In Vitro Digestibility of Aluminum from Hibiscus sabdariffa Hot Watery Infusion and Its Concentration in Urine of Healthy Individuals

Excessive Consumption Hibiscus sabdariffa L. Increases Inflammation and Blood Pressure in Male Wistar Rats via High Antioxidant Capacity: The Preliminary Findings

Hibiscus sabdariffa L. (HSL) has high amounts of antioxidants and many beneficial effects in several pathologies. However, few studies describe the possible harmful effects of high concentrations of HSL. Here we evaluate the effect of excessive and chronic consumption of infusions with different percentages of HSL on some oxidative stress markers in serum, and the possible association with inflammation and increased systolic blood pressure (SBP), in healthy rats. A total of 32 male Wistar rats were used to form 4 groups with 8 animals each. Group 1 control (drinking tap water), group 2, 3 and 4, drinking water supplemented with 15, 30 and 60 g/L of HSL calyxes respectively. SBP was evaluated and determinations in serum of the NO₃⁻/NO₂⁻ ratio, glutathione (GSH), total antioxidant capacity (TAC), selenium (Se), TNF-α, IL-1α/IL-1F1, IL-1β, IL-10, extracellular superoxide dismutase (EcSOD), thioredoxin reductase (TrxR) and glutathione peroxidase (GPx) activities, were evaluated. The SBP (p = 0.01), GPx activity, GSH, TAC, Se, TNF-α and EcSOD activities (p ≤ 0.001) and IL-1α/IL-1F1, IL-1β, TrxR and NO₃⁻/NO₂⁻ (p ≤ 0.05), were increased but IL-10 (p < 0.001) was decreased in rats that consumed the 3 and 6% HSL infusions. The excessive and chronic consumption of HSL may increase the TAC that could lead to a proinflammatory state which is associated with hypertension.

Increased urinary excretion of aluminium after ingestion of the food additive sodium aluminium phosphate (SALP) - a study on healthy volunteers

Food is an important source of human aluminium (Al) exposure and regular consumption of foods containing Al-based food additives may result in high Al intakes above health-based tolerable intakes. However, some additives are Al salts with low solubility, and little is known about bioavailability of Al in these additives. We investigated urine Al concentrations in healthy adult volunteers (N = 18, women/men) before (base-line) and after 7 days of ingestion of pancakes with a low Al content (median: <0.5 mg Al/kg) and high Al content (median: 860 mg/kg). The high-Al pancakes contained the common additive sodium aluminium phosphate (SALP). The participants did not know if the pancakes contained SALP or not during the experiment. After adjusting for creatinine content of the urine samples, median base-line Al concentrations before pancake ingestion were in the range 30-40 µmol Al/mol creatinine. Urine Al concentrations after ingestion of low-Al pancakes (average intake: <0.042 Al mg/day) did not differ significantly from the base-line levels. After ingestion of high-Al pancakes (72 mg Al/day) the median Al concentration in urine was more than 2-fold higher than at the base-line sampling before the high-Al pancake ingestion. At the end of the experiment the volunteers ingested an Al-containing antacid (Al-OH, 1800 mg Al/day) for 7 days as a positive control of Al absorption. This caused a 10-fold increase in median urine Al concentration compared to base-line. Our results strongly suggest that Al in the form of SALP in a pancake mix is bioavailable for absorption in humans, which should be taken into account in risk assessment of Al in food in countries with a high use of SALP as a food additive.