Older news items (pre-2010) brought over from the old website
Mixed results from trials of DHA
A large 18-month trial of the effects of DHA, an omega 3 fatty acid, on 402 people with mild to moderate Alzheimer's found no evidence of benefit. However, there were indications that those without the “Alzheimer’s gene” ApoE-e4 showed slower cognitive decline. A 6-month trial involving 485 healthy seniors with mild memory complaint also found a benefit on a test of memory and learning.
Quinn, J.F. et al. 2009. A clinical trial of docosahexaenoic acid (DHA) for the treatment of Alzheimer's disease. Presented at the Alzheimer's Association International Conference on Alzheimer's Disease July 11-16 in Vienna.
Yurko-Mauro, K. et al. 2009. Results of the MIDAS Trial: Effects of Docosahexaenoic Acid on Physiological and Safety Parameters in Age-Related Cognitive Decline. Presented at the Alzheimer's Association International Conference on Alzheimer's Disease July 11-16 in Vienna.
http://www.eurekalert.org/pub_releases/2009-07/aa-rft070709.php
Fish eating associated with higher IQ scores in teenage boys.
IQ records from some 4000 Swedish males at 18 who had also taken part in a survey of fish consumption at age 15 has revealed that those who ate fish once a week at 15 had IQ scores 7% higher (on average) than those who didn’t eat fish that often. Those who ate fish more than once a week showed an improvement of 12%. The effect was independent of education.
[1018] Åberg, M AI., Åberg N., Brisman J., Sundberg R., Winkvist A., & Torén K.
(2009). Fish intake of Swedish male adolescents is a predictor of cognitive performance.
Acta Pædiatrica. 98(3), 555 - 560.
http://www.physorg.com/news155810958.html
Intake of certain fatty acid appears to improve neurodevelopment for preterm girls, but not boys
A large randomized trial of infants born at less than 33 weeks' gestation from five Australian hospitals has found that girls who received a high supplementary daily dose of DHA (an omega-3 fatty acid) in either their breast milk or infant formula until their expected delivery date performed significantly better on a mental development test when they were 18 months old than girls who received a low dose. However, bafflingly, boys showed no effect.
[402] Smithers, L. G., Willson K., Ryan P., Makrides M., Gibson R. A., McPhee A. J., et al.
(2009). Neurodevelopmental Outcomes of Preterm Infants Fed High-Dose Docosahexaenoic Acid: A Randomized Controlled Trial.
JAMA. 301(2), 175 - 182.
http://www.eurekalert.org/pub_releases/2009-01/jaaj-ioc010809.php
Eating fish may prevent memory loss and stroke in old age
A large study involving 3,660 people age 65 and older over five years, has found that those who ate broiled or baked tuna and other fish high in omega-3 fatty acids three times or more per week had a nearly 26% lower risk of having silent brain infarcts that can cause dementia and stroke, compared to people who did not eat fish regularly. One serving a week reduced risk by 13%. Regular fish consumption was also associated with fewer changes in white matter. Types of fish that contain high levels of DHA and EPA nutrients include salmon, mackerel, herring, sardines, and anchovies. Eating fried fish was not protective. Silent brain infarcts are only detected by brain scans, and are found in about 20% of otherwise healthy elderly people.
However, in the same journal, another study reports findings that in a double-blind, placebo-controlled, study of 302 healthy older adults, 26 weeks of EPA-DHA supplements had no effect on cognitive performance. Of course, if the effect of fish oil is primarily on preserving brain health, it may well be (indeed is likely) that the study was too short to impact cognitive performance. It is also possible that supplements are not as effective as whole foods — many studies have found that it is much more effective to receive needed vitamins and minerals through nutrition rather than supplementation.; Reference
[265] van de Rest, O., Geleijnse J. M., Kok F. J., van Staveren W. A., Dullemeijer C., OldeRikkert M. G. M., et al.
(2008). Effect of fish oil on cognitive performance in older subjects: A randomized, controlled trial.
Neurology. 71(6), 430 - 438.
[308] Virtanen, J. K., Siscovick D. S., Longstreth W. T., Kuller L. H., & Mozaffarian D.
(2008). Fish consumption and risk of subclinical brain abnormalities on MRI in older adults.
Neurology. 71(6), 439 - 446.
http://www.eurekalert.org/pub_releases/2008-08/aaon-efm072908.php
How food affects the brain
I’ve reported on quite a lot of studies finding beneficial effects of one food or another on the brain. Now a researcher has analyzed more than 160 studies about food's affect on the brain, and here’s the bottom line. He comes out for omega-3 fatty acids, as both improving synaptic plasticity and the expression of several molecules proteins to learning and memory, as well as protecting against attention-deficit disorder, dyslexia, dementia, depression, bipolar disorder and schizophrenia. He suggests it’s better to get it from food than supplements (which is always recommended). Salmon, walnuts and kiwi fruit are all good sources. They’re still working out which fatty acids are most important, but one is definitely docosahexaenoic acid, or DHA — which like vitamin C we’re not good at making for ourselves; we have to ingest it. He also concludes that diets high in trans fats and saturated fats are bad for cognition.
Studies also support the need for folic acid (found in spinach, orange juice and yeast), which is essential for brain function, and appears to reduce age-related cognitive decline and dementia. And BDNF, important for learning and memory as well as metabolic regulation (so there’s a connection there with obesity), is helped by omega-3 fatty acids and the curry spice curcumin, and also, it seems, smaller food portions.
[1293] Gómez-Pinilla, F.
(2008). Brain foods: the effects of nutrients on brain function.
Nat Rev Neurosci. 9(7), 568 - 578.
Full text is available online at www.nature.com/nrn/journal/v9/n7/abs/nrn2421.html
http://www.eurekalert.org/pub_releases/2008-07/uoc--slh070908.php
A study of 55 healthy adults has found that those who had high levels of long-chain omega-3 fatty acids had more grey matter in areas of the brain associated with emotional arousal and regulation — the bilateral anterior cingulate cortex, the right amygdala and the right hippocampus. Although this doesn’t mean omega-3 necessarily causes such changes, the finding does support a recent study that found higher levels of omega-3 were associated with a more positive outlook, and animal studies showing that increasing omega-3 intake leads to structural changes in the brain. Good sources of omega-3 fatty acids are walnuts, flax, and fatty fish such as salmon and sardines.
The findings were presented March 7 at the American Psychosomatic Society's 2003 Meeting, in Budapest, Hungary.
http://www.sciencedaily.com/releases/2007/03/070307080827.htm
http://www.webmd.com/diet/news/20070307/omega-3-fatty-acids-may-boost-brain
Higher level of certain fatty acid associated with lower dementia risk
A nine year study of 899 participants in the Framingham Heart Study (average age 76 years) has found that those with the highest levels of an omega-3 polyunsaturated fatty acid known as docosahexaenoic acid (DHA) had a 47% lower risk of developing dementia and 39% lower risk of developing Alzheimer's. Among the participants who completed the dietary questionnaire, those in this top quartile of blood DHA levels reported that they ate an average of .18 grams of DHA a day and an average of three fish servings a week. Those in the other quartiles ate substantially less fish.
[2408] Schaefer, E. J., Bongard V., Beiser A. S., Lamon-Fava S., Robins S. J., Au R., et al.
(2006). Plasma Phosphatidylcholine Docosahexaenoic Acid Content and Risk of Dementia and Alzheimer Disease: The Framingham Heart Study.
Arch Neurol. 63(11), 1545 - 1550.
http://www.eurekalert.org/pub_releases/2006-11/jaaj-hlo110906.php
Omega-3 fatty acids may slow cognitive decline in some patients with very mild Alzheimer's disease
Several studies have shown that eating fish, which is high in omega-3 fatty acids, may protect against Alzheimer's disease. A Swedish study has now tested whether supplements could have similar effects. Patients with mild-to-moderate Alzheimer’s who took 1.7 grams of DHA and .6g of EPA showed the same rate of cognitive decline as those taking a placebo, however, among a subgroup of 32 patients with very mild cognitive impairment, those who took the fatty acids experienced less decline in six months compared with those who took placebo. It may be that anti-inflammatory effects are an important reason for the benefit, potentially explaining why effects were seen only in those with very early-stage disease, when levels of inflammation seem to be higher.
[2401] Freund-Levi, Y., Eriksdotter-Jonhagen M., Cederholm T., Basun H., Faxen-Irving G., Garlind A., et al.
(2006). {omega}-3 Fatty Acid Treatment in 174 Patients With Mild to Moderate Alzheimer Disease: OmegAD Study: A Randomized Double-blind Trial.
Arch Neurol. 63(10), 1402 - 1408.
http://www.eurekalert.org/pub_releases/2006-10/jaaj-ofa100506.php
Eating fish associated with slower cognitive decline
Analysis of data from an ongoing longitudinal study of older adults has found that the rate of cognitive decline over a six-year period was reduced by 10-13% in those who ate fish at least once a week.
[534] Morris, M C., Evans D. A., Tangney C. C., Bienias J. L., & Wilson R. S.
(2005). Fish Consumption and Cognitive Decline With Age in a Large Community Study.
Arch Neurol. 62(12), 1849 - 1853.
http://www.eurekalert.org/pub_releases/2005-10/jaaj-efa100605.php
Fish oil may help prevent Alzheimer's
A study involving genetically engineered mice has found that a diet high in docosahexenoic acid, or DHA — an omega-3 fatty acid found in relatively high concentrations in cold-water fish — dramatically slowed the progression of Alzheimer's, by cutting the harmful brain plaques that mark the disease. An earlier study showed that DHA protected against damage to the "synaptic" areas where brain cells communicate and enabled mice to perform better on memory tests. Food sources of omega-3 fatty acids include fish such as salmon, halibut, mackerel and sardines, as well as almonds, walnuts, soy, and DHA-enriched eggs.
Lim, G.P., Calon, F., Morihara, T., Yang, F., Teter, B., Ubeda, O., Salem, N.Jr, Frautschy, S.A. & Cole, G.M. 2005. A Diet Enriched with the Omega-3 Fatty Acid Docosahexaenoic Acid Reduces Amyloid Burden in an Aged Alzheimer Mouse Model. Journal of Neuroscience, 25(12), 3032-3040.
http://www.eurekalert.org/pub_releases/2005-03/vrcs-foh032405.php
Omega-3 fatty acid may prevent Alzheimer's disease and slow its progression
A study using genetically engineered mice has shown that a diet high in the omega-3 fatty acid DHA helps protect the brain against the memory loss and cell damage caused by Alzheimer's disease. Cheap sources of DHA include coldwater fish, like salmon, halibut, mackerel, sardines and herring. These fish consume algae, which is high in DHA. Because these fishes' oiliness makes them absorb more mercury, dioxin, PCP and other metals, however, a less risky yet more costly strategy is to consume fish oil or purified DHA supplements made from algae. Other options include DHA-rich eggs laid by chickens that eat DHA-supplemented feed.
[2397] Calon, F., Lim G. P., Yang F., Morihara T., Teter B., Ubeda O., et al.
(2004). Docosahexaenoic Acid Protects from Dendritic Pathology in an Alzheimer's Disease Mouse Model.
Neuron. 43(5), 633 - 645.
http://www.eurekalert.org/pub_releases/2004-09/uoc--ddp082604.php
Eating fish cuts risk of dementia
Using data from a French epidemiological study of cognitive and functional aging, researchers found that those who ate fish or seafood at least once a week had a significantly lower risk of being diagnosed as having dementia (including Alzheimer’s) over the seven years follow-up. This confirms earlier findings from the Rotterdam Study, which had a much shorter follow-up (a mean of 2.1 years). There was an association between level of education and diet which partly, but not completely, explains this. It does appear that this is a benefit from eating fish / seafood, possibly from the fatty acids found in fish oils. There was no significant association between meat consumption and risk of dementia.
Barberger-Gateau, P., Letenneur, L., Deschamps, V., Pérès, K., Dartigues, J. & Renaud, S. 2002. Fish, meat, and risk of dementia: cohort study. BMJ, 325, 932-933.
http://www.eurekalert.org/pub_releases/2002-10/bmj-efc102302.php
What about mercury?
No strong evidence linking mercury levels with worse cognitive performance in older adults
We are encouraged to eat fish for its health benefits, but there has been some concern about mercury levels. Now the first study of mercury and cognitive function in 1140 urban U.S. adults between the ages of 50 and 70 years has found that blood mercury levels were not consistently associated with adverse performance on a broad range of tests of cognitive function. Most of the large number of tests showed no correlation with mercury and there was a lack of consistency of mercury effects in different aspects of brain function.
[1313] Weil, M., Bressler J., Parsons P., Bolla K., Glass T., & Schwartz B.
(2005). Blood Mercury Levels and Neurobehavioral Function.
JAMA. 293(15), 1875 - 1882.
http://www.eurekalert.org/pub_releases/2005-04/jhub-mla041505.php
http://www.eurekalert.org/pub_releases/2005-04/jaaj-nse041405.php
Eating methylmercury contaminated fish causes problems in adults
Pregnant women and children have been warned about eating methylmercury contaminated fish. New research now suggests that all adults should be wary. The study involved 129 men and women living in fishing communities of the Pantanal region of Brazil. About one out of four were found to have mercury levels that exceeded the 'safe' level set by the World Health Organization for women and children. Those individuals fared worse on tests for motor skills, memory and concentration.
The major source of methylmercury is diet, particularly large fish like shark and swordfish.
[1423] Yokoo, E. M., Valente J. G., Grattan L., Schmidt S L., Platt I., & Silbergeld E. K.
(Submitted). Low level methylmercury exposure affects neuropsychological function in adults.
Environmental Health. 2, 8 - 8.
http://www.eurekalert.org/pub_releases/2003-06/bc-fin060403.php
The article is available at http://www.ehjournal.net/content/2/1/8