The small study conducted by researchers from Taiwan adds to a substantial body of evidence linking the use of omega-3 supplements for mental health problems in general, and dementia and Alzheimer's in particular.
Building on this science, the 24-week, randomised, double-blind study with 46 people receiving placebo or omega-3 reports an improvement in cognitive scores for people with mild cognitive impairment, but not mild or moderate Alzheimer’s disease.
The study’s findings are published in Progress in Neuro-Psychopharmacology and Biological Psychiatry.
The researchers, led by Chih-Chiang Chiu from Taipei City Hospital, recruited 23 people with mild or moderate Alzheimer’s disease and 23 people with mild cognitive decline. They were randomly assigned to receive 1.8 grams of omega-3 per day giving 1080 mg of EPA and 720 mg of DHA, or placebo (olive oil) for 24 weeks. The average age of participants was 75.3.
Based on data for the 35 participants who finished the study, Chiu and co-workers report improvements in the people receiving the omega-3 supplements on the Clinician’s Interview-Based Impression of Change Scale (CIBIC-plus), compared to people receiving the placebo. The CIBIC-plus is a measure of disease severity and progression of illness.
While no significant changes were observed in the cognitive portion of the Alzheimer’s Disease Assessment Scale (ADAS-cog) between the omega-3 receiving individuals and those receiving placebo, when the researchers considered the mild or moderate Alzheimer’s disease people and people with mild cognitive decline separately, a “significant improvement in ADAS-cog” was observed, they said.
“Omega-3 fatty acids may improve general clinical function in patients with mild or moderate Alzheimer’s disease and mild cognitive impairment, but not their cognitive function,” wrote the researchers.
“The cognitive effects of omega-3 fatty acids might be favoured in patients with mild cognitive impairment rather than those with Alzheimer’s disease.”
The need for more research
According to the researchers, their preliminary results indicate that a further study with omega-3 in patients with Alzheimer’s disease or mild cognitive impairment is “feasible”.
“Further studies should be considered with a larger-sample size, diet registration, higher dosage, comparison between different combinations of EPA and DHA (such as pure EPA, pure DHA and placebo), a more inert placebo, and greater homogeneity of participants, especially those with mild Alzheimer’s disease or mild cognitive impairment,” they concluded.
Two earlier studies published in April 2007 in the American Journal of Clinical Nutrition reported that regular consumption of omega-3-rich food could prevent age-related cognitive decline.
The studies, from the Dutch National Institute for Public Health and the Environment, and the University of North Carolina, stated that only a limited number of studies have looked at the decline in cognitive function that precedes these diseases.
The majority of science for the health benefits of fish and omega-3 consumption has focused on cardiovascular health, but the science for cognitive benefits is growing and almost as compelling as the heart health data.
Moreover, the number of studies reporting potential risk reduction of certain cancers, improved development of a baby during pregnancy, joint health, and improved behaviour and mood, are also growing.
Source: Progress in Neuro-Psychopharmacology and Biological PsychiatryAugust 2008, Volume 32, Issue 6, Pages 1538-1544"The effects of omega-3 fatty acids monotherapy in Alzheimer's disease and mild cognitive impairment: A preliminary randomized double-blind placebo-controlled study"Authors: C-C. Chiu, K.-P. Su, T.-C. Cheng, H.-C. Liu, C.-J. Chang, M.E. Dewey, R. Stewart, S.-Y. Huang