Scientific Opinion on the substantiation of health claims related to acetic
acid and maintenance of normal blood pressure (ID 1447) pursuant to
Article 13(1) of Regulation (EC) No 1924/2006[sup]1[/sup]
EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA)2, 3
European Food Safety Authority (EFSA), Parma, Italy
3. Naukowe uzasadnienia wpływu na zdrowie człowieka - Utrzymanie prawidłowego ciśnienia krwi
-
Utrzymanie prawidłowego ciśnienia krwi
The references provided for the scientific substantiation of the claim included two links to web pages in Japanese, one article in Japanese reporting on a human intervention study on the effects of a drink containing vinegar on blood pressure, which could not be retrieved and for which no translation into an EU language was provided, and narrative reviews which were either not related to the claimed
effect or did not contain any original data which could be used for the scientific substantiation of the claim. The Panel considers that no conclusions can be drawn from these references for the scientific substantiation of the claim.
One article in Japanese with a full-text English translation was provided which reported on a human intervention study on the effects of apple and rice vinegar drinks on blood pressure (Kajimoto et al., 2003). A total of 104 adult subjects with high normal blood pressure or grade I hypertension (systolic blood pressure (SBP) between 130 and 159 mmHg, diastolic blood pressure (DBP) between 85 and 99 mmHg) were recruited. Need of emergency antihypertensive therapy, cerebrovascular disorders, history of cardiac failure, atrial fibrillation or serious arrhythmia, severe liver or kidney dysfunction, and uncontrolled diabetes were among the exclusion criteria. Medication use among participants, including the use of antihypertensive medications, was not reported. Six subjects were excluded from data analysis because of severe renal dysfunction (one), out of range blood pressure (one) and inability to start the trial due to personal reasons (four). After a two-week run-in period, subjects were randomised to consume 100 mL of a drink containing 15 g of apple vinegar (n=33, 17 female) or rice vinegar (n=34, 17 female) with acetic acid (750 mg) at a concentration of 5 % (w/v), or 100 mL of a placebo drink containing 1 g of lactic acid (n=31, 16 female) for 10 weeks, followed by a four-week observation period with no drinks. The test and placebo drinks were otherwise comparable regarding their macronutrient composition and their content of potassium, sodium, calcium and vitamin C, and subjects were not able to distinguish them on the basis of their organoleptic properties. Office blood pressure was measured after an overnight fast using a standard protocol. Data were analysed for the whole study population, and separately for subjects with high normal blood pressure and grade I hypertension. The Panel notes that it is not stated in the publication whether sub-group comparisons were pre-planned, and considers that no conclusions can be drawn from these analyses for the scientific substantiation of the claim. SBP significantly decreased in the apple and rice vinegar groups compared to placebo at weeks 2 (-6.6 mmHg and -7.6 mmHg vs. +1.0 mmHg, respectively, p<0.05), 6 (-12.8 mmHg and -11.6 mmHg vs. -3 mmHg, respectively, p<0.01), 8 (-11.2 mmHg and -12.9 mmHg vs. -2.2 mmHg, respectively, p<0.01) and 10 of the study (-12.0 mmHg and -9.6 mmHg vs. -2.3 mmHg, p<0.01 and p<0.05, respectively), whereas no significant differences were observed between groups at week 4 of the study. No interaction between test drinks and intake duration on blood pressure values was observed. Follow-up values were not significantly different from baseline in any of the groups. No significant differences between the apple and the rice vinegar groups were observed at any time point. No significant differences in DBP, heart rate, body weight or body composition were observed between the three groups throughout the study.
Another human intervention study retrieved by the Panel reported on the effects on blood pressure of apple vinegar drinks containing different amounts of acetic acid (Kondo et al., 2009). After a three-week run-in period, a total of 155 adult overweight subjects (out of 175 recruited), who were not using medications, were randomised to consume 500 mL of a placebo drink containing 1,250 mg lactate (n=50, 18 female), or 500 mL of a drink containing 15 mL (n=54, 20 female) or 30 mL (n=51, 20 female) of apple vinegar daily for 10 weeks, followed by a four-week observation period with no test or placebo drinks. The acetic acid content of the drinks was 0, 750 and 1,500 mg, respectively. The test and placebo drinks were otherwise comparable regarding their macronutrient composition and their content of potassium, sodium, calcium and vitamin C, and subjects were not able to distinguish them on the basis of their organoleptic properties. Office blood pressure was measured after an overnight fast using a standard protocol. Compared to placebo SBP significantly decreased in the apple vinegar group containing 1,500 mg acetic acid at week 12 only (-4.5 mmHg vs. +0.1 mmHg, p<0.01). No other significant differences on blood pressure were observed between the three groups for the entire duration of the study. The Panel notes that differences in body weight changes during the study between the high acetic acid dose group and the placebo group (reported to be about -3 kg) could account for the significant differences in SBP values observed at week 12 of the study. The Panel also notes that the results from this study are in conflict with those obtained by Kajimoto et al.
(2003), who reported a significant effect (of about -10mmHg) on SBP with 750 mg/day of acetic acid, with effects that were already statistically significant after two weeks of consumption.
One study on spontaneously hypertensive rats (SHR) was also provided (Kondo et al., 2001). Four-week old (n=18) SHR were randomised to consume standard laboratory diets with a 6.0 % solution (w/w) of either acetic acid (containing 46.2 g/L acetic acid), vinegar (containing 46.2 g/L acetic acid) or no solution (control) for eight weeks after a six-week run-in period in which only the standard diet was consumed. No significant differences in body weight, water consumption or food intake were observed between groups. SBP (p<0.05) and plasma renin activity (p<0.01) significantly decreased in the acetic acid and vinegar groups compared to placebo, whereas no significant differences were observed in angiotensin I-converting enzyme activity in various organs, or in plasma angiotensin II. Plasma aldosterone concentrations significantly decreased in the vinegar group compared to the acetic acid group and the control group (p<0.05). No significant differences between the acetic acid and the vinegar groups were observed during the study with respect to SBP values. It was hypothesised that acetic acid could exert the claimed effect by reducing renin secretion, and by inducing a subsequent decrease in angiotensin II. The Panel notes that this study does not provide clear evidence on a mechanism by which acetic acid could exert the claimed effect.
A recently published randomised, cross-over, human intervention study retrieved by the Panel (Sugiyama et al., 2010), addressed the bioavailability of acetate from two vinegar supplements (as capsules or drinks) compared to water as reference in 30 healthy Japanese subjects. The vinegar drink (100 mL containing 750 mg acetic acid) and water control were consumed after an overnight fast. Serum acetate concentrations increased immediately after intake of the vinegar drink, peaked at 15 min and returned to baseline at 90 min. No significant changes in serum acetate concentrations were observed after the water control. The Panel notes that acetic acid in the vinegar drink at the dose used in the human intervention study by Kajimoto et al. (2003) was rapidly absorbed and cleared from the circulation after consumption, and thus the Panel considers that an effect of orally administered acetic acid on blood pressure lasting 12 hours or more (e.g. after an overnight fast) is unlikely.
In weighing the evidence, the Panel took into account that although one animal study showed an effect of acetic acid administration on systolic blood pressure, results from two human intervention studies are conflicting, and that a sustained effect of orally administered acetic acid on blood pressure is unlikely because of the rapid absorption and clearance from the circulation after consumption.
The Panel concludes that a cause and effect relationship has not been established between the consumption of acetic acid and maintenance of normal blood pressure.
