AUTHOR=Reed Emma L. , Worley Morgan L. , Kueck Paul J. , Pietrafasa Leonard D. , Schlader Zachary J. , Johnson Blair D. 

TITLE=Cerebral vascular function following the acute consumption of caffeinated artificially- and sugar sweetened soft drinks in healthy adults

JOURNAL=Frontiers in Human Neuroscience

VOLUME=16

YEAR=2022

URL=https://www.frontiersin.org/journals/human-neuroscience/articles/10.3389/fnhum.2022.1063273

DOI=10.3389/fnhum.2022.1063273

ISSN=1662-5161

ABSTRACT=<p>Chronic consumption of sugar- and artificially-sweetened beverages (SSB and ASB) are associated with an increased risk of stroke but it is unclear how acute consumption influences cerebral vascular function.</p><p><bold>Purpose:</bold> We hypothesized that: (1) acute consumption of SSB and ASB would augment dynamic cerebral autoregulation (dCA) and attenuate cerebral vascular reactivity to hypercapnia (CVR<sub>CO2</sub>) compared to water; and (2) dCA and CVR<sub>CO2</sub> would be attenuated with SSB compared to ASB and water.</p><p><bold>Methods:</bold> Twelve healthy adults (age: 23 ± 2 years, four females) completed three randomized trials where they drank 500 ml of water, SSB (Mountain Dew<sup>®</sup>), or ASB (Diet Mountain Dew<sup>®</sup>). We measured mean arterial pressure (MAP), middle and posterior cerebral artery blood velocities (MCAv and PCAv), and end-tidal CO<sub>2</sub> tension (PETCO<sub>2</sub>). Cerebral vascular conductance was calculated as cerebral artery blood velocity/MAP (MCAc and PCAc). Twenty min after consumption, participants completed a 5 min baseline, and in a counterbalanced order, a CVR<sub>CO2</sub> test (3%, 5%, and 7% CO<sub>2</sub> in 3 min stages) and a dCA test (squat-stand tests at 0.10 Hz and 0.05 Hz for 5 min each) separated by 10 min. CVR<sub>CO2</sub> was calculated as the slope of the linear regression lines of MCAv and PCAv vs. PETCO<sub>2</sub>. dCA was assessed in the MCA using transfer function analysis. Coherence, gain, and phase were determined in the low frequency (LF; 0.07–0.2 Hz) and very low frequency (VLF; 0.02–0.07 Hz).</p><p><bold>Results:</bold> MCAv and MCAc were lower after SSB (54.11 ± 12.28 cm/s, 0.58 ± 0.15 cm/s/mmHg) and ASB (51.07 ± 9.35 cm/s, 0.52 ± 1.0 cm/s/mmHg) vs. water (62.73 ± 12.96 cm/s, 0.67 ± 0.11 cm/s/mmHg; all <italic>P</italic> &lt; 0.035), respectively. PCAc was also lower with the ASB compared to water (<italic>P</italic> = 0.007). MCA CVR<sub>CO2</sub> was lower following ASB (1.55 ± 0.38 cm/s/mmHg) vs. water (2.00 ± 0.57 cm/s/mmHg; <italic>P</italic> = 0.011) but not after SSB (1.90 ± 0.67 cm/s/mmHg; <italic>P</italic> = 0.593). PCA CVR<sub>CO2</sub> did not differ between beverages (<italic>P</italic> &gt; 0.853). There were no differences between beverages for coherence (<italic>P</italic> ≥ 0.295), gain (<italic>P</italic> ≥ 0.058), or phase (<italic>P</italic> ≥ 0.084) for either frequency.</p><p><bold>Discussion:</bold> Acute consumption of caffeinated SSB and ASB resulted in lower intracranial artery blood velocity and conductance but had a minimal effect on cerebral vascular function as only MCA CVR<sub>CO2</sub> was altered with the ASB compared to water.</p>