Mild cognitive impairment (MCI) is a relatively broad clinical state with mild memory impairment and a precursor to dementia of Alzheimer type (DAT) reported to be 10–20% in people over 65 years of age.
There is no effective pharmacological therapy for MCI but dietary interventions may help. Specifically, the Med diet is known to have a neuroprotective effect by reducing inflammation and oxidative stress.
A recent study investigating natural and synthetic over-the-counter supplements in MCI and AD patients reported the ineffectiveness of ω-3 fatty acids, soy, ginkgo biloba, folic acid, vitamins B, and antioxidative nutrient in protecting MCI and AD. However, phytochemicals have been reported to improve specific cognitive domains in AD patients.
Sesame seeds (Sesamun indicum L.) contain phenolic lignans, which exhibit antioxidant actions in vitro and in vivo, regulate hyper-unsaturated fatty acid metabolism, detoxify the liver, and inhibit the absorption of cholesterol. After roasting the sesame seeds at an appropriate temperature and extracting the oil by pressing, sesame oil cakes (SOCs) are obtained as a by-product.
SOC has been shown to protect against cognitive impairment in both in vitro and in animal models. High SG-containing sesame oil cake extract (SOCE) effectively suppresses nerve cell apoptosis and inflammatory reactions caused by amyloid β (Aβ) induction and lipopolysaccharide exposure. Hence, SOCE may be effective against memory damage and inhibiting memory loss caused by β-amyloid deposition. However, there are no reports on the potential effects of SOCE on cognitive function in humans.
The current research therefore aimed to determine the effects of SOCE on cognitive function in older adults (aged above 60 years) with memory impairment. This study is the first randomized clinical trial (RCT) to evaluate the efficacy and safety of SOCE supplementation to prevent MCI in older adults with memory impairment.
This random, double-blind, and placebo-controlled human study included 70 subjects (average age 69.9 years). Subjects were assigned in a 1:1 random manner to the SOCE group or placebo group and were asked to consume their product (dose of 1.5 g) before breakfast, lunch, and dinner for 12 weeks. In the sixth week, subjects were asked to visit the CTCF2, where vital signs, drug tolerance, medical conditions, and adverse reactions were noted, in addition to other tests being performed.
The first test was the screening. The second test (week 0) was conducted before the participants started taking the test products, and the third test (week 12) was conducted after completion of 12 weeks. Computerized Neurological Function Test (CNT) was used to evaluate adult neurocognitive function. Subjects underwent this test before baseline (week 0) and after 12 weeks of the study.
Blood (3 mL) for plasma amyloid-β (Aβ) assessment was collected and urine samples were collected in order to measure of 8-OHdG (8-hydroxy-2′-deoxyguanosine) levels (marker of oxidative damage to DNA).
The results suggest a dose of 1.5 g of SOCE three times a day improved the verbal memory in the SOCE group than the placebo group and significantly reduced the levels of blood amyloid-β fragments in SOCE group. The absence of adverse reaction confirms the safety of SOCE supplementation during the study.
Mechanism of action
In general, aggregation and accumulation of Aβ proteins in the brain have been considered a defining pathology associated with AD, and an increase in plasma amyloid β levels is closely related to the development of AD. The observations of previous investigations suggest strong correlations between the plasma Aβ and areas of high Aβ deposition in the brain. Moreover, plasma Aβ42/Aβ40 ratio is a promising AD biomarker that predicts cerebral amyloid and AD pathology in at-risk individuals.
The significant decreases in Aβ (1–40) and Aβ (1–42) levels in the SOCE group after 12 weeks of intake compared to before intake in the current study suggests that intake of SOCE protected against a decline in memory by reducing the concentration of Aβ.
Jung, S.J.; Jung, E.S.; Ha, K.C.; Baek, H.I.; Park, Y.K.; Han, S.K.; Chae, S.W.; Lee, S.O.; Chung, Y.C.
"Efficacy and Safety of Sesame Oil Cake Extract on Memory Function Improvement: A 12-Week, Randomized, Double-Blind, Placebo-Controlled Pilot Study"