Topical Area: Energy and Macronutrient Metabolism
Objectives : Histidine is an essential amino acid found in the diet through protein-rich foods. Previous research demonstrated benefits of histidine due to anti-inflammatory, anti-oxidant, and glucoregulatory properties. To date, histidine requirement for adults has not be established; current expert opinion for histidine is 8 and 12 mg/(kg body weight x day), an estimate that was extrapolated from the infant requirement for histidine. Further, the clinical safety of histidine supplementation above the average dietary intake has not been determined. Objective: To determine the safety of graded-doses of histidine in a healthy adult population.
Methods : Our preliminary study includes 30 adults (n=12 males and n=18 females, aged 21-50 y). Following the completion and review of a health history questionnaire, vitals, and a biochemical panel, participants were deemed healthy and able to participate. After baseline measures were obtained, participants consumed encapsulated histidine pills daily for four weeks followed by a three-week washout period between each dose. Participants consumed one of three doses (4 g, 8 g, and 12 g) of histidine during each of the four-week supplement periods. A complete biochemical panel was run at baseline, week 2 and 4 of supplement, as well as washout. Anthropometric, body composition, sleep patterns, dietary intake, and urine samples were also collected throughout the study (analyses underway).
Results : Baseline descriptive statistics are as follows for females [males]: body weight 65±0.55 kg [62.91±3.17 kg], systolic pressure 113±.54 mmHg [125 ± 2.93 mmHg], diastolic pressure 70±.48 mmHg [74± 3.22 mmHg], and heart rate 74±0.56 bpm [63±3.17 bpm]. There were no observed differences between baseline and measurements taken at any of the three doses for body weight, systolic blood pressure, diastolic blood pressure, and heart rate. There was no effect of histidine dose on the biochemical measures of aspartarte amino transferase (U/L, p=0.096), alanine amino transferase (U/L, p= 0.47), creatinine (mg/dL, p=0.79), glucose (mg/dL, p=0.06), insulin (μIU/ml, p=0.48), or c-reactive protein (mg/L, p=0.19).
Conclusions : In our current analyses, we observe no deleterious effects of taking up to 12 grams of histidine in healthy young adults.
Funding Sources : International Council on Amino Acid Science