Does Breastfeeding Really Make Kids Smarter, More Educated, And Richer?

Breastfeeding is wonderful, best, and natural. It comes with a whole range of health benefits for mothers and babies alike, from a reduced risk of diarrhea and ear infections to lower odds of obesity and diabetes, and a less of a chance of developing breast cancer for moms. It also promotes mother-baby bonding and encourages easier postpartum weight loss.

If you breastfed and never encountered complications, or if you successfully overcame complications and still managed to nurse your baby, these things make you feel good. If you couldn't or simply didn't breastfeed, they may make you feel guilty. The guilt may be self-imposed, but it can also be imposed by other mothers around you and on the internet. Who doesn't want the best for their baby, after all? If you didn't manage to provide all these wonderful and long-term health benefits to your child by nursing, the message you'll get is unsettling: you fell short. 

You may have heard that breastfeeding makes your child smarter too, and more specifically that it enables your child to perform better on IQ tests. A new and large-scale Brazilian study into the correlation between breastfeeding and IQ, academic performance and income has made that message go viral over the last few weeks. News outlets from all over the world have been loud and clear. Breastfeeding makes your kid smarter, and the longer you breastfeed, the more intelligent they'll be. Now you'll really need to feel guilty if you didn't breastfeed, right?

How Was The Brazilian Study Designed?

The authors of the study, titled "Association between breastfeeding and intelligence, educational attainment, and income at 30 years of age: a prospective birth cohort study from Brazil", noted that breastfeeding has clear and pretty well-researched short-term benefits, but that the long-term benefits of nursing your baby were still not clear. They set out to change that by enrolling a large number of Brazilian babies in a study that would span decades.

When those babies reached age 30, they examined:

• Their IQ, using the Wechsler Adult Intelligence Scale, 3rd version.
• How many years of schooling they had, and what their educational attainments were.
• Their income.

The study team started with nearly 6,000 babies, but were able to follow up on about 3,500 of them three decades on. The conclusion? "Breastfeeding is associated with improved performance in intelligence tests 30 years later, and might have an important effect in real life, by increasing educational attainment and income in adulthood."

See Also: Breastfeeding Myths People Actually Believe

Dr Bernardo Lessa Horta, from the Federal University of Pelotas in Brazil, described the study as unique, because breastfeeding was evenly practiced by members of all social classes in the population they studied. Indeed, the researchers did try to adjust for other factors that could explain differences in IQ level, notably maternal education, birth weight, and family income. 

What Impact Does Breastfeeding Really Have On IQ?

The study authors write: "In this population-based, prospective birth cohort, breastfeeding duration was positively and linearly associated with performance in intelligence tests, educational attainment, and income at age 30 years. The magnitude of the identified effects was important in public health terms. The difference in IQ between the most extreme groups was nearly four points, or about a third of a standard deviation; the increase of 0·9 years in education corresponds to roughly a quarter of a standard deviation, and the difference in income of R$341 was equivalent to about a third of average income."

What Did The Study Actually Show?

A graph looking at breastfeeding duration, family income at birth, and IQ produced by the research team shows that breastfeeding for longer than a year had no impact on the highest-income babies, as compared to high-income babies who were breastfeed between six and 11 months. The same held true for babies from low-income families. Meanwhile, the data shows babies from middle-income families did benefit more if they were breastfed for longer than 12 months, rather than between six and 11 months.

Breastfeeding for less than a month was shown not to impact IQ in any way. While the group of babies from higher-income families ended up with a significantly higher IQ than those from low-income families, there was no difference between the "never breastfed" and "breastfed for less than a month" groups, regardless of income level.

In higher-income countries such as the United States, more educated mothers with higher incomes are more likely to breastfeed than low-income mothers. The authors of this study point out that no such correlation existed in Brazil at the time the study started. Those mothers with the highest income levels were as likely to breastfeed as those with the lowest income levels. Interestingly, however, the poorest mothers with the lowest levels of formal education were most likely to breastfeed for longer than a year, and those women also tended to have more African ancestry than the other groups. 

The study authors pointed out:

They noted that other studies found that breastfeeding led to a higher IQ even after controlling for home environment.

Interestingly enough, however, the authors did not look at another very important factor likely to predict IQ in children: the IQ of the parents. Considering the fact that previous research shows a high parent-child IQ correlation, this can certainly be seen as a major flaw. 

What's more, 41 percent of the original participants were not included in the follow-up. If they had been, a different picture may have emerged. 

What Can We Learn From This Data?

What can you take away from this particular study? Most importantly, you can conclude that your own education and income are likely to positively impact your children's IQ scores, educational attainments, and future income. You can indeed also conclude that breastfeeding for at least six months can make a small but measurable contribution to your children's IQ (3.75 points on average). 

Well, let's put it this way. Breastfeeding certainly offers quite a few benefits. It's also, if you don't suffer complications, a very convenient and cheap way to feed your baby. However, your income, education, own IQ and the stimulation and relationship you offer your children are all much more likely to impact how successful they will be in life than how long you breastfeed and whether you breastfeed at all.

See Also: Breastfeeding In Public: Your Rights