randomized-trial

The L.A. Times reports today the neg­a­tive results of the lat­est ran­dom­ized tri­al test­ing the effects of DHA sup­ple­ments on Alzheimer’s symp­toms (DHA is an omega‑3 fat­ty acid).

The study … exam­ined 402 peo­ple with mild to mod­er­ate Alzheimer’s. They were ran­dom­ly assigned to take 2 grams a day of omega‑3 cap­sules con­tain­ing docosa­hexaenoic acid (or DHA) or a place­bo cap­sule. The par­tic­i­pants were fol­lowed for 18 months, and their cog­ni­tive and func­tion­al abil­i­ties were reassessed. They also under­went MRI to look at the brain.

There was no ben­e­fit seen in the patients tak­ing omega‑3 fat­ty-acid sup­ple­ments in either brain vol­ume or cog­ni­tive function.

Com­ments: Does this study mean that DHA or omega‑3 in gen­er­al are not good for the brain? No! This study sug­gests that tak­ing DHA sup­ple­ments after Alzheimer’s diag­no­sis is not help­ful. Pri­or evi­dence shows that omega‑3 con­sump­tion (espe­cial­ly DHA) long before the onset of Alzheimer’s symp­toms reduces the risk of devel­op­ing the dis­ease. Indeed, sev­er­al stud­ies have shown that eat­ing fish (the pri­ma­ry source in our diet of omega‑3 fat­ty acids) is asso­ci­at­ed with a reduced risk of cog­ni­tive decline or dementia.

The authors of the JAMA study also spec­u­late that DHA sup­ple­ments could be used as a treat­ment for peo­ple who have not yet been diag­nosed with Alzheimer’s but are already devel­op­ing demen­tia pathol­o­gy in their brain: “Indi­vid­u­als inter­me­di­ate between healthy aging and demen­tia, such as those with mild cog­ni­tive impair­ment, might derive ben­e­fit from DHA sup­ple­men­ta­tion, although fur­ther study will be nec­es­sary to test this hypoth­e­sis.”