Curcumin a brain food for older Asians

Eating curcumin-rich foods may be one key to a healthy brain, with a recent Singapore study showing that it can curb forgetfulness and the declines in attention, language, and visuospatial ability that come with advancing age.

“We found in this observational cohort study that the consumption of curcumin … in food was associated with the maintenance of higher levels of cognitive functioning over time among community-dwelling middle-aged and older Asian adults in Singapore,” according to investigators from the National University of Singapore.

Compared with curcumin-rich curry consumption level of “never or rare” (less than once a year), “very often” (at least once a week or daily) and “often” (at least once a month to less than once a week) consumption levels were associated with better attention and working memory, as assessed using the Digit Span Forward and Backward tests. [Nutrients 2022;14:1189]

The “very often” level of consumption was also associated with more favourable performance on language (Categorical Verbal Fluency-Animals) and visuospatial constructive ability (Block Design). Likewise, the “occasional” (at least once a year to less than once a month) and “often” consumption levels correlated with enhanced visuospatial constructive ability when compared with “never or rare.”

Among participants with cardiometabolic and cardiac diseases (CMVD), those who consumed curry vs “never or rarely” exhibited better attention, working memory, and language. Among CMVD-free participants, curry consumption showed similar associations, with the addition of greater visuospatial constructive ability.

The analysis included 2,734 community-dwelling adults (mean age 65.9 years, 63.6 percent women). The frequency of consumption of curcumin-rich curry in meals was “never or rarely” in 519 participants, “occasionally” in 1,306, “often” in 559, and “very often” in 367.

Participants who reported higher consumption levels were more likely to be younger, men, of non-Chinese (Malay and Indian) ethnicity, and better educated; they also had higher levels of productive (mentally stimulating) activity, central obesity, and lower depressive symptoms.

“Curcumin exposure from curry consumption appeared in this study to be associated with enhanced cognitive functioning on attention, short-term working memory, visuospatial constructive ability, language, and executive function, and evidently not with long-term memory ability,” the investigators said.

“This suggests that, notwithstanding its known antiamyloid, antitau, antioxidant and anti-inflammatory activities, curcumin exposure from dietary ingestion appears to offer neuroprotection especially through its beneficial metabolic, antiplatelet, and cardioprotective properties,” they pointed out.

How does curcumin boost brain health?

Curcumin is known to have poor aqueous solubility, making the bioavailability from oral ingestion of the chemical compound low. How the dietary ingestion of curcumin from natural food sources could make a difference in achieving desired physiological effects in various biological tissues, including the brain, may be attributed to its preparation, according to the investigators.

Spices and spice oils, such as chilli, pepper, cumin, coriander and plant-based cooking oils, are commonly blended with turmeric in the preparation of curry meals, and such substances may act as curcumin’s own lipid-based oral delivery systems for enhanced solubility and bioavailability, the investigators explained.

“[In fact], there is evidence that the combination of piperine in black pepper with curcumin in turmeric increases the bioavailability of curcumin by 2,000 percent and inhibits the intestinal and hepatic glucuronidation of curcumin,” they added. [Planta Med 1998;64:353-356]

Furthermore, there are potential leads that connect dietary curcumin to the “gut–brain” axis development of cognitive disorders. A current working hypothesis, according to the investigators, is that curcumin could act primarily in the gastrointestinal tract, exerting direct regulatory effects on the brain in a bidirectional “gut–brain” communication axis, thereby influencing core neurological processes. [Mol Psychiatry 2016;21:738-748]

Some reports indicate that by enhancing the diversity of the gut microbiota, curcumin and its metabolites can restore gut microbial dysbiosis, as well as reduce gut permeability, inflammation, and the presence of endotoxins associated with a high-fat diet, obesity, metabolic syndrome, diabetes, cardiovascular and neurodegenerative diseases. [Adv Nutr 2018;9:41-50; Nutrients 2019;11:2426]

“These observations suggest that population health in terms of healthy cognitive ageing and potential reduction of risks of dementia could be enhanced by increased consumption of curcumin in a turmeric-rich diet,” the investigators said.

“The observed effect sizes were small, but nontrivial from a population health perspective. Further studies are desired to replicate these findings in other populations with measurable frequencies of turmeric consumption,” they added.