Researchers Find Omega-3 Dietary Supplements Reach the Brain
Every cell in our body is encased in a cell membrane consisting of fatty acids. Fatty acid tails face into the lipid bilayer and membrane fluidity is a reflection of fatty acid length (number of carbons) and degree of saturation (proportion of double vs single carbon-carbon bonds. Increasing the omega-3 long-chain polyunsaturated fatty acids (LCPUFA) increases fluidity and the functioning of proteins traversing the membrane.
Higher plasma eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) levels are associated with lower total mortality (27% across quintiles) and the evidence is strongest for cardiovascular deaths. In fact, Mozaffarian and colleagues reported earlier this year that people over 65y with the highest plasma omega-3 levels (highest quintile) lived ~2.2 years longer than those in the lowest quintile. The benefits of omega-3 LCPUFA go beyond cardiovascular health .
The brain concentrates omega-3 LCPUFA, especially DHA. When our diets are low in omega-3 LCPUFA, the supply of DHA to our brain can be limiting (see review by Denis et al, 2013). Yet, we still don’t know how the transfer of long-chain fatty acids from the bloodstream into the brain are regulated. To understand how the blood-brain barrier works, Levi and colleagues administered 2.3g omega-3 LCUFA orally (vs placebo in a double-blinded randomized design) to 33 patients with mild Alzheimer’s disease. After 6 months, cerebrospinal fluid (CSF) and blood plasma samples were obtained for fatty acid analysis. Omega-3 LCPUFA supplementation increased plasma and CSF concentrations of EPA, DHA and total omega-3 fatty acids. Levels did not change in placebo-treated individuals. As plasma omega-3 fatty acids levels increased in plasma, they also did in CSF. The association was statistically significant for EPA and docosapentaenoic acid but not DHA. Statistically significant correlations were found between DHA concentrations in CSF and markers of inflammation associated with changes in brain cognitive function.
In summarizing the study, ScienceDaily wrote “Researchers in the field have long been interested in this link between Alzheimer’s disease and inflammation, but attempts to treat the disease using traditional anti-inflammatory drugs have failed to produce any improvements in memory function.”
It is important to remember that nutrients are not drugs. They do not cure diseases. However, nutrition is key to maintaining the normal structure-function of our cells, hearts and brains. Most expert scientific groups recommend consuming 250-500mg of omega-3 long-chain polyunsaturated fatty acids (LCPUFA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) daily.
Levi YF, Vedin I, Cederholm T, Basun H, Irving GF, Eriksdotter M, Hjorth E, Schultzberg M, Vessby B, Wahlund L-O, Salem Jr N, Palmbad J. Transfer of omega-3 fatty acids across the blood-brain barrier after supplementation with a docosahexaenoic acid (DHA)-rich omega-3 fatty acid preparation in patients with Alzheimer’s disease: the OmegAD study. 2013 J Intern Med doi: 10.1111/joim.12166
Mozaffarian D, Lemaitre RN, King IB, Song Z, Huang H, Sacks FM, Rimm EB, Wang M, Siscovick DS. Plasma phospholipid long-chain omega-3 fatty acids and total cause-specific mortality in older adults: the Cardiovascular Health Study. 2013 Ann Intern Med doi: 10.7326/0003-4819-158-7-201304020-0003
Denis I, Potier B, Vancassel S, Heberden C, Lavialle M. Omega-3 fatty acids and brain resistance to ageing and stress: body of evidence and possible mechanisms. 2013 Ageing Res Rev doi: 10.1016/j.arr.2013.01.007