It also probably helps transmit essential bacteria and other critters to the digestive system of the infant. We are just now finding out how important the right bacteria are to health. They’ve even found that some produce chemicals used by the brain. And because so many people with autism have stomach problems, and we live in an overclean society that kills off bacteria and keeps it out of our digestive systems (and mothers no longer pre-masticate), that there might be a connection between it and autism.
In reality, maternal oral flora is not considered a significant source of normal gut flora in infants. Skin and breast milk are contributors. Vaginal and even fecal flora are encountered during (non-Caesarean) birth and help colonize the infant gut.
But we’re talking about normal and beneficial changes that occur very early in life - not at the time of weaning.
A careful reading would have revealed that the “potentially decisive covariate” they’re talking about is increased risk of HIV transmission by mothers in (presumably) Third World settings pre-chewing their kids food.
I do not see any explanation of supposed benefits of this practice. The thrust of the linked letter is that 1) breastfeeding along with giving solid food to infants might offer some protection against HIV transmission, and 2) prechewing babies’ food appears to increase risk of HIV transmission.
Apart from linking to this one letter to a journal editor (which doesn’t provide any basis for supporting “pre-mastication”) you’ve been remarkably silent about risks of disease transmission (involving multiple pathogens as well as HIV which are prevalent around the world, including wealthy societies where washed-up actresses indulge weird health practices and preach pseudoscience).
*“The most commonly reported reasons for premastication, reported from a predetermined list, were “child wanting some of the caregiver’s food” (64%), “caregiver not wanting the child to choke” (62%), and “prechewing is done in my family” (31%) (Table 2)…”
“In 2008, a case series of three pediatric HIV cases concluded that premastication was the likely mode of transmission for these children, a route not reported previously (1). Bleeding gums at the time of premastication were reported in caregivers of two of the three children in the case series. The third caregiver could not recall her dental condition at the time of premastication…”
In addition to HIV, transmission of hepatitis B virus (3) and group A streptococcus (6) by premastication has been documented. Furthermore, premastication has been found to be associated with increased risk for infection with Helicobacter pylori (7), Streptococcus mutans (2), human herpesvirus 8 (4), and Epstein Barr virus (5). Only one study has indicated that premastication can be associated with decreased risk for infection; that study involved respiratory syncytial virus in Alaska Native infants aged <6 months* (note that this possible benefit disappeared under additional statistical analysis).*
The prevalence of premastication observed in this investigation is particularly important because most of the caregivers and premasticators were biologic mothers; thus, most caregivers were HIV-infected, posing a potential risk for HIV transmission to children in their care who are uninfected. Furthermore, the higher prevalence of premastication among black and younger caregivers suggests the need for targeted prevention messages for these populations."*
Ugh. Again: People, stop pretending that actors (or any other “star”, for that matter) has anything more valuable to say on a matter outside of their field than the random guy you ask on the street. The only thing special about their point of view is that it’s got a soapbox to broadcast from.