Fish Fat May Help Fight Alzheimer's Disease
DHA, a Fatty Acid in Fish Such as Salmon, May Help Save Brain Cells
Sept. 8, 2005 -- New research shows how a fat found in fish such as salmon,
mackerel, and herring might help fight Alzheimer's disease.
The fat is called DHA. That's short for docosahexaenoic acid. Technically,
it's an omega-3 fatty acid.
DHA and human brain cells were recently studied by researchers including
Nicolas Bazan, MD, PhD, of Louisiana State University's Neuroscience Center of
The scientists noticed that DHA helped brain cells in two ways:
- Curbing production of beta-amyloid proteins, which are seen in Alzheimer's
- Boosting production of another protein called NPD1 that helps brain cells
The findings appear in The Journal of Clinical Investigation.
Fat to the Rescue
The researchers examined the brain of someone with Alzheimer's disease who
had died. Such brains tend to have tangles and clumps of proteins, as well as
signs of inflammation.
Scientists don't know exactly what triggers Alzheimer's disease to develop.
However, they've noticed clumps of amyloid protein and bundles of tangles
(twisted fibers) in brains of people who suffer with the condition. Brain nerve
cell death, which is the hallmark of the memory-robbing disorder, is associated
with these proteins and leads to the personality changes and other
abnormalities that occur with the disease.
It's unclear whether plaques or tangles cause Alzheimer's disease or whether
these are a byproduct of some other process that causes the condition.
DHA may help put the brakes on beta-amyloid proteins and rev up NPD1, write
Bazan and colleagues. NPD1 acts like a bodyguard for brain cells, blocking the
disease's attempts to make brain cells die, the study shows.
Fish as Brain Food
Bazan's study was done in a lab. They didn't serve anyone fish for supper
every night or dole out fish oil capsules.
The researchers also don't recommend any particular dose of DHA for
Alzheimer's disease. But they note that DHA is essential for the brain.
Past studies have shown that people who eat a lot of fish tend to be less
likely to develop Alzheimer's disease than those who hardly ever eat fish. For
instance, a study published in 2003 showed that elderly Chicagoans who reported
eating fish once a week for four years developed Alzheimer's less often than
those who rarely or
That doesn't prove that fish prevents Alzheimer's, but the pattern is
getting lots of attention. DHA has also been found to be important for
Government's Fish Advice
If you choose to eat more fish, you may want to consider mercury levels in
For most people, the mercury risk from fish and shellfish is not a health
concern, states the web site of the Environmental Protection Agency (EPA). The
FDA and EPA offer this advice for women who are or may become pregnant, nursing
mothers, and young children:
- Don't eat shark, swordfish, king mackerel, or tilefish due to high mercury
- Eat up to 12 ounces (two average meals) per week of a variety of fish and
shellfish that are lower in mercury (such as shrimp, canned light tuna, salmon,
pollock, and catfish).
- Know that albacore tuna has more mercury than light tuna.
- Check local advisories about the safety of locally caught fish. If no
advice is available, eat up to 6 ounces (one average meal) per week of fish
from local waters, but don't eat any other fish that week.