Alzheimer’s disease is in the news today as a small human trial (Mawuenyega et al., 2010) suggests that reduced β-amyloid clearance in the brain may be a key factor in Alhzeimer’s pathogenesis which is associated with accumulation of β-amyloid plaque. The study found that in Alzheimers sufferers, clearance rates of β-amyloid were impaired compared to healthy subjects, with production rates reamining similar.
A healthy immune system is fundamental to clearance of β-amyloid as macrophage cells of the immune system are involved in clearance of β-amyloid and other waste products. A healthy lifestyle and diet in general is of fundamental importance in maintaining a well-functioning immune system. However, more specifically, recent studies (University of California, 2006) have shown that curcuminoids from turmeric (Curcuma longa) enhanced the surface binding of amyloid beta to macrophages. It was also found, in conjunction with curcumin, that vitamin D strongly stimulated the uptake and absorption of amyloid beta in macrophages and elderly people often suffer from low vitamin D.
In fact, there’s been considerable interest recently into curcumin (the principal curcuminoid) from turmeric and Alzheimer’s generally. Research has shown that curcumin inhibited β-amyloid oligomer (polymer) formation in-vitro (Yang et al., 2005) and has been shown to cross the blood-brain barrier, although oral absorption is limited. However, anecdotally, it has been observed that aged Asian brains at autopsy are stained yellow from a lifetime consumption of turmeric, suggesting a certain level of absorption from oral administration and levels of Alzheimers are lower in those aged populations generally. Additionally in animal studies of Alzheimer’s disease, although limited by nature, dietary curcumin has decreased Alzheimer’s-associated inflammation and oxidative damage, amyloid plaque burden in the brain, and amyloid beta-induced memory deficits (Frautschy et al., 2001; Lim et al., 2001; Pan et al., 2008). There are currently human trials being carried out on the effect of curcumin in Alzheimer’s, however, there is little focus on whole turmeric extract although there are many other curcuminoids present in turmeric other than curcumin that may be beneficial for use in Alzheimer’s (Ahmed and Gilani, 2009). A regular consumption of turmeric, either in cooking or as a supplement may be beneficial at least as part of a long term strategy for preventing Alzheimers.
References
Ahmed T, Gilani AH. (2009) ‘Inhibitory effect of curcuminoids on acetylcholinesterase activity and attenuation of scopolamine-induced amnesia may explain medicinal use of turmeric in Alzheimer’s disease’. Pharmacol Biochem Behav. 91(4):554-9. Epub 2008 Oct 1.
Frautschy SA, Hu W, Kim P, et al. (2001) ‘Phenolic anti-inflammatory antioxidant reversal of Abeta-induced cognitive deficits and neuropathology’. Neurobiol Aging. 22(6):993-1005. (PubMed)
Lim GP, Chu T, Yang F, Beech W, Frautschy SA, Cole GM. (2001) ‘The curry spice curcumin reduces oxidative damage and amyloid pathology in an Alzheimer transgenic mouse’. J Neurosci. 21(21):8370-8377. (PubMed)Mawuenyega KG, Sigurdson W, Ovod V, Munsell L, Kasten T, Morris JC, Yarasheski KE, Bateman RJ (2010) ‘Decreased Clearance of CNS β-Amyloid in Alzheimer’s Disease ‘, Science, 1197623, published online 9 Dec 2010
Pan R, Qiu S, Lu DX, Dong J. (2008) ‘Curcumin improves learning and memory ability and its neuroprotective mechanism in mice’. Chin Med J (Engl). 121(9):832-839. (PubMed)
Yang F, Lim GP, Begum AN, et al. (2005) ‘Curcumin inhibits formation of amyloid beta oligomers and fibrils, binds plaques, and reduces amyloid in vivo’. J Biol Chem. 280(7):5892-5901. (PubMed)
Zhang C, Browne A, Child D, Tanzi RE. (2010) ‘Curcumin decreases amyloid-beta peptide levels by attenuating the maturation of amyloid-beta precursor protein’. J Biol Chem. 285(37):28472-80. Epub 2010 Jul 9.
