Dietary Protein and Blood Pressure: A Systematic Review

Background - Elevated blood pressure (BP), which is a major risk factor for cardiovascular disease, is highly prevalent worldwide. Recently, interest has grown in the role of dietary protein in human BP. We performed a systematic review of all published scientific literature on dietary protein, including protein from various sources, in relation to human BP. Methodology/Principal Findings - We performed a MEDLINE search and a manual search to identify English language studies on the association between protein and blood pressure, published before June 2010. A total of 46 papers met the inclusion criteria. Most observational studies showed no association or an inverse association between total dietary protein and BP or incident hypertension. Results of biomarker studies and randomized controlled trials indicated a beneficial effect of protein on BP. This beneficial effect may be mainly driven by plant protein, according to results in observational studies. Data on protein from specific sources (e.g. from fish, dairy, grain, soy, and nut) were scarce. There was some evidence that BP in people with elevated BP and/or older age could be more sensitive to dietary protein. Conclusions/Significance - In conclusion, evidence suggests a small beneficial effect of protein on BP, especially for plant protein. A blood pressure lowering effect of protein may have important public health implications. However, this warrants further investigation in randomized controlled trials. Furthermore, more data are needed on protein from specific sources in relation to BP, and on the protein-BP relation in population subgroup

Aldose reductase in the BB rat: isolation, immunological identification and localization in the retina and peripheral nerve

Aldose reductase was purified from testis of nondiabetic BB rats using DEAE cellulose, hydroxylapatite and sephadex G-100 column chromatography. The molecular weight of the isolated enzyme was found to be 36,500±1000. Antibody against the isolated enzyme was raised in rabbits. It was purified by affinity chromatography, characterised by double immunodiffusion and Western blot analysis and used to localize the enzyme in retina and in peripheral nerve of the BB rat. In the retina, aldose reductase immunoreactivity was seen in the ganglion cells, Müller cell processes, retinal pigment epithelium and in the pericytes and endothelial cells of retinal capillaries. In peripheral nerve, aldose reductase immunoreactivity was found in the paranodal cytoplasm of Schwann cells and in pericytes and endothelial cells of endoneurial capillaries.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46019/1/125_2004_Article_BF00270423.pd

Metabolic implications when employing heavy pre- and post-exercise rapid-acting insulin reductions to prevent hypoglycaemia in Type 1 diabetes patients: a randomised clinical trial

Aim To examine the metabolic, gluco-regulatory-hormonal and inflammatory cytokine responses to large reductions in rapid-acting insulin dose administered prandially before and after intensive running exercise in male type 1 diabetes patients. Methods This was a single centre, randomised, controlled open label study. Following preliminary testing, 8 male patients (24±2 years, HbA1c 7.7±0.4%/61±4 mmol.l−1) treated with insulin's glargine and aspart, or lispro attended the laboratory on two mornings at ∼08:00 h and consumed a standardised breakfast carbohydrate bolus (1 g carbohydrate.kg−1BM; 380±10 kcal) and self-administered a 75% reduced rapid-acting insulin dose 60 minutes before 45 minutes of intensive treadmill running at 73.1±0.9% VO2peak. At 60 minutes post-exercise, patients ingested a meal (1 g carbohydrate.kg−1BM; 660±21 kcal) and administered either a Full or 50% reduced rapid-acting insulin dose. Blood glucose and lactate, serum insulin, cortisol, non-esterified-fatty-acids, β-Hydroxybutyrate, and plasma glucagon, adrenaline, noradrenaline, IL-6, and TNF-α concentrations were measured for 180 minutes post-meal. Results All participants were analysed. All glycaemic, metabolic, hormonal, and cytokine responses were similar between conditions up to 60 minutes following exercise. Following the post-exercise meal, serum insulin concentrations were lower under 50% (p<0.05) resulting in 75% of patients experiencing hyperglycaemia (blood glucose ≥8.0 mmol.l−1; 50% n = 6, Full n = 3). β-Hydroxybutyrate concentrations decreased similarly, such that at 180 minutes post-meal concentrations were lower than rest under Full and 50%. IL-6 and TNF-α concentrations remained similar to fasting levels under 50% but declined under Full. Under 50% IL-6 concentrations were inversely related with serum insulin concentrations (r = −0.484, p = 0.017). Conclusions Heavily reducing rapid-acting insulin dose with a carbohydrate bolus before, and a meal after intensive running exercise may cause hyperglycaemia, but does not augment ketonaemia, raise inflammatory cytokines TNF-α and IL-6 above fasting levels, or cause other adverse metabolic or hormonal disturbances. Trial Registration ClinicalTrials.gov NCT0153185