The amount of omega-3 docosahexaenoic acid (DHA) in a mother’s milk is the strongest predictor of children’s academic performance, according to a new study by researchers at the University of California, Santa Barbara (USCB), and the University of Pittsburgh.
The research, published in the journal Prostaglandins, Leukotrienes and Essential Fatty Acids, compared the fatty acid profiles of breast milk from women in over two dozen countries with the academic test scores of children.
DHA alone accounted for about 20 percent of the differences in test scores among countries. In fact, DHA outweighs national income and the number of dollars spent per pupil in schools.
On the other hand, the amount of omega-6 fat in breast milk was linked to lower test scores. When the amount of DHA and linoleic acid (LA) — the most common omega-6 fat — were considered together, they explained nearly half of the differences in test scores. In countries where mother’s diets contain more omega-6, the benefits of DHA seem to be reduced.
“Human intelligence has a physical basis in the huge size of our brains — some seven times larger than would be expected for a mammal with our body size,” said Dr. Steven Gaulin, UCSB professor of anthropology and co-author of the paper.
“Since there is never a free lunch, those big brains need lots of extra building materials — most importantly, they need omega-3 fatty acids, especially DHA. Omega-6 fats, however, undermine the effects of DHA and seem to be bad for brains.”
The academic test results came from the Programme for International Student Assessment (PISA). Gaulin and Lassek averaged the three PISA tests — math, science, and reading ability — as their measure of cognitive performance. There were 28 countries for which the researchers found information about both breast milk and test scores.
“Looking at those 28 countries, the DHA content of breast milk was the single best predictor of math test performance,” Gaulin said. The second best indicator was the amount of omega-6, and its effect is opposite.
“Considering the benefits of omega-3 and the detriment of omega-6, we can get pretty darn close to explaining half the difference in scores between countries,” he added. When DHA and LA are considered together, he added, they are twice as effective at predicting test scores as either is alone, Gaulin said.
Gaulin and his co-author, William D. Lassek, M.D., a professor at the University of Pittsburgh’s Graduate School of Public Health and a retired assistant surgeon general, conclude that both economic wellbeing and diet make a difference in cognitive test performance, and children are best off when they have both factors in their favor.
“But if you had to choose one, you should choose the better diet rather than the better economy,” Gaulin said.
Their results are particularly interesting in 21st-century North America, Gaulin noted, because our current agribusiness-based diets provide very low levels of DHA — among the lowest in the world. Thanks to two heavily government-subsidized crops — corn and soybeans — the average U.S. diet is heavy in the omega-6 fatty acids and far too light on the good omega-3s, Gaulin said.
“Back in the 1960s, in the middle of the cardiovascular disease epidemic, people got the idea that saturated fats were bad and polyunsaturated fats were good,” he explained. “That’s one reason margarine became so popular.
“But the polyunsaturated fats that were increased were the ones with omega-6, not omega-3. So our message is that not only is it advisable to increase omega 3 intake, it’s highly advisable to decrease omega-6 — the very fats that in the 1960s and ’70s we were told we should be eating more of.”
Gaulin added that mayonnaise is, in general, the most omega-6-laden food in the average person’s refrigerator. “If you have too much of one — omega-6 — and too little of the other — omega 3 — you’re going to end up paying a price cognitively,” he said.
The issue is a huge concern for women, Gaulin said, because “that’s where kids’ brains come from. But it’s important for men as well because they have to take care of the brains their moms gave them. Just like a race car burns up some of its motor oil with every lap, your brain burns up omega-3 and you need to replenish it every day,” he said.