Depressed humoral immunity after weight reduction in competitive judoists

Seikou Ohta, Shigeyuki Nakaji*, Katsuhiko Suzuki, Manabu Totsuka, Takashi Umeda, Kazuo Sugawara

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

27 Citations (Scopus)


We studied changes in serum opsonic activity (SOA) in male judoists who were engaged in active weight reduction. Serum immunoglobulins, complements and SOA, measured by neutrophil-associated chemiluminescence responses, were investigated 20 days, 7 days and 1 day before a competition and 5 days after the competition. In addition, muscle strength and anaerobic work capacity, as well as body composition, were also determined. A dietary survey was conducted daily during the observation period. Body weight decreased by 4.2 kg over 19 days. SOA significantly decreased 5 days after the competition, as well as the concentrations of serum immunoglobulins, complements and total proteins. These trends were noted in the marked weight reduction group (i.e. reduction weight of body fat/body fat weight before weight reduction ≧25%) more than the slight reduction group (<25%). Depressed SOA was closely correlated with the decreased concentrations of immunoglobulins and complements. These results suggest that the decrease in immunoglobulins and complements following weight reduction is associated with reduced SOA, which might cause susceptibility to infections. This study demonstrated that such immunosuppression appeared in the recovery period after the competition rather than immediately before the competition.

Original languageEnglish
Pages (from-to)150-157
Number of pages8
Issue number3
Publication statusPublished - 2002 May
Externally publishedYes


  • Complements
  • Immunoglobulins
  • Judoist
  • Serum opsonic activity
  • Weight reduction

ASJC Scopus subject areas

  • Biophysics
  • Chemistry (miscellaneous)


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