Response of Red Blood Cell Folate to Supplementation in Nonpregnant Women is Predictable: A Proposal for Personalized Supplementation

SCOPE: We modeled red blood cell (RBC)‐folate response to supplementation and developed personalized folate supplementation concepts. METHODS AND RESULTS: The changes of RBC‐folate were modeled in a time‐ (4 or 8 weeks) and dose‐ (400 or 800 μg d(−1) folate) dependent manner. Post‐supplementation RBC‐folate levels were predicted from folate‐loading capacities (= measured RBC‐folate – [baseline RBC‐folate × RBC‐survival]). The prediction equations were validated in 119 participants. The median increase of RBC‐folate was higher in the 800 μg d(−1) than in the 400 μg d(−1) group (275 vs 169 nmol L(−1) after 4 weeks, and 551 vs 346 nmol L(−1) after 8 weeks). Medians (interquartile range) of RBC‐folate loading were (4 weeks: 299 (160) vs 409 (237) nmol L(−1)) and (8 weeks: 630 (134) versus 795 (187) nmol L(−1)) in the 400 and 800 μg d(−1) group, respectively. The individual measured and predicted RBC‐folate values (after 4 weeks/400 μg d(−1) = 25 + 1.27 × baseline RBC‐folate) and (after 4 weeks/800 μg d(−1) = 65 + 1.41 × baseline RBC‐folate) did not differ significantly. The measured and predicted concentrations showed high agreement in the validation cohort. CONCLUSIONS: The models can guide nutritional recommendations in women when baseline RBC‐folate concentrations are measured and the time to pregnancy between 4 and 8 weeks.