Study under review: Effect of n-3 PUFA supplementation on cognitive function throughout the lifespan from infancy to old age: a systematic review and meta-analysis of randomized controlled trials
Omega-3 fatty acids, also known as n-3 polyunsaturated fatty acids or n-3 PUFAs, are some of the most extensively researched nutritional supplements in the world. Examine.com’s fish oil page boasts 724 citations, more than any other supplement in the database. Sometimes the challenge is trying to make sense of all the data! Studies test different doses on a variety of different participants, while also collecting data for different periods of time.
Even similarly conducted studies can have conflicting results, and those studies that don’t find a positive effect may not get published, or at least not noticed in the media. Partly because of this, looking at any one single study often isn’t enough to draw conclusions about the effectiveness of a particular supplement. Looking at many different studies in a systematic fashion can help counter these issues.
Omega-3 supplementation in adults typically comes from fish or flaxseed oil. Fish oil and other marine oils primarily contain eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), while flaxseed oil and other plant based oils contain primarily alpha-linolenic acid (ALA). In someone eating a typical western diet high in omega-6 fatty acids, less than 10% of the shorter ALA molecules are converted to longer, more beneficial DHA and EPA molecules. In infants, supplementation is usually in the form of formula that has added DHA. DHA is a required molecule for brain growth. It is particularly important in infancy and early childhood, as over half of the postnatal brain growth occurs in the first year of life, with most of the remainder completed by age six.
Omega-3 supplementation has been linked to several positive effects on a number of functions in the body, including blood pressure, triglyceride levels, symptoms of depression, and cognitive function. Previous cognition trials have shown benefits in infants and conflicting results in adults. The study being reviewed aimed to separate the data from many previous n-3 PUFA supplementation studies based on the age group of the participants (infants, children and adults, or the elderly) to determine how supplementation may or may not affect cognitive function at different stages of life.
A huge amount of data exists for omega-3 fatty acids, with a good deal of the studies having conflicting results. While omega-3s have shown positive results for a variety of cardiovascular outcomes, data on cognition effects have been more mixed.
Other Articles in Issue #02 (December 2014)
- Interview: Bojan Kostevski, MD
Resveratrol and high-intensity interval training
Resveratrol supplementation does not augment performance adaptations or fiber-type–specific responses to high-intensity interval training in humans.
Diet: The whole is greater than the sum of its parts
Discussing the benefits of food (not just supplements) and diet on health, while examining our diet as a whole.
Of mice and guts (and exercise performance)
Effects of intestinal microbiota on exercise performance in mice.
Quantifying the effect of water intake on mood
Effect of changes in water intake on mood of high and lower water drinkers.
Don’t forget the cocoa
Enhancing dentate gyrus function with dietary flavanols improves cognition in older adults. Research shows that chocolate provides a variety of health benefits — many related to cardiovascular health.
Gut bugs and fiber: A novel way to keep dyslipidemia at bay?
A systematic review and meta-analysis of the prebiotics and synbiotics effects on glycaemia, insulin concentrations and lipid parameters in adult patients with overweight or obesity.
Vitamin C and E supplementation may hinder strength training
Vitamin C and E supplementation alters protein signalling after a strength training session, but not muscle growth during 10 weeks of training.
Whey and guar gum: unlikely heroes for people with diabetes
Effect of a lose dose whey/guar preload on glycemic control in people with type 2 diabetes- a randomized controlled trial.
Interview: Shou-Ching Jaminet, Ph.D., Cancer Researcher
Shou-Ching is a molecular biologist and cancer researcher at Beth Israel Deaconess Medical Center and Harvard Medical School, and Director of BIDMC’s Multi-Gene Transcriptional Profiling Core.