Docosahexaenoic acid (DHA) levels are low in Alzheimer’s disease. DHA is synthesized from alpha-linoelic acid which is an essential fatty acid which must be obtained from the diet. For DHA to be synthesized from alpha-linoelic acid, alpha linoleic acid must first be absorbed.
A meta-analysis indicates that homocysteine levels are significantly high in Alzheimer’s disease. High homocysteine levels in Alzheimer’s disease indicate the transsulfuration pathway is dysregulated in Alzheimer’s disease as homocysteine is not being metabolized to L-cysteine which is what the transsulfuration pathway does.
With low levels of L-cysteine there will be low levels of taurine. Taurine is synthesized from L-cysteine. Taurine is needed for the formation of bile acids which are needed for fat absorption. With alpha-linoelic acid not absorbed in Alzheimer’s disease due to low levels of taurine synthesis of DHA will be impaired in Alzheimer’s disease which is what is seen is Alzheimer’s disease. Effectiveness of supplementation with DHA in Alzheimer’s disease could be limited due to a failure to absorb DHA due to low levels of taurine in Alzheimer’s disease.
Taurine only poorly crosses the blood-brain barrier. However, to assist with essential fatty acid absorption taurine does not have to cross the blood-barrier. Taurine by enhancing fat absorption can enhance brain function.
Homotaurine has has been shown to be a promising therapy for Alzheimer’s disease. In Alzheimer’s disease taurine could be taken with with fatty acid supplements high in alpha linoelic acid, such as lignan free flax seed oil. Lignans are polyphenols so flax seed oil with lignans is avoided.