OASIS Study: Vitamin D Deficiency Prevention Among Older Adults in Ireland

Phase

N/A

Condition

N/A

Treatment

Unfortified bread

Fortified Bread

Clinical Study ID

NCT06705582

OASIS

Ages > 65
All Genders
Accepts Healthy Volunteers

Study Summary

Vitamin D deficiency is common. It is caused by limited sun availability together with a low supply of vitamin D in the food system. There is a high prevalence of low vitamin D status around the world. In Ireland, our relatively northern latitude and prevailing weather mean that UVB availability for skin synthesis of vitamin D is limited in this country and our population relies on the dietary supply of vitamin D to prevent deficiency. Thus, the endemic Irish problem of vitamin D malnutrition is due to the lack of vitamin D in our food system. Dietary guidelines cannot address this issue because foods naturally rich in vitamin D are very few and infrequently consumed.

The OASIS study will test the hypothesis that a vitamin D-fortified bread as part of a healthy diet that includes vitamin D-fortified foods is effective in preventing low vitamin D status during winter, and safe for older adults to consume.

Eligibility Criteria

Inclusion

Inclusion Criteria:

Provide written informed consent.
Be an adult ≥65 years.
Willing to consume bread provided and have storage capacity for frozen bread.
Be in good general health.
Be willing to follow the assigned diet for 10 weeks and attend the requiredappointments.

Exclusion

Exclusion Criteria:

Regularly consume a single high dose vitamin D supplement (>10µg/d /400 IU equivalent).

Exposure to factors that may influence vitamin D status, such as winter sun holiday,tanning bed usage.
Are following a medically prescribed diet. 4. Have a diagnosis of an acute orchronic medical condition that in the opinion of the investigator would interferewith the outcomes of the study such as Coeliac disease, Inflammatory Bowel Disease,liver disease, renal disease, pancreatic disease or gastric disease.
Have a history of active cancer or a diagnosis of cancer within the past 5 years.
Are taking certain medications that can impact vitamin D status, such asglucocorticoids.
Have regular excessive alcohol intake (≥28 units per week). 9. Have a known foodallergy. 10. Are participating in another research study with an intervention orother lifestyle programme that would interfere with the outcomes of the study.
Are unable to read, write, or understand English.

Study Design

Unfortified bread

November 11, 2024

March 31, 2025

Study Description

This randomised controlled dietary intervention study aims to recruit 200 older adults (>65 years) who will be randomised to receive vitamin D-fortified bread and advice to consume additional commercially available fortified foods (Treatment group) or identical unfortified bread and advice to consume additional commercially available fortified foods (Control group). The outcome of the study is to test whether increasing vitamin D intake through food (Treatment group) is sufficient to prevent wintertime vitamin D deficiency (measured using serum concentrations of 25-hydroxyvitamin D <30 nmol/L) in comparison with the Control group.

The target vitamin D intake for the treatment group in this study is >15-20 μg/day vitamin D. This will maintain serum concentrations of 25-hydroxyvitamin D (25(OH)D) (the biomarker of vitamin D status) > 30 nmol/L, the clinical deficiency threshold to prevent metabolic bone disease, in over 90% of participants. At this vitamin D intake level, about 80% of participants will have a 25(OH)D concentration > 50 nmol/L, the personal intake target in the US and EU.

Connect with a study center

Human Nutrition Studies Unit, School of Food and Nutritional Sciences
Cork, T12 K8AF
Ireland
Site Not Available
UCD Institute of Food and Health
Dublin, D04 N2E5
Ireland
Site Not Available

Not the study for you?

Let us help you find the best match. Sign up as a volunteer and receive email notifications when clinical trials are posted in the medical category of interest to you.