Alzheimer's + Omega 3 Fatty Acids
Brain atrophy in cognitively impaired elderly: the importance of long-chain ω-3fatty acids and B vitamin status in a randomized controlled trial1,2,3,4
- Fredrik Jernerén⇑,
- Amany K Elshorbagy,
- Abderrahim Oulhaj,
- Stephen M Smith,
- Helga Refsum, and
- A David Smith
Background: Increased brain atrophy rates are common in older people with cognitive impairment, particularly in those who eventually convert to Alzheimer disease. Plasma concentrations of omega-3 (ω-3) fatty acids and homocysteine are associated with the development of brain atrophy and dementia.
Objective: We investigated whether plasma ω-3 fatty acid concentrations (eicosapentaenoic acid and docosahexaenoic acid) modify the treatment effect of homocysteine-lowering B vitamins on brain atrophy rates in a placebo-controlled trial (VITACOG).
Design: This retrospective analysis included 168 elderly people (≥70 y) with mild cognitive impairment, randomly assigned either to placebo (n = 83) or to daily high-dose B vitamin supplementation (folic acid, 0.8 mg; vitamin B-6, 20 mg; vitamin B-12, 0.5 mg) (n = 85). The subjects underwent cranial magnetic resonance imaging scans at baseline and 2 y later. The effect of the intervention was analyzed according to tertiles of baseline ω-3 fatty acid concentrations.
Results: There was a significant interaction (P = 0.024) between B vitamin treatment and plasma combined ω-3 fatty acids (eicosapentaenoic acid and docosahexaenoic acid) on brain atrophy rates. In subjects with high baseline ω-3fatty acids (>590 μmol/L), B vitamin treatment slowed the mean atrophy rate by 40.0% compared with placebo (P = 0.023). B vitamin treatment had no significant effect on the rate of atrophy among subjects with low baseline ω-3 fatty acids (<390 μmol/L). High baseline ω-3 fatty acids were associated with a slower rate ofbrain atrophy in the B vitamin group but not in the placebo group.
Conclusions: The beneficial effect of B vitamin treatment on brain atrophy was observed only in subjects with high plasma ω-3 fatty acids. It is also suggested that the beneficial effect of ω-3 fatty acids on brain atrophy may be confined to subjects with good B vitamin status. The results highlight the importance of identifying subgroups likely to benefit in clinical trials.
Source : American Journal of Clinical Nutrition
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Omega-3 Dietary Supplements Pass Blood-Brain Barrier
New research from Karolinska Institutet in Sweden shows that omega-3 fatty acids in dietary supplements can cross the blood brain barrier in people with Alzheimer's disease, affecting known markers for both the disease itself and inflammation. The findings are presented in the Journal of Internal Medicine, and strengthen the evidence that omega-3 may benefit certain forms of this seriously debilitating disease.
"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," says the study's lead author Dr Yvonne Freund-Levi.
Omega-3 and other essential polyunsaturated fatty acids accumulate in the central nervous system (CNS) during gestation. It has been assumed that these acids are continually replaced throughout life, but little is known about how this occurs and whether changes in diet can affect the transport of important fatty acids across the blood-brain barrier. The blood-brain barrier serves to protect the brain from harmful chemicals existing naturally in the blood, but also blocks the delivery of drug substances to the brain.
Several diseases can affect the fatty acid profile of the CNS; in patients with Alzheimer's disease, for example, previous research has observed lower than normal brain concentrations of docosahexaenoic acid (DHA), an omega-3 fatty acid.
In the present study, part of the larger OmegAD project, scientists examined whether omega-3 dietary supplements change the fatty acid profile of the CNS in patients with mild Alzheimer's disease. Thirty-three patients participated in the study, 18 of whom received a daily omega-3 supplement and 15 a placebo for six months. The results show that the first group had higher levels of both DHA and eicosapentaenoic acid (EPA, another omega-3 fatty acid) in their cerebrospinal fluid (which surrounds the CNS) and blood. No such change was seen in the placebo group.
Moreover, they also found that levels of DHA correlated directly with the degree of change in Alzheimer's disease and inflammatory markers in the cerebrospinal fluid. 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.
"In animals, DHA dietary supplements can lead to an increase in DHA concentrations in the CNS," says Professor Jan Palmblad, who initiated the study. "Here we show that the same applies to humans, which suggests that omega-3 fatty acids in dietary supplements cross the blood-brain barrier. However, 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."
Source : Science Daily
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Effects of supplementation with n-3 polyunsaturated fatty acids on cognitive performance and cardiometabolic risk markers in healthy 51 to 72 years old subjects: a randomized controlled cross-over study
Higher plasma n-3 polyunsaturated fatty acids (PUFA) have been associated with a lower risk of age related cognitive decline, and to beneficially affect cardiometabolic risk factors. A relation exists between metabolic disorders such as diabetes type 2 and cognitive decline. Results regarding the potential effects of n-3 PUFA on risk factors in healthy subjects are divergent, and studies regarding the possible relation between cardiometabolic parameters and cognitive performance are scarce. The objective was to evaluate the effects of five weeks intake of long chain n-3 PUFA on cognitive performance in healthy individuals, and to
exploit the possible relation between outcomes in cognitive tests to cardiometabolic risk parameters.
Fish oil n-3 PUFA (3g daily) were consumed during 5weeks separated by a 5 week washout period in a cross-over placebo controlled study, including 40 healthy middle aged to elderly subjects. Cognitive performance was determined by tests measuring working memory (WM) and selective attention.
Supplementation with n-3 PUFA resulted in better performance in the WM-test compared with placebo (p < 0.05). In contrast to placebo, n-3 PUFA lowered plasma triacylglycerides (P < 0.05) and systolic blood pressure (p < 0.0001). Systolic blood pressure (p < 0.05), fglucose (p = 0.05), and s-TNF-α (p = 0.05), were inversely related to the performance in cognitive tests.
Intake of n-3 PUFA improved cognitive performance in healthy subjects after five weeks compared with placebo. In addition, inverse relations were obtained between cardiometabolic risk factors and cognitive performance, indicating a potential of dietary prevention strategies to delay onset of metabolic disorders and associated cognitive decline.
Source : Journal of Nutrition
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Eating Fish, Chicken, Nuts May Lower Risk of Alzheimer’s Disease
A new study suggests that eating foods that contain omega-3 fatty acids, such as fish, chicken, salad dressing and nuts, may be associated with lower blood levels of a protein related to Alzheimer’s disease and memory problems. The research is published in the May 2, 2012, online issue of Neurology®, the medical journal of the American Academy of Neurology. “While it’s not easy to measure the level of beta-amyloid deposits in the brain in this type of study, it is relatively easy to measure the levels of beta-amyloid in the blood, which, to a certain degree, relates to the level in the brain,” said study author Nikolaos Scarmeas, MD, MS, with Columbia University Medical Center in New York and a member of the American Academy of Neurology.
For the study, 1,219 people older than age 65, free of dementia, provided information about their diet for an average of 1.2 years before their blood was tested for the beta-amyloid. Researchers looked specifically at 10 nutrients, including saturated fatty acids, omega-3 and omega-6 polyunsaturated fatty acids, mono-unsaturated fatty acid, vitamin E, vitamin C, beta-carotene, vitamin B12, folate and vitamin D.
The study found that the more omega-3 fatty acids a person took in, the lower their blood beta-amyloid levels. Consuming one gram of omega-3 per day (equal to approximately half a fillet of salmon per week) more than the average omega-3 consumed by people in the study is associated with 20 to 30 percent lower blood beta-amyloid levels.
Other nutrients were not associated with plasma beta-amyloid levels. The results stayed the same after adjusting for age, education, gender, ethnicity, amount of calories consumed and whether a participant had the APOE gene, a risk factor for Alzheimer’s disease.
“Determining through further research whether omega-3 fatty acids or other nutrients relate to spinal fluid or brain beta-amyloid levels or levels of other Alzheimer’s disease related proteins can strengthen our confidence on beneficial effects of parts of our diet in preventing dementia,” said Scarmeas.
Source : Newswise
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Reduced Omega-3 Speeds Brain Aging
By Michael Smith,
Reviewed by Dori F. Zaleznik, MD; Associate Clinical Professor of Medicine, Harvard Medical School, Boston.
Lower blood levels of omega-3 fatty acids are associated with smaller brain volumes and worse cognitive performance, researchers reported.
The structural findings suggest that people with low levels of the nutrients -- found mainly in fish -- have brains that appear to have aged faster than normal, according to Zaldy Tan, MD, of the University of California Los Angeles, and colleagues.
And the cognitive findings suggest they also are likely to lose some of their ability to think abstractly and remember some things, Tan and colleagues reported in the Feb. 28 issue of Neurology.
Lower blood levels of omega-3 fatty acids are "associated with markers of accelerated structural and cognitive aging," the researchers concluded.
For instance, Tan said in a statement, the lower brain volumes "were equivalent to about two years of structural brain aging."
But he and colleagues cautioned that the findings are based a snapshot study, so there are no measurements of rates of change of either brain volume or cognitive performance.
The two omega-3 fatty acids under study were docosahexaenoic and eicosapentaenoic acid (DHA and EPA, respectively), which have been related to a reduced risk for dementia, the researchers noted.
But there has been no research on any links between the acids and subclinical markers of future dementia, they added.
To help fill the gap, they turned to participants in the long-running Framingham Offspring cohort who had physical examinations from March, 2005 to January, 2008 (including blood sampling to measure omega-3 levels), followed by brain imaging and a neuropsychological assessment.
All told, the study group included 1,575 people with an average age of 67, who were free of dementia at the time.
The researchers analyzed red blood cell levels of DHA and the so-called omega-3 index, defined as the combination of DHA and EPA, seeking associations between omega-3 levels, imaging findings, and results on cognitive tests involving verbal memory, visual memory, executive function, and abstract thinking.
- Participants with DHA in the lowest quartile had significantly lower total brain and greater white matter hyperintensity volumes (P=0.009 and P=0.049, respectively) than those in the higher quartiles.
- The associations with total brain volume persisted in multivariable analyses.
- Lower DHA levels also were associated in multivariable analyses with poorer scores on tests of visual memory, executive function, and abstract thinking. The differences between the lowest quartile and the higher three groups were significant (P=0.008, P=0.004, and P=0.004, respectively).
- Results were similar for the omega-3 index.
- There was no association between levels of DHA or omega-3 index, and verbal memory.
The study was supported by the National Heart, Lung, and Blood Institute and the National Institute on Aging. Tan did not report any financial links with industry.
Primary source: Neurology
Tan ZS, et al "Red blood cell omega-3 fatty acid levels and markers of accelerated brain aging" Neurology 2012; 78: 658–664.
- A study of cognitively normal patients in the Framingham Heart Study offspring cohort found smaller brain volumes associated with lower blood levels of omega-3 fatty acids.
- Note that the study was not longitudinal and did not measure change in omega-3 fatty acid levels, brain volume, or cognitive function over time.
Source : MedPage Today
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