Metabolism and physiological actions of milled flaxseed in humans as a function of dose, participant age and cardiovascular disease status
| dc.contributor.author | Edel, Andrea L | |
| dc.contributor.examiningcommittee | Zahradka, Peter (Physiology and Pathophysiology) Taylor, Carla (Human Nutritional Sciences) O, Karmin (Animal Science) Anderson, Hope (Pharmacology and Therapeutics) Kyselovic, Jan (Pharmacology and Toxicology, Comenius University Bratislava) | en_US |
| dc.contributor.supervisor | Pierce, Grant (Physiology and Pathophysiology) Aliani, Michel (Human Nutritional Sciences) | en_US |
| dc.date.accessioned | 2016-04-11T15:58:42Z | |
| dc.date.available | 2016-04-11T15:58:42Z | |
| dc.date.issued | 2013-01 | en_US |
| dc.date.issued | 2014-12 | en_US |
| dc.date.issued | 2015-03 | en_US |
| dc.date.issued | 2015-04 | en_US |
| dc.date.issued | 2015-08 | en_US |
| dc.date.issued | 2015-11 | en_US |
| dc.degree.discipline | Physiology and Pathophysiology | en_US |
| dc.degree.level | Doctor of Philosophy (Ph.D.) | en_US |
| dc.description.abstract | Basic and clinical research documents the benefits of dietary milled flaxseed (MFX), a rich source of alpha-linolenic acid (ALA) and lignans, in the attenuation of risk factors key to regulating cardiovascular disease (CVD) progression. ALA has antihypertensive properties and the lignan metabolites, enterodiol (END) and enterolactone (ENL), have antioxidative potential. The effectiveness of these bioactives to reduce risk factors of CVD may be dependent upon their plasma concentrations. To study this, we first designed and validated a method using supported liquid extraction and gas chromatography/mass spectrometry to isolate and quantify enterolignans in plasma. Applying this technique, we examined MFX doses of 10-40 g/d administered to healthy, younger adults (18-49 years of age) for 4 weeks. Ten g/d was sufficient to significantly increase circulating ALA (1.5 fold) and enterolignans (5-31 fold). There was no significant dose-dependent response. In another investigation, younger (18-29 years of age) and older (45-69 years of age) healthy adults were studied to determine if age influenced enterolignan metabolism. CVD is associated with advanced age but older people may not be able to obtain lignan metabolites from dietary MFX. Following 4 weeks of MFX consumption, both age groups increased plasma total enterolignans (END + ENL) with no between-group differences. This suggested that older and younger adults metabolize MFX lignans equally. A final study assessed MFX bioactives in plasma of peripheral artery disease patients >40 years of age. Plasma enterolignans increased 10-50 fold and ALA 1-2 fold after only one month of MFX ingestion. Dietary MFX also attenuated total (11%) and LDL (15%) cholesterol in these patients after 1-6 months of administered MFX compared to placebo. The attenuation in cholesterol was due to the high fiber content of flaxseed, and not to ALA and enterolignans, despite their marked increase in circulation. MFX did not interfere with cholesterol-lowering medications but instead decreased cholesterol levels beyond the effects of medications alone. To conclude, dietary supplementation with MFX resulted in an increase in plasma enterolignan and ALA concentrations in healthy younger and older adults and in patients with pre-existing CVD. The cholesterol-lowering benefits of MFX were additional to cholesterol-lowering drugs and likely attributed to MFX fiber. | en_US |
| dc.description.note | May 2016 | en_US |
| dc.identifier.citation | MLA | en_US |
| dc.identifier.uri | http://hdl.handle.net/1993/31194 | |
| dc.language.iso | eng | en_US |
| dc.publisher | Springer | en_US |
| dc.publisher | American Society for Nutrition | en_US |
| dc.publisher | Elsevier | en_US |
| dc.rights | open access | en_US |
| dc.subject | Flaxseed | en_US |
| dc.subject | Lignans | en_US |
| dc.subject | Polyunsaturated fatty acids | en_US |
| dc.subject | Cardiovascular disease | en_US |
| dc.title | Metabolism and physiological actions of milled flaxseed in humans as a function of dose, participant age and cardiovascular disease status | en_US |
| dc.type | doctoral thesis | en_US |
| local.subject.manitoba | yes | en_US |