BH 4 Improves Postprandial FMD in Older Adults

Menopause is associated with an increased risk for cardiovascular disease (CVD) and is likely related to a decrease in nitric oxide (NO) bioavailability. The flow mediated dilation (FMD) test is a non‐invasive assessment of NO bioavailability in humans. Tetrahydrobiopterin (BH 4 ) represents a therapeutic agent that may offer a novel means to increase NO bioavailability, preserve vascular integrity, and reduce overall CVD risk. Accordingly, we hypothesized that the ingestion of BH 4 will counteract the attenuation in NO bioavailability typically observed following a high fat meal (HFM). In a randomized, double‐blinded, crossover design, 22 older adults (9 postmenopausal women within 3 years, 6 postmenopausal women for greater than 10 years, and 7 men) ingested a HFM with and without the co‐ingestion of BH 4 (5 mg·kg −1 of body weight dissolved in apple juice). FMD was measured at baseline and 4 hours post‐ingestion in each trial. A significant treatment effect for delta (Δ) FMD was identified (p=0.048). Specifically, an increase in FMD was observed following the HFM with BH 4 (5.4±0.8% to 6.5±1.0%; Δ1.1±0.7%), whereas a slight decrease in FMD was observed following the HFM alone (6.7±0.7% to 6.0±0.7%; Δ−0.7±0.6%). In summary, co‐ingestion of BH 4 with a HFM improves postprandial FMD, regardless of postmenopausal status or sex.