by Craig Weatherby
Encouraging findings from a pilot clinical trial add more evidence that omega-3s boost brain function in people suffering from mild mental decline.
The results flowed from a group of volunteers diagnosed either with Alzheimer’s disease or with “age-related cognitive decline or ARCD (garden variety senility).
And they fit with the implications of a concise evidence review published last year by researchers from Quebec’s Laval University.
The Quebec team paid particular attention to DHA: the omega-3 that constitutes a large proportion of the fatty acids in brain cell membranes and is essential to proper brain function. Along with EPA, brainy DHA is one of the two key omega-3s in human cells, with fish and fish oil being the only substantial food sources.
As the Canadians wrote, experimental studies show that rodents bred to develop Alzheimer’s-like conditions easily are more likely to do so when their bodies are deficient in DHA.
Likewise, most lab studies show that rodents fed more DHA acquire fewer, milder signs and symptoms of Alzheimer’s, and get them more slowly.
Plus, a strong preponderance of the published epidemiological (population) studies indicate that people who report eating diets high in DHA—from fish and/or fish oil—are less likely to develop Alzheimer’s disease and other forms of senility (Calon F, Cole G 2007).
The Quebecois cited these facts in explaining their conclusion: “the knowledge gathered in recent years holds out a hope for prevention and suggests that the elderly and people bearing a genetic risk for Alzheimer’s disease should at least avoid DHA deficiency” (Calon F, Cole G).
We should note, as they did, that the results of the few, mostly small and short-term clinical studies done to date do not show that fish or supplemental omega-3s improve behavior or test scores in Alzheimer’s or ARCD patients, once senility progresses past its earlier, milder stages.
The Canadians’ encouraging words echo ones from a Swedish team’s 2006 report on a clinical trial that showed reduced agitation among some Alzheimer’s patients who took omega-3 fish oil:
“Combined data from… epidemiologic [population-and-diet] studies point to preventive effects from long-term fish intake. Those results and the results from the present study support the idea that omega-3 fatty acids have a role in primary prevention of Alzheimer’s disease...” (Freund-Levi Y et al. 2006; see “Omega-3 DHA Alleviates Agitation in Early-Onset Alzheimer’s”).
As the Canadians reported, there are multiple, plausible mechanisms by which DHA could reduce the risk of Alzheimer’s disease—and its close cousin, ARCD—whose overlapping symptoms include progressive memory loss and deepening dementia.
The potentially brain-protective effects of DHA include its antioxidant and anti-inflammatory properties, and its beneficial influence on critical cell signaling pathways and genetic “switches” (e.g., Nf-KappaB and PPARs).
For more on omega-3s and brain aging—including genetic variations in the brain benefits of DHA—see “Dementia Danger Slashed by Brainy Marine Omega-3,” “Fish Oil May Halt Memory Decline in Alzheimer's,” and “Omega-3s May Help Prevent ‘Brain Plaque’”.
Taiwanese study supports omega-3s for mild senility
Today’s news comes from researchers at Taipei Medical University, who conducted a small clinical trial designed to test the short-term effects of omega-3s in people with cognitive impairment, including Alzheimer's disease (Chiu CC et al. 2008).
The 24-week trial involved 23 participants with mild or moderate Alzheimer's disease and 23 with mild cognitive impairment. It met the highest standards of rigor, being randomized, double-blind, and placebo-controlled.
The volunteers were randomized to receive either 1.8 grams of omega-3s (EPA+DHA) per day or a placebo (olive oil).
Three-quarters of the patients (35) made it to at least one post-treatment examination, during which their mental states were examined using standard tests: the Clinician's Interview-Based Impression of Change Scale (CIBIC-plus), and the Alzheimer's Disease Assessment Scale (ADAS-cog).
Compared with the placebo group, people from the fish oil group showed more improvement on the CIBIC-plus test.
In contrast, there was no significant difference between the fish oil and placebo groups in the cognitive portion of the ADAS-cog test scores.
However, among participants with mild cognitive impairment, the fish oil group showed significant improvement compared to the placebo group. This improvement was not seen in those with Alzheimer's disease.
And the patients who showed higher proportions of omega-3s in their red blood cells had better cognitive outcomes. This confirmed that the omega-3s in the fish oil made the difference.
Given these findings and others, it seems safe to say that omega-3s are an essential tool in the fight to reduce the risk of developing Alzheimer’s disease or ARCD, and reducing the severity of either form of senility.
How much omega-3?
The Canadians' advice to avoid DHA deficiency—with ample intake being the real goal—begs a key question: “How much omega-3 is enough?”
The volunteers in past clinical trials and the one we report on below took pretty high doses, to get their blood levels up quickly. But lower doses will produce the high blood levels, if sustained over a longer period than the few months of most trials.
Senility is driven by many of the same factors underlying cardiovascular disease, and omega-3s hold brain-boosting promise for many of the same reasons.
Hence, it makes sense to look to cardiovascular health advice on omega-3s for dosage guidance with regard to dementia deterrence.
For leading scientists’ suggestions on doses of omega-3s suitable for cardiovascular prevention, see “How Much Omega-3s Should I Take? Pointers from Two Expert Panels” and “Omega-3s Yield Heart-Saving Effects Even in Small Amounts.
And leading heart researchers point to evidence that the risk of sudden cardiac death drops substantially when omega-3s constitute at least 8 percent of the fatty acids in people’s red blood cells (erythrocytes).
This suggests a real need to test omega-3 blood levels to help ensure achievement of adequate ones.
We addressed this topic in “Mayo Clinic Report Affirms Omega-3s’ Heart Benefits”. As described there, William Harris, Ph.D., notes that the percentage of omega-3s in red blood cells predicts a person’s risk of sudden cardiac death as well or better than conventional measures such as cholesterol or triglyceride levels (Harris WS 2008):
- Less than 4 percent omega-3s = High risk
- 4-8 percent omega-3s = Intermediate risk
- More than 8 percent omega-3s = Low risk
But routine assessment of what Dr. Harris calls the “omega-3 index” will not become a routine part of annual physicals and examination of heart patients until two criteria are met:
1. The value of measuring people’s “omega-3 index” becomes widely accepted.
2. Standardized test methods and materials become available in all medical labs and hospitals.
If and when that happens, we'll report it here.
In the meantime, eat plenty of fish and take regular fish oil supplements, checking with a nutrition-savvy physician about fish oil first, if you are pregnant or have a serious health condition.
- Calon F, Cole G. Neuroprotective action of omega-3 polyunsaturated fatty acids against neurodegenerative diseases: evidence from animal studies. Prostaglandins Leukot Essent Fatty Acids. 2007 Nov-Dec;77(5-6):287-93. Epub 2007 Nov 26. Review.
- Chiu CC, Su KP, Cheng TC, Liu HC, Chang CJ, Dewey ME, Stewart R, Huang SY. The effects of omega-3 fatty acids monotherapy in Alzheimer's disease and mild cognitive impairment: a preliminary randomized double-blind placebo-controlled study. Prog Neuropsychopharmacol Biol Psychiatry. 2008 Aug 1;32(6):1538-44. Epub 2008 May
- Freund-Levi Y, Eriksdotter-Jönhagen M, Cederholm T, Basun H, Faxén-Irving G, Garlind A, Vedin I, Vessby B, Wahlund LO, Palmblad J. Omega-3 fatty acid treatment in 174 patients with mild to moderate Alzheimer disease: OmegAD study: a randomized double-blind trial. Arch Neurol. 2006 Oct;63(10):1402-8.