With an aging population, one of the most intractable problems facing the biomedical research community today is the challenge of developing effective treatment and prevention strategies for neurodegenerative diseases. As researchers have explored various pharmacological, behavioral, and nutritional intervention options, curcumin has emerged as a potential therapeutic for patients with these conditions. Long recognized for its anti-inflammatory properties and antioxidant activities, scientists have hypothesized that curcumin might be able to combat the inflammation and free radical damage that are associated with a number of neurodegenerative diseases. There was also evidence that curcumin could modulate multiple target proteins in pathways that had been associated with the pathogenesis of conditions such as dementia.
However, until recently, the most promising studies suggesting the potential benefits of curcumin were conducted in vitro and in animal models, while the results of clinical trials were mixed at best. Indeed, in a 2017 review paper published in the Journal of Medicinal Chemistry, researchers concluded that, based on over 120 clinical trials on the potential role of curcumin in several different diseases, there was no clear medicinal benefit to supplementation with the compound. However, the publication of a new double-blind, placebo-controlled trial on the potential benefits of curcumin for patients with neurodegenerative disorders is forcing the research community to take a second look—not only due to the strength of the results but also because of its focus on the bioavailability of curcumin supplementation.
The Potential Role of Curcumin in Protecting Against Neurodegenerative Disease
In March 2018, The American Journal of Geriatric Psychiatry published the groundbreaking study, which was conducted by a group of researchers at the University of California, Los Angeles. The study stood out from previous neurodegenerative disease research on curcumin for three reasons: it was a long-term clinical trial (lasting a total of 18 months), it was both double-blinded and placebo-controlled, and it involved a bioavailable form of curcumin. The researchers’ setup directly sidestepped some of the criticisms of previous clinical trials, such as non-randomization, lack of a control group, and short-term time frames, which lends credence to this study over some of the previous research in the field.
To test the potential benefits of using curcumin for the prevention of neurodegenerative disease, specifically dementia, the researchers recruited forty subjects between the ages of 51 and 84 who did not show significant signs of dementia. They were randomized into two groups: the treatment group (21 patients) received 90 mg of a bioavailable form of curcumin, twice-daily for 18 months, while the control group (19 patients) took no supplement. After the 18-month study period, the researchers examined the effects based on three tests for symptoms of dementia (a verbal memory test, a visual memory test, and an attention test), alongside PET scans of various regions of the patients’ brains, which measured the amount of tau and amyloid plaque buildup—both known contributors to neurodegenerative disease.
The UCLA researchers reported that the patients in the treatment group demonstrated statistically significant improvements on each one of the three tests for symptoms of dementia, while those in the control group showed no clear change over the course of the 18-month study. These changes were directly associated with statistically significant changes in tau and amyloid plaque buildup in the patients who took the bioavailable curcumin supplement. Before the trial, there was no statistically measurable difference between the two groups in terms of tau and amyloid plaque buildup in any region of the brain, but after the 18-month trial, the measured amount of tau and amyloid plaque buildup in the amygdala in patients in the treatment group had decreased. Also, while the amount of tau and amyloid plaque buildup increased in the hypothalamus in patients in the control group, it remained the same in patients in the treatment group. Notably, both the amygdala and the hypothalamus are regions of the brain that are associated with the modulation of mood and memory, both of which are affected by neurodegenerative disease.
The Implications of the Results for Neurodegenerative Disease Research
The results of this study have significant implications for the future of neurodegenerative disease research. Not only do they suggest that curcumin supplementation may be able to protect against plaque buildup, but they also indicate that curcumin may contribute to the reduction of existing plaque buildup. Even more remarkably, the study shows that brain changes were directly associated with measurable symptom changes in patients. Within the neurodegenerative disease research literature, there are relatively few studies that rigorously support such a direct connection between changes in the brain and improvements in scores on tests for dementia, so these findings truly stand out. Given that dementia is a complication associated with multiple neurodegenerative diseases, including both Alzheimer’s disease and Parkinson’s disease, these findings on the buildup of tau and amyloid plaques present intriguing opportunities for future research.
One potential reason this clinical trial succeed in demonstrating significant benefits of curcumin supplementation, despite the inconclusiveness of so much of the previous work in the field, is that the researchers used a highly bioavailable form of curcumin. Prior to the study, many researchers blamed the failure of previous clinical trials on the low bioavailability of curcumin, which results from the fact that the natural form of the compound is poorly absorbed, rapidly metabolized, and quickly eliminated. However, the researchers used a form of curcumin that is absorbed more quickly in the GI tract than traditionally formulated curcumin supplements, as demonstrated by blood samples taken at intervals after supplement intake, which meant that the curcumin could actually have an effect on patients’ bodies.
In recent years, researchers have been exploring a variety of possible delivery methods to improve the bioavailability of curcumin supplements. The meaningful results of this study indicate that embracing such supplements can mean the difference between inconclusive results and groundbreaking findings with significant implications for the future of neurodegenerative disease research—not to mention research on other diseases where curcumin may offer protective benefits and/or effectively treat symptoms. As more researchers conduct studies using cutting-edge delivery methods, it will be exciting to see how the field progresses. In the meantime, some cutting-edge nutraceutical manufacturers are already offering state-of-the-art ingredients and delivery systems designed to optimize bioavailability, offering clinicians and patients the ability to take advantage of curcumin’s possible therapeutic benefits today.
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