Journal Article

Histidine supplementation improves insulin resistance through suppressed inflammation in obese women with the metabolic syndrome: a randomised controlled trial

Feng, R. N., Sun, C. H., Li, Q., Sun, X. W., Zhao, C., Wang, C., Guo, F. C., Li, Y., Niu, Y. C.

2013

Overview

Aims/hypothesis Increased inflammation and oxidative stress are associated with insulin resistance (IR) and metabolic disorders. Serum histidine levels are lower and are negatively associated with inflammation and oxidative stress in obese women. The objective of this study was to evaluate the efficacy of histidine supplementation on IR, inflammation, oxidative stress and metabolic disorders in obese women with the metabolic syndrome (MetS). Methods A total of 100 obese women aged 33–51 years with BMI ≥ 28 kg/m 2 and diagnosed with MetS were included following a health examination in the community hospital in this randomised, double-blinded, placebo-controlled trial. Participants were allocated to interventions by an investigator using sequentially numbered sealed envelopes and received 4 g/day histidine ( n  = 50) or identical placebo ( n  = 50) for 12 weeks. Participants then attended the same clinic every 2 weeks for scheduled interviews and to count tablets returned. Serum histidine, HOMA-IR, BMI, waist circumference, fat mass, serum NEFA, and variables connected to inflammation and oxidative stress were measured at baseline and 12 weeks. Participants, examining physicians and investigators assessing the outcomes were blinded to group assignment. In addition, the inflammatory mechanisms of histidine were also explored in adipocytes. Results At 12 weeks, a total of 92 participants completed this trail. Compared with the placebo group ( n  = 47), histidine supplementation significantly decreased HOMA-IR (−1.09 [95% CI −1.49, −0.68]), BMI (−0.86 kg/m 2 [95% CI −1.55, −0.17]), waist circumference (−2.86 cm [95% CI −3.86, −1.86]), fat mass (−2.71 kg [95% CI −3.69, −1.73]), serum NEFA (−173.26 μmol/l [95% CI −208.57, −137.94]), serum inflammatory cytokines (TNF-α, −3.96 pg/ml [95% CI −5.29, −2.62]; IL-6, −2.15 pg/ml [95% CI −2.52, −1.78]), oxidative stress (superoxide dismutase, 17.84 U/ml [95% CI 15.03, 20.65]; glutathione peroxidase, 13.71 nmol/ml [95% CI 9.65, 17.78]) and increased serum histidine and adiponectin by 18.23 μmol/l [95% CI 11.74, 24.71] and 2.02 ng/ml [95% CI 0.60, 3.44] in histidine supplementation group ( n  = 45), respectively. There were significant correlations between changes in serum histidine and changes of IR and its risk factors. No side effects were observed during the intervention. In vitro study indicated that histidine suppresses IL6 and TNF mRNA expression and nuclear factor kappa-B (NF-κB) protein production in palmitic acid-induced adipocytes in a dose-dependent manner, and these changes were diminished by an inhibitor of NF-κB. Conclusions/interpretation Histidine supplementation could improve IR, reduce BMI, fat mass and NEFA and suppress inflammation and oxidative stress in obese women with MetS; histidine could improve IR through suppressed pro-inflammatory cytokine expression, possibly by the NF-κB pathway, in adipocytes. Trial registration www.chictr.org/cn/ChiCTR-TRC-11001551 Funding The study was supported by the National Natural Science Fund of China (No. 81202184, 81130049, 81102112), Heilongjiang Post/doctoral Fund (No. LBN-Z12193) and Key Laboratory of Nutrition and Food Hygiene (Harbin Medical University, Heilongjiang Higher Education Institutions, No. YYKFKT1202).

• Publisher: Springer-Verlag,Springer,Springer Nature B.V
• Subject: Adipocytes / Adipose Tissue, White - immunology / Adipose Tissue, White - metabolism / Adult / Anti-Inflammatory Agents, Non-Steroidal - adverse effects / Anti-Inflammatory Agents, Non-Steroidal - blood / Anti-Inflammatory Agents, Non-Steroidal - metabolism / Anti-Inflammatory Agents, Non-Steroidal - therapeutic use / Biological and medical sciences / Blood pressure / Body Mass Index / Cardiovascular disease / Cell Line / Chronic illnesses / Cytokines - antagonists & inhibitors / Cytokines - genetics / Cytokines - metabolism / Diabetes / Diabetes. Impaired glucose tolerance / Dietary Supplements - adverse effects / Disease control / Double-Blind Method / Down-Regulation / Endocrine pancreas. Apud cells (diseases) / Endocrinopathies / Etiopathogenesis. Screening. Investigations. Target tissue resistance / Female / Histidine - adverse effects / Histidine - blood / Histidine - metabolism / Histidine - therapeutic use / Human Physiology / Humans / Hypotheses / Inflammation / Insulin Resistance / Internal Medicine / Medical sciences / Medicine / Medicine & Public Health / Metabolic Diseases / Metabolic disorders / Metabolic syndrome / Metabolic Syndrome - complications / Metabolic Syndrome - diet therapy / Metabolic Syndrome - immunology / Metabolic Syndrome - metabolism / Middle Aged / Miscellaneous / Nutrition / Obesity / Obesity - complications / Other metabolic disorders / Oxidative Stress / Pilot Projects / Public health / Waist Circumference / Weight Loss / Womens health