No effect of 12 weeks' supplementation with 1 g DHA-rich or EPA-rich fish oil on cognitive function or mood in healthy young adults aged 18–35 years

Abstract

The n-3 PUFA are a unique class of fatty acids that cannot be manufactured by the body, and must be acquired via dietary sources. In the UK, as well as in other Western nations, these 'essential' fatty acids are consumed in quantities that fall below government guidelines. The present study explored the effects of 12 weeks' dietary supplementation with 1 g/d of two types of fish oil (FO; DHA-rich and EPA-rich) in 159 healthy young adults aged 18 -35 years. An assessment of performance on a battery of computerised cognitive tasks and mood measures took place before and following the 12-week treatment regimen. Venous blood samples were also supplied by participants at both time points which were later analysed for serum fatty acid concentrations. Despite good adherence to the study protocol -as reflected in increased concentrations of n-3 serum fatty acids -compared with placebo, the observed effects of both active treatments were minimal. The only finding of note revealed that supplementation with EPA-rich FO may reduce subjective mental fatigue at times of high cognitive demand, although further investigation is required. These findings, taken together with other recent reports of null effects, suggest that dietary supplementation with n-3 PUFA in healthy, normally developing and impairment-free populations is unlikely to result in cognitive enhancement.

The effect of increasing physical activity and/or omega-3 supplementation on fatigue in inflammatory bowel disease

“…Results from RCTs in healthy individuals have shown varied effects of ω-3 FA supplementation (up to 12 weeks) on cognitive function and mood [37,38,47], and a 6-week intervention including ω-3 FA significantly reduced fatigue in patients with lung cancer [48].…”

“…Current guidelines suggest that doses up to 3g per day of marine derived ω-3 FAs are safe [36]; a high EPA:DHA ratio is thought to be preferable [27,37,38 Participants in all groups were contacted by the researcher (AM) via telephone or email on six occasions during the intervention, a week following commencement of the interventions and then approximately every two weeks. Topics of conversation covered their well-being, whether they were taking the capsules as instructed, and the occurrence of any adverse effects.…”

Nutra-ergonomics: influence of nutrition on physical employment standards and the health of workers

“…Omega-3 fatty acid supplementations containing EPA and DHA in varying amounts have been reported to improve visual attention and information processing speed in some (Fontani et al 2005(Fontani et al , 2009) but not all (Antypa et al 2009;Jackson et al 2012) studies. De Groot et al (2007) found higher levels of AA were associated with a faster learning curve on the Stroop task measuring general speed of information processing; however, the opposite was found with DHA.…”

An evidence-based method for examining and reporting cognitive processes in nutrition research

“…Weigl sorting test (36) , peg-and-ball task, Wisconsin card sort task (32) Comprehension knowledge -Visual processing Rey -Osterrieth complex figure (copy), Rey -Osterrieth complex figure (recall), copy of simple drawings (36) Auditory processing -Short-term memory Immediate word recall (28) ; immediate word recall, digits forward, digits backward, letter -number sequencing (37) ; immediate word recall, N-back, Corsi blocks span, letter -number sequencing (38) ; immediate word recall, spatial working memory, numeric working memory (24) ; memory of digits, memory of story, selective attention test (35) ; N-back (34) ; immediate word recall, digit span, verbal span, Corsi test (36) ; Corsi blocks task, N-back task, numeric working memory (31) ; N-back task (32) ; immediate free recall (33) ; immediate word recall, Corsi blocks task, N-back task, numeric working memory, alphabetic working memory, telephone number working memory task (30) Long-term storage/retrieval Delayed word recall, delayed recognition memory, verbal fluency, Boston naming task (37) ; delayed word recall, delayed word recognition, delayed picture recognition (38) ; delayed word recall, delayed picture recognition, delayed word recognition (24) ; delayed word recall (28) ; delayed word recall, short story test, phonological fluency, semantic fluency (36) ; delayed free recall (33) ; delayed word recall, delayed word recognition, delayed picture recognition, names-to-faces recall, verbal fluency (30) …”

“…Trail making task composite score of A and B, Stroop task (37) ; finding A's task, digit vigilance, Stroop task (38) ; digit vigilance (24) ; RVIP (28) ; Stroop task (33) ; trail making part A and B (33) ; Stroop task, RVIP, serial 7 subtraction (31) ; Stroop task (32) ; serial 3 subtraction, serial 7 subtraction, RVIP, Stroop task (30) Reaction/decision speed Choice RT (38) ; simple RT, choice RT (24) ; Jensen's decision time two, four and eight choice (28) ; simple RT, two-choice RT, four-choice RT (31) ; simple RT, two-choice RT, four-choice RT (30) Quantitative knowledge -Reading/writing -Unclassified tests MMSE, attentive matrices (36) ; MMSE (29) are going to be statistically combined to create the broader factor. Simply adding task scores together can result in factors that are biased towards one particular cognitive test.…”