Do omega-3s prevent dementia?
And can they boost brain functions in apparently healthy seniors?
Most of the available evidence comes from animal and epidemiological (population) studies.
In epidemiological studies, researchers either compare participants’ estimated omega-3 intakes to their scores on brain tests, or compare peoples’ omega-3 blood levels to their test scores … an approach that yields more reliable results.
The epidemiological and lab evidence that omega-3s protect or actually boost aging brains is mixed, but mostly positive.
While some omega-3 fish oil trials saw no significant benefits for healthy seniors or Alzheimer's patients, others found improved cognition (thinking, working memory) in healthy seniors and those with mild cognitive impairment or very mild Alzheimer’s.
(For some examples of clinical and other research, see our sidebar, “Omega-3s and brain aging: A sampling of recent research”, below.)
So the potential scale of thinking and memory benefits from taking omega-3 fish oil supplements – while strongly indicated by lab and population studies – remains a matter of debate.
We also have much to discover about the ways in which omega-3s exert beneficial effects on the nervous system … and on the hormone (endocrine) and immune systems with which it coordinates seamlessly.
These lingering uncertainties prompted German scientists to test the effects of omega-3 fish oil supplements on brain performance in a small group of healthy older adults.
Omega-3s and brain aging
This is sampling of the evidence does not reflect the full range, but indicates why scientists remain excited about the potential for omega-3 supplements to help many if not all brains stay healthy.
and lab research
Clinical trials in
German clinical trial offers encouragement and new insights
The researchers came from leading German brain research institutes, and medical schools at the Universities of Berlin and Leibniz (Witte AV et al. 2013).
They recruited 65 healthy people – 35 men and 30 women – for a randomized, placebo-controlled clinical trial lasting 26 weeks.
The subjects were divided into two groups, each assigned to a different daily regimen:
- Placebo capsules
- Fish oil capsules providing 2.2 grams total
Before and after the 26 week trial, the volunteers underwent test of several key aspects of brain health:
Brain scan imaging
Gray matter volume
- White matter integrity
- Cognitive performance
- Artery thickness (CIMT)
Blood levels of omega-3s (DHA and EPA)
Blood levels of neurotrophins – proteins that promote the survival, growth, interconnections, and functions of brain cells (neurons)
The results were both encouraging and enlightening, as they provide new insights into the beneficial effects that omega-3s exert on key aspects of brain performance and overall health.
First, as the German team wrote, “We found a significant increase in executive functions after [taking omega-3 fish oil] compared with placebo.” (Witte AV et al. 2013)
The term “executive functions” refers to the brain systems that control reasoning, problem solving, planning, execution, and working (short-term) memory.
Significantly, the fish oil group’s objective gains in executive capacity paralleled increases in their blood levels of omega-3s and a key neurotrophin (brain growth/health protein) called BDNF.
Unsurprisingly – given the harm that high blood sugar does to brain health – the gains in executive capacity also paralleled healthful declines in the fish oil group’s fasting insulin levels.
The omega-3 group also displayed beneficial gains in the structural integrity of their brains’ white matter and the volume of gray matter … two more key factors in brain health.
Finally, the fish oil group showed reductions in carotid artery thickness and diastolic blood pressure: two key risk factors for heart disease.
As the German team said, “This double-blind randomized interventional study provides first-time evidence that [fish-source omega-3s] exert positive effects on brain functions in healthy older adults, and elucidates underlying mechanisms.” (Witte AV et al. 2013)
In other words, a hefty daily dose of omega-3 fish oil produced rapid gains in brain performance … and the results shed new light on how omega-3s yield those benefits.
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