No evidence of hypoglycemia or hypotension in older adults during 6 months of flax lignan supplementation in a randomized controlled trial: A safety evaluation

January 1, 2013 Human Health and Nutrition Data 0 Comments

No evidence of hypoglycemia or hypotension in older adults during 6 months of flax lignan supplementation in a randomized controlled trial: A safety evaluation

Year: 2013
Authors: Billinsky, J. Glew, R.A. Cornish, S.M. Whiting, S.J. Thorpe, L.U. Alcom, J. Paus-Jenssen, L. Hadjistavropoulos, T. et al
Publication Name: Pharma Bio.
Publication Details: Volume 51; Issue 6; Pages778–782


Context: The natural health product, BeneFlax, is a standardized flaxseed [Linum usitatissimum L. (Linaceae)] lignan enriched product with evidence of product quality and known quantity of
the bioactive component, lignan. The acceptance of this natural health product for its various health benefits requires greater evidence of its safety in the general population. Objective: We determined whether flaxseed lignan causes clinical hypoglycemia or hypotension in healthy older adults as an important aspect of safety. Materials and methods: Participants aged 49 to 87 years were randomized in a double-blind trial to receive flaxseed lignan (543 mg/day in BeneFlax) or placebo while completing a 6 month walking program. The 94 participants who completed the study were stratified by age (565 years versus 65 years) and treatment category to determine whether older adults were more susceptible to adverse effects. Results: After 6 months of treatment, average plasma glucose level (5.4 0.6 mmol/L), systolic blood pressure (127 14mmHg), and diastolic blood pressure (80 9mmHg) were within normal clinical range. Controlling for sex and body mass index covariates resulted in no observed differences between plasma glucose or blood pressure measurements between treatment or age groups . No incidents of hypoglycemia or hypotension were observed during BeneFlax treatment, suggesting that 543mg falls at or below the no observable adverse effect level (NOAEL). Discussion and conclusion: These data suggest the flaxseed lignan product BeneFlax does not pose a risk of hypoglycemia or hypotension in healthy adults aged 49 to 87 years. (Authors abstract)
Flaxseed (Linum usitatissimum L.) foods and derived products are beneficial for improving blood lipid profile and to protect against some types of cancer in human clinical trials and animal models. While other flaxseed constituents may contribute to these effects, the authors recently reported that the lignans of flaxseed may provide antioxidant and anti-estrogen protection to cell and tissue processes, thus contributing to overall protection from these chronic conditions.
Following oral consumption, the predominant lignin in flaxseed, secoisolariciresinol diglucoside (SDG), was converted to the mammalian lignans, enterodiol (ED) and enterolactone (EL), by bacteria in the human colon. During absorption, EL and ED undergo further metabolism by phase II biotransformation processes with extensive formation of glucuronide and sulfate conjugates, thereby reducing the oral bioavailability of EL and ED . Despite a lower oral bioavailability, the mammalian lignans seem to mediate beneficial health effects. EL and ED have structural similarity to estradiol, the active form of estrogen in the body. Binding of these lignans to estrogen receptors can exert weak estrogenic or anti-estrogenic effects , and such activity is believed to decrease the risk of hormone-sensitive cancers. EL and ED also possess antioxidant activity which may contribute to a reduction in risk of diseases and conditions associated with increased inflammation and oxidative damage such as metabolic syndrome. Finally, lignans may provide health benefits through the induction of phase II proteins (e.g., antioxidant enzymes), thus promoting the scavenging of oxidants or decreasing the probability of oxidant formation. Archer Daniels Midland has produced BeneFlax, which contains a standardized amount of SDG and can thus provide a known dose of lignan.  Older humans, i.e., age 65 years may benefit most from antioxidant activity and anti estrogen effects of lignans to ameliorate chronic inflammation. In proposing a clinical trial of SDG supplementation in adults over 60 years of age living in longterm care, concerns were raised about reported reductions in blood glucose levels  and blood pressure with SDG supplementation and whether this could cause hypoglycemia or hypotension in older, frailer participants. To address the concern of potential age-related adverse effects, data was used from a completed community based 6 month efficacy intervention trial of BeneFlax , containing 543 mg SDG, which had not been previously evaluated for age or treatment effects on hypoglycemia or hypotension.
Observed main findings were that SDG supplementation did not cause incidents of clinical hypoglycemia, defined as laboratory confirmed hypoglycemia with plasma glucose
53.9 mmol/L, or of clinical hypotension, defined as SBP 580mmHg. Furthermore, no differences between treatment and placebo groups were observed over time across different age categories with respect to SBP, DBP, or plasma glucose. The differences that were found represented generally weak effects. After controlling for BMI and sex, the largest effect was found between age categories for DBP where older participants had lower DBP. Younger participants are expected to have higher DBP as this physiological parameter is known to decrease with age. BeneFlax at a daily dose of 543 mg does not appear to pose a risk of causing hypoglycemia or hypotension in healthy older adults aged 65 years and older. This suggests a dose of 543 mg BeneFlax falls at or below the no observable adverse effect level (NOAEL) for hypoglycemia or hypotension. (Editors comments)

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