Increased postprandial homocysteinemia in a group of depressed patients

The acute postprandial response of homocysteine to multivitamin and mineral supplementation with a standard meal is not impaired in older compared to younger adults

PURPOSE

B vitamins are required for the complex regulation of homocysteine and one-carbon (1C) metabolism. Nutritional supplements are frequently used by older adults to counter nutritional inadequacies. However, the postprandial use of B vitamins from supplements in 1C metabolism may be altered with age owing to impaired nutrient absorption and metabolic regulation. Despite implications for health and nutritional status, postprandial 1C metabolite responses have not been characterised in older adults.

METHODS

Healthy older (n = 20, 65-76 years) and younger (n = 20, 19-30 years) participants were recruited through online and printed advertisements in Auckland, New Zealand. Participants consumed a multivitamin and mineral supplement with a standard breakfast meal. Blood samples were collected at baseline and hourly for 4 h following ingestion. Plasma 1C metabolites (betaine, choline, cysteine, dimethylglycine, glycine, methionine, serine) were quantified using liquid chromatography coupled with mass spectrometry. Serum homocysteine, folate and vitamin B₁₂ were quantified on a Cobas e411 autoanalyzer.

RESULTS

Older adults had higher fasting homocysteine concentrations (older: 14.0 ± 2.9 µmol/L; younger: 12.2 ± 2.5 µmol/L; p = 0.036) despite higher folate (older: 36.7 ± 17.4 nmol/L; younger: 21.6 ± 7.6 nmol/L; p < 0.001) and similar vitamin B₁₂ concentrations (p = 0.143) to younger adults. However, a similar postprandial decline in homocysteine was found in older and younger subjects in response to the combined meal and supplement. Except for a faster decline of cystathionine in older adults (p = 0.003), the postprandial response of other 1C metabolites was similar between young and older adults.

CONCLUSION

Healthy older adults appear to maintain postprandial responsiveness of 1C metabolism to younger adults, supported by a similar postprandial decline in homocysteine concentrations.

Treatment of depression: time to consider folic acid and vitamin B12

We review the findings in major depression of a low plasma and particularly red cell folate, but also of low vitamin B12 status. Both low folate and low vitamin B12 status have been found in studies of depressive patients, and an association between depression and low levels of the two vitamins is found in studies of the general population. Low plasma or serum folate has also been found in patients with recurrent mood disorders treated by lithium. A link between depression and low folate has similarly been found in patients with alcoholism. It is interesting to note that Hong Kong and Taiwan populations with traditional Chinese diets (rich in folate), including patients with major depression, have high serum folate concentrations. However, these countries have very low life time rates of major depression. Low folate levels are furthermore linked to a poor response to antidepressants, and treatment with folic acid is shown to improve response to antidepressants. A recent study also suggests that high vitamin B12 status may be associated with better treatment outcome. Folate and vitamin B12 are major determinants of one-carbon metabolism, in which S-adenosylmethionine (SAM) is formed. SAM donates methyl groups that are crucial for neurological function. Increased plasma homocysteine is a functional marker of both folate and vitamin B12 deficiency. Increased homocysteine levels are found in depressive patients. In a large population study from Norway increased plasma homocysteine was associated with increased risk of depression but not anxiety. There is now substantial evidence of a common decrease in serum/red blood cell folate, serum vitamin B12 and an increase in plasma homocysteine in depression. Furthermore, the MTHFR C677T polymorphism that impairs the homocysteine metabolism is shown to be overrepresented among depressive patients, which strengthens the association. On the basis of current data, we suggest that oral doses of both folic acid (800 microg daily) and vitamin B12 (1 mg daily) should be tried to improve treatment outcome in depression.

Homocysteine during the menstrual cycle in depressive women

BACKGROUND

Two possible factors that may have a causal relation with both depressive disorder and cardiovascular disease are elevated homocysteine and steroid hormones. Our previous study found significant changes in the plasma homocysteine concentration during the menstrual cycle in healthy women. The purpose of this study therefore was to test homocysteine in depressive women treated with fluoxetine during the menstrual cycle.

MATERIALS AND METHODS

Thirteen premenopausal women suffering from mixed anxiety-depressive disorder and a control group of 15 healthy women were enrolled in this study. The homocysteine concentration was determined by high-performance liquid chromatography with fluorescence detection, and estradiol, progesterone and cortisol by RIA methods.

RESULTS

We found significantly higher plasma homocysteine concentrations in the follicular phase than in the luteal phase of the menstrual cycle in both the depressive group (P < 0.003) and the controls (P < 0.0009). Moreover, the patient values of total homocysteine were significantly higher in the follicular phase (P < 0.03) and also in the luteal phase (P < 0.007) than the values of the controls. Estradiol and cortisol were significantly higher in the follicular phase of the patients compared with the control group.

CONCLUSION

According to our results, women suffering from mixed anxiety-depressive disorder have not only significantly different concentrations of homocysteine in the follicular and luteal phase of the menstrual cycle but also higher plasma homocysteine compared with healthy women. More elevated homocysteine in the depressive than in the healthy premenopausal women points to the notion that psychological factors might be important when considering the homocysteine concentration.

Subclinical protein malnutrition is a determinant of hyperhomocysteinemia

OBJECTIVES

Hyperhomocysteinemia is regarded as a public health problem of increasing importance likely to contribute to vascular disorders and premature mortality. Folate, cobalamin, pyridoxine, and riboflavin dietary deficiencies are currently regarded as causative factors. However, several investigations have indicated that the theory of vitamin B deprivation provides only a partial explanation for the observed abnormalities of sulfur-containing amino acids. We investigated the potential contributory role played by protein malnutrition.

METHODS

For that purpose, three cohorts of 20 adult patients presenting stage I, II, and III goiter underwent careful medical history, dietary inquiry, and clinical examination. Their overall health and nutrition states were assessed with classic anthropometry, measurement of vitamin B blood parameters, visceral protein markers, essential amino acids, total homocysteine, and cystathionine.

RESULTS

The concentrations of transthyretin, seven essential amino acids, and cystathionine progressively decreased as the thyroid gland increased. Methionine was the sole essential amino acid whose values did not change; total homocysteine was unique in that increased levels correlated negatively with transthyretin values. Taken together, the data point to a progressive deterioration of protein nutrition status impairing the transsulfuration pathway and is best explained by an acquired defect of cystathionine-beta-synthase activity.

CONCLUSIONS

Hyperhomocysteinemia may arise from the shrinking of endogenous nitrogen pools as a result of decreased protein intake or stress-induced increased losses. Raised total homocysteine may result from the attempt of the malnourished and/or stressed body to preserve methionine homeostasis.

Total homocysteine and cardiovascular disease

Recent data have shown that an elevated plasma level of the amino acid homocysteine (Hcy) is a common, independent, easily modifiable and possibly causal risk factor for cardiovascular disease (CVD) which may be of equal importance to hypercholesterolemia, hypertension and smoking. This paper reviews the biochemical, clinical, epidemiological and experimental data underlying this conclusion and is critically questioning whether elevated tHcy is a causal factor.