Alzheimer's disease in Vitamin E Points of view

Alzheimer's disease is a brain disorder correlated with major reductions in the addition of new neurons to the respective target areas through destruction of brain cells, causing cognitive modalities severe enough to affect language communication, memory, lifelong hobbies or social life. Alzheimer's gets worse over time, and it is fatal.
According to statistic, over 25 million people in the world today are affected by dementia and most are suffering from Alzheimer's disease.
Vitamin E,  a fat soluble vitamin, consisting eight different variants (alpha-, beta-, gamma-, and delta-tocopherol and alpha-, beta-, gamma-, and delta-tocotrienol) with varying levels of biological activity(2), found abundantly in corn oil, soybean oil, margarine, wheat germ oil, sunflower,safflower oils, etc. plays an important role in neurological functions and inhibition of platelet aggregation, regulation of enzymatic activity, free radical scavenger, etc..

1. The serum of vitamin E
Epidemiological studies, in determination of the form of vitamin E in reduced risk of Alzheimers disease have been inclusive. According to the joint study by the University and University of Perugia,  elevated levels of tocopherol and tocotrienol forms are associated with reduced risk of cognitive impairment in older adults(1). In other study of vitamin E and risk if AD in advanced age, high plasma levels of beta-tocopherol was associated to reduced risk of developing AD but levels of alpha-tocopherol, alpha- tocotrienol, and beta-tocotrienol showed only a marginally significant effect in the multiadjusted model(2).In the differentiation of vitamin E marker in mild cognitive impairment (MCI) from cognitively intact control (CTL) subjects, suggested that nutritional biomarkers detected in plasma-tocopherols and tocotrienols-as indirect indicators of the onset of AD(3). Other researchers suggest that various tocopherol forms rather than alpha- tocopherol alone may be important in the vitamin E protective association with Alzheimer disease(4) and low plasma tocopherols and tocotrienols levels are associated with increased odds of MCI and AD(5)(6).

2. The conflict results
A Double-blind, placebo-controlled, parallel-group, randomized clinical trial involving 613 patients with mild to moderate AD, combination of 2000 IU/d of alpha tocopherol and memantine, exhibited the slower functional decline in mild to moderate AD(7). A placebo-controlled, clinical trial of vitamin E in patients with moderately advanced Alzheimer disease treatment with with 2000 IU (1342 alpha-tocopherol equivalents) vitamin E/d. may slow functional deterioration and prevent a clinical diagnosis of Alzheimer disease in elderly persons with mild cognitive impairment(8).  In the testing of the hypothesis of oxygen free radicals are probably involved in the deterioration of cognitive function, showed a positive effect of  alpha-tocopherol in reduced risk of the cognitive impairment but in consistent for women taking vitamin E alone, with no evidence of higher scores with longer durations of use(9). The double-blind, randomised trials in which treatment with vitamin E at any dose was compared with placebo for patients with mild cognitive impairment (MCI) and Alzheimer's dementia (AD) showed a positive effects of the vitamin E in  treatment of AD or MCI, but future trials assessing vitamin E treatment in AD should not be restricted to alpha-tocopherol(10). Unfortunately, there is no evidence of vitamin E in in the prevention or treatment of people with AD or MCI, according to the study by the Milton Court Resourse Centre(11) and The Maudsley Hospital(12).

Taking altogether, without going into reviews, serum of vitamin E may be used as an indicator for the early onset and in reduced risk and treatment of Alzheimers' disease. Over doses of vitamin E supplement can cause symptoms of blurred vision, weakness, dizziness, nausea, diarrhea, etc., please make sure you follow the guideline of the Institute of Medicine of the National Academies.

References
(1) Serum levels of vitamin E forms and risk of cognitive impairment in a Finnish cohort of older adults by Mangialasche F¹, Solomon A, Kåreholt I, Hooshmand B, Cecchetti R, Fratiglioni L, Soininen H, Laatikainen T, Mecocci P, Kivipelto M.(PubMed)
(2) High plasma levels of vitamin E forms and reduced Alzheimer's disease risk in advanced age by Mangialasche F¹, Kivipelto M, Mecocci P, Rizzuto D, Palmer K, Winblad B, Fratiglioni L.(PubMed)
(3) Classification and prediction of clinical diagnosis of Alzheimer's disease based on MRI and plasma measures of α-/γ-tocotrienols and γ-tocopherol by Mangialasche F¹, Westman E, Kivipelto M, Muehlboeck JS, Cecchetti R, Baglioni M, Tarducci R, Gobbi G, Floridi P, Soininen H, Kłoszewska I, Tsolaki M, Vellas B, Spenger C, Lovestone S, Wahlund LO, Simmons A, Mecocci P; AddNeuroMed consortium.(PubMed)
(4) Relation of the tocopherol forms to incident Alzheimer disease and to cognitive change by Morris MC¹, Evans DA, Tangney CC, Bienias JL, Wilson RS, Aggarwal NT, Scherr PA(PubMed)

(5) Tocopherols and tocotrienols plasma levels are associated with cognitive impairment by Mangialasche F¹, Xu W, Kivipelto M, Costanzi E, Ercolani S, Pigliautile M, Cecchetti R, Baglioni M, Simmons A, Soininen H, Tsolaki M, Kloszewska I, Vellas B, Lovestone S, Mecocci P; AddNeuroMed Consortium.(PubMed)
(6) Serum levels of vitamin E forms and risk of cognitive impairment in a Finnish cohort of older adults by Mangialasche F¹, Solomon A, Kåreholt I, Hooshmand B, Cecchetti R, Fratiglioni L, Soininen H, Laatikainen T, Mecocci P, Kivipelto M.(PubMed)

(7) Effect of vitamin E and memantine on functional decline in Alzheimer disease: the TEAM-AD VA cooperative randomized trial by Dysken MW¹, Sano M², Asthana S³, Vertrees JE⁴, Pallaki M⁵, Llorente M⁶, Love S¹, Schellenberg GD⁷, McCarten JR¹, Malphurs J⁸, Prieto S⁸, Chen P⁵, Loreck DJ⁹, Trapp G¹⁰, Bakshi RS¹⁰, Mintzer JE¹¹, Heidebrink JL¹², Vidal-Cardona A¹³, Arroyo LM¹³, Cruz AR¹⁴, Zachariah S¹⁴, Kowall NW¹⁵, Chopra MP¹⁵, Craft S¹⁶, Thielke S¹⁶, Turvey CL¹⁷, Woodman C¹⁷, Monnell KA¹⁸, Gordon K¹⁸, Tomaska J¹, Segal Y¹, Peduzzi PN¹⁹, Guarino PD.(PubMed)
(8) Vitamin E and Alzheimer disease: the basis for additional clinical trials by Grundman M.(PubMed)
(9) High-dose antioxidant supplements and cognitive function in community-dwelling elderly women by Grodstein F¹, Chen J, Willett WC.(PubMed)
(10) Vitamin E for Alzheimer's dementia and mild cognitive impairment by Farina N¹, Isaac MG, Clark AR, Rusted J, Tabet N.(PubMed|)
(11) Vitamin E for Alzheimer's disease and mild cognitive impairment by Isaac MG¹, Quinn R, Tabet N.(PubMed)
(12) Vitamin E for Alzheimer's disease by Tabet N¹, Birks J, Grimley Evans J.(PubMed)