Comparison of Beta-cryptoxanthin Bioavailability From Biofortified Maize in Humans

Study Overview
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Brief Summary
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The purpose of this study is to determine how well the body absorbs the carotenoid beta-cryptoxanthin (BCX) from a type of corn that has been naturally bred (not genetically engineered) to contain higher amounts of BCX than traditional breeds of corn. Because this new type of corn contains higher amounts of BCX, it appears more orange in color than traditional types of corn. Understanding how well the body can absorb the BCX from the corn may help companies develop food products that may have improved nutritional quality.

Detailed Description
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Randomized, blinded, 3 x 3 crossover intervention. Each treatment will last 12 d, followed by a 7-d wash-out period. After the washout, subjects will go back to their regular diet for two weeks before beginning the next cycle. Subjects will report to the research kitchen in the Nutritional Sciences building for their breakfast. Maize will be incorporated into two muffins. Other food choices will be yogurt and other low-fiber foods. Blood samples will be taken at baseline and days 3, 6, 9, 12, 15, and 19. Natural abundance measurements of 13-carbone to 12-carbon will be taken at baseline, day 12 and day 19. Retinol isotope dilution testing will be done at the end of the study to determine total body stores of vitamin A in the subjects. This will include the day 19 blood sample of intervention phase 3 and a final blood sample 14 days after the isotope dose administration.

Official Title
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Comparison of Beta-cryptoxanthin Bioavailability From Biofortified Maize in Humans

Conditions
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β-cryptoxanthin Bioavailability From Biofortified Maize in Humans

Intervention / Treatment
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* Other: Whole grain high-BCX maize
* Other: Refined grain high-BCX maize
* Other: Whole grain white maize


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age 20 - 28 y, BMI 19 - 26 kg/m2, non-smoking, not pregnant or trying to become pregnant, and not lactating. Exclusion Criteria: Smoker BMI < 19 kg/m^2 or BMI > 26 kg/m^2 Women: pregnant or trying to become pregnant, breast-feeding Weight loss greater than or equal to 10 pounds (4.5 kilograms) during the 3 months prior to recruitment Actively trying to lose weight Fat malabsorptive disorders Inability to refrain from drinking alcohol when requested Amenorrhea Acute or chronic illness, including hepatitis Current or previous history of anorexia or bulimia History of iron deficiency anemia Inability to pick up food from research facility and eat meals on site when requested Planned vacation of >1 week duration during the study Known scheduling conflict with the blood draws Major food allergies/intolerance to ingredients used in the meals Unwillingness to discontinue personal nutritional supplements/vitamins when asked to Concurrent participation in other studies Social circumstances that would make it difficult to consume a study food Family member already enrolled in the study

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 28 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Whole grain high-BCX maize<br>Whole grain, high-beta-cryptoxanthin (BCX; orange) maize will be incorporated into two muffins to be fed daily for 12 days. Complementary diet will be low in carotenoids. | Other: Whole grain high-BCX maize<br>* The whole grain orange maize will be milled and prepared into muffins to be consumed daily. Muffins will contain a target of 500 µg beta-cryptoxanthin per day.<br>* Other names: Whole grain orange maize;|
| Experimental: Refined grain high-BCX maize<br>Refined (degermed) grain, high-beta-cryptoxanthin (BCX; orange) maize will be incorporated into two muffins to be fed daily for 12 days. Complementary diet will be low in carotenoids. | Other: Refined grain high-BCX maize<br>* The refined grain orange maize will be degermed, milled, and prepared into muffins to be consumed daily. Muffins will contain a target of 500 µg beta-cryptoxanthin per day.<br>* Other names: Refined grain orange maize;|
| Placebo Comparator: Whole grain white maize<br>Whole grain, white maize (low in beta-cryptoxanthin) will be incorporated into two muffins to be fed daily for 12 days. Complementary diet will be low in carotenoids. | Other: Whole grain white maize<br>* The whole grain white maize will be milled and prepared into muffins to be consumed daily. Muffins will contain minimal beta-cryptoxanthin, matched for dry maize weight.<br>* Other names: Whole grain low-beta-cryptoxanthin maize;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Serum beta-cryptoxanthin concentration area under the curve ((µmol/L)*t) | Serum beta-cryptoxanthin concentration area under the curve calculated from samples on days 0, 3, 6, 9, 12, 15, 19 of treatment phase | 19 days with blood samples drawn on days 0, 3, 6, 9, 12, 15, 19 of treatment phase | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Serum retinol carbon-13 natural abundance (δ 13C‰) | Change in serum retinol carbon-13 natural abundance will be assessed from beginning to after each treatment period. This will be done on baseline, day 12 and day 19 blood samples. | 19 days and will be measured on days 0, 12, and 19 | 
| Vitamin A total body stores (µmol vitamin A) by retinol isotope dilution | After a blood draw, a carbon-13 labeled vitamin A oral dose will be given to subjects after all treatments. After 14 days, another blood draw will be taken to determine dilution of the stable isotope dose. This will used the final blood sample of intervention phase 3 and a final blood draw 14 days later. | 14 days and will include the final blood of phase three and another sample 14 days later | 
| Vitamin A estimated total liver reserves (µmol vitamin A/g liver) by retinol isotope dilution | After a blood draw, a carbon-13 labeled vitamin A oral dose will be given to subjects after all treatments. After 14 days, another blood draw will be taken to determine dilution of the stable isotope dose. This will used the final blood sample of intervention phase 3 and a final blood draw 14 days later. | 14 days and will include the final blood of phase three and another sample 14 days later | 
| Serum zeaxanthin, lutein, and beta-carotene concentration area under the curves ((µmol/L)*t) | Serum carotenoid concentration area under the curves calculated from samples on days 0, 3, 6, 9, 12, 15, 19 of treatment phase | 19 days with blood samples drawn on days 0, 3, 6, 9, 12, 15, 19 of treatment phase |