Probiotics Blunt the Anti-Hypertensive Effect of Blueberry Feeding in Hypertensive Rats without Altering Hippuric Acid Production

Abstract

Previously we showed that feeding polyphenol-rich wild blueberries to hypertensive rats lowered systolic blood pressure. Since probiotic bacteria produce bioactive metabolites from berry polyphenols that enhance the health benefits of berry consumption, we hypothesized that adding probiotics to a blueberry-enriched diet would augment the anti-hypertensive effects of blueberry consumption. Groups (n = 8) of male spontaneously hypertensive rats were fed one of four AIN ‘93G-based diets for 8 weeks: Control (CON); 3% freeze-dried wild blueberry (BB); 1% probiotic bacteria (PRO); or 3% BB + 1% PRO (BB+PRO). Blood pressure was measured at weeks 0, 2, 4, 6, and 8 by the tail-cuff method, and urine was collected at weeks 4 and 8 to determine markers of oxidative stress (F2-isoprostanes), nitric oxide synthesis (nitrites), and polyphenol metabolism (hippuric acid). Data were analyzed using mixed models ANOVA with repeated measures. Diet had a significant main effect on diastolic blood pressure (p = 0.046), with significantly lower measurements in the BB- vs. CON-fed rats (p = 0.035). Systolic blood pressure showed a similar but less pronounced response to diet (p = 0.220), again with the largest difference between the BB and CON groups. Absolute increase in blood pressure between weeks 0 and 8 tended to be smaller in the BB and PRO vs. CON and BB+PRO groups (systolic increase, p = 0.074; diastolic increase, p = 0.185). Diet had a significant main effect on hippuric acid excretion (p<0.0001), with 2- and ~1.5-fold higher levels at weeks 4 and 8, respectively, in the BB and BB+PRO vs. PRO and CON groups. Diet did not have a significant main effect on F2-isoprostane (p = 0.159) or nitrite excretion (p = 0.670). Our findings show that adding probiotics to a blueberry-enriched diet does not enhance and actually may impair the anti-hypertensive effect of blueberry consumption. However, probiotic bacteria are not interfering with blueberry polyphenol metabolism into hippuric acid.

Mechanistic insights into the vascular effects of blueberries: Evidence from recent studies

“…Intestinal bacteria play a key role in metabolizing polyphenols and flavonoids to bioactive metabolites. Based on this reasoning, recent studies investigated whether probiotics have an effect on the anti‐hypertensive effects of blueberries . The effect of blueberries fermented overnight with the bacteria Lactobacillus plantarum DSM 15313 on the anti‐hypertensive properties of blueberries was investigated .…”

“…The authors proposed that the anti‐hypertenstive effect of fermented blueberries could be mediated through a nitric oxide (NO) ‐dependent pathway. Another recent animal study investigated whether probiotic supplementation can enhance the anti‐hypertensive effects of blueberries by increasing the anti‐hypertensive metabolites of anthocyanins . Spontaneously hypertensive rats were fed a diet containing 3% freeze‐dried blueberries with or without probiotic supplementation for 8 weeks.…”

“…The authors speculate that this could be attributed to a difference in the intestinal microbiota composition induced by the probiotic treatment. Furthermore, the addition of blueberries to the probiotic diet could have altered the bacterial strain composition of the probiotic diet .…”

A Systems Pharmacology Approach for Identifying the Multiple Mechanisms of Action for the Rougui‐Fuzi Herb Pair in the Treatment of Cardiocerebral Vascular Diseases

“…According to literature research, PTGS2 rs20417CC genotype was significantly higher in patients with plaque compared with patients without plaque, and PTGS1 catalyses the conversion of arachidonic acid (AA) into prostaglandin H2 intermediates and thromboxane Evidence-Based Complementary and Alternative Medicine A2 (TxA2) [65]. Compared with healthy controls, hypertensive patients possess enhanced F2 generation, and diastolic blood pressure level of hypertensive patients is independently correlated with increased F2 generation [66]. PLG is a precursor of plasmin that degrades fibrin [67].…”

Antihypertensive Effects of Probiotics

“…By contrast, adding probiotics to a blueberry-enriched diet does not enhance and actually may impair the antihypertensive effect of blueberry consumption. However, probiotic bacteria are not interfering with blueberry polyphenol metabolism into hippuric acid [59].…”