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United States Department of Agriculture

Agricultural Research Service

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Cobalamin Absorbtion from Fortified Food in Older Adults with and without Atrophic Gastritis


"PPI Subjects"


USDA, ARS Western Human Nutrition Research Center invites healthy men and women, ages 60 years and older, who use proton pump inhibitors daily (Prilosec, Nexium, Aciphex, Prevacid, or Protonix), to participate in an 8 day study with a total of 10 study visits on the UC Davis campus.  The study will test how the human body absorbs Vitamin B-12 from B12 fortified bread.


Who is conducting this study?

The study is conducted by Lindsay Allen, PhD and Marge Garrod, PhD. The study has been reviewed and approved by the UC Davis Committee for the Protection of Human Studies. There is only minimal health risk associated with participation in this study.


What is the purpose of the study?

The study will investigate how much vitamin B12 is absorbed by the human body after consuming a food (wheat bread).


Who can participate?

Healthy men and women, ages 60 and older, who use Prilosec, Nexium, Aciphex, Prevacid, or Protonix (proton pump inhibitors) daily, may be eligible to participate. Volunteers must be willing and able to come to the research center (WHNRC) on the UC Davis campus for a total of 10 study visits; an 8day study as well as 2study visits for screening and preparation.  Volunteers must be able to commit to 9 consecutive days for the study - a single preparation day and 8 days participation in the actual study.


Who is NOT eligible to participate?

* Persons who are younger than 60 years of age,


* Persons with Vitamin B-12 deficiency (we will check this at screening)


* Persons who are unable to eat wheat due to allergy or intolerance


* Persons with known medical conditions, including anemia, kidney disease, or  

  gastrointestinal disease or surgery.


*Excessive alcohol consumption


* Women who are taking oral contraceptives, or who are pregnant or nursing


What do I need to do to participate?

You will complete a health screening at WHNRC, 430 West Health Sciences Drive on the UC Davis campus. The screening visit will last about 60 minutes, and will occur in the morning after an overnight fast. This means that no food or drink is consumed for 12 hours prior to the appointment, but water is allowed and encouraged. A blood sample will be taken for measurement of vitamin B-12 status and to check for anemia. A health history questionnaire will be completed.


If you are selected as a participant in this study, you will be asked to consume a wheat bread roll containing vitamin B-12 that has been labeled with the radioactive isotope 14C.  You will also be asked to provide blood samples at various times over an 8-day period and to collect all yoururine and stool for all 8 days of the study.  There is one study visit lasting ~12 hours on study day one, and a morning study visit that lasts about 30 minutes on each of the next 8consecutive days. During the 12-hour visit you will have an indwelling catheter for blood drawing, and will not be able to leave the WHNRC. You can bring books, magazines, or other media to keep you occupied during the visit. You will receive 3 meals to eat, snacks, and beverages to drink. Overnight you will be asked to continue collection of all your urine and stool.  You will then return to the WHNRC for a single blood draw the following morning (study day 2).  At that visit you will deliver your overnight urine and stool collections and you will receive new containers for the next 24 hour collection.  You will repeat this schedule of visits and urine and stool collections through study day 8. 


What are your compensations from this study?

You will receive 3 meals on the long day of the study as well as monetary compensation. Volunteers will be compensated at the rate of $6 per biological sample for a total of $250.


What should I do if I have questions?

Call (530) 752-5177 and press #7. 







Last Modified: 8/13/2016
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