A focus on homocysteine in autism.

Homocysteine is an amino acid, which plays several important roles in human physiology. A wide range of disorders, including neuropsychiatric disorders and autism, are associated with increased homocysteine levels in biological fluids. Various B vitamins: B6 (pyridoxine), B12 (cobalamin), and B9 (folic acid) are required as co-factors by the enzymes involved in homocysteine metabolism. Therefore, monitoring of homocysteine levels in body fluids of autistic children can provide information on genetic and physiological diseases, improper lifestyle (including dietary habits), as well as a variety of pathological conditions. This review presents information on homocysteine metabolism, determination of homocysteine in biological fluids, and shows abnormalities in the levels of homocysteine in the body fluids of autistic children.

Vitamin supplementation reduces the level of homocysteine in the urine of autistic children.

Significant differences in homocysteine levels in the urine of autistic children are observed. We hypothesized that vitamin supplementation might reduce the level of urinary homocysteine. To rationalize such a hypothesis, analyses were performed using the gas chromatography/mass spectrometry method. The homocysteine level in the urine of autistic children was measured twice: (1) before vitamin supplementation (group C, 30 autistic children) and (2) after supplementation, with either folic acid and vitamins B(6) and B(12) (group A1, 24 autistic children) or vitamins B(6) and B(12) alone (group A2, 6 autistic children). The homocysteine level in the urine of autistic children before vitamin supplementation was 2.41 ± 1.10 mmol/mol creatinine (mean ± SD difference). After treatment, the homocysteine level was reduced to 1.13 ± 0.44 and 1.33 ± 0.39 mmol/mol creatinine for A1 and A2 groups, respectively. The intake of vitamins B(6) and B(12), together with folic acid, was found to be more effective in lowering the levels of urinary homocysteine than the intake of vitamins B(6) and B(12) alone. Our findings may lead to the recommendation of including vitamins B(6) and B(12) together with folic acid supplementation in the diets of children with autism.

Does ingestion of regular coffee influence serum lipid profile in dialysis patients?

We checked whether dialysis patients who drink coffee might have a serum lipid profile different from that of nondrinkers of coffee. The study was performed in 30 patients (26 on peritoneal dialysis, 4 on hemodialysis). Group I included patients who drank 1 - 3 cups of coffee daily (140 - 420 mg caffeine) for at least 2 years before the study [n = 11; dialysis vintage: 29.1 months (range: 8.7 - 59.6 months); age: 56.0 +/- 14.6 years]. Group II consisted of patients who said that they were nondrinkers of caffeinated coffee [n = 19; dialysis vintage: 15.2 months (range: 6.3 - 45.4 months); age: 56.3 +/- 19.8 years). Serum lipid profile, anthropometric and bioimpedance measurements, and laboratory indices of nutrition and inflammation status were examined. Compared with group II, group I showed higher serum high-density lipoprotein (HDL) cholesterol (45.1 +/- 12.8 mg/dL vs. 37.7 +/- 6.6 mg/dL, p = 0.045) and lower low-density lipoprotein (LDL) cholesterol (104.7 +/- 15.7 mg/dL vs. 139.0 +/- 41.8 mg/dL, p = 0.007). Other examined parameters did not differ significantly between the groups, with the exception of serum albumin [4.0 g/dL (range: 3.1 - 4.3 g/dL) in group I vs. 3.3 g/dL (range: 2.9 - 4.4 g/dL) in group II, p = 0.020]. Adjustment for age and sex additionally showed differences in bioimpedance and anthropometric measurements. Compared with group II, group I showed lower waist and hip circumferences, a lower waist/height ratio, a lower fat body mass, and a higher lean body mass as a percentage of total body mass. When adjustments were made for age, sex, and fat body mass, differences in lipid profile were nonsignificant. In the overall group, a correlation was seen between lean body mass and total cholesterol (r = -0.487, p = 0.006). Lower LDL and higher HDL serum cholesterol may occur in dialyzed patients who drink coffee not only because of the direct influence of coffee ingredients on serum lipid profile, but mainly because of a more favorable body composition and better protein nutrition in coffee drinkers.

Coffee consumption and bone mineral density in dialysis patients.

The influence of ingested coffee on bone mineral density (BMD) and the related risk of pathologic fractures is controversial. We decided to check if dialysis patients drinking coffee may have a BMD different from that of non coffee drinkers. We studied 30 dialysis patients (26 on hemodialysis, 4 on peritoneal dialysis). Group I (n = 11, 5 women) included patients who regularly drank at least 1 cup of coffee daily [dialysis duration: 29.1 months (range: 8.7- 59.6 months); age: 56.0 +/- 14.6 years]. Group II (n = 19, 13 women) consisted of patients who said that they were nondrinkers of coffee [dialysis duration: 15.2 months (range: 6.3 - 45.4 months); age: 56.3 +/- 19.8 years]. We examined BMD in all subjects in two sites (femoral neck and L2 - L4 lumbar region) by dual-energy X-ray absorptiometry. Serum parathyroid hormone, calcium-phosphate balance parameters, blood pH, serum markers of inflammation, bioimpedance records of body composition, and markers of nutrition were simultaneously evaluated. Compared with group II, group I showed significantly lower L2 -L4 parameters: BMD (0.906 +/- 0.236 g/cm2 vs. 1.172 +/- 0.227 g/cm2, p = 0.005), percent of peak BMD (78.4% +/- 18.9% vs. 98.4% +/- 17.0%, p = 0.006), percent of age norm (82.7% +/- 18.2% vs. 105.9% +/- 17.7% p = 0.002), T-score [-2.07 (range: -3.95 to 2.02) vs. -0.51 (range: -2.29 to 4.07), p = 0.020], and Z-score [-1.25 (range: -4.41 to 1.90) vs. 0.26 (range: -1.48 to 4.49), p = 0.006]. Serum albumin concentration was higher in group I [4.0 g/dL (range: 3.1 - 4.3 g/dL) vs. 3.3 g/dL (range: 2.9 - 4.4 g/dL), p = 0.020]. Our results suggest that regular coffee consumption may contribute to BMD loss in dialysis patients.