The blood-brain barrier protects the brain from harmful chemicals in the blood, but it also blocks drugs from reaching it. However, researchers have suggested that omega-3 fatty acid supplements can cross this barrier in Alzheimer's patients, influencing markers for the disease and inflammation.
The researchers, from the Karolinska Institutet in Sweden, have published their research in the Journal of Internal Medicine.
They note that omega-3s, along with other polyunsaturated fatty acids, accumulate in the central nervous system (CNS) throughout gestation.
Although the prevailing belief is that these fatty acids are repeatedly replaced throughout life, the team says little is known about how this happens and whether diet changes can impact transportation of these acids across the blood-brain barrier.
According to the researchers, several diseases can change the fatty acid characteristics of the CNS. They cite Alzheimer's disease patients, who normally have lower concentrations of an omega-3 called docosahexaenoic acid (DHA).
Lead author Dr. Yvonne Freund-Levi says:
"Earlier population studies indicate that omega-3 can protect against Alzheimer's disease, which makes it interesting to study the effects of dietary supplements containing this group of fatty acids in patients who have already developed the disease."
As part of a larger study - the OmegAD project, which follows 204 patients with Alzheimer's - the researchers assessed whether omega-3 supplements change the CNS fatty acid profile.
Fatty acid levels increased in blood and cerebrospinal fluid
Researchers observed higher levels of fatty acids in the CNS of Alzheimer's patients who took omega-3 supplements, which suggests these acids crossed the blood-brain barrier.
A total of 33 individuals took part in this recent study. Of these, 18 received an omega-3 supplement each day for 6 months, while 15 received a placebo during this time.
By the end of the study, the omega-3 group had higher levels of DHA and EPA (eicosapentaenoic acid, which is another omega-3) in their cerebrospinal fluid and blood, whereas the placebo group did not show any change.
Additionally, the researchers observed that the DHA levels corresponded with the degree of change in Alzheimer's disease and markers of inflammation in the cerebrospinal fluid.
The researchers say these observed changes suggest transfer of the fatty acids across the blood-brain barrier.
Prof. Jan Palmblad, another study author, notes that it was previously observed in animals that "DHA dietary supplements can lead to an increase in DHA concentrations in the CNS."
Previous attempts to treat Alzheimer's disease in humans using traditional anti-inflammatory drugs have not produced memory function improvements, the researchers note. But now that they have observed increased DHA concentrations in the central nervous system of humans, they are hopeful about future treatments for the disease.
"However," adds Prof. Palmblad, "much work remains to be done before we know how these fatty acids can be used in the treatment of Alzheimer's disease to halt memory loss."
Medical News Today recently reported on a study that suggested exercise is beneficial for dementia patients.