title: Blood pressure-lowering effects of beetroot juice and novel beetroot-enriched bread products in normotensive male subjects.
abstract: A number of vegetables have a high nitrate content which after ingestion can be reduced to nitrite by oral bacteria, and further to vasoprotective NO endogenously. In the present study, two separate randomly controlled, single-blind, cross-over, postprandial studies were performed in normotensive volunteers. Ambulatory blood pressure (BP) was measured over a 24 h period following consumption of either four doses of beetroot juice (BJ), 0, 100, 250 and 500 g (n 18), or three bread products, control bread (0 g beetroot), red beetroot- and white beetroot-enriched breads (n 14). Total urinary nitrate/nitrite (NO(x)) was measured at baseline, and at 2, 4 and 24 h post-ingestion. BJ consumption significantly, and in a near dose-dependent manner, lowered systolic BP (SBP, P < 0·01) and diastolic BP (DBP, P < 0·001) over a period of 24 h, compared with water control. Furthermore, bread products enriched with 100 g red or white beetroot lowered SBP and DBP over a period of 24 h (red beetroot-enriched bread, P <0·05), with no statistical differences between the varieties. Total urinary NO(x) significantly increased following the consumption of 100 g (P < 0·01), 250 g (P <0·001) and 500 g BJ (P <0·001) and after red beetroot-enriched bread ingestion (P <0·05), but did not reach significance for white beetroot-enriched bread compared with the no-beetroot condition. These studies demonstrated significant hypotensive effects of a low dose (100 g) of beetroot which was unaffected by processing or the presence of betacyanins. These data strengthen the evidence for cardioprotective BP-lowering effects of dietary nitrate-rich vegetables.
authors.affiliation: Hugh Sinclair Unit of Human Nutrition, Department of Food and Nutritional Sciences, School of Chemistry, Food and Pharmacy, The University of Reading, Whiteknights, PO Box 226, Reading, Berks              RG6 6AP, UK.
authors.forename: Ditte A
authors.initials: DA
authors.lastname: Hobbs
authors.forename: Nedi
authors.initials: N
authors.lastname: Kaffa
authors.forename: Trevor W
authors.initials: TW
authors.lastname: George
authors.forename: Lisa
authors.initials: L
authors.lastname: Methven
authors.forename: Julie A
authors.initials: JA
authors.lastname: Lovegrove
mesh_terms: D000328:Adult; D000959:Antihypertensive Agents / Q000008:administration & dosage / Q000737:chemistry / Q000627:therapeutic use*; D027461:Beta vulgaris / Q000737:chemistry*; D050859:Betacyanins / Q000008:administration & dosage / Q000032:analysis; D001628:Beverages / Q000032:analysis; D001939:Bread / Q000032:analysis; D002316:Cardiotonic Agents / Q000008:administration & dosage / Q000737:chemistry / Q000627:therapeutic use*; D018592:Cross-Over Studies; D004739:England; D006801:Humans; D008297:Male; D009566:Nitrates / Q000008:administration & dosage / Q000032:analysis / Q000652:urine; D009573:Nitrites / Q000032:analysis / Q000652:urine; D010858:Pigmentation; D010865:Pilot Projects; D018517:Plant Roots / Q000737:chemistry*; D058246:Prehypertension / Q000178:diet therapy* / Q000517:prevention & control / Q000652:urine; D016037:Single-Blind Method; D013997:Time Factors; D055815:Young Adult
chemical_list: D000959:Antihypertensive Agents; D050859:Betacyanins; D002316:Cardiotonic Agents; D009566:Nitrates; D009573:Nitrites