Thursday, June 22, 2006

Breast Milk

Last week in the New York Times Science section, there was an article that reported on a national breast-feeding awareness program that is suggesting that not breast-feeding your children is tantamount to negligence. Now, I'm all for breast feeding, I think it probably is the best food for an infant. However, I think there is also lots of misinformation about why breast feeding is good.

One of the reasons I often hear is that breast milk confers extra immunity to the infant. I get this from everyone including pediatricians and scientists, and it also appeared in that Times article. The argument stems from the fact that breast milk contains immunoglobulins and lymphocytes. Well, let's think about this more clearly. Immunoglobulins or antibodies are proteins and digestion breaks proteins down into amino acids. That is why pharma always tries to develop small molecule drugs. Protein-based drugs must be injected. You can't take them orally. Now, in certain mammal species, neonates possess pathways to transport proteins in breast milk directly into the blood stream. The jury is still out on humans but it looks like we're not in that category. So, I'm sorry to say, your baby is probably not getting extra antibodies from breast milk.

So why should a baby be breast fed? One thing that has been found is that the microflora of breast-milk fed babies differ significantly from formula-fed babies. You're body has more bacterial cells than it's own cells so having the right mix of micro-organisms is very important. I think this is the main reason we should push breast milk. Establishing the correct microflora environment is probably crucial for digestion and fending off infections. Additionally, the contents of breast milk will vary depending on what the mother eats. Formula always tastes the same. Breast fed babies have been known to prefer what their mothers eat and to have more diversity in their food preferences in general. Cultural tastes may partially be propagated through breast feeding. Also, babies seem to control the amount they eat much better with breast feeding than with a bottle. That may partially be because parents encourage their babies to finish each bottle even if the baby is already full. The bottom line is that their are many benefits to breastfeeding but obtaining antibodies is not one of them.

Friday, June 09, 2006

Hybrid fallacy and car seats

I think the Toyoto Prius is a great car. It's efficient and looks cool. However, hybrids are not the panacea for our energy problems they are made out to be. For one, the actual gains in fuel efficiency over a well designed gasoline car is not as great as presumed. In fact, if you mostly do highway driving, it may actually do worse because of the extra weight. A diesel powered car is likely to do better. A more insidious problem is that for the most part car companies are not producing hybrids so that they are more fuel efficient but because they can make for a more powerful engine. Ford and Lexus both have SUV hybrids that don't have much higher fuel efficiency than their conventional counterparts but do have a lot more horse power. Despite this shortcoming, these cars still get to go on the HOV lanes. Plug-in-hybrids have more promise if they are used around town but won't be of much help for long haul travel.

I don't fully blame the car companies because that public likes and wants big powerful cars. I think one reason is the infant car seat. We can barely fit our Britax Roundabout seat into our Honda CRV (yes, we own an SUV but it is mostly a tall Civic). We probably couldn't get two in and three is definitely out. In the old days, people would just stuff their kids into the back seat. Now, if you have three kids under eight you would need a minivan or equivalent. I'm pretty sure there could be ways to engineer a fuel efficient car that can safely transport three kids but it would require a collaboration between auto manufacturers and car seat companies. Gas would probably have to hit four or five dollars a gallon before such a thing would happen is my guess. Ultimately, we have to change the way we live and work. The demise of the personal car could be the best thing to happen to cities since the invention of the subterranean sewer.