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Read our Health & Safety Commitment in response to COVID-19.

Purpose of this study
The purpose of this study is to compare different types of iron supplements on intestinal health, inflammation, and the response of immune cells to bacteria and viruses.

Target Population
Men and post-menopausal women aged 50-80 years old

Major Exclusions
BMI <18 or >35 kg/m2
• GI disease, conditions or medications known to influence GI absorption (peptic ulcer disease, IBD, Crohn’s disease, pancreatic insufficiency)

• Anticoagulants (blood thinners), aspirin, NSAIDs (non-steroidal anti-inflammatory drugs), steroids, diabetes meds
• Regular use of any dietary supplements containing vitamins and minerals; however, subjects who are willing to refrain from the use of these supplements for 2 weeks prior to their enrollment and throughout the entire study may be considered eligible; subjects will be excluded if they are taking physician prescribed vitamin and/or mineral supplements, including iron
• History of malaria, vaccination or treatment for malaria in 3 months prior to enrollment
• Daily alcohol intake of >2 drinks, or >14 drinks/week
• Irregular bowel movements (<3 times per week)

Length of Study
4 weeks


Number of visits
1 screening visit; 1 enrollment visit to receive stool sample collection kit; 2 study visits for collection of blood and stool samples, as well as collecting and dietary and clinical information (i.e., blood pressure, weight, etc.) at the start of the study (week 0) and at the end of the study (week 4).

Study diet
Subjects must maintain their regular diet throughout the 4 week trial.

Participants must be willing to stop all dietary supplements for the duration of the study. Participants will be asked to consume different types of iron supplements (or a placebo) provided by the Jean Mayer USDA Human Nutrition Research Center on Aging for 4 weeks

$25 for screening, and up to $400 for participants who qualify and complete the entire study

Can I work?
Yes, but if subjects employed by Tufts University qualify to participate in the study, they cannot participate as volunteers during hours in which they are being compensated by Tufts University for their regular work. This includes the use of vacation, personal days and sick time.

Length of study

Total length of the study including resident stays and nonresident visits.
This does not mean you will be testing the entire time.

The length of time volunteers are required to stay overnight at the HNRCA. Residents have their own private room, bathroom, television, VCR, and phone during their stay.

The amount of reimbursement for travel and inconvenience.
Number of visits

Total number of nonresident visits.
Study diet

Indicates meals which will be provided by the HNRCA
Can I work?

Indicates if you will be able to work and if so, when.

For more information about this study, please call Volunteer Services at 1-800-738-7555 .

We appreciate your interest in our program and we hope to work with you in the future.

Thank you,
The Recruitment Office
Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University