TITLE:
Effects of Cow Milk Intake at Breakfast on the Circadian Typology and Mental Health of Japanese Infants Aged 1 - 6 Years
AUTHORS:
Hitomi Takeuchi, Kai Wada, Kiyoko Kawasaki, Milada Krejci, Teruki Noji, Takahiro Kawada, Miyo Nakade, Tetsuo Harada
KEYWORDS:
Cow Milk in the Morning; Circadian Typology; Mental Health; Japanese Infants
JOURNAL NAME:
Psychology,
Vol.5 No.2,
February
27,
2014
ABSTRACT: Tryptophan
intake at breakfast has been known to be effective on promoting better mental
health and morning-typed life through serotonin and melatonin synthesis. For
Japanese children, milk seems to be important resource for taking tryptophan at
breakfast because of limited meal time in the morning. This study tries to show
the effects of milk intake at breakfast on circadian typology and mental health
of Japanese infants aged 1 - 6 years. An integrated questionnaire was
administrated to 1100 infants aged 1 - 6 years attending nursery schools or
kindergarten in June 2012. Seven hundred and forty participants (67.3%, 360
females and 380 males, mean age: 3.5 ± 1.4) answered the questionnaire. The
questionnaire included questions on sleep habits, the diurnal type scale by
Torsvall and ?kerstedt (1980), questions on mental health (anger and
depression), and meals contents and time. Infants who took milk at breakfast
showed 21.2 (±3.4, n = 537) of the diurnal type scale scores on average which
tended to be higher (more morning-typed) than 20.7 (±3.5, n = 142) (p = 0.085) shown by those who did not
take milk. Infants who took carbohydrate (or carbohydrate and protein resource)
plus milk at breakfast were significantly morning-typed than those who took
only carbohydrate (or carbohydrate and protein resource) (p p = 0.098). Taking milk at breakfast might be effective to promote
serotonin synthesis in the morning which could improve mental health directly
and become “inner” zeitgeber for circadian clocks in infants.