Why Would Breastfed Children Be Less Depressed?

I had an interesting call this week from a reporter. A new study is being released showing that children who were breastfed for 6 months or longer were significantly less likely be depressed several years later. Did I have any ideas about why they might have found that?

Actually, I did. It all comes back to the human stress response.

We know from a number of different studies that women who breastfeed past six months are doing a lot of things differently than women who stop in the first few weeks. For example, women who are still breastfeeding at six months are more likely to sleep near their babies, increasing the ease of nighttime breastfeeding while also sustaining their milk supply. These mothers are more likely to practice babywearing, or carrying their babies on their bodies rather than in a carseat or stroller. Finally, they are more likely to breastfeed their babies on cue rather than according to a schedule.

It's this total constellation of behaviors that sustains breastfeeding past the first few days and weeks, and I believe it accounts for the lower rates of depression among breastfed children. This pattern of behavior increases mothers' responsiveness to their babies, which lowers babies' stress levels. That is the key to understanding their lower risk.

When babies are ignored, or left to cry it out, their stress levels rise. If this only happens from time to time, babies adapt. But when this pattern becomes the norm, it has a fundamental effect on babies' developing brains. When their brains are bathed in stress hormones on a regular basis, they become more vulnerable to stress. Further, their bodies become hyper-responsive to stressful stimuli. That increases their vulnerability to depression not only in childhood, but throughout their lives.

By breastfeeding, and parenting in a responsive way, mothers are ensuring that their babies are not chronically stressed--and that shows up years later as decreased rates of depression and myriad other health problems.

Can a non-breastfeeding mother get the same effect? Yes, of course. But she will consciously need to be responsive to her baby's cues. From a practical standpoint, the beauty of breastfeeding is that this responsiveness is built into the system.

I think the takeaway message from this study is that responsive parenting does make a difference in how children fare throughout their lives. So it's something important for parents to consider next time someone advises them to let their babies cry it out.

Depression and Inflammation: The Surprising Link

Depression is risk factor for depression. Researchers have known that for many years but couldn't really explain why—until now.

In the past 10 years, researchers have firmly established that a lot of common diseases--such as diabetes, cancer, Alzheimer’s, and yes, even heart disease--are due to inflammation. For example, physicians have noted that elevated levels of an inflammatory marked called C-reactive protein is an early harbinger of heart disease.

But here’s where the plot really thickens. Depression is also caused by inflammation, and specifically by elevated levels of molecules called proinflammatory cytokines. In fact, by specifically treating people with cytokines, as they do for conditions such as MS, doctors have actually caused depression. The more cytokines patients received, the more depressed they got. When the patients started to taper off of the cytokines, the depression got better too.

Depressed people have significantly higher levels of the cytokines in their plasma than non-depressed people. And this is where the disease-depression link comes from. High levels of proinflammatory cytokines damage blood vessels, and elevate other factors in the blood that increases the risk of clots.

And in another interesting twist, we now know that most of the effective treatments for depression have one thing in common: they are also anti-inflammatory. In fact, that knowledge has fueled some very interesting discoveries. For example, antidepressants lower inflammation levels in cardiac patients. And they’ve been added to steroids for treating asthma, leading to the use of fewer steroids in these patients.

This discovery has also led to some novel ways of treating depression. For example, anti-inflammatory medications, such as ibuprofen, which is not an antidepressant, have been added to antidepressants to make them more effective. Adding Omega-3 fatty acids to a treatment regimen helps with depression for the same reason.

Knowing about the anti-inflammatory connection also gives us a framework for understanding why non-medication treatments for depression would also work.