|
|
| アミノ酸のトリプトファンが不足すると、食欲と炭水化物に対する欲求をコントロールする神経伝達物質のセロトニンの不足を招き、肥満の原因になります 。 |
| Serotonin is an important neurotransmitter
that controls appetite and carbohydrate craving. Serotonin is
produced from tryptophan and 5-hydroxytryptophan. The blood
concentrations of tryptophan and 5-hydroxytryptophan determine
the brain concentration of serotonin. This paper shows that
patients with obesity have low concentrations of circulating
tryptophan. They have a deficiency of blood tryptophan. This
deficiency does not return to normal after the obesity is reduced.
Thus, patients with obesity require larger amount of ingested
tryptophan and 5-hydroxytrptophan to suppress appetite and carbohydrate
craving. Weight reduction diets with low calories and reduced
proteins will further cause obese patients to experience hunger
and sugar craving. Weight reduction in obese patients will require
management of tryptophan deficiency. |
reum,L.; Rasmussen,M.H.; Hilsted,J.; Fernstrom,J.D.
Department of Internal Medicine and Endocrinology, HS Hvidovre
Hospital, University of Copenhagen, Hvidovre, Denmark. rklbr@ra.dk
Am.J.Clin.Nutr. 77:1112-1118:2003
BACKGROUND: Plasma tryptophan concentrations and the ratio of
tryptophan to other large neutral amino acids (plasma tryptophan
ratio) are reportedly low in obese subjects. The plasma tryptophan
ratio predicts brain tryptophan uptake and serotonin production.
If this ratio is low in obese subjects, serotonin function may
also be low. Plasma tryptophan concentrations and ratios have
been measured only at single time points in obese subjects;
it is not known whether low values for these 2 variables persist
throughout a 24-h period. OBJECTIVE: Our objective was to determine
whether plasma tryptophan concentrations and ratios in obese
subjects are lower than those in normal-weight subjects throughout
a 24-h period and whether they increase when body weight is
reduced. DESIGN: Plasma tryptophan concentrations and ratios
were examined in obese subjects before and after weight loss
and in nonobese control subjects. Blood samples were drawn frequently
throughout the 24-h period. An insulin tolerance test was also
used to determine whether weight loss altered the ability of
insulin to modify plasma concentrations of tryptophan and of
the other large neutral amino acids. RESULTS: Plasma tryptophan
concentrations and ratios in obese subjects were low at all
times; these effects persisted after weight reduction. Plasma
concentrations of all the large neutral amino acids decreased
during insulin infusion in all the groups. CONCLUSIONS: The
low 24-h plasma tryptophan ratios in obese and formerly obese
subjects suggest that brain tryptophan uptake may be continuously
diminished and may remain below normal despite weight reduction |
|
|
