High Bioavailability of Spinach Folate Evaluated by Functional Biomarkers in a Folate Depletion-Repletion Mouse Model

Area of Science:

• Nutritional Biochemistry
• Food Science
• Toxicology

Background:

• Natural folates have lower bioavailability than synthetic folic acid (FA).
• The universal applicability of this 50% lower bioavailability to all food folates is uncertain.
• Spinach folate bioavailability requires specific investigation.

Purpose of the Study:

• To investigate the bioavailability of folate from spinach.
• To compare spinach folate bioavailability with synthetic folic acid (FA) using multiple biomarkers.
• To assess the impact of folate source on folate status and chromosomal damage in a mouse model.

Main Methods:

• A folate depletion-repletion mouse model was employed.
• Mice were fed a folate-deficient diet, then repleted with either FA or spinach folate.
• Biomarkers included folate levels (plasma, liver, bone marrow), plasma homocysteine, and chromosomal damage post-irradiation.

Main Results:

• Spinach folate repletion restored tissue folate levels to 69-68% of FA levels.
• Spinach folate reduced plasma homocysteine and chromosomal damage to 83% and 93-117% of FA levels, respectively.
• Functional biomarkers indicated spinach folate bioavailability exceeded 83% of FA.

Conclusions:

• The bioavailability of folate from spinach is comparable to synthetic folic acid (FA), particularly when functional biomarkers are considered.
• Dietary folate from spinach effectively mitigates markers of folate deficiency and chromosomal damage.
• Findings challenge the generalized assumption of significantly lower bioavailability for all natural folates compared to FA.