear more effective when initiated early in the disease [but] careful prospective studies are needed with these molecules in patients with mild cognitive impairment or in early stages of Alzheimer’s disease.” Importantly, identifying the onset of mild Alzheimer’s disease is extremely difficult, meaning that by the time patients receive a diagnosis, it may be too late for curcumin to help them. This underlines the idea that only fastidious supplementation over the long term can reliably reduce the risk of Alzheimer’s disease and other types of cognitive impairment.
Duration of supplementation is not the only concern for patients considering curcumin supplementation, however. Because of curcumin’s chemical properties, it can be difficult for the body to absorb. When the chemical isn’t absorbed, the body can’t use it to reduce inflammation. This means that patients can’t take just any curcumin supplement and expect to derive protective benefits. Instead, patients will need to find a curcumin supplement designed for high bioavailability, allowing the body to absorb the chemical where and when it can derive the greatest benefit. These supplements may also contain variations of the curcumin molecule which are known to be more bioavailable, such as tetrahydrocurcumin. Should patients find the right supplement and use it consistently, they may be able to protect themselves from the onset of aging-related cognitive dysfunction, Alzheimer’s disease, or Parkinson’s disease.
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