Brief report
Lower serum vitamin E concentrations in major depression: Another marker of lowered antioxidant defenses in that illness

https://doi.org/10.1016/S0165-0327(99)00121-4Get rights and content

Abstract

Objective: Major depression is associated with defective antioxidant defenses. Vitamin E is the major fat soluble antioxidant in the body. The aim of the present study is to examine serum vitamin E concentrations in major depressed patients versus normal volunteers. Method: Serum vitamin E concentrations were measured in 26 healthy volunteers and 42 major depressed patients by means of HPLC. Since vitamin E is a fat soluble vitamin, and serum vitamin E concentrations are strongly related to these of low-density-lipoprotein cholesterol (LDL-C) and triglycerides, we have adjusted the results for possible differences in these lipids. The numbers of peripheral blood leukocytes were measured. Results: Patients with major depression had significantly lower serum vitamin E concentrations than healthy controls. The area under the ROC (receiver operating characteristics) curve was 83%. There were significant and negative correlations between serum vitamin E and number of total leukocytes and neutrophils. Conclusions: Major depression is accompanied by significantly lower serum vitamin E concentrations, suggesting lower antioxidant defenses against lipid peroxidation. The results could, in part, explain previous findings, which suggest increased lipid peroxidation in major depression.

Introduction

Defective plasma antioxidant defenses, enhanced susceptibility to lipid peroxidation and increased oxidative stress may occur in major depression. Plasma tryptophan and tyrosine (Maes et al., 1994a, Maes and Meltzer, 1995), which have antioxidant activity (Meucci and Mele, 1997), and serum albumin (Swartz, 1990, Maes et al., 1991, Van Hunsel et al., 1996), a major contributor to the oxygen radical absorbing capacity (Cao et al., 1993) are significantly decreased in depression. In mice, a significant depletion of brain glutathione, another antioxidant, occurs in stress-induced depression (Gutteridge and Halliwell, 1994, Pal and Dandiya, 1994).

Depression is associated with significantly lower ω3 polyunsaturated fatty acid (PUFA) fractions (Maes et al., 1996a, Maes and Smith, 1998, Peet et al., 1998) and oxidative potential index (OPI) of serum phospholipids (Maes et al., 1999), suggesting oxidative damage. Incubation of red blood cell (RBC) membranes of healthy volunteers with hydrogen peroxide induces decreases in total ω3 (PUFAs) comparable to that found in depression (Peet et al., 1998).

Depression is characterized by activation of the inflammatory response system (IRS) with increased production of proinflammatory cytokines (Maes, 1997, Seidel et al., 1995, Sluzewska et al., 1995, Sluzewska et al., 1996). Proinflammatory cytokines and cytokine-induced reactive oxygen species (ROS) may increase lipid peroxidation (Maziere et al., 1994). Psychological stress, which accompanies severe depression, may increase lipid peroxidation (Hibbeln and Salem, 1995).

Vitamin E is another contributor to the radical-trapping antioxidant parameter of plasma (Wayner et al., 1987). Vitamin E is the major fat-soluble antioxidant, which is transported in the blood in lipids, e.g. triglycerides and low-density lipoprotein cholesterol (LDL-C) (Farrell, 1988, Gutteridge and Halliwell, 1994, Maes et al., 1996b, Cham et al., 1998). Vitamin E halts the chain reaction of PUFA peroxidation in membranes (Farrell, 1988, Packer and Fuchs, 1993). Lowered serum vitamin E levels occur during IRS activation (Louw et al., 1992).

The aims of the present study were to examine whether, (i) major depression is accompanied by lower serum vitamin E; and (ii) there are significant inverse relationships between lower serum vitamin E and signs of IRS activation, e.g. increased numbers of leukocytes and neutrophils.

Section snippets

Subjects and methods

Twenty six healthy volunteers and 42 depressed patients participated. Controls were free of any medication for at least one month prior to the study. No one had ever been taking psychotropic drugs or was a regular drinker. Controls were excluded for past, present and family history of psychiatric disorders. The structured interview of the DSM-III-R (Spitzer et al., 1990) was used to make the diagnosis of major depression (APA, 1987). Severity of depression was measured with the 17 item Hamilton

Results

There were no significant differences (F=2.0, df=1/66, p=0.2) in age or male/female ratio between patients (mean=54.0±13.6 years; 12/30) and controls (mean=49.7±8.7 years; 11/15). There was no significant correlation (r=0.14, p=0.3) between vitamin E and age. There was no significant difference in vitamin E (F=0.7, df=1/64, p=0.6) between men and women. There was a significant positive correlation between serum vitamin E and LDL-C (r=0.51, p=0.00009), but not triglycerides (r=0.21, p=0.09). All

Discussion

We found that depressed patients have lower serum vitamin E concentrations than controls.

The causes have remained elusive. (1). Protein energy malnutrition may decrease the antioxidant status (Sauerwein et al., 1997). However, no protein energy malnutrition could be found in depression (Maes et al., 1991). Vitamin E deficiency due to inadequate dietary intake is not known to occur in humans (Tietz, 1990). No significant effects of diets on serum vitamin E were observed (Young, 1993). Moreover,

Acknowledgements

The research reported was supported in part by the Funds for Scientific Research, Vlaanderen, Belgium (FWO) and the Clinical Research Center Mental Health, (CRC-MH), Antwerp, Belgium; and the Staglin Investigator Award (NARSAD, USA) for Dr. M. Maes. The secretarial assistance of Mrs. M. Maes is greatly appreciated.

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