A new study shows that supplementing children's diets with fish oil, enrolling them in quality preschool and engaging them in interactive reading are all effective ways to raise their IQ.

A meta-analysis carried out at the NYU Steinhardt School of Culture, Education, and Human Development combined data from previous studies to measure the overall effectiveness of each type of intervention.

Only the best available studies using data on children from birth and kindergarten were used, from the newly assembled ‘Database of Raising Intelligence’ - created to find out what works and what doesn't work when it comes to raising intelligence.

All studies in this database relied on participants without any diagnoses of intellectual disabilities and who were selected at random to receive one of the interventions. They also focused on interventions over long periods of time, using widely accepted measures of intelligence.

Overall, the results of the meta-analyses indicate that certain dietary and environmental interventions can indeed raise children's IQ.

For example, supplementing pregnant women and newborns with foods rich in essential omega-3 fatty acids was found to boost children's IQ by more than 3.5 points. These fatty acids may raise intelligence by providing building blocks for nerve cell development that the body cannot produce on its own.

However, data on the benefits other supplements such as iron, B-complex vitamins, riboflavin, thiamine, niacin, and zinc may have on intelligence were inconclusive.

Interestingly, enrolling an economically disadvantaged child into an early education intervention was found to raise IQ by more than four points; while interventions that specifically included a center-based education component raised it by more than seven points.

This may happen because early education intervention increases exposure to complex, cognitively stimulating and demanding environments.

Surprisingly, there is no evidence that early education interventions that take place earlier in childhood are more effective than those that begin later.

Interactive reading interventions raised children's IQ by over six points but didn’t have an effect over the age of four years, suggesting that they likely accelerate language development first and then boost IQ.

Sending a child to preschool was found to raise his or her IQ by more than four points, and preschools that include a language development component were found to boost IQ by more than seven points.

Overall, these findings strengthen earlier conclusions that complex environments build intelligence but also cast doubt on others - including the idea that earlier interventions are always the most effective.

The goal of this analysis was to understand the nature of intelligence and how it can be nurtured at every stage of development. One of the main conclusions that emerged was how little high quality research exists on this topic and how much more needs to be done.