Impact of folic acid supplementation on the epigenetic profile in healthy unfortified individuals – a randomized intervention trial

Figures & data

Figure 1. Graphic representation of a) RBC and b) serum folate levels of the 16 study participants after daily consumption of 400 or 800 µg folic acid. Normal range of RBC folate: 263–1028 ng/ml; serum folate: 4.6–18.7 ng/ml. Two participants had serum folate values >40 ng/ml, above the detection limit.

Table 1. Study participant characteristics at blood draws.

Characteristic		Baseline (n = 16)	Follow-up (n = 16)
Baseline Age [years; Mean (SD)]		39.22 (10.99)	–
MTHFR Genotype [N (%)]
	C/C	9 (56.25)	–
	C/T	7 (43.75)	–
Folic Acid Formulation [N (%)]
	400 μg	9 (56.25)	–
	800 μg	7 (43.75)	–
RBC Folate [ng/ml; Mean (SD)]		644.20 (151.96)	800.67 (171.96)
Serum Folate [ng/ml; Mean (SD)]		9.64 (3.10)	18.01 (7.19)
Epigenetic Clock [Mean (SD)]
	DNAmAge	41.63 (10.13)	41.79 (11.25)
	DNAmAgeHannum	37.89 (11.56)	39.46 (11.41)
	DNAmDunedinPACE	0.70 (0.10)	0.73 (0.08)
	DNAmGrimAge	39.57 (8.73)	39.11 (8.94)
	DNAmGrimAge2	42.25 (8.70)	42.15 (9.11)
	DNAmPhenoAge	24.40 (12.13)	23.26 (13.24)
	DNAmTL	7.38 (0.29)	7.30 (0.28)
	Genome-Wide Mean	0.53 (0.00)	0.53 (0.00)
DNAm-based Estimates of Cell Composition [Mean (SD)]
	CD8+ T Cells	0.23 (0.08)	0.23 (0.08)
	CD4+ T Cells	0.31 (0.08)	0.29 (0.09)
	Natural Killer Cells	0.13 (0.05)	0.15 (0.07)
	B-Cells	0.11 (0.04)	0.11 (0.04)
	Monocytes	0.21 (0.07)	0.23 (0.07)
	Neutrophils	0.02 (0.03)	0.01 (0.01)

Figure 2. Correlation between AgeAccel and a) RBC folate, and b) serum folate at baseline. Point colour corresponds to participant.

Figure 3. The longitudinal change in AgeAccel a) over follow-up, and in relation to the change in b) RBC folate, and c) serum folate. Point colour corresponds to participant.

Table 2. Association between AgeAccel and folate levels.

		RBC Folate (per 100 ng/ml)		Serum Folate (per 10 ng/ml)
AgeAccel Outcome		Estimate (95% CI)	P-value	Estimate (95% CI)	P-value
Baseline Associations^A
	DNAmAge	0.50 (−1.59, 2.60)	0.613	1.68 (−8.89, 12.25)	0.737
	DNAmAgeHannum	0.62 (−1.27, 2.51)	0.490	1.62 (−8.01, 11.25)	0.722
	DNAmDunedinPACE	0.01 (−0.02, 0.04)	0.438	0.01 (−0.16, 0.18)	0.897
	DNAmGrimAge	0.53 (−0.15, 1.22)	0.115	1.89 (−1.72, 5.50)	0.279
	DNAmGrimAge2	0.42 (−0.39, 1.23)	0.286	0.93 (−3.30, 5.15)	0.643
	DNAmPhenoAge	0.75 (−0.56, 2.07)	0.239	4.51 (−1.92, 10.94)	0.154
	DNAmTL	−0.01 (−0.08, 0.05)	0.740	−0.06 (−0.38, 0.27)	0.716
	Genome-Wide Mean	0.00 (0.00, 0.00)	0.080	0.00 (−0.01, 0.00)	0.209
Associations of Change^B
	DNAmAge	2.33 (−0.35, 5.00)	0.083	−1.36 (−6.82, 4.10)	0.599
	DNAmAgeHannum	0.31 (−1.09, 1.70)	0.644	−0.90 (−3.42, 1.62)	0.454
	DNAmDunedinPACE	0.00 (−0.04, 0.05)	0.857	0.03 (−0.05, 0.10)	0.483
	DNAmGrimAge	−0.50 (−2.12, 1.12)	0.515	1.34 (−1.56, 4.25)	0.335
	DNAmGrimAge2	−0.66 (−2.32, 1.01)	0.411	1.45 (−1.56, 4.47)	0.316
	DNAmPhenoAge	1.63 (−1.44, 4.70)	0.272	−0.36 (−6.26, 5.53)	0.896
	DNAmTL	−0.05 (−0.14, 0.04)	0.290	0.06 (−0.11, 0.23)	0.442
	Genome-Wide Mean	0.00 (0.00, 0.00)	0.525	0.00 (0.00, 0.00)	0.378

AgeAccel was modelled as a function of each folate measure separately, adjusting for baseline chronological age (years) using a linear model; providing association estimate (95% confidence interval (CI)) and Wald test p-value for the coefficient. ^AAgeAccel and folate levels evaluated at baseline; ^Bmodeling the change in AgeAccel and change in folate levels.

Data availability statement

The data that support the findings of this study are available upon request from the corresponding author. The data are not publicly available due to privacy restrictions.