Table 1.
Detailed report of plasma VC values for studies described in this review, where such data are available.
| Authors | Population | Plasma VC μM (μmol/l) Mean ± S.D. Group N | Percent of total study population with depleted or deficient VC (<28 μM) or for alternative cut- offs (as provided) | Percent of population taking a supplement containing VC |
|---|---|---|---|---|
| Cahill et al. [8] | 20–29 years, healthy young men and women Toronto Nutrigenomics and Health Study |
Deficient (< 11) 6.2 ± 10.4a N=133 |
46.8 % | 30 % |
| Suboptimal (11–28) 21.0 ± 10.9a N=325 |
34 % | |||
| Adequate (> 28) 42.9 ± 9.1a N=521 a S.D. calculated from S.E.M. and N provided in [8] Table 1 |
40 % | |||
| Gale et al. [33] | 65 years and over, non- institutionalized, UK | <11.91, N = 275 | 67.8 % | |
| 11.91–27.82, N = 302 | ||||
| >27.82, N = 274 | ||||
| Gan et al. [9] | 14–89 years, Hospitalized and normally- nourished controls, Canada | Reference group 52.7 ± 22.5 |
16 % | 36 % (normal serum vitamin C group) 21 % (depleted vitamin C group) 7 % (deficient vitamin C group) |
| Hospitalized group 27.6 ± 19.2 |
60 % | |||
| Garry et al. [4] (VC data from population described by Goodwin et al. [34]) | 60 years and over non- institutionalized, no other illnesses, USA | Male - No supplements 51.7 ± 21.0, N = 55 |
4 % | |
| Female - No supplements 64.7 ± 20.4, N= =58 |
||||
| Male - supplements 74.4 ± 23.9, N = 70 |
56 % | |||
| Female - supplements 80.1 ± 17.6, N = 85 |
59 % | |||
| Hampl et al. [12] | 12–74 years Community sample, NHANES III, USA | Male – 65–74 years (example age group) 44.9 ± 33.99b N = 955 Total male population N = 7355 |
34 % | 29 % |
| Female – 65–74 years (example age group) 55.1 ± 34.21b N = 967 Total female population N = 8414 b S.D. calculated from S.E.M. and N provided in [12] Table 1 |
27 % | 34 % | ||
| Johnston & Thompson [7] | 6–92 years Generally healthy outpatient population, (subjects presenting for general check-up or gynecological exam only), USA | Overall mean 33.5 ± 14.8 N = 124 |
33.9% | |
| Deficient (<11.4) 7.3 ± 1.9 N = 8 (out of 124) | ||||
| Depleted (11.4 to < 28.4) 20.5 ± 4.7 N = 34 (out of 124) | ||||
| Johnston et al. [6] | College students, USA | October sample 44.7 ± 15.9 N = 134 |
17 % | |
| February sample 41.5 ± 13.1 N = 98 |
14 % | |||
| La Rue et al. [35] (Follow-up study in same population as Garry et al. and Goodwin et al. [4, 34]) | 60 years and over, community dwelling, healthy, USA New Mexico Aging Process Study |
1980: 69.3 ± 19.7, (range 9.1–134.6) N = 122 |
59 % | |
| 1986: 70.9 ± 20.3, (range 14.8–154.4) N = 122 |
63 % | |||
| Lindemann et al. [63] | 65 years and older, community dwelling, USA | Male Hispanic No supplement 49 ± 19, N = 121 Supplement 70 ± 25, N = 74 |
38 % | |
| Male Non-Hispanic White No supplement 57 ± 23, N = 93 Supplement 80 ± 28, N = 133 |
59 % | |||
| Female Hispanic No supplement 60 ± 24, N = 89 Supplement 80 ± 31, N = 81 |
48 % | |||
| Female Non-Hispanic White No supplement 70 ± 24, N = 72 Supplement 89 ± 26, N = 130 |
64 % | |||
| Mosdøl et al. [11] | >19 years, Community sample of 15% most deprived households, Low Income Diet and Nutrition study (LIDNS), UK | Male N=433 |
46.3 % | 20.7 % |
| Female N=876 |
34.6 % | |||
| Perrig et al. [36] | 65 – 94 years, Switzerland | 59.4 ± 21.4, N = 442 | ||
| Richardson et al. [88] | In-patient admissions to Care of Elderly ward 65–97 years, Australia | N = 37 | 30 % < 11 μM 73 % < 40 μM |
|
| Rinaldi et al. [58] | Patients with Mild Cognitive Impairment (MCI) Patients with Alzheimer’s disease Control, Italy | 52.4 ± 16.5, N = 25 | 0% | |
| 24.9 ± 2.4, N = 63 | ||||
| 25.9 ± 8.9, N = 53 | ||||
| Schmidt et al. [52] | 50 – 75 years, community dwelling, Austrian Stroke Prevention Study | 56.6 ± 20.3, N = 1769 | ||
| Sinclair et al [70] | Mean 73–75 years, community dwelling, UK | Alzheimer patients 47.16 (IQ range 35.2– 59.1), N=25 |
0 % | |
| Controls 56.82 (IQ Range 47.6– 65.9), N=41 | ||||
| Sato et al. [37] | 65 years and older, community dwelling, USA | Normal MMSE 74.9 (IQ range 57.9– 90.8), N = 111 |
3 % < 40 μM (total population) 25 % < 59 μM MMSE<27 | 40 % |
| Cardiovascular Health Study (CHS) | MMSE <27 78.9 (IQ range 64.2– 99.4), N = 433 |
|||
| Whalley et al. [64] | ~77 years, healthy, non- demented, UK | Male Supplement 48.7 ± 23.7, N = 9 |
8.5 % | |
| Male No Supplement 26.5 ± 23.1, N = 38 | ||||
| Female Supplement 47.6 ± 27.6, N = 22 | ||||
| Female No supplement 40.9 ± 29.2, N = 41 | ||||
| Wrieden et al. [10] | 25–74 years, Community sample, MONICA study, UK | N = 1276 | 44 % < 22.7 μM | 0 % 285 of original sample of 1958 (14.5 %) excluded for vitamin supplement use |
Values reported as mg/dL in the literature have been converted to μM (μmol/l) using the conversion factor for ascorbic acid of 56.78. Values reported as μg/ml have been converted to μM (μmol/l) using the conversion factor 0.176 based on the molecular weight of ascorbic acid. Data shown are group means ± S.D., and where indicated, data range, or inter-quartile (IQ) range. MMSE, Mini Mental State Exam.