Biomarkers · Vitamins & Endocrine

Serum Folate

Higher values go with lower risk of death. Not measured in our NHANES panel. The curve is drawn from the published study (source below).

Serum Folate and risk of death

Published curve higher than the NHANES fitNHANES fit higher

Risk of death relative to the curve's reference value, drawn from the published study (source below).

Published risk of death0.78×highest vs lowest quartile of serum folate (protective form as reported) (95% CI 0.69–0.88) · NHANES III U.S. adults, mortality via National Death Index to Dec 31, 2019

Serum Folate by age and sex

Each bar runs from the 5th to the 95th percentile, the darker part from the 25th to the 75th, and the tick is the median. Not a reference range or a target.

The percentiles as a table

Each row is one sex and age band: the values below which 5%, 25%, 50%, 75% and 95% of people fall (ng/mL), from the survey named in the row. Not a reference range or a target.
Sex	Age	5th	25th	Median	75th	95th	n	Cycle / source
All	20-39	5.96	9.80	13.0	18.4	29.3	1,092	NHANES 2017-2018
All	40-59	6.05	10.8	15.5	21.5	33.9	954	NHANES 2017-2018
All	60+	6.93	12.3	19.7	30.7	49.9	987	NHANES 2017-2018
All	all	6.23	10.5	15.2	22.5	39.2	3,033	NHANES 2017-2018
Men	20-39	5.77	9.55	12.7	16.8	25.3	337	NHANES 2017-2018
Men	40-59	5.30	10.3	14.7	19.5	28.3	351	NHANES 2017-2018
Men	60+	7.59	11.9	19.3	27.5	45.1	506	NHANES 2017-2018
Men	all	6.07	10.1	14.3	20.8	34.0	1,194	NHANES 2017-2018
Women	20-39	6.06	10.1	13.9	20.5	31.7	755	NHANES 2017-2018
Women	40-59	6.84	11.0	16.7	23.9	37.6	603	NHANES 2017-2018
Women	60+	6.76	12.4	20.5	33.6	51.7	481	NHANES 2017-2018
Women	all	6.36	10.9	16.5	24.4	42.1	1,839	NHANES 2017-2018

What studies found when this marker was changed

They describe what happened in those study groups, not a recommendation. See all catalogued interventions.

Measured changes in Serum Folate, study by study

5 effects with a numeric size, each from one study arm: the dot is the reported change, the line its 95% interval where one was given. Green points move the marker the way lower risk of death lies; amber the other way. Study results in the groups studied, not predictions for a person.

Each row is one study: what was changed, the effect it reported on this marker, and the source.
Type	Intervention	Reported effect	Evidence	Source
diet	Folic acid-fortified maize porridge vs no intervention in pregnant women (Cochrane review)	Plasma folate 6.611 ng/mL higher (95% CI 4.250 to 8.972; reported as 14.98 nmol/L) vs no intervention; duration not stated; 1 study, n=38	systematic review	Centeno Tablante E, et al. Cochrane Database Syst Rev. 2019;7:CD012150.
diet	Rice fortified with iron plus folic acid and other micronutrients vs unfortified rice (Cochrane review)	Serum/plasma folate 1.898 ng/mL higher (95% CI 0.8826 to 2.913; reported as 4.30 nmol/L) vs unfortified rice; duration not stated; 1 study, n=215	systematic review	Peña-Rosas JP, et al. Cochrane Database Syst Rev. 2019;2019(10):CD009902.
environmental	Population-level mandatory folic acid fortification of wheat flour, maize flour or rice (pre- vs post-fortification meta-analysis)	Serum/plasma folate 6.620 ng/mL higher (95% CI 4.148 to 9.047; reported as 15.0 nmol/L) after vs before mandatory fortification; duration not stated	meta-analysis	Parker J, et al. J Nutr. 2026;156(3):101291.
supplement	Daily multivitamin/multimineral supplement for 16 weeks in adults aged 45-75 taking diuretics, metformin and/or proton pump inhibitors (double-blind RCT)	Serum folate rose 7.5 ng/mL from baseline after 16 weeks of MVMS (placebo -1.6 ng/mL); 35 MVMS completers	RCT	Chen O, et al. J Diet Suppl. 2022;19(1):20-33.
supplement	Oral folic acid 5 mg daily for 12 weeks vs placebo in middle-aged antidepressant-treated patients with low or marginal vitamin B-12 (FolATED trial)	Serum folate 21.6 ng/mL higher (95% CI 8.13 to 25.02) vs placebo at 12 weeks (reported as μg/L, numerically identical); n=166	RCT	Carter B, et al. J Nutr. 2021;151(12):3738-3745.

Sources

Risk curve: Zhao Y 2024 (PMID 39055385): all-cause HR 0.78 (0.69-0.88) highest vs lowest quartile of serum folate (protective form as reported). Scaled to US values (NHANES).
Zhao Y, Lv J, Liu Y, Hu H, Zhan H. Association between serum folate concentrations and all-cause mortality in U.S. adults: a cohort study based on National Health and Nutrition Examination Survey III. Frontiers in Nutrition. 2024.

Map Serum Folate against another biomarker.

Map Serum Folate against another marker