Using lutein-fortified yoghurt as a vehicle to deliver lutein to humans – a bioavailability study

Fortification with Xanthophylls trial

Status

Active, not recruiting

Phases

Unknown

Study type

Interventional

Source

ISRCTN

Registry ID

ISRCTN45322893

Enrollment

Registered

2022-06-28

Start date

2022-02-14

Completion date

Unknown

Last updated

2023-09-18

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Improve the nutritional quality of the human diet in order to prevent and/or reduce the risk of chronic diseases (e.g. Alzheimer's disease, macular degeneration). Not Applicable

Interventions

Random allocation sequencing will be performed by the study statistician. Participants will be randomly allocated between two active and one placebo intervention groups and a 5% level of significance

Eligibility

Sex/Gender

All

Inclusion criteria

Inclusion criteria: 1. Aged 18 - 64 years. 2. Not consumed any carotenoid food supplements in the last 3 months. 3. No dairy or fish allergy. 4. Never diagnosed with a form of cognitive impairment (e.g. Alzheimer's disease), stroke, or eye disease (e.g. glaucoma) by a medical professional.

Exclusion criteria

Exclusion criteria: 1. Under 18 years of age or older than 65 years. 2. Has consumed regularly a carotenoid food supplements in the last 3 months. 3. Has an allergy to dairy or fish. 4. Has been diagnosed with a form of cognitive impairment (e.g. Alzheimer's disease), stroke, or eye disease (e.g. glaucoma) by a medical professional.

Design outcomes

Primary

Measure	Time frame
Serum carotenoid concentrations (umol/L) of lutein, zeaxanthin and meso-zeaxanthin will be measured in blood at baseline, 2 weeks and 4 weeks, and quantified using high-performance liquid chromatography. Of note, while meso-zeaxanthin is not contained in the fortified yoghurt, its quantification is required as part of the HPLC methodology in order to determine zeaxanthin levels in blood.	—

Secondary

Measure	Time frame
1. Tissue carotenoid concentrations measured at baseline and 4 weeks using the Pharmanex BioPhotonic Scanner. 2. Inflammatory cytokines (IL-6, IL-1ß, and TNF-a) measured measured in blood at baseline, 2 weeks and 4 weeks and quantified using solid-phase sandwich enzyme-linked immunosorbent assay (ELISA). 3. Total antioxidant capacity measured in blood at baseline, 2 weeks and 4 weeks using colorimetric microplate assay.	—

Measure

Time frame

1. Tissue carotenoid concentrations measured at baseline and 4 weeks using the Pharmanex BioPhotonic Scanner. 2. Inflammatory cytokines (IL-6, IL-1ß, and TNF-a) measured measured in blood at baseline, 2 weeks and 4 weeks and quantified using solid-phase sandwich enzyme-linked immunosorbent assay (ELISA). 3. Total antioxidant capacity measured in blood at baseline, 2 weeks and 4 weeks using colorimetric microplate assay.

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Countries

Ireland

Outcome results

None listed

Source: ISRCTN (via WHO ICTRP) · Data processed: Feb 4, 2026