This study investigated the effects of docosahexaenoic acid (DHA) supplementation on cognition in adults with age-related cognitive decline. The randomized, double-blind, placebo-controlled trial involved 485 participants who received 900 mg/day of DHA or a placebo for 24 weeks. Results showed that DHA supplementation significantly reduced errors on a visuospatial learning and episodic memory test by 2-fold compared to placebo. Plasma DHA levels doubled in the DHA group and correlated with improved memory scores. However, DHA did not affect other measures of cognition. The study provides initial evidence that DHA may improve learning and memory function in age-related cognitive decline.

1. www.pronutritionist.net
Beneficial effects of
docosahexaenoic acid on
cognition in age-related
cognitive decline
Yurko-Mauro et al.
Alzheimers Dement 2010;6:456-464
Page 1 Yurko-Mauro et al. Alzheimers Dement 2010;6:456-464

2. Page 2
Pronutritionist’s background
• Docosahexanoic acid (DHA) is the major omega-3 fatty
acid found in neurons
• Epidemiological studies suggest that fish intake might
reduce the risk of Alzheimer´s disease (AD) (Kalmijn et al.
1997, Barberger-Gateau et al. 2007)
• In addition, DHA intake is inversely correlated with the risk
of AD (Morris et al. 2003)
• However, studies have failed to demonstrate DHAs
efficacy in the treatment of AD (Quinn et al. 2010)
• Beneficial effects of DHA supplementation might depend
on the stage of disease  people with mild memory
complaints may benefit the most
Yurko-Mauro et al. Alzheimers Dement 2010;6:456-464 www.pronutritionist.net

3. Methods
• a randomized, double-blind, placebo-controlled study
• n = 485
– age ≥ 55 years
– healthy adults with age-related cognitive decline:
• Mini-Mental State Examination (MMSE) score > 26
• Logical Memory (Wechsler Memory Scale III) baseline score > 1
standard deviation below younger adults
• 900 mg/d of DHA orally or matching placebo
• duration 24 weeks
• the primary outcome:
– CANTAB Paired Associate Learning (PAL), a visuospatial learning
and episodic memory test
– Measures visuospatial learning and episodic memory errors made
during the test (lower the score the better)
Page 3 Yurko-Mauro et al. Alzheimers Dement 2010;6:456-464 www.pronutritionist.net

4. Results (1/3)
• DHA supplementation produced a significant 2-fold
reduction in the number of visuospatial learning
and episodic memory errors on the CANTAB PAL
6 pattern test at 24 weeks
– There were no significant differences between groups on
the PAL and other CANTAB tests at week 12
• Plasma DHA levels doubled and correlated with
improved memory scores in the DHA group
• In addition, DHA supplementation was associated
with improved immediate and delayed Verbal
Recognition Memory scores
www.pronutritionist.netYurko-Mauro et al. Alzheimers Dement 2010;6:456-4644

5. Results: PAL scores at baseline and after 24
weeks (errors made in test)
13.4
8.8
12.1
9.7
8
9
10
11
12
13
14
baseline score week 24 score
DHA
Placebo
www.pronutritionist.netYurko-Mauro et al. Alzheimers Dement 2010;6:456-4645
Numberoferrors

6. Results (3/3)
• “A 3.4 year net improvement in learning and memory
function with DHA” was achieved
• Self-assessment tests of memory and daily living skills
showed no differential effects with DHA.
• DHA supplementation did not produce changes in
– working memory (SWM)
– executive function (SOC)
• DHA was well tolerated with no reported treatment-
related serious adverse events
www.pronutritionist.netYurko-Mauro et al. Alzheimers Dement 2010;6:456-4646

7. Pronutritionist’s discussion (1/2)
• This is the first clinical trial (RCT) to report that DHA (900
mg/d) improve learning and memory function in age-related
cognitive decline
• It is unclear if the effects of supplementation last beyond 24
weeks (or if they become even more pronounced)
• EPA was virtually lacking in the used supplement.
• The supplement also included vitamin C + E and rosemary
extract. These ingredients are confounding factors in this trial
(authors do not discuss this)
• In another recent larger study DHA/EPA supplementation (18
months) did not result in improvement in memory learning
among patients with Alzheimer’s disease (Quinn et al. 2010).
In this study different test pattern (MMSE/CDER) was used to
evaluate cognition. Maybe it’s too late after onset of AD?
www.pronutritionist.netYurko-Mauro et al. Alzheimers Dement 2010;6:456-4647

8. Pronutritionist’s discussion (2/2)
• It is unclear how much the choice of test patterns (MMSE
vs .PAL etc.) affects the outcomes of omega-3 trials in
cognitive impairment. Authors claim that PAL is more
sensitive than MMSE or CDR or ADAS-cog in mild
cognitive impairment
• Even if the authors speculate that DHA supplementation
would delay memory impairment by 3,4 years, the clinical
relevance of the findings is unclear. After all, participants
did not report themselves that their memory improved , nor
did MMSE points change
• More studies verifying the results of this intriguing trial are
needed
www.pronutritionist.netYurko-Mauro et al. Alzheimers Dement 2010;6:456-4648