The primary objective of this study is to investigate the acute physiological and metabolic effects of ingesting the short-chain fatty acids (SCFA)s propionate (three carbon atoms long; C3:0) and butyrate (C4:0) in healthy men and women. This aim will be addressed through a block-randomized cross-over study including two visits with acute intake of propionate and butyrate, respectively. The hypothesis is that plasma ketone body levels will increase during the first three hours after intake of butyrate, but not propionate, in healthy individuals in the overnight fasted state.
The study will be conducted as a block-randomized cross-over study in healty participants (n=10). The participants will undergo two experimental days of three hours separated by a two to four weeks wash-out period. At the test days, participants will consume 3 grams of either propionate or butyrate in the form of sodium-propionate or sodium-butyrate together with 250 ml of water. The order of ingestion is determined by randomization. The day prior to the experimental days, participants will consume a standardized control dinner and evening snack and abstain from alcohol and vigorous physical activity to ensure similar conditions on the experimental days. The standardized meal will be provided to the participants. On the test days, participants will be instructed to arrive by passive transport in an overnight fasted state (10 hours). Upon arrival, a DXA scan will be performed, after which a catheter will be inserted into an antecubital vein. Following 30 minutes of supine rest, baseline measurements will be performed, including indirect calorimetry, blood pressure measurement, flow-mediated vasodilation (FMD), and a fasting venous blood sample. Participants will then ingest 3 grams of propionate or butyrate within 5 minutes, together with 250 ml of water. After ingestion, participants will remain resting in bed for 3 hours, during which blood samples (15 ml each) will be collected continuously throughout the test day. Indirect calorimetry, blood pressure measurements, and FMD will be repeated at various time points post-ingestion. The test day will end with an ad libitum meal. The entire procedure will be repeated on the second test day.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
SINGLE
Enrollment
10
The participants will consume Short-chain fatty acid propionate (SCFA-PRO) followed by Short-Chain Fatty Acid Butyrate (SCFA-BUT).
• The participants will consume Short-chain fatty acid Butyrate (SCFA-BUT) followed by Short-Chain Fatty Acid Propionate (SCFA-PRO).
• The participants will consume Short-Chain Fatty Acid propionate (SCFA-PRO) followed by Short-Chain Fatty Acid Butyrate (SCFA-BUT).
The participants will consume Short-Chain Fatty Acid Butyrate (SCFA-BUT) followed by Short-Chain Fatty Acid Propionate (SCFA-PRO).
University of Copenhagen
Copenhagen, Copenhagen N, Denmark
RECRUITINGKetone Bodies
To measure the effect of Short-Chain Fatty Acid Butyrate (SCFA-BUT) and Short-Chain Fatty Acid Propionate (SCFA-PRO) on circulating ketone body concentrations.
Time frame: On day 1 (test day 1) and day 2 (test day 2) at baseline (-30 min and 0 min) and post intake (10 min, 15 min, 22.5 min, 30 min, 45 min, 60 min, 90 min, 120 min, and 180 min).
Glucose
To measure the effect of Short-Chain Fatty Acid Butyrate (SCFA-BUT) and Short-Chain Fatty Acid Propionate (SCFA-PRO) on circulating glucose.
Time frame: On day 1 (test day 1) and day 2 (test day 2) at baseline (-30 min and 0 min) and post intake (10 min, 15 min, 22.5 min, 30 min, 45 min, 60 min, 90 min, 120 min, and 180 min).
Fatty acids
To measure the effect of Short-Chain Fatty Acid Butyrate (SCFA-BUT) and Short-Chain Fatty Acid Propionate (SCFA-PRO) on circulating Short-Chain Fatty Acids.
Time frame: On day 1 (test day 1) and day 2 (test day 2) at baseline (-30 min and 0 min) and post intake (10 min, 15 min, 22.5 min, 30 min, 45 min, 60 min, 90 min, 120 min, and 180 min).
Flow mediated dilation measurement
To measure the vasodilatory effects of the short-chain fatty acids butyrate (SCFA-BUT) and propionate (SCFA-PRO) during flow-mediated dilation measurement.
Time frame: On day 1 (test day 1) and day 2 (test day 2) at baseline (min -15) and post intake (min 90).
Resting metabolic rate
To measure the effect of Short-Chain Fatty Acid Butyrate (SCFA-BUT) and Short-Chain Fatty Acid Propionate (SCFA-PRO) on resting metabolic rate.
Time frame: On day 1 (test day 1) and day 2 (test day 2) at baseline (min -15) and post intake (30 min, 60 min, 120 min)
Respiratory exchange ratio
To measure the effect of Short-Chain Fatty Acid Butyrate (SCFA-BUT) and Short-Chain Fatty Acid Propionate (SCFA-PRO) on respiratory exchange ratio.
Time frame: On day 1 (test day 1) and day 2 (test day 2) at baseline (min -15) and post intake (30 min, 60 min, 120 min)
Fatty Acid Composition
To measure the effect of Short-Chain Fatty Acid Butyrate (SCFA-BUT) and Short-Chain Fatty Acid Propionate (SCFA-PRO) on fatty acid composition.
Time frame: On day 1 (test day 1) and day 2 (test day 2) at baseline (-30 min and 0 min) and post intake (10 min, 15 min, 22.5 min, 30 min, 45 min, 60 min, 90 min, 120 min, and 180 min).
Metabolites
To measure the effect of Short-Chain Fatty Acid Butyrate (SCFA-BUT) and Short-Chain Fatty Acid Propionate (SCFA-PRO) on circulating ketone body concentrations.
Time frame: On day 1 (test day 1) and day 2 (test day 2) at baseline (-30 min and 0 min) and post intake (10 min, 15 min, 22.5 min, 30 min, 45 min, 60 min, 90 min, 120 min, and 180 min).
Hepatokines
To measure the effect Short-Chain Fatty Acid Butyrate (SCFA-BUT) and Short-Chain Fatty Acid Propionate (SCFA-PRO) on circulating hepatokine concentrations.
Time frame: On day 1 (test day 1) and day 2 (test day 2) at baseline (-30 min and 0 min) and post intake (10 min, 15 min, 22.5 min, 30 min, 45 min, 60 min, 90 min, 120 min, and 180 min).
HOMA-Index
To measure the effect of Short-Chain Fatty Acid Butyrate (SCFA-BUT) and Short-Chain Fatty Acid Propionate (SCFA-PRO) on HOMO-index.
Time frame: On day 1 (test day 1) and day 2 (test day 2) at baseline (-30 min and 0 min) and post intake (10 min, 15 min, 22.5 min, 30 min, 45 min, 60 min, 90 min, 120 min, and 180 min).
Satiety
To measure the effect of Short-Chain Fatty Acid Butyrate (SCFA-BUT) and Short-Chain Fatty Acid Propionate (SCFA-PRO) on satiety using the Visual Analog Scale (VAS), going from 0 (none) to 10 (worst possible) at a 10cm scale.
Time frame: On day 1 (test day 1) and day 2 (test day 2) at baseline (-15 min) and post intake (30 min, 60 min, 90 min and 120 min).
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