Curcumin and Neurocognitive Health: Another Reason to Eat Turmeric?
- Madison Morris, MS, RDN
- Feb 5
- 13 min read
Below is a scientific exploration of turmeric (curcumin) and some of its potential health benefits. Many years ago, I recall our neighbor (a doctor) sharing at length about the power and potential of turmeric as a therapeutic and preventative agent against dementia and Alzheimer's. When an opportunity arose to select a topic of my choosing while completing my Master's in Nutrition, I jumped at the opportunity to learn more about this incredible spice. While a staple ingredient in many dishes and cultures around the world, turmeric is less commonly used in the States. By reading or skimming this, I hope you might feel inspired to incorporate and/or sneak more turmeric (curcumin) into your diet and dishes. It can easily be added to dressings, dips, smoothies and beverages, hummus, soups, stews, curries, roasted veggies, eggs, rice, quinoa, couscous (honorable mention: Mendocino Farm's Curried Couscous), and even snacks like popcorn and roasted nuts/seeds. Perhaps, you may even find yourself reaching for some golden milk (a.k.a. a turmeric latte) or a turmeric tea. If you do, enjoy!
TIP: For optimal absorption and benefits, consume turmeric/curcumin with black pepper and foods rich in fats.
Curcumin and Alzheimer’s Disease:
An Exploration of Curcumin’s Impacts on Neurocognitive Health
A Literature Review by Madison Morris, MS, RDN
As people are living longer, society is experiencing an increase in diseases of old age such as Alzheimer’s and dementia. These diseases impact neurocognitive health and are most notably marked by memory loss and decreased cognitive function. With this comes a deep desire to find solutions and therapies. Regarding nutritional strategies, the Mediterranean diet and certain flavonoids have been highlighted and explored as potentially supportive. Turmeric (curcumin) is one such spice, flavonoid, and phytoceutical thought to be supportive to neurocognitive functioning. It boasts anti-inflammatory, antioxidant, antibacterial, anti-amyloid, and even anti-cancer properties. It is also lipophilic and capable of crossing the blood-brain barrier (Kushwah, 2023). In this literature review, we will explore findings related to curcumin’s physical health benefits, potential as a preventative/therapeutic agent in neurocognitive health, and explore potential mechanisms. We will also consider some strengths and weaknesses of these studies and highlight some gaps which could inform or guide future explorations.
Curcumin has long been believed and understood to have health benefits. Many countries and cultures regularly incorporate curcumin in their diet and credit it with numerous health promoting and disease preventing effects. Among the claims are decreased oxidative stress and inflammation, decreased arthritis, improved blood flow, improved cardiovascular function, and positive changes to gut microbiome. Chronic inflammation is known to wreak havoc on the body. It can overload and compromise various body systems leading to a wide range of diseases and infirmities. In fact, it could be argued that most of curcumin’s health benefits may be attributed to its uniquely potent and powerful anti-inflammatory properties. Inflammation can negatively impact many areas; therefore, curcumin (via its action on inflammation) can positively impact many areas. Arthritis is a specific condition observed to be impacted by curcumin. While the root cause of arthritis is often inflammation, it is interesting to consider that curcumin has significant impacts on this specific expression of inflammation. In Zeng et. al (2022), efficacy and safety of curcumin treatments for arthritis were thoroughly explored. While more studies are needed, this study demonstrated curcumin may prove a safe and powerful agent capable of reducing inflammation, pain, and symptoms of arthritis (Zeng, 2022). Curcumin has also been seen to improve the cardiovascular system and blood flow. Interestingly, this may also have trickle down effects on the kidneys. Recently, curcumin has been observed to impact chronic kidney disease (CKD) and even the gut microbiome. According to Pivari et. al (2022), curcumin demonstrated significant, desirable effects on various CKD factors including reducing plasma proinflammatory mediators and lipid peroxidation. In the last three months of curcumin supplementation (from months 3-6), the Lactobacillaceae family levels in the gut microbiome significantly increased (see Figure 1 for an interesting visual depiction of baseline differences in gut microbiomes of CKD patients compared to the control group). Additionally, specific microbe shifts were observed: Escherichia shigella and Lachnoclostridium saw significant, desirable shifts after 6 months of curcumin supplementation.
“Globally, mental disorders are one of the main reasons for disability and pointing concerns for public health issues,” (Shabbir, 2020). In recent years, another area of interest remains curcumin’s therapeutic potential towards Alzheimer’s disease, dementia, and other neurocognitive conditions. This leads us to our second key insight and finding: Curcumin has proved promising in the neurocognitive health space. To start, it is interesting to consider that curcumin may have positive impacts on neurocognitive performance and health promotion (not just combative or countering effects on disease). A double-blind, placebo-controlled, 18-month trial of curcumin in “non-demented” adults demonstrated significant memory and attention benefits. Based on pre and post treatment scans from Small et. al (2018), it is thought these benefits may be due in part to preservation of mood and memory modulating regions of the brain which experienced decreased plaque and tangle accumulation (Small, 2018). Curcumin has been shown to counter and improve memory impairment (MI) in numerous animal studies. For instance, two studies out of China, Liu et. al (2018) and Lu et. al (2019), saw significant improvements in memory deficits and improved learning abilities in mouse models of Alzheimer’s disease as evidenced by the curcumin test group performing better on the Morris Water Maze test. Another study in rat models of Alzheimer’s disease which rendered improved cognitive abilities examined the brain tissue of these rats. Histological alterations/reversal, decreased hippocampus inflammation markers, and neuroprotective results were observed in the curcumin test group (Sharma, 2024). Furthermore, according to Sanei et. al (2019), “Curcumin moderates short-term and long-term MI in various laboratory models such as aging, acute and chronic stress, anxiety, smoking, benzodiazepine and anticonvulsant consumption, and other conditions associated with increased oxidative stress.” This study demonstrated outcomes were more than a placebo effect and that curcumin regulated or reversed MI in rodents and may play a preventive and therapeutic role. A study conducted by Cox et al (2020) rendered some fascinating observations surrounding curcumin’s potential for decreasing fatigue and improving working memory. This study involved daily administration of lipidated curcumin (Longvida) to ~80 healthy older adults (ages 50-85) and was a 12-week, double-blind, placebo-controlled RCT. It was also a replication of a previously conducted 4-week study and sought to confirm and replicate findings as well as extend the trial timeframe to expand the study and further observations. The test group received a 400mg oral dose of Longvida (in solid-lipid curcumin preparation form) which renders ~80mg of curcumin while the control group received a daily oral dose of a yellow dextrin counterfeit. Assessments were performed at the baseline, 4-weeks, and 12-week points. The hypothesis: “Curcumin treatment would lead to reduced fatigue, improved working memory and attenuated stress reactivity” compared to placebo, (Cox, 2020). Findings largely supported the researchers’ hypothesis as well as replicated and confirmed prior findings. Reduction of fatigue was experienced and observed at both the 4-week and 12-week marks. Improved mood and cognition were also observed. Interestingly, participants in the curcumin group displayed slightly elevated glucose levels at the 12-week mark. It is important to note that elevated glucose levels did not approach diabetes risk levels, and that these levels may have been supportive and might offer a possible mechanism for the observed cognitive enhancement in the curcumin group.
This brings us to our third key insight: Potential mechanisms. While exact mechanisms are unknown, many are being explored. These include curcumin’s prospective action surrounding glucose, lactate, inflammation, and neural stem cells. While the exact etiologies of Alzheimer’s disease are unknown, it is important to consider possible etiologies as they might shed light on possible mechanisms and therapies. There is clearly a relationship between curcumin and glucose as well as between glucose and the brain (and Alzheimer’s disease). As discussed above, regular administration of curcumin led to increased glucose levels (Cox, 2020). This is noteworthy as a possible contributing factor or mechanism, because glucose is the brain’s preferred fuel source and elevated glucose levels are known to be supportive to cognitive functioning (i.e. improved working memory and Serial Sevens performance were observed in Cox, 2020). Additionally, Alzheimer’s has been nicknamed “Type 3 Diabetes” and is sometimes referred to as “diabetes of the brain.” It is interesting to consider diabetes and/or insulin resistance may be etiologies of Alzheimer’s disease. As Thota et. al (2020) explored, curcumin supplementation can decrease insulin resistance (thereby increasing insulin sensitivity and allowing glucose to more readily enter cells). This suggests curcumin may reduce risk of type 2 diabetes and Alzheimer’s disease via acting on and alleviating insulin resistance. Another potential mechanism which also relates to metabolic health involves lactate. Like glucose, lactate is also a precursor for metabolic energy pathways. While glucose is more readily utilized for energy, lactate is a precursor for gluconeogenesis. It has been observed that curcumin increases lactate content in brains of mice (Lu, 2019). While the brain’s preferred fuel source is glucose (a quick, easy, efficient, cost-effective energy source), some neurons are also capable of utilizing lactate. It is possible this could explain how the increase in lactate led to improved memory in mice. Another potential mechanism is arguably the most obvious: Curcumin’s effects on inflammation. Kushwah et. al (2022) notes one of curcumin’s pleiotropic effects includes anti-inflammatory response (see Figure 2). There are at least two aspects to curcumin’s anti-inflammatory response which have been observed and confirmed: 1) reduction of inflammatory markers and 2) increase in antioxidant activity (Dehzad, 2023). In other words, the pleiotropic cascade continues.
Finally, while there are proposed mechanisms related to cellular energy sources (i.e. glucose and lactate) and inflammation, a final mechanism merits exploration: Neural stem cells. Curcumin is associated with increased hippocampal neurogenesis. In an animal study in Alzheimer’s disease mice models, this presented as both fewer apoptotic neurons and an increase in new neural stem cells. These results suggested that curcumin activated endogenous neural stem cell proliferation and improved cognitive impairment (Li, 2019).
It is important to consider the methodologies, strengths, and weaknesses of the studies mentioned throughout this literature review. Strengths include selection criteria, study types, and measurements. Strict criteria were utilized in selecting articles. For instance, this literature review is heavily weighted towards a specific type of article (empirical articles) and within a certain time frame (published since 2018). This allowed for a thorough exploration within a precise and narrow scope. Relevant study types were incorporated ranging from clinical trials involving human and animal Alzheimer’s models to healthy control groups. Measurements and assessments were appropriate to the topic of interest. These included cognitive, spatial, and memory performance measures (i.e. Serial Sevens in humans and Morris Water Maze in mice), brain scans, histology reports, and biochemical measures (i.e. relevant bloodwork to observe inflammation markers, glucose levels, etc). While the findings and observations of this literature review may be fascinating, it is also important to consider limitations including selection criteria, study types, number of variables, and sample size. Interestingly, while the selection criteria utilized was a strength, it could also be considered a weakness. This literature review is by no means conclusive or comprehensive. For instance, selection criteria could also be considered restrictive, because it limited the researcher and reader’s exploration to a very narrow time frame (considering only articles since 2018) and article type (a strong emphasis on inclusion of empirical articles). While there are reasons for these restrictions and it is important to designate and determine scope and selection criteria, it is also important to acknowledge the associated limitations and gaps which result in a more limited product and discussion. Further study and expansion of selection criteria could prove insightful and supportive and render a more comprehensive exploration of this topic. Secondly, a number of animal studies were incorporated in this literature review. While results of these studies might provide tremendous insight, allow for a controlled environment, and seem promising, it is important to consider these results may not directly translate to humans. Third, isolation of variables was not always possible or practiced. For instance, in Maugeri a turmeric and cinnamon mixture was used introducing compounding variables. In Sharma, a mixture of turmeric and coconut shreds were utilized. Finally, in these studies sample sizes varied vastly, and some of the sample sizes were rather small. While there are numerous strengths and weaknesses to consider, overall, I believe the insights described above to be reasonably strong based on the quality of the samples, collection methods, measurements and how results and considerations align with physiology and physiological processes.
Given the nature of research and scientific processes which involve defining specific scope, variables, and methodologies, it is important to consider the targeted nature of scientific study is also bound to render gaps. With this said, acknowledging and identifying these gaps can help guide and inform further studies. Certain gaps identified in this case include gender, mechanisms, time frame, and the pleiotropic angle. It may be interesting to consider gender differences: Both gender differences in Alzheimer’s disease and in curcumin efficacy. As discussed, mechanisms for curcumin’s impact on neurocognitive health are still unknown. While theories exist, this area certainly merits further study and exploration. Another gap involves the selection processes and time frame explored. It appears there is more literature on this issue predating 2018. It may be worth expanding the time frame criteria to gain a more comprehensive perspective. As mentioned earlier, curcumin has pleiotropic effects meaning there are multiple pathways and modes of action. Scientific processes are not well equipped to tackle pleiotropic action and concepts (given the nature of needing to isolate variables); however, it ought to be considered that curcumin’s efficacy may come from having multiple modes of action (attacking multiple angles) rather than one “magic bullet” mode of action.
In conclusion, curcumin continues to make a name for itself and proves to have a wide range of promising clinical applications. From its established impacts on inflammation, arthritis, cardiovascular health, and the gut microbiome to its prospective neurocognitive applications, it is clearly a force to be reckoned with. While further studies are needed to prudently and comprehensively consider neurocognitive applications and to explore precise mechanisms and modes of action, it is thrilling to consider the possible neurocognitive health implications of curcumin. In 2022, the World Journal of Biological Psychiatry published “Clinician guidelines for the treatment of psychiatric disorders with nutraceuticals and phytoceuticals: The World Federation of Societies of Biological Psychiatry (WFSBP) and Canadian Network for Mood and Anxiety Treatment (CANMAT) Taskforce” (Sarris, 2022). In this, curcumin was rated as a Grade A, evidence-backed phytoceutical and some therapeutic dosage recommendations were outlined (i.e. 500-1000mg was deemed supportive in cases of mild to moderate depression). Clearly, there is still a great deal of research to be done to determine precise applications and therapeutic dosages of curcumin as it relates to various conditions; however, it is clear curcumin continues to demonstrate promising effects on overall health and may soon be an approved therapeutic component in targeted treatment or prevention of Alzheimer’s disease and other neurocognitive related impairments.
References:
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