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Attention Deficit Hyperactivity Disorder, or ADHD, as it's commonly known, is on the rise. But why? Is it just that we’re becoming more aware and accepting of the disorder or is something else causing the increase?

“It was already known that children with ADHD have higher omega-6 to omega-3 ratios,” researcher Monica Lopez told us, “so we wanted to test whether these higher omega-6 to omega-3 ratios were involved in the origin of the symptoms.”

Lopez is the lead author of a recent study which looked at whether a fatty acid imbalance during pregnancy has anything to do with rising ADHD rates. The rationale? Children with ADHD are known to have a higher ratio of omega-6 to omega-3 fatty acids than the rest of the population.

Fatty acids are used for energy storage in our bodies. They transport oxygen throughout the body. Omega-3 fatty acids are a crucial part of cell membranes. They are also important for heart health, they reduce blood pressure and produce good cholesterol. While omega-6 fatty acids are also beneficial to our health, providing energy, the Western diet contains much more omega-6 fatty acids than omega-3. The ratio should be 4:1, but in the Western diet, it's a whopping 10:1 and sometimes even 50:1.

“This study is about the association between fatty acid balance during pregnancy and ADHD symptoms in the offspring,” Lopez told us. “We expected to find that a lower proportion of omega-3 in relation to omega-6 during pregnancy would have an impact on ADHD symptoms during childhood.”

According to a 2016 survey by the Centers for Disease Control (CDC), the prevalence of ADHD in kids aged four to 17 increased from 7.8 per cent in 2003 to 9.5 per cent in 2007 and to 11 per cent in 2011-12. The survey showed that the reported number of young children aged two to five diagnosed with ADHD increased by 50 per cent between survey years 2007-2008 and 2011-12. 

“Both omega-6 and omega-3 are important for brain function and development and they have opposing physiological effects,” Lopez told us. “It is important to keep balanced levels of both types of omegas because when omega-6 levels are much higher than omega-3 levels, as is the case in the current Western diet, it promotes a pro-inflammatory response in the brain.”

Lopez and colleagues expected that an alteration in omega levels during pregnancy, the period when babies' brains are developing, would have a key role in the origin of ADHD symptoms, the most common neurodevelopmental disorder.

“I found very interesting how both types of omegas interact and the effects of this interaction in the brain's function,” Lopez told us, “and also the possibilities that the results of the study could offer for improving dietary recommendations during pregnancy and the impact of these recommendations for the general health and productivity of the population.”

Researchers used a population-based birth cohort in four different Spanish regions (Catalonia, Valencia, Basque Country and Asturias). They collected the levels of omega in umbilical cord plasma. Teachers reported ADHD symptoms of children when they were four years old through questionnaires. Parents did it when the children were seven years old. Researchers ran statistical models for each age period controlling for other factors that could influence the associations, such as maternal education or gender. They used the ADHD variable as continuous (number of symptoms) and as dichotomous (six or more ADHD symptoms which is the diagnostic criteria vs. less than six symptoms).

“We observed that the number of ADHD symptoms at seven years of age increased by 13 per cent per each omega-6 to omega-3 ratio unit increase in umbilical cord plasma. This association was not observed at four years of age,” Lopez told us. “No associations were observed using the diagnostic criteria. So, we did not find any relation between the omega-6 to omega-3 ratio during pregnancy and the development of the disorder (ADHD) in the offspring.”

Lopez says that while the results were in the direction she expected, what surprised her was the clarity and robustness of the findings, which she says is quite uncommon in research.

“We didn't find associations at a clinical level, therefore, higher omega-6 to omega-3 ratios were not related to the risk of developing the disorder,” Lopez told us. “On the contrary, we found associations at a population level, which may have a negative impact on the community's health costs and productivity.”

Lopez says longer follow-up times are warranted to explore the stability of the long-term association until adolescent periods. Also, randomized trials are needed to explore the potential nutritional sources of ratios to improve nutritional guidelines during pregnancy. And despite the study’s findings, Lopez wants to remind pregnant women that they should continue to increase their omega-3 intake during pregnancy for the overall health of the baby.