Effects of Folic Acid Supplementation on Hearing in Older Adults

2007 ◽  
Vol 146 (1) ◽  
pp. 1 ◽  
Author(s):  
Jane Durga ◽  
Petra Verhoef ◽  
Lucien J.C. Anteunis ◽  
Evert Schouten ◽  
Frans J. Kok
2018 ◽  
Vol 103 (8) ◽  
pp. 1123-1131 ◽  
Author(s):  
Daniel Gagnon ◽  
Steven A. Romero ◽  
Matthew N. Cramer ◽  
Ken Kouda ◽  
Paula Y S. Poh ◽  
...  

2017 ◽  
Vol 312 (5) ◽  
pp. R681-R688 ◽  
Author(s):  
Anna E. Stanhewicz ◽  
Jody L. Greaney ◽  
Lacy M. Alexander ◽  
W. Larry Kenney

During heat stress, blunted increases in skin sympathetic nervous system activity (SSNA) and reductions in end-organ vascular responsiveness contribute to the age-related reduction in reflex cutaneous vasodilation. In older adults, folic acid supplementation improves the cutaneous vascular conductance (CVC) response to passive heating; however, the influence of folic acid supplementation on SSNA:CVC transduction is unknown. Fourteen older adults (66 ± 1 yr, 8 male/6 female) ingested folic acid (5 mg/day) or placebo for 6 wk in a randomized, double-blind, crossover design. In protocol 1, esophageal temperature (Tes) was increased by 1.0°C (water-perfused suit) while SSNA (peroneal microneurography) and red cell flux in the innervated dermatome (laser Doppler flowmetry; dorsum of the foot) were continuously measured. In protocol 2, two intradermal microdialysis fibers were placed in the skin of the lateral calf for graded infusions of acetylcholine (ACh; 10−10 to 10−1 M) with and without nitric oxide synthase (NOS) blockade (20 mM nitro-l-arginine methyl ester). Folic acid improved reflex vasodilation (46 ± 4% vs. 31 ± 3% CVCmax for placebo; P < 0.001) without affecting the increase in SSNA (Δ506 ± 104% vs. Δ415 ± 73% for placebo; NS). Folic acid increased the slope of the SSNA-to-CVC relation (0.08 ± 0.02 vs. 0.05 ± 0.01 for placebo; P < 0.05) and extended the response range. Folic acid augmented ACh-induced vasodilation (83 ± 3% vs. 66 ± 4% CVCmax for placebo; P = 0.002); however, there was no difference between treatments at the NOS-inhibited site (53 ± 4% vs. 52 ± 4% CVCmax for placebo; NS). These data demonstrate that folic acid supplementation enhances reflex vasodilation by increasing the sensitivity of skin arterioles to central sympathetic nerve outflow during hyperthermia in aged human subjects.


2015 ◽  
Vol 129 (2) ◽  
pp. 159-167 ◽  
Author(s):  
Anna E. Stanhewicz ◽  
Lacy M. Alexander ◽  
W. Larry Kenney

Folic acid supplementation improves nitric-oxide dependent vasodilatation in the cutaneous circulation of older adults. This suggests that folic acid may be a viable intervention strategy for improvement or maintenance of microvascular health in older adulthood.


The Lancet ◽  
2007 ◽  
Vol 369 (9557) ◽  
pp. 208-216 ◽  
Author(s):  
Jane Durga ◽  
Martin PJ van Boxtel ◽  
Evert G Schouten ◽  
Frans J Kok ◽  
Jelle Jolles ◽  
...  

2005 ◽  
Vol 94 (07) ◽  
pp. 96-100 ◽  
Author(s):  
Mariska Klerk ◽  
Jane Durga ◽  
Evert G. Schouten ◽  
Cornelis Kluft ◽  
Frans J. Kok ◽  
...  

SummaryElevated homocysteine levels are associated with an increased cardiovascular disease (CVD) risk, but the underlying mechanism is still unclear. High homocysteine might affect the endothelium, and consequently lead to impaired haemostasis. In a randomized placebo controlled trial among 276 older adults with plasma total homocysteine concentrations above 13 mM at screening, we investigated the effect of homocysteine lowering by folic acid supplementation (0.8 mg/day) for 1 year on markers of endothelial function (vonWillebrand factor), coagulation (tissue factor, factor VIIa, fragments 1+2), and fibrinolysis (fibrin degradation products, tissue-type plasminogen activator), and inflammation (C-reactive protein). Despite a 24% reduction in plasma homocysteine concentration and four-fold increase in serum folate concentration in the folic acid group compared to the placebo group, there was no clear change in any of the haemostasis markers, nor CRP. Although homocysteine is associated with vascular disease risk in the general population, marked lowering of slightly elevated homocysteine concentrations by one-year folic acid supplementation does not influence haemostasis markers.


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