Formic acid, a novel metabolite of chronic ethanol abuse, causes neurotoxicity, which is prevented by folic acid.

BACKGROUND: Methanol is endogenously formed in the brain and is present as a congener in most alcoholic beverages. Because ethanol is preferentially metabolized over methanol (MeOH) by alcohol dehydrogenase, it is not surprising that MeOH accumulates in the alcohol-abusing population. This suggests that the alcohol-drinking population will have higher levels of MeOH's neurotoxic metabolite, formic acid (FA). FA elimination is mediated by folic acid. Neurotoxicity is a common result of chronic alcoholism. This study shows for the first time that FA, found in chronic alcoholics, is neurotoxic and this toxicity can be mitigated by folic acid administration. OBJECTIVE: To determine if FA levels are higher in the alcohol-drinking population and to assess its neurotoxicity in organotypic hippocampal rat brain slice cultures. METHODS: Serum and CSF FA was measured in samples from both ethanol abusing and control patients, who presented to a hospital emergency department. FA's neurotoxicity and its reversibility by folic acid were assessed using organotypic rat brain hippocampal slice cultures using clinically relevant concentrations. RESULTS: Serum FA levels in the alcoholics (mean +/- SE: 0.416 +/- 0.093 mmol/l, n = 23) were significantly higher than in controls (mean +/- SE: 0.154 +/- 0.009 mmol/l, n = 82) (p < 0.0002). FA was not detected in the controls' CSF (n = 20), whereas it was >0.15 mmol/l in CSF of 3 of the 4 alcoholic cases. Low doses of FA from 1 to 5 mmol/l added for 24, 48 or 72 hours to the rat brain slice cultures caused neuronal death as measured by propidium iodide staining. When folic acid (1 micromol/l) was added with the FA, neuronal death was prevented. CONCLUSIONS: Formic acid may be a significant factor in the neurotoxicity of ethanol abuse. This neurotoxicity can be mitigated by folic acid administration at a clinically relevant dose.

Effect of wheat bran on glycemic control and risk factors for cardiovascular disease in type 2 diabetes.

OBJECTIVE: Cohort studies indicate that cereal fiber reduces the risk of diabetes and coronary heart disease (CHD). Therefore, we assessed the effect of wheat bran on glycemic control and CHD risk factors in type 2 diabetes. RESEARCH DESIGN AND METHODS: A total of 23 subjects with type 2 diabetes (16 men and 7 postmenopausal women) completed two 3-month phases of a randomized crossover study. In the test phase, bread and breakfast cereals were provided as products high in cereal fiber (19 g/day additional cereal fiber). In the control phase, supplements were low in fiber (4 g/day additional cereal fiber). RESULTS: Between the test and control treatments, no differences were seen in body weight, fasting blood glucose, HbA(1c), serum lipids, apolipoproteins, blood pressure, serum uric acid, clotting factors, homocysteine, C-reactive protein, magnesium, calcium, iron, or ferritin. LDL oxidation in the test phase was higher than that seen in the control phase (12.1 +/- 5.4%, P < 0.034). Of the subjects originally recruited, more dropped out of the study for health and food preference reasons from the control phase (16 subjects) than the test phase (11 subjects). CONCLUSIONS: High-fiber cereal foods did not improve conventional markers of glycemic control or risk factors for CHD in type 2 diabetes over 3 months. Possibly longer studies are required to demonstrate the benefits of cereal fiber. Alternatively, cereal fiber in the diet may be a marker for another component of whole grains that imparts health advantages or a healthy lifestyle.