Sardines and salmon: gold for our brain


The results of a new study ( DOI: suggest the brain-boosting benefits of omega-3 PUFAs begin in midlife.

The main dietary sources of omega-3 include oily fish, such as salmon and sardines.

Previous research has linked higher levels of omega 3s with better cognitive function and decreased risk for dementia in older individuals.

The current analysis included 2183 participants without dementia or stroke from the Framingham Heart Study. Of these, 2109 were from the Third-generation cohort, and 74 were from the non-White Omni cohort.

From red blood cells, researchers measured levels of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), two of the most abundant omega-3 PUFAs. They also calculated the omega-3 index as the sum of EPA and DHA.

All participants underwent brain MRI. Among other brain measures, researchers were interested in hippocampal volume and white matter hyperintensities (WMHs).

Participants completed a detailed neuropsychological battery. Tests assessed delayed episodic memory, processing speed, and executive function. The Similarities test was used to assess abstract reasoning.

Results showed that every standard deviation units (SDU) increase of log-transformed omega-3 index was related to 0.003 cm3 larger hippocampal volume relative to intracranial volume (P = .04). Similar results were obtained for DHA or EPA concentrations individually.

There was a threshold effect for DHA levels and the Omega-3 index in which participants in the top three quartile levels had larger hippocampal volumes compared with those in the bottom quartile.

Regarding cognition, the researchers found higher levels of all omega-3 predictors were associated with better abstract reasoning.

Previous animal studies have shed some light on a possible mechanism for omega 3. DHA and EPA deficiency in mice has been shown to lead to downregulation of the presynaptic vesicle proteins and glutamate receptor subunits in hippocampal synapses. Aged mice that were fed a diet enriched with omega-3s had larger hippocampal volumes and other signals of brain health.