Clinical trial NCT03030703: Cystatin SN Binds to Phytic Acid and Predicts Non-heme Iron Bioavailability
Official title: Salivary Cystatin SN Binds to Phytic Acid and is a Predictor of Non-heme Iron Bioavailability With Phytic Acid Supplementation
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Iron-deficiency
Iron Deficiency Anemia
Keywords: Phytic acid
Cystatin
Salivary proline-rich protein
antinutrient
Lead sponsor: Kansas State University
Sponsor class: OTHER
Collaborators: name: United States Department of Agriculture Foreign Agricultural Service
name: American Academy of Nurse Practitioners
First posted: 2017-01-25
Enrollment: 7
Sex: FEMALE
Minimum age (years): 18
Maximum age (years): 35
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: NA
Intervention model: SINGLE_GROUP
Primary purpose: PREVENTION

Brief summary: Phytic acid is a known inhibitor of iron bioavailability, although long term studies have suggested possibly exaggerated findings compared to single meal studies, pointing to phytic acid adaptation over time. Salivary proline-rich proteins have been found to reduce tannin-iron chelation, but studies have not explored changes in salivary proteins that may result in phytic acid adaptation. The primary objectives of this study are: 1) To determine whether phytic acid impacts iron bioavailability or status when consumed over time 2) to test whether salivary protein production may impact iron bioavailability with phytic acid supplementation, and 3) to explore in vitro phytic acid salivary binding. Secondary objectives included assessment of the reliability of astringency as a measure of salivary protein production and iron absorption.

The study was conducted in an iron absorption study of 7 women, aged 18-35 years old, to determine iron bioavailability with supplementation of 350 mg phytic acid before and after regular, three times daily supplementation for four weeks. Direct iron absorption was measured using area under the curve. Iron status was measured by changes in hemoglobin and ferritin, and was adjusted by participant c-reactive protein levels. Salivary samples were collected before and after supplement consumption during meal challenges, and analyzed on HPLC and by ELISA. Astringency testing was conducted at the end of each meal challenge. In vitro saliva-phytic acid modeling was explored on HPLC, MALDI-TOF, and ELISA. Iron absorption and status markers were analyzed by ANOVA, and mixed-modeling followed by pairwise comparison by least significant differences. Pearson's correlations were used to correlated salivary proteins and astringency with iron bioavailability.

The present study will provide important information regarding the approximate influence of phytic acid consumption on iron bioavailability and storage over time in regards to salivary proteins. It will also give context to the role of salivary proteins with phytic acid consumption over time. Data will also help to delineate possible physiological mechanisms underlying phytic acid adaptation and possible ways to detect individuals who better adapt than others.


Eligibility criteria: Inclusion Criteria:

* Female, 18-35 years' old
* Non-obese BMI (18-29.9)
* Signed informed consent

Exclusion Criteria:

* Oral disease
* Gastrointestinal disease
* Tobacco user
* Heavy alcohol user
* Pregnancy (assessed by pregnancy test)
* Lactation
* Medications affecting iron bioavailability
* Vitamin or mineral supplementation (other than vitamin B12)

Primary outcomes:
measure: Change in baseline to endline area under the curve after meal challenge at weeks 0 and 4 of intervention
timeFrame: Baseline and 4 weeks
measure: Change in baseline to endline hemoglobin and serum ferritin at weeks 0 and 4 of intervention
timeFrame: Baseline and 4 weeks
measure: Change in salivary proteins at weeks 0 and 4 of intervention
timeFrame: Baseline and 4 weeks
Secondary outcomes:
Other outcomes:
Locations:
city: Manhattan
country: United States
facility: Physical Activity and Nutrition Research Consortium
state: Kansas
Study officials:
affiliation: Kansas State University
name: Brian L Lindshield, Ph.D.
role: PRINCIPAL_INVESTIGATOR
References: