What is the question?

• What is the relationship between seafood consumption during childhood and adolescence (up to 18 years of age) and neurocognitive development?

What is the answer to the question?

Developmental domains: 

• Cognitive development: Insufficient evidence is available to determine whether there is a favorable relationship between seafood intake during childhood and adolescence and measures of cognitive development in children and adolescents. However, no unfavorable relationships were found between seafood consumption during childhood and adolescence and measures of cognitive development. 
• Language and communication development: Insufficient evidence is available to determine whether there is a favorable relationship between seafood intake during childhood and adolescence and measures of language and communication development in children and adolescents. However, no unfavorable relationships were found between seafood consumption during childhood and adolescence and measures of language and communication development. 
• Movement and physical development: Insufficient evidence is available to determine the relationship between seafood intake during childhood and movement and physical development in children. 
• Social-emotional and behavioral development: Insufficient evidence is available to determine the relationship between seafood intake during childhood and adolescence and social-emotional and behavioral development in children and adolescents. 

Attention deficit disorder and Attention-deficit/hyperactivity disorder: Insufficient evidence is available to determine the relationship between seafood consumption during childhood and adolescence and attention deficit disorder or attention-deficit/hyperactivity disorder-like traits or behaviors. 

Autism spectrum disorder: No evidence is available to determine the relationship between seafood intake during childhood and adolescence and autism spectrum disorder-like traits or behaviors or autism spectrum disorder diagnosis. 

Academic performance: Insufficient evidence is available to determine the relationship between seafood intake during adolescence and academic performance in adolescents. 

Anxiety and Depression: Insufficient evidence is available to determine the relationship between seafood consumption during childhood and adolescence and anxiety and depression.

Why was this question asked?

• This important public health question was identified by the U.S. Departments of Agriculture (USDA) and Health and Human Services (HHS) to be examined by the 2020 Dietary Guidelines Advisory Committee.

How was this question answered?

• The 2020 Dietary Guidelines Advisory Committee, Dietary Fats and Seafood Subcommittee, conducted a systematic review to answer this question with support from the Nutrition Evidence Systematic Review (NESR) team.

What is the population of interest? 

• Generally healthy children and adolescents from birth to 18 years at the time of the exposure and children and adolescents from 2 years to 18 years and adults 19 years and older at the time of the outcome. 

What evidence was found? 

• This review includes 13 articles.
• Seafood intake during childhood and adolescence had a predominantly beneficial or null relationship across developmental domains, specifically in cognitive development, language and communication development, and movement and physical development.
• However, no conclusion regarding the relationship between seafood intake during childhood and adolescence and developmental domains could be drawn due to an inadequate number of studies, inconsistency in results, risk of bias in classification of exposures, and heterogeneity of outcome assessments.
• No conclusion regarding the relationship between seafood intake during childhood and adolescence and academic performance, attention deficit disorder (ADD) or attention-deficit/hyperactivity disorder (ADHD), anxiety and depression, and autism spectrum disorder (ASD) could be drawn due to an inadequate number of studies.  

How up-to-date is this systematic review?

• This review searched for studies from January, 2000 to October, 2019.

Background

• This important public health question was identified by the U.S. Departments of Agriculture (USDA) and Health and Human Services (HHS) to be examined by the 2020 Dietary Guidelines Advisory Committee.
• The 2020 Dietary Guidelines Advisory Committee, Dietary Fats and Seafood Subcommittee conducted a systematic review to answer this question with support from the Nutrition Evidence Systematic Review (NESR) team.
• The goal of this systematic review was to examine the following question: What is the relationship between seafood consumption during childhood and adolescence (up to 18 years of age) and neurocognitive development?

Conclusion statements and grades

Developmental domains: 

• Cognitive development: Insufficient evidence is available to determine whether there is a favorable relationship between seafood intake during childhood and adolescence and measures of cognitive development in children and adolescents. However, no unfavorable relationships were found between seafood consumption during childhood and adolescence and measures of cognitive development. (Grade: Grade not assignable)
• Language and communication development: Insufficient evidence is available to determine whether there is a favorable relationship between seafood intake during childhood and adolescence and measures of language and communication development in children and adolescents. However, no unfavorable relationships were found between seafood consumption during childhood and adolescence and measures of language and communication development. (Grade: Grade not assignable)
• Movement and physical development: Insufficient evidence is available to determine the relationship between seafood intake during childhood and movement and physical development in children. (Grade: Grade not assignable)
• Social-emotional and behavioral development: Insufficient evidence is available to determine the relationship between seafood intake during childhood and adolescence and social-emotional and behavioral development in children and adolescents. (Grade: Grade not assignable)

Attention deficit disorder and Attention-deficit/hyperactivity disorder: Insufficient evidence is available to determine the relationship between seafood consumption during childhood and adolescence and attention deficit disorder or attention-deficit/hyperactivity disorder-like traits or behaviors. (Grade: Grade not assignable)

Autism spectrum disorder: No evidence is available to determine the relationship between seafood intake during childhood and adolescence and autism spectrum disorder-like traits or behaviors or autism spectrum disorder diagnosis. (Grade: Grade not assignable)

Academic performance: Insufficient evidence is available to determine the relationship between seafood intake during adolescence and academic performance in adolescents. (Grade: Grade not assignable)

Anxiety and Depression: Insufficient evidence is available to determine the relationship between seafood consumption during childhood and adolescence and anxiety and depression. (Grade: Grade not assignable)

Methods 

• A literature search was conducted using four databases (i.e., PubMed, Cochrane, Embase, and CINAHL) to identify published literature that evaluated the intervention or exposure of seafood consumption during childhood and adolescence and the outcome of neurocognitive development. A manual search was conducted to identify articles that may not have been included in the electronic databases searched. Articles were screened by two NESR analysts independently for inclusion based on pre-determined criteria. 
• Data extraction and risk of bias assessment were conducted for each included study, and both were checked for accuracy. The Committee qualitatively synthesized the body of evidence to inform development of conclusion statements, and graded the strength of evidence using pre-established criteria for risk of bias, consistency, directness, precision, and generalizability.

Summary of the evidence

• This review includes 13 articles, six articles from three randomized controlled trials (RCTs) and seven articles from six prospective cohort studies (PCSs), published between January 2000 and October 2019.
• The 2020 Dietary Guidelines Advisory Committee used the following seafood definition: marine animals that live in the sea and in freshwater lakes and rivers. Seafood includes fish (e.g., salmon, tuna, trout, and tilapia) and shellfish (e.g., shrimp, crab, and oysters).
• The majority of studies addressed developmental domains – cognitive development (seven articles), language and communication development (five articles), movement and physical development (two articles), and social-emotional and behavioral development (three articles).
• No conclusion regarding the relationship between seafood intake during childhood and adolescence and developmental domains could be drawn due to an inadequate number of studies, inconsistency in results, risk of bias in classification of exposures, and heterogeneity of outcome assessments.
  • Seafood intake during childhood and adolescence had a predominantly beneficial or null relationship across all domains, and had a few detrimental relationships, primarily in social-emotional and behavioral development. 
    • Results from three RCTs found that three fatty fish meals per week (~50-80 grams per meal) compared to meat meals for 12 weeks in adolescents or 16 weeks in children had a predominantly null effect on developmental domain outcomes. 
    • Results from three PCSs generally found a beneficial association between fish intake in children and adolescents and developmental domains.
  • The vast majority of analyses showed no detrimental relationship between seafood intake during childhood and adolescence and cognitive, language and communication, and movement and physical development. 
• No conclusion regarding the relationship between seafood consumption during childhood and adolescence and academic performance, attention deficit disorder (ADD) or attention-deficit/hyperactivity disorder (ADHD), anxiety and depression, and autism spectrum disorder (ASD) could be drawn due to an inadequate number of studies and variation in outcome assessment and child age.