A cross-sectional study of nutritional status in healthy, young, physically-active German omnivores, vegetarians and vegans reveals adequate vitamin B12 status in supplemented vegans

Figures & data

Figure 1. Flow diagram of eligibility criteria of the present study. A total of 40 omnivores, 37 lacto-ovo-vegetarians and 38 vegans were enrolled in the study. The resulting cohort was comprised of three dietary groups with comparable age, sex, marital status, educational level, and ethnicity.

Table 1. Sociodemographic and anthropometric data of study participants by dietary group.

	Omnivores (n = 40)	Lacto-Ovo-Vegetarians (n = 37)	Vegans (n = 38)	p-value
Age (years)	30.5 (10.5)	27 (9)	27.5 (11)	.683^c
Sex				546^b
Male	n = 16 (40%)	n = 12 (32.43%)	n = 17 (44.74%)
Female	n = 24 (60%)	n = 25 (67.57%)	n = 21 (55.26%)
Marital status				.620^b
Single	n = 29 (72.5%)	n = 30 (81.08%)	n = 28 (73.68%)
Married	n = 9 (22.5%)	n = 7 (18.92%)	n = 10 (26.32%)
Divorced	n = 1 (2.5%)	n = 0 (0%)	n = 0 (0%)
Other	n = 1 (2.5%)	n = 0 (0%)	n = 0 (0%)
Race/ethnicity				.360^b
Caucasian	n = 40 (100%)	n = 40 (100%)	n = 37 (97.37%)
Turk	n = 0 (0%)	n = 0 (0%)	n = 1 (2.63%)
Height (cm)	172 (11)	173 (10)	175 (13)	.849^c
Weight (kg)	69 (20)	64 (10)	70 (16)	.207^c
Body Mass Index (kg/m²)	22.91 (4.99)	21.61 (2.30)	22.59 (3.84)	.078^c
Dietary adherence (months)	336 (162)	70 (168)	48 (51)	<.001^c
Educational level				.985^b
Secondary school	n = 4 (10%)	n = 3 (8.11%)	n = 4 (10.53%)
German Abitur	n = 19 (47.5%)	n = 17 (45.95%)	n = 16 (42.11%)
University degree	n = 17 (42.5%)	n = 17 (45.95%)	n = 18 (47.37%)
MacArthur Scale of Subjective Social Status	6.38 ± 0.21	6.54 ± 0.20	6.32 ± 0.25a	.799^c
Fortified food consumption				.681^b
No	n = 34 (85%)	n = 32 (86.49%)	n = 29 (76.32%)
Yes	n = 5 (12.5%)	n = 5 (13.51%)	n = 8 (21.05%)
Not sure	n = 1 (2.5%)	n = 0 (0%)	n = 1 (2.63%)
Physical activity (MET-minutes)	4513.5 (4934.5)	5116 (4678)	4129.5 (2845.5)	.239^c
MET-Category				.985^b
Low	n = 1 (2.5%)	n = 0 (0%)	n = 1 (2.63%)
Moderate	n = 4 (10%)	n = 5 (13.51%)	n = 6 (15.79%)
High	n = 35 (87.5%)	n = 32 (86.49%)	n = 31 (81.58%)

Normally distributed data is shown with its mean ± standard deviation; not normally distributed data is shown with its median and IQR in parenthesis.

^aBased on 37 observations.

^bBased on Stata’s Chi-Square Test of independence.

^cBased on Kruskal–Wallis H test. Metabolic Equivalents (MET) minutes represent the amount of energy expended carrying out physical activity.

Table 2. Nutrient intake data of study participants by dietary group.

	Omnivores (n = 40)	Lacto-Ovo-Vegetarians (n = 37)	Vegans (n = 38)	p-value
Energy intake (kcal/d)	1995.14 (938.71)	2085.86 (692.42)	2068.29 (881.86)	0.819^a
Carbohydrate intake (g/d)	242.71 (101.94)	241.75 (122.73)	256.48 (140.863)	0.193^a
Protein intake (g/d)	73.66 (45.43)	65.88 (22.80)	62.33 (39.64)	0.297^a
Fat intake (g/d)	81.39 (49.26)	75.85 (35.77)	83.92 (31.58)	0.981^a
Fiber intake (g/d)	24.21 (20.14)	31.2 (14.75)	33.61 (19.54)	0.001^a
Alcohol intake (g/d)	0.062 (4.95)	0.08 (2.82)	0.028 (2.76)	0.891^a
Cholesterol intake (mg/d)	177.93 (224.77)	70.85 (154.58)	17.75 (49.40)	<0.001^a
Uric acid intake (mg/d)	257.65 (134.37)	234.56 (104.29)	259.72 (191.70)	0.451^a
Polyunsaturated fatty acid intake (g/d)	10.20 (10.91)	10.42 (12.2)	13.10 (11.231)	0.194^a
Monounsaturated fatty acid intake (g/d)	21.90 (17.66)	18.51 (14.81)	18.39 (13.74)	0.320^a
Saturated fatty acid intake (g/d)	31.97 (18.71)	23.00 (14.33)	18.55 (9.61)	<0.001^a
Sodium intake (mg/d)	2102.30 (1174.06)	1846.57 (722.31)	2257.65 (1199.241)	0.087^a
Potassium intake (mg/d)	2079.19 (1642.59)	2090.95 (689.273)	2549.37 (1114.57)	0.077^a
Calcium intake (mg/d)	541.24 (448.97)	571.70 (370.56)	475.38 (198.13)	0.259^a
Phosphorus intake (mg/d)	788.27 (489.44)	798.65 (400.25)	664.14 (529.19)	0.288^a
Magnesium intake (mg/d)	246.76 (177.96)	270.62 (180.05)	312.96 (169.47)	0.053^a
Iron intake (mg/d)	7.83 (4.45)	9.22 (4.24)	10.39 (5.87)	0.142^a
Vitamin A intake (mg/d)	0.29 (0.30)	0.23 (0.22)	0.07 (0.08)	<0.001^a
Vitamin C intake (mg/d)	103.21 (67.19)	139.94 (93.96)	172.41 (132.71)	<0.001^a
Vitamin D intake (μg/d)	2.07 (3)	1.24 (1.37)	0.92 (0.97)	<0.001^a
Vitamin E intake (mg/d)	9.74 (9.80)	10.90 (11.64)	13.39 (10.26)	0.177^a
Vitamin B1 intake (mg/d)	0.66 (0.56)	0.84 (0.63)	1.02 (1.05)	0.059^a
Vitamin B2 intake (mg/d)	0.81 (0.54)	0.77 (0.38)	0.86 (0.38)	0.680^a
Niacin intake (niacin equivalents, μg/d)	18,448.72 (12511.15)	14,047.95 (5471.74)	13993.22 (6421.36)	0.047^a
Vitamin B6 intake (mg/d)	1.30 ± 0.58	1.24 ± 0.48	1.54 ± 0.61	0.046^b
Vitamin B12 intake (μg/d)	2.14 (2.29)	0.98 (1.34)	0.43 (0.58)	<0.001^a
Folic acid intake (μg/d)	224.39 (138.74)	241.92 (114.62)	287.76 (149.34)	0.025^a
Zinc intake (mg/d)	6.41 (4.30)	6.37 (2.92)	5.33 (3.61)	0.727^a
Iodine intake (μg/d)	54.03 (39.71)	38.14 (33.74)	37.88 (20.18)	0.030^a

Normally distributed data is shown with its mean ± standard deviation; not normally distributed data is shown with its median and IQR in parenthesis.

^aBased on Kruskal–Wallis H test.

^bBased on analysis of variance. Nutrient intakes given in this table are from foodstuffs only and do not include nutrients taken in the form of supplements. Nutrient intakes from supplements are provided in Table 3.

Table 3. Supplementation characteristics of study participants by dietary group.

	Omnivores (n = 40)	Lacto-Ovo-Vegetarians (n = 37)	Vegans (n = 38)	p-value
Supplement intake				.090^a
Yes	n = 31 (77.5%)	n = 30 (81.08%)	n = 36 (94.74%)
No	n = 9 (22.5%)	n = 7 (18.92%)	n = 2 (5.26%)
Multivitamin supplement intake				.045^a
Yes	n = 9 (22.5%)	n = 10 (27.03%)	n = 18 (47.37%)
No	n = 31 (77.5%)	n = 27 (72.97%)	n = 20 (52.63%)
Vitamin B 12 supplement intake				<.001^a
Yes	n = 11 (27.5%)	n = 19 (51.35%)	n = 35 (92.11%)
No	n = 29 (72.5%)	n = 18 (48.65%)	n = 3 (7.89%)
Dosage (μg)	25 (335.5)	400 (977.5)	250 (980)	.136^b
Frequency (day/year)	180 (287)	40 (144)	365 (209)	.001^b
Vitamin D supplement intake				.561^a
Yes	n = 25 (62.5%)	n = 20 (54.05%)	n = 25 (65.79%)
No	n = 15 (37.5%)	n = 17 (45.95%)	n = 13 (34.21%)
Dosage (IU)	1000 (4600)	2350 (2200)	2000 (4000)	.753^b
Frequency (day/year)	156 (313)	90 (335)	365 (235)	.083^b
Iron supplement intake				.033^a
Yes	n = 8 (20%)	n = 11 (29.73%)	n = 18 (47.37%)
No	n = 32 (80%)	n = 26 (70.27%)	n = 20 (52.63%)
Dosage (mg)	22.5 (39)	36.8 (86)	11.75 (14)	.263^b
Frequency (day/year)	302.5 (208.5)	84 (128)	365 (317)	.091^b
Iodine supplement intake				.034^a
Yes	n = 5 (12.5%)	n = 4 (10.81%)	n = 12 (31.58%)
No	n = 35 (87.5%)	n = 33 (89.19%)	n = 26 (68.42%)
Dosage (μg)	75 (50)	70 (92.5)	150 (29.5)	.074^b
Frequency (day/year)	180 (84)	242.5 (291)	365 (0)	.016^b
Calcium supplement intake				.002^a
Yes	n = 3 (7.5%)	n = 2 (5.41%)	n = 12 (31.58%)
No	n = 37 (92.5%)	n = 35 (94.59%)	n = 26 (68.42%)
Dosage (mg)	200 (210)	100 (0)	200 (300)	.385^b
Frequency (day/year)	240 (182)	196.5 (337)	365 (91)	.651^b
Eicosapentaenoic acid supplement intake				.016^a
Yes	n = 5 (12.5%)	n = 3 (8.11%)	n = 12 (31.58%)
No	n = 35 (87.5%)	n = 34 (91.89%)	n = 26 (68.42%)
Dosage (mg)	220 (144)	225 (320)	217.5 (366.5)	.815^b
Frequency (day/year)	156 (53)	365 (209)	365 (52.5)	.082^b
Docosahexaenoic acid acid supplement intake				.052^a
Yes	n = 6 (15%)	n = 4 (10.81%)	n = 12 (31.58%)
No	n = 34 (85%)	n = 33 (89.19%)	n = 26 (68.42%)
Dosage (mg)	185 (330)	441 (469)	354 (560)	.227^b
Frequency (day/year)	143 (79)	260.5 (227)	365 (52.5)	.051^b
Zinc supplement intake				.106^a
Yes	n = 16 (40%)	n = 7 (18.92%)	n = 14 (36.84%)
No	n = 24 (60%)	n = 30 (81.08%)	n = 24 (63.16%)
Dosage (mg)	10 (10)	10 (5)	10 (3.14)	.498^b
Frequency (day/year)	168 (329)	156 (335)	365 (182)	.065^b
Magnesium supplement intake				.210^a
Yes	n = 16 (40%)	n = 8 (21.62%)	n = 11 (28.95%)
No	n = 24 (60%)	n = 29 (78.38%)	n = 27 (71.02%)
Dosage (mg)	300 (220)	309.5 (296.7)	142 (178.5)	.252^b
Frequency (day/year)	168 (309)	142 (259.5)	365 (268)	.534^b
Selenium supplement intake				.003^a
Yes	n = 3 (7.5%)	n = 4 (10.81%)	n = 13 (34.21%)
No	n = 37 (92.5%)	n = 33 (89.19%)	n = 25 (65.79%)
Dosage (μg)	25 (10)	55 (82.5)	55 (0)	.021^b
Frequency (day/year)	240 (185)	92 (240.5)	365 (0)	.105^b
Vitamin C supplement intake				.077^a
Yes	n = 14 (35%)	n = 5 (13.51%)	n = 8 (21.05%)
No	n = 26 (65%)	n = 32 (86.49%)	n = 30 (78.95%)
Dosage (mg)	140 (260)	250 (125)	80 (100.23)	.493^b
Frequency (day/year)	302.5 (209)	365 (0)	286.5 (261)	.545^b
Folic acid supplement intake				.055^a
Yes	n = 8 (20%)	n = 8 (21.62%)	n = 16 (42.11%)
No	n = 32 (80%)	n = 29 (78.38%)	n = 22 (57.89%)
Dosage (μg)	250 (200)	300 (343.75)	350 (200)	.847^b
Frequency (day/year)	302.5 (210)	247.5 (291)	365 (169.5)	0.531^b
Vitamin B1 supplement intake				.449^a
Yes	n = 6 (15%)	n = 7 (18.92%)	n = 10 (26.32%)
No	n = 34 (85%)	n = 30 (81.08%)	n = 28 (73.68%)
Dosage (mg)	1.1 (2.3)	11.25 (25)	1.1 (2.2)	.283^b
Frequency (day/year)	302.5 (182)	365 (337)	365 (0)	.148^b
Vitamin B2 supplement intake				.110^a
Yes	n = 5 (12.5%)	n = 7 (18.92%)	n = 12 (31.58%)
No	n = 35 (87.5%)	n = 30 (81.08%)	n = 26 (68.42%)
Dosage (mg)	1.4 (1.1)	11.4 (13.6)	1.4 (0.91)	.263^b
Frequency (day/year)	365 (125)	365 (337)	365 (0)	.278^b
Niacin supplement intake				.677^a
Yes	n = 7 (17.5%)	n = 6 (16.22%)	n = 9 (23.68%)
No	n = 33 (82.5%)	n = 31 (83.78%)	n = 29 (76.32%)
Dosage (mg)	16 (32)	35.5 (29)	16 (0)	.406^b
Frequency (day/year)	365 (185)	365 (235)	16 (0)	.328^b
Vitamin B5 supplement intake				.417^a
Yes	n = 5 (12.5%)	n = 6 (16.22%)	n = 9 (23.68%)
No	n = 35 (87.5%)	n = 31 (83.78%)	n = 29 (76.32%)
Dosage (mg)	6 (2)	18.125 (17)	6 (0)	.105^b
Frequency (day/year)	365 (125)	274 (235)	365 (0)	.177^b
Vitamin B6 supplement intake				.449^a
Yes	n = 6 (15%)	n = 7 (18.92%)	n = 10 (26.32%)
No	n = 34 (85%)	n = 30 (81.08%)	n = 28 (73.68%)
Dosage (mg)	1.4 (3)	10.32 (18.6)	1.4 (2.2)	.256^b
Frequency (day/year)	302.5 (185)	365 (337)	365 (0)	.151^b
Biotin supplement intake				.604^a
Yes	n = 6 (15%)	n = 8 (21.62%)	n = 9 (23.68%)
No	n = 34 (85%)	n = 29 (78.38%)	n = 29 (76.32%)
Dosage (μg)	50 (40)	31 (72.5)	50 (100)	.126^b
Frequency (day/year)	302.5 (185)	156 (195)	365 (0)	.016^b
Vitamin K1 supplement intake				.186^a
Yes	n = 3 (7.5%)	n = 1 (2.70%)	n = 0 (0%)
No	n = 37 (92.5%)	n = 36 (97.30%)	n = 38 (100%)
Dosage (mg)	37.5 (1220)	30 (0)	–	.346^b
Frequency (day/year)	52 (179)	365 (0)	–	.178^b
Vitamin K2 supplement intake				.251^a
Yes	n = 8 (20%)	n = 6 (16.22%)	n = 12 (31.58%)
No	n = 32 (80%)	n = 31 (83.78%)	n = 26 (68.42%)
Dosage (μg)	200 (85)	154.49 (140)	56.3 (37.5)	.005^b
Frequency (day/year)	104 (266.5)	260.5 (209)	365 (52.5)	.031^b
Vitamin E supplement intake				.755^a
Yes	n = 4 (10%)	n = 2 (5.41%)	n = 3 (7.89%)
No	n = 36 (96%)	n = 35 (94.59%)	n = 35 (92.11%)
Dosage (mg)	9.25 (14.75)	66.6 (73.2)	12 (30.5)	.256^b
Frequency (day/year)	210 (173.5)	365 (0)	365 (157)	.231^b
Vitamin A supplement intake				.026^a
Yes	n = 3 (7.5%)	n = 1 (2.70%)	n = 8 (21.05%)
No	n = 37 (92.5%)	n = 36 (97.30%)	n = 30 (78.95%)
Dosage (mg)	0.668 (0.6)	0.668 (0)	0.45 (0.225)	.666^b
Frequency (day/year)	180 (287)	365 (0)	365 (0)	0.231^b

^aBased on Stata’s Chi-Square Test of independence.

^bBased on Kruskal–Wallis H test.

Table 4. Laboratory measurements by dietary group.

	Omnivores (n = 40)	Lacto-Ovo-Vegetarians (n = 37)	Vegans (n = 38)
White blood cell count (1000 cells/μL)	5.91 (2.07)c	5.16 (2.03)^d	4.97 (1.63)^e	0.258^a
Platelet count (1000 cells/μL)	243 (74)^c	230 (47)^d	211 (73)^e	0.070^a
Red blood cell count (million cells/μL)	4.64 ± 0.36^c	4.55 ± 0.48^d	4.50 ± 0.46^e	0.414^b
Hemoglobin (g/dl)	13.71 ± 1.13^c	13.46 ± 1.48^d	13.51 ± 1.49^e	0.726^b
Hematocrit (%)	40.79 ± 3.11^c	40.02 ± 3.66^d	40.22 ± 3.76^e	0.639^b
Mean corpuscular volume (fL)	88.00 ± 3.17^c	88.19 ± 3.60^d	88.93 ± 4.48^e	0.551^b
Mean corpuscular hemoglobin (pg)	29.65 (2)^c	29.6 (1.7)^d	29.9 (2)^e	0.066^a
Mean corpuscular hemoglobin concentration (g/dl)	33.65 ± 0.86^c	33.59 ± 1.14^d	33.56 ± 1.17^e	0.939^b
Red cell distribution width	12.45 (0.7)^c	12.6 (0.95)^d	12.6 (0.7)^e	0.499a
Neutrophil count (1000 cells/μL)	3.2 (1.78)^c	2.75 (1.56)^d	2.74 (1.38)^e	0.637^a
Lymphocyte count (1000 cells/μL)	1.83 (0.49)^c	1.74 (0.57)^d	1.53 (0.52)^e	0.018^a
Monocyte count (1000 cells/μL)	0.50 (0.13)^c	0.48 (0.17)^d	0.44 (0.11)^e	0.052^a
Eosinophils count (1000 cells/μL)	0.12 (0.11)^c	0.12 (0.11)^d	0.11 (0.08)^e	0.788^a
Basophils count (1000 cells/μL)	0.05 (0.02)^c	0.04 (0.02)^d	0.04 (0.02)^e	0.257^a
HbA1c (%)	5.25 ± 0.29^f	5.20 ± 0.28^e	5.07 ± 0.32^e	0.017^b
Vitamin B12 (pg/ml)	377 (225)g	310 (190)^e	404.5 (195)f	0.023^a
Holotranscobalamin 2 (pmol/l)	71.5 (63.6)g,h	40.1 (52.6)^e^,h	74 (87.2)f,h	0.001^a
Folic acid (ng/ml)	9.1 (7.3)g,i	8.6 (5.9)^e	10.85 (6.5)^f	0.138^a
Vitamin A (μg/l)	620 (250)g	560 (200)^e	570 (190)d	0.546^a
Vitamin B1 (μg/l)	56 (12)^g,j	57 (14)^e	57.5 (11)f	0.528^a
Vitamin B2 (μg/l)	181 (35)^g	184 (46)^e	173.5 (29)f	0.637^a
Vitamin B6 (μg/l)	34 (17)^g,j	31 (14)^e	35 (21)f	0.631^a
Vitamin D (ng/ml)	27.00 ± 8.49e	29.46 ± 12.00^e	33.38 ± 19.28f	0.144^b
Vitamin E (μg/l)	16.44 ± 5.29^g	13.75 ± 4.69^e	13.89 ± 3.85f	0.020^b
Vitamin K1 (μg/l)	0.43 (0.58)g	0.59 (0.61)^e	0.64 (0.78)f	0.077^a
Vitamin K2 (Menachinon-4, μg/l)	0.29 (0.11)g	0.28 (0.13)^e	0.275 (0.08)f	0.792^a
Vitamin K2 (Menachinon-7, μg/l)	0.26 (0.23)^g,^k	0.2 (0.15)^e	0.36 (0.27)f	0.012^a
Niacin (μg/l)	31 (8.6)^e	29.2 (11.2)^e	31.85 (9.1)f	0.705^a
Albumin (g/dl)	4.74 ± 0.24^e	4.78 ± 0.23^e	4.80 ± 0.28f	0.646^b
Blood urea nitrogen (mg/dl)	25 (6)^e	22 (8)^e	21 (9)f	0.015a
Cystatine C (mg/l)	0.84 (0.08)^e	0.84 (0.11)^e	0.87 (0.16)f	0.664a
Creatinine (mg/dl)	0.78 (0.17)^e	0.73 (0.15)^e	0.75 (0.17)f	0.036^a
Iron (μg/dl)	63.95 ± 27.71^e	62.76 ± 25.71^e	71.66 ± 28.22f	0.309^b
Ferritin (ng/ml)	42 (47)^e	31 (52)^e	35.5 (44)f	0.563^a
Transferrin (mg/dl)	246 (42)^e	262 (50)^e	259.5 (56)f	0.625^a
Transferring saturation (%)	18.11 ± 8.40^e	17.57 ± 7.91^e	19.63 ± 7.94f	0.519^b
TSH (Thyroid-stimulating hormone; μU/ml)	2.1 (1.12)^e	2.16 (1.01)^e	2.07 (1.43)f	0.952^a
Triiodothyronine (free T3; pmol/l)	4.86 ± 0.67^e	4.57 ± 0.53^e	4.72 ± 0.59^f	0.130^b
Thyroxine (free T4; pmol/l)	16.07 ± 2.40^e	15.39 ± 1.98^e	15.88 ± 2.27^f	0.406^b
Parathyroid hormone (pg/ml)	37 (15)^e	37 (14)^e	38 (15)^f	0.83^a
Glutamic oxaloacetic transaminase (U/l)	24 (7)^e	22 (5)^e	21 (6)^f	0.361^a
Glutamic-pyruvate-transaminase (U/l)	21 (12)e	18 (7)^e	17.5 (9)^f	0.011^a
High-density lipoprotein (mg/dl)	54 (22)^e	58 (16)^e	55 (19)^f	0.315^a
Low-density lipoprotein (mg/dl)	106 (40)^e	89 (37)^e	79 (32)^f	0.001^a
Triglycerides (mg/dl)	82 (31)^e	70 (34)	76 (35)	0.308^a
High sensitive C-reactive protein (mg/l)	0.6 (1.7)e,k	0.4 (0.6)e,k	0.5 (0.7)f,k	0.093^a
Selenium (μg/l)	90 (17)l	78 (18)l	75 (30)m	0.007^a
Uric acid (mg/dl)	4.3 (1.3)^e	4 (1)^e	4.95 (1.3)^f	0.005^a

Normally distributed data is shown with its mean ± standard deviation; not normally distributed data is shown with its median and IQR in parenthesis.

^aBased on Kruskal-Wallis H test.

^bBased on analysis of variance.

^cBased on n = 34 observations.

^dBased on n = 36 observations.

^eBased on n = 37 observations.

^fBased on n = 38 observations.

^gBased on n = 39 observations.

^hValues >128 pmol/l which exceeded the reference range and which were no longer measurable were entered as 128 pmol/l into the analysis.

ⁱValues >40 ng/ml which exceeded the reference range and which were no longer measurable were entered as 40 ng/ml into the analysis.

^jValues >100 μg/ml which exceeded the reference range and which were no longer measurable were entered as 100 μg/ml into the analysis.

^kValues <0,1 mg/l which exceeded the reference range and which were no longer measurable were entered as 0,1 mg/l into the analysis.

^lBased on n = 34 observations.

^mBased on n = 34 observations.

Figure 2. Multivariate analysis of laboratory biomarkers of health. (A) Main contributing biomarkers to the variance of the first principal component resulting from the PPCA analysis. The analysis retrieved biomarkers of vitamin B12 status (vitamin B12, holoTC, Hcy), iron (iron, ferritin, transferrin) and lipid metabolism (vitamin A, HDL, LDL, total cholesterol, TAG) as most contributors to the separation across dietary types. (B) Nonmetric dimension scaling analysis (NMDS). each point represents the laboratory biomarker profile of each individual (dots) in 3-dimensions separated in six plots (NMDS2 versus NMDS1, NMDS3 versus NMDS1 and NMSD3 versus NMDS2). points closer to each other represent more similar biomarker profiles, and points away from each other represent more different biomarker profiles. Squares represent the centroid across individuals with the same diet (average across individuals for each dimension).

Table 5. Results of PERMANOVA analysis.

Effect	F	p-value	Levels of diet	p-value (FDR adj.)
Diet	22.693	.010	OMN vs LOV	0.036
Sex	32.046	.006	OMN vs VEG	0.153
Diet x Sex	0.9540	.446	LOV vs VEG	0.034

Figure 3. Biomarkers of vitamin B12 status. (A) Plasma vitamin B12. (B) Plasma holoTC. (C) Plasma MMA. (D) Plasma Hcy. Dark red shadowing denotes values below or above reference ranges indicative of vitamin B12 deficiency. Light red shadowing depicts values that classify as low vitamin B12 or subclinical vitamin B12 deficiency. p values were adjusted for multiple comparisons using the holm method. The reference ranges utilized in this study were as follows: Hcy: 5–15 µM; MMA: <0.260 µM; holoTC: <35 pM, and vitamin B12: <149 pM deficiency; 149–250 pM subclinical deficiency; and >250 pM normal.

Figure 4. Combined vitamin B12 index (cB12). The status of vitamin B12 was assessed using the four-biomarker cB12 index, with adjustment for age and plasma folate concentration, as described in the studies by Fedosov et al. [36]. The area shadowed with light red corresponds to a status of low vitamin B12 wherein the initiation of supplementation has been recommended [36]. In this study, lacto-ovo-vegetarians followed by the vegan group possessed the greatest number of individuals with low vitamin B12.

Figure 5. Correlation of biomarkers of vitamin B12 status. (A) Plasma vitamin B12 and holo-TC were positively correlated independently of dietary pattern. (B) Correlation between MMA and plasma vitamin B12. (C) Correlation between Hcy and plasma vitamin B12. (D) Correlation between MMA and plasma holoTC. (E) Correlation between Hcy and plasma holoTC. A negative correlation was identified between plasma vitamin B12 or holo-TC and the metabolites MMA and Hcy (panels B–E). MMA and vitamin B12 were negatively correlated in plant-based diets but not in omnivores. Light blue shadowing around the regression line: confidence interval. R²: coefficient of determination; p: p-value.

Fedosov SN, Brito A, Miller JW, et al. Combined indicator of vitamin B12 status: modification for missing biomarkers and folate status and recommendations for revised cut-points. Clin Chem Lab Med. 2015;53:1215–1225.

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Data availability statement

Data contained in this manuscript will be made available upon reasonable request.