Note: Sorry to those who were interested in hearing about this topic a month ago. I was sidetracked. Life moves pretty fast – I didn’t want to miss it.
Birds do it. No, not THAT. Premastication. The process of chewing food before giving it to your young. Alicia Silverstone also does it. There has been a lot of “gross” utterances after viewing this video. Although Alicia Silverstone has done much more than Clueless (and Aerosmith videos!), she is best known for that classic 90’s movie. Perhaps her inner Clueless Cher was coming out when she posted that video, because “anything you can do to draw attention to your mouth is good.” She has been lampooned almost everywhere, especially by Jimmy Kimmel telling parents to premasticate for their own children. I think he just likes torturing kids. So I decided to look at this objectively and see if there are advantages to pre-chew food for children.
Premastication has been used to feed infants and wean them off breast milk in many cultures. A 2009 article from Gretel Pelto and colleagues, “Premastication: the second arm of infant and young child feeding for health and survival?”, attempted to determine the prevalence of premastication. The group mined Human Relations Area Files (HRAF) containing data on 370 different cultural groups around the world from the past 50 years. They found 119 files from different cultures that contained text about infant feeding or weaning, and 38 of those mentioned premastication. Of those 38 cultures, 31 practiced premastication solely to provide food to children (the others references spiritual or medicinal reasons). That means, from this sample, at least 1/4 of cultures from hunter-gatherers to agricultural societies have practiced premastication. To determine whether premastication may be under-reported in these ethnographic studies, they recruited Chinese students from the University of Beijing to interview their mothers or caregivers and ask about infant feeding practices. From 104 interviews, 63% of caregivers had practiced premastication. Based on these snapshots, the actual number of caregivers that use premastication to feed their children may be higher than reported. A 2008 FDA study in the U.S. found only 14% of mothers pre-chewed their infant’s food, with an inverse correlation to education. Premastication can vary greatly between regions and cultures within America, as 65% of African-American mothers and grandmothers from Omaha, Nebraska reported premastication practices. These numbers my be surprisingly high for those that have not been exposed to this behavior, but clearly show that premastication is used to feed children in many modern societies. The real controversy stems from whether this practice is actually beneficial to children.
Breast milk should be supplemented with other foods for children around 6 months old to provide proper nutrition. Several studies have determined that production of salivary enzymes change with age, tooth eruption, and diet. There is an increase in amylase, or the enzyme that breaks down starches, as the child grows. By 3 months of age, children have 66% salivary amylase activity as adults. The importance of salivary amylase is somewhat controversial because the pancreas also secretes this enzyme into the small intestine during digestion. By 9 months of age, children have adult levels of pancreatic amylase production. In fact, many digestive enzymes that break down protein and fat are found past the mouth in the digestive tract. Unless there is a known problem with a child’s salivary enzymes, there are no data I could find to support the need for adult salivary enzymes in children’s mouths. In fact, as children are exposed to more foods, their bodies adapt to produce more enzymes on their own.
On the other hand, there is actually a lot of overlap between antimicrobial factors (which help the immune system), hormones, and growth factors between breast milk and saliva. When a child is weaning off breast milk, premastication could provide some beneficial factors that the child is losing from reduced consumption of breast milk, but again, many of those factors children begin producing themselves. Some believe premastication is a way to bond with your child, although you don’t have to perform mouth-to-mouth to transfer pre-chewed food. A hug and a kiss might work to bond also.
The biggest problem with premastication arises from the transfer of pathogens. This is especially problematic in less developed countries where more people unknowingly carry hepatitis, herpes, HIV, Epstein-Barr, and other viruses. Peridontic diseases can also be transmitted from the mother to the child. Even in developed countries where mothers know their viral status, premastication could transmit H. pylori, the bacteria that causes stomach ulcers.
Although some argue that premastication is beneficial and has just fallen ‘out of vogue’ much like breastfeeding did 50 years ago, the major benefits of premastication remain unproven. There are no controlled trials on premastication because they would be unethical to perform. Premastication was probably necessary before the average person could easily make or buy their own baby food. The science behind premastication is just not there yet to promote the practice if other means to feed a child are available. However, I don’t think anyone should be condemned if they choose to premasticate. If a mother is free from transmissible diseases and feels like this might help a child wean off breast milk, then she could try it…but maybe don’t post a video of it on the internet. For everyone else, just put the meat in the blender.