Unfortunately, the capacity to create DHA from ALA may
partly decline as a result of menopause, perhaps playing a
role in the increased risk that women face for both
Alzheimer’s disease and depression.^27
Factors other than gender influence the conversion of
plant-based ALA to DHA and EPA. People of European
origin who possess “newer” genes (they just don’t make
’em like they used to) may have reduced conversion
abilities compared to those of African descent—it’s possible
that the ability to convert plant forms of ALA became
relegated with the increasing availability of more reliable
sources of omega-3s from meat, fish, and eggs.^28
Ironically, and adding to the considerable consequences
of polyunsaturated oil consumption, the enzymes that
convert ALA to EPA and DHA also convert linoleic acid,
the predominant omega-6 fat in the diet, to its usable pro-
inflammatory form (called arachidonic acid). These
benevolent worker chemicals are indifferent to our needs—
they just convert what we feed them, and today, we’re
feeding them mostly omega-6s. In the case of people who
get little preformed EPA and DHA and lots of omega-6s
from their diets (vegans who consume lots of processed
foods, for example), the brain may actually become omega-
3 deficient for this reason.
To eliminate the guesswork when it comes to nourishing
your brain with EPA and DHA, I suggest the “set it and
forget it” method: be vigilant in your avoidance of
polyunsaturated oils—corn, soy, canola, and other grain and
seed oils—and ensure that you’re getting preformed EPA
and DHA from whole-food sources like fish (wild salmon