Determination of Folate Bioavailability From Brewer's Yeast in a Dual Isotope Randomized Human Intervention Study

Area of Science:

• Nutritional biochemistry
• Human physiology
• Food science

Background:

• Adequate folate intake is crucial for health.
• Folate bioavailability varies significantly.
• Brewer's yeast is a potential folate source.

Purpose of the Study:

• To assess the bioavailability of folate from brewer's yeast.
• To utilize a novel dual isotope design for accurate measurement.
• To establish brewer's yeast folate bioavailability relative to a reference standard.

Main Methods:

• Human pilot study with 6 volunteers.
• Dual isotope design using ¹⁵N-labeled yeast and ¹³C-labeled folate reference.
• Stable isotope dilution assays on 21 plasma samples per volunteer.

Main Results:

• Yeast folates exhibited a mean bioavailability of 74% relative to 5-methyltetrahydrofolate.
• The dual isotope method provided accurate bioavailability data.
• Intrinsically labeled foods are suitable for natural folate bioavailability assessment.

Conclusions:

• Brewer's yeast provides a bioavailable source of folate.
• Intrinsically labeled food matrices enhance folate bioavailability studies.
• This method is valuable for understanding nutrient absorption from whole foods.