Effect of curcumin on memory in non-demented older adults.
Small GW, Siddarth P Li Z, Miller KJ, Ercoli L, Emerson ND, Martinez J et al. Memory and brain amyloid and tau effects of a bioavailable form of curcumin in non-demented adults: A double-blind, placebo-controlled 18 month trial. Am J Geriatr Psychiatry 2018;26:266-277.
Curcumin has previously demonstrated a number of therapeutic effects including being anti-inflammatory, antioxidant, and potentially neuroprotective. Epidemiological studies have suggested lower prevalence of Alzheimer's disease in Indian people with dietary intake of curry containing curcumin. However, early studies of curcumin for neuroprotective benefits in humans have not been supported. Proposed reasons include limited bioavailability of curcumin supplementation, and intervention in people with established dementia may not be optimal for therapeutic benefit. The current study aimed to determine the effect of daily oral use of a highly bioavailable curcumin intervention on memory performance in middle-aged and older non-demented adults.
The 18-month study was randomised, double-blind and placebo-controlled with participants recruited through media and referrals. Inclusion criteria included objective cognitive performance scores and clinical histories consistent with normal ageing or mild cognitive impairment (MCI). Subjects were aged between 50 and 90 years and undertook screening laboratory tests and ECGs to ensure no significant medical abnormalities that might interfere with the study. Exclusion criteria included significant cerebrovascular disease, probable Alzheimer's disease or other dementia, neurological or physical illness that can produce cognitive deterioration, history of myocardial infarction within the previous year or unstable cardiac disease, significant liver or pulmonary disease, diabetes, cancer, major depression or other psychiatric disorder, amongst others. Baseline screening included bloods and MRI to exclude reversible causes of cognitive impairment in addition to the cognitive, depression, memory and neuropsychological assessments. Subjects were assigned to receive bioavailable curcumin 90 mg twice daily (Theracurmin[R]) or placebo for 18 months. The primary outcome was verbal and visual memory tests. Revised memory and attention tests were secondary outcomes. PET imaging scans were undertaken in a small number of subjects.
From the potential pool of 259 subjects, 46 met study criteria and were randomised for treatment. Groups did not differ significantly in baseline demographics. After 18 months' intervention, the curcumin group demonstrated significant improvement from baseline in the verbal memory and visual memory outcome measures. The between group analysis demonstrated significant improvement for only some of the parameters, with the authors noting small sample sizes may have affected this. Secondary outcomes demonstrated significant improvements from baseline in measures of attention and depression for the curcumin group only; however, between group changes were not significantly different. At baseline, regional values identified in PET scans did not differ significantly; however, curcumin supplementation for 18 months demonstrated an effect in the amygdala and hypothalamus regions.
This study reports to be the first long-term double-blind, placebo-controlled study of a bioavailable form of curcumin in a non-demented adult population and suggests improvements in memory performance in middle-aged and older non-demented adults.
It should be recognised that the study population was indeed a healthy older population with extensive exclusion criteria. While this helps to understand the clinical effect of the intervention without other disease confounding the results, it limits the ability to extrapolate these findings beyond this limited population. While the study demonstrated promising findings, the relatively small sample size infers the need for caution in interpreting results. Future studies with larger sample sizes are required to confirm and understand the role of curcumin on cognition in a non-demented older population.
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|Publication:||Australian Journal of Herbal and Naturopathic Medicine|
|Date:||Jun 1, 2018|
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