Turmeric is a spice commonly used in Asian foods and is made of three main components: curcumin, demthoxycurcumin, and bisdemethoxycurcumin. As the main component, curcumin makes up about 77% of turmeric and contains the yellow color typically seen in curries [1]. Despite giving turmeric spice its vibrant color, curcumin is a polyphenol compound that has been studied both in vitro and in vivo and has been shown to have antioxidant properties [1]. Curcumin’s unique molecular structure allows it to cross the blood-brain barrier, illustrating that it could potentially bring its healing properties directly to the brain as a neuroprotective agent. Although curcumin has been a staple in cuisine and culture for centuries, studies about its effects on animals and humans are relatively new.
Before scientific studies demonstrated how and why curcumin has anti-inflammatory, anti-oxidative stress, cognition improving and tumor reducing properties, it was improving the lives of many individuals all around the world [1]. There was less dementia and memory loss reported in South Asia, a place where turmeric is used daily in cooking [2]. Singapore citizens who consumed curry very often had better cognitive abilities than those whose diet did not contain ample amounts of turmeric [2]. Most fascinating, the Japanese island of Okinawa is home to hundreds of people who are over the age of 100 who attribute their very long lives (which are some of the longest on the planet) to daily physical activity, strong social connections, and a diet full of healthy nutrients including many dishes and teas with turmeric [3]. Yes, people around the globe could have a healthier brain due to curcumin, but what studies have been done to help us understand how it works?
What studies about curcumin improving memory, stress, and behavior have been done on animals?
Transgenic animals are those that have had their genetic makeup changed to study gene expression and function, and they are popular test subjects for studies on curcumin. In one study, mice were altered to accelerate aging and were observed with and without introducing curcumin into their diet. The researchers treated the senescence-accelerated mice (SAM) with either 20 mg/kg or 50 mg/kg of curcumin for 25 days and found that there was a dose-dependent decrease in oxidative stress which is a hallmark of aging [3].
In another study, mice were genetically altered to have increased tissue degeneration and were studied with curcumin treatment. These mice were either given 160 ppm or 1000 ppm doses of curcumin for six months, and results showed dose-dependent improvements on working and long term memory, as well as fewer markers for tissue and cell degeneration [3].
Besides aging and memory, curcumin has also been researched for benefits to stress and environmental factors. First, mice were injected with 200 mg/kg or 400 mg/kg curcumin for 28 days and introduced to mild environmental stressors between days 20-28. The scientists looked at blood sugar and steroid levels and the results showed that curcumin significantly improved spatial learning and memory, and reduced stress in mice [3].
A fourth study looked at behavioral changes and cell growth in the hippocampus which is the area of the brain responsible for learning and memory. In this research, rats were given curcumin for six or twelve weeks and completed the social recognition test, the water maze test, and immunostaining to identify changes in gene expression over time [1].
The social recognition test on rats can be simplified by an example using neighbors. Say you were living in your house and got a new neighbor. Your neighbor knocks on your door and comes in holding a plate of warm cookies, and you spend some time getting to know each other. After a couple minutes of introductions, the neighbor returns home. 30 minutes later the neighbor comes back over, but this time he brings a new friend. In the actual social recognition test, researchers measured how long the rat sniffed, climbed, groomed, and/or followed the new neighbor rat during the first encounter compared to how long he sniffed, climbed, groomed, and/or followed the new neighbor rat the second time once a new friend was introduced. The rats given six weeks of curcumin treatment had a significantly higher social recognition index (the ratio of time the rat explored the neighbor rat or his friend) than the control group not given curcumin which suggests that curcumin helps with memory. Just six weeks of curcumin treatment led to significantly less sniffing, climbing, and grooming of the neighbor rat once the new friend was introduced since the rat could remember the past encounter. The rats given twelve weeks of curcumin treatment had a significantly higher recognition index than the control as well, seen by the lower exploration of the neighbor rat during the second exposure. These two groups suggest that six and twelve weeks of curcumin supplementation could improve social recognition and memory in rats.
In the water maze test, a circular water tank was divided into four sections with a platform placed in one of these sections. Rats were released into the water and swam around four times per day to try and find the platform. After the fourth time, the platform was removed and the rats were allowed to swim freely while the researchers recorded how long the rats spent in each section. This experiment can be simplified by thinking about swimming in an ocean. If you were swimming every day and realized that there was a rock you could rest on just off the shore, you would probably choose to swim to the rock or close to it as long as you remembered where it was. In the actual experiment, there was no significant difference between how long the control group (with no curcumin) and the six-week curcumin treatment group spent in the target section where the platform was, but the twelve-week curcumin treatment group spent significantly more time in the target section suggesting that long-term curcumin can improve spatial memory in rats. With the twelve weeks of curcumin, rats remembered which area had the platform and spent more time in that section than the three others.
Finally, the last test of this study showed that there were more than 1.5X the number of genes associated with development in the brains of rats given curcumin compared to rats in the control group [1]. Rats given curcumin for twelve weeks had fewer transcription factors that historically led to short and long-term memory loss as well, illustrating that curcumin could play a role in neuron development, brain signaling, and transcription. Overall, this data proposes that curcumin, the major component in turmeric, can be good for brain health by benefiting cognition.
You’re probably getting bored of reading about rodents by now, so I’ll tell you that there has also been research on worms! Transgenic worms were created to express a certain protein in all neurons which made them have uncontrolled movements and resulted in inflammation of their nervous system. When these worms were given 30 µM of curcumin per day, they had a significant decrease in behavioral abnormalities and fewer uncontrolled movements. Although the mechanism of this action isn’t completely known, scientists predicted that the curcumin stabilized certain proteins in the worm and could decrease inflammation [1].
Have human studies shown that turmeric is good for your brain or that turmeric helps to improve memory?
Now you know about how curcumin affects rats, mice, and worms, but what about humans? There have been a handful of studies on turmeric benefits for brain health in humans, but the results aren’t conclusive. One study following 96 healthy older adults for one year looked at their cognitive function when they were given a placebo versus 1500 mg of curcumin per day. There was a significant cognitive decline in the placebo group at the six-month time point, but there were no significant changes in self-reported memory, mood, mental health, or measured cognition at any other time point [2]. So, curcumin could potentially slow cognitive decline after six months of daily use, but this study is too small to generalize. Another study followed 60 people between the ages of 60 and 85 for four weeks and found that the curcumin treatment group had improved working memory and mood, and improved performance on tasks as early as one hour after taking curcumin. This researched working memory only, and there isn’t any data from this study to say whether these benefits could persist past four weeks [2].
Not only have turmeric and curcumin been studied in the United States, but they’ve also been studied in India, Singapore, Japan, and Australia. A two-year study in an Indian village found that the clinical dementia rating of their villagers who consumed turmeric daily was significantly lower than the rating of an age-matched rural US community [3]. Another study done in 2006 found that Singapore adults between the ages of 60 and 93 who consumed curry daily did better on a Mini-Mental State Exam (a test used to measure cognitive impairment) than those who never or rarely consumed curry-containing turmeric [2].
Apart from seemingly healthy patients with no dementia or memory problems, patients with progressive cognitive decline have also been studied. One scientist studied 34 subjects with dementia and found that 0-4g of curcumin daily for six months did not show any improvements in Mini-Mental State Exam scores or other measures of brain function compared to the placebo group [3]. There are also three relevant case studies on elderly people that show the effects of twelve weeks of turmeric treatment. The first person was given 764 mg of turmeric per day (100 mg of curcumin daily) and had less irritation, anxiety, agitation, and apathy after twelve weeks, but they didn’t show any improvements in their cognition. Similarly, a second person was given 100 mg of curcumin daily and had a significant decrease in irritation and anxiety, and their caregiver expressed feeling less overwhelmed and burdened after twelve weeks. Finally, the third person was given 100 mg of curcumin daily and had a similar increase in behavior as the other two case studies, and increased their Mini-Mental State Exam by five points after twelve weeks [3].
Overall, these human studies all reported turmeric and curcumin safe but not significantly efficient at improving cognitive functions. One unforeseen benefit was that daily consumption did reduce total and LDL cholesterol in patients, improved mood, and decreased fatigue [3]! There are flaws due to the limited bioavailability of curcumin, the short duration of these studies, and predetermined cognitive impairments which could have led to a loss of significant results [2].
What are the benefits of turmeric for boosting brain health?
Although it’s been popular for centuries, many studies are still being done on turmeric and its benefits to human brain health. Regardless, this spice’s major component curcumin has shown to be advantageous in helping with memory, improving mood, and decreasing fatigue which are all things that can be very helpful, especially in busy daily life.
Where should you buy brain supplements?
If you’re looking for a safe supplement that could improve your mental clarity, help you focus, and increase your brain performance, look no further! Try Superfood Science’s Vitality Rescue with curcumin, black pepper, and fish oil to help enhance the absorption of curcumin in your body for extra benefits!
Resources
- Dong, Suzhen, et al. “Curcumin Enhances Neurogenesis and Cognition in Aged Rats: Implications for Transcriptional Interactions Related to Growth and Synaptic Plasticity.” PLOS ONE, Public Library of Science, 16 Feb. 2012, https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0031211.
- Rainey-Smith, Stephanie R., et al. “Curcumin and Cognition: a Randomised, Placebo-Controlled, Double-Blind Study of Community-Dwelling Older Adults: British Journal of Nutrition.” Cambridge Core, Cambridge University Press, 22 Apr. 2016, www.cambridge.org/core/journals/british-journal-of-nutrition/article/curcumin-and-cognition-a-randomised-placebocontrolled-doubleblind-study-of-communitydwelling-older-adults/83419D0C8B37ACD8BBC7C27B91FBAF58#metrics.
- Sarker, Marjana Rahman, and Susan F Franks. “Efficacy of Curcumin for Age-Associated Cognitive Decline: a Narrative Review of Preclinical and Clinical Studies.” GeroScience, Springer International Publishing, Apr. 2018, www.ncbi.nlm.nih.gov/pmc/articles/PMC5964053/.