Dr Paul Clayton 2010
Avoiding a stroke is surprisingly easy (ie Karppanen & Mervaala ’06). But what of those who are already at high risk? A new study suggests that one of the tocotrienols (those forgotten
isomers of E which are rarely found in supplements) can prevent nerve cell death in the brain
following a stroke.
When a stroke occurs, a neurotransmitter called glutamate is released in the affected brain
tissues. The glutamate rush is neurotoxic in its own right, but it also activates a harmful
enzyme called cystolic calcium-dependent phospholipase A2, or cPLA2. This enzyme in turn
produces a burst of arachidonic acid, which kills brain cells. Alpha-tocotrienol has just
been shown to inhibit cPLA2, thereby blocking a considerable part of
the sequence of events that kills brain cells after a stroke (Khanna et al ’10). These positive effects were observed at low levels of the nutrient, by researchers from Ohio State University.
“Our research suggests that the different forms of natural vitamin E have distinct functions.
The relatively poorly studied tocotrienol form of natural vitamin E targets specific pathways
to protect against neural cell death and rescues the brain after stroke injury,” said Professor
Chandan Sen, lead researcher of the study. “We studied an enzyme that is present in the brain, and that is activated after a stroke in a way that causes nerve damage. We found that the enzyme is blocked by very low levels of tocotrienol. So what we have here is a naturally derived
nutrient, rather than a drug, that provides this beneficial impact.”
The levels of tocotrienol that produced this benefit were very low, and were evident at a concentration easily achieved by supplementation. The researchers said, “On a concentration basis, this finding represents the most potent of all biological functions exhibited by any natural
vitamin E molecule.” And the protective results were highly significant. Alpha tocotrienol reduced arachidonic acid synthesis by 60%, and increased the number of surviving brain cells four-fold.
Karppanen H, Mervaala E. Sodium intake and hypertension. Prog Cardiovasc Dis. 2006 Sep-Oct;49(2):59-75. Review.
Khanna S, Parinandi NL, Kotha SR, Roy S, Rink C, Bibus D, Sen CK. Nanomolar vitamin E alpha-tocotrienol inhibits glutamate-induced activation of phospholipase A2 and causes neuroprotection.
J Neurochem. 2010 Mar;112(5):1249-60