title: 5-aminolevulinic acid, a precursor of heme, reduces both fasting and postprandial glucose levels in mildly hyperglycemic subjects.
abstract: OBJECTIVE
  The aim of this study was to evaluate the combined effects of 5-aminolevulinic acid phosphate (ALA-P) and iron on the glycemic index in mildly hyperglycemic adults.
  
  
  METHODS
  This double-blind, randomized placebo-controlled trial comprised 212 subjects (ages 35-70 y, fasting plasma glucose 105-125 mg/dL or hemoglobin (Hb)A1c 6.1%-7.1%). These participants were randomly assigned to four groups receiving either one of three doses of ALA-P and iron as sodium ferrous citrate (5 mg and 0.6 mg, 5 mg and 1.8 mg, or 15 mg and 1.8 mg, respectively) or a placebo, administered orally once a day over a 12-wk period.
  
  
  RESULTS
  Fifteen mg ALA-P plus 1.8 mg iron decreased the fasting plasma glucose level (2.32 mg/dL, 95% confidence interval [CI], 0.24-4.42, P = 0.029), serum glycoalbumin (0.22%, 95% CI, 0.02-0.42; P = 0.031), and 2h-oral glucose tolerance test levels (14.2 mg/dL, 95% CI, 1.8-26.6; P = 0.025) more than the placebo. However, the levels of HbA1c, fasting insulin, serum 1,5-anhydro-d-glucitol, and Homeostasis Model of Assessment-Insulin Resistance showed no appreciable changes. The participant numbers with impaired glucose tolerance and impaired fasting glucose decreased in the highest dosage group of ALA-P plus iron compared with the placebo group.
  
  
  CONCLUSIONS
  An oral intake of ALA would be a novel approach to prevent type 2 diabetes mellitus.
authors.affiliation: Project Research Center for Clinical Trial and Preventive Medicine, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.
authors.forename: Fumiko
authors.initials: F
authors.lastname: Higashikawa
authors.forename: Masafumi
authors.initials: M
authors.lastname: Noda
authors.forename: Tomokazu
authors.initials: T
authors.lastname: Awaya
authors.forename: Tohru
authors.initials: T
authors.lastname: Tanaka
authors.forename: Masanori
authors.initials: M
authors.lastname: Sugiyama
mesh_terms: D000328:Adult; D000368:Aged; D000622:Aminolevulinic Acid / Q000008:administration & dosage*; D001786:Blood Glucose / Q000032:analysis; D004311:Double-Blind Method; D005215:Fasting / Q000097:blood; D005260:Female; D005951:Glucose Tolerance Test; D006418:Heme / Q000378:metabolism*; D006801:Humans; D006943:Hyperglycemia / Q000188:drug therapy*; D007004:Hypoglycemic Agents / Q000008:administration & dosage; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance; D019266:Iron, Dietary / Q000008:administration & dosage; D008297:Male; D008875:Middle Aged; D019518:Postprandial Period / Q000187:drug effects* / Q000502:physiology
chemical_list: D001786:Blood Glucose; D007004:Hypoglycemic Agents; D007328:Insulin; D019266:Iron, Dietary; D006418:Heme; D000622:Aminolevulinic Acid