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Crit Care. 2017 Dec 11;21(1):300. doi: 10.1186/s13054-017-1891-y.

Hypovitaminosis C and vitamin C deficiency in critically ill patients despite recommended enteral and parenteral intakes.

Author information

1
Department of Pathology, University of Otago, Christchurch, PO Box 4345, Christchurch, 8140, New Zealand. anitra.carr@otago.ac.nz.
2
Department of Pathology, University of Otago, Christchurch, PO Box 4345, Christchurch, 8140, New Zealand.
3
Department of Intensive Care Medicine, Christchurch Hospital, Private Bag 4710, Christchurch, 8140, New Zealand.

Abstract

BACKGROUND:

Vitamin C is an essential water-soluble nutrient which cannot be synthesised or stored by humans. It is a potent antioxidant with anti-inflammatory and immune-supportive roles. Previous research has indicated that vitamin C levels are depleted in critically ill patients. In this study we have assessed plasma vitamin C concentrations in critically ill patients relative to infection status (septic shock or non-septic) and level of inflammation (C-reactive protein concentrations). Vitamin C status was also assessed relative to daily enteral and parenteral intakes to determine if standard intensive care unit (ICU) nutritional support is adequate to meet the vitamin C needs of critically ill patients.

METHODS:

Forty-four critically ill patients (24 with septic shock, 17 non-septic, 3 uncategorised) were recruited from the Christchurch Hospital Intensive Care Unit. We measured concentrations of plasma vitamin C and a pro-inflammatory biomarker (C-reactive protein) daily over 4 days and calculated patients' daily vitamin C intake from the enteral or total parenteral nutrition they received. We compared plasma vitamin C and C-reactive protein concentrations between septic shock and non-septic patients over 4 days using a mixed effects statistical model, and we compared the vitamin C status of the critically ill patients with known vitamin C bioavailability data using a four-parameter log-logistic response model.

RESULTS:

Overall, the critically ill patients exhibited hypovitaminosis C (i.e., < 23 μmol/L), with a mean plasma vitamin C concentration of 17.8 ± 8.7 μmol/L; of these, one-third had vitamin C deficiency (i.e., < 11 μmol/L). Patients with hypovitaminosis C had elevated inflammation (C-reactive protein levels; P < 0.05). The patients with septic shock had lower vitamin C concentrations and higher C-reactive protein concentrations than the non-septic patients (P < 0.05). Nearly 40% of the septic shock patients were deficient in vitamin C, compared with 25% of the non-septic patients. These low vitamin C levels were apparent despite receiving recommended intakes via enteral and/or parenteral nutritional therapy (mean 125 mg/d).

CONCLUSIONS:

Critically ill patients have low vitamin C concentrations despite receiving standard ICU nutrition. Septic shock patients have significantly depleted vitamin C levels compared with non-septic patients, likely resulting from increased metabolism due to the enhanced inflammatory response observed in septic shock.

KEYWORDS:

C-reactive protein; Critical illness; Enteral nutrition; Hypovitaminosis C; Intensive care; Parenteral nutrition; Sepsis; Septic shock; Vitamin C

PMID:
29228951
PMCID:
PMC5725835
DOI:
10.1186/s13054-017-1891-y
[Indexed for MEDLINE]
Free PMC Article

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