There is an increasing interest in the involvement of trace elements such as zinc in the pathogenesis of cardiovascular diseases. This study was designed to examine whether moderate zinc deficiency during growth influences blood pressure (BP) and vascular nitric oxide (NO) pathway. Three-week-old weaned male Wistar rats were randomly divided into two dietary groups and fed either a moderately zinc-deficient diet (zinc content 9 mg/kg; n ϭ 12) or a control diet (zinc content 30 mg/kg; n ϭ 12) for 60 d. The following were measured: systolic BP, nitrates and nitrites urinary excretion, urinary chemiluminescence intensity, NADPH-diaphorase activity in the thoracic aorta and intestinal arterioles, and NO synthase (NOS) catalytic activity using L-[U14C]-arginine as substrate in the thoracic aorta. Zinc deficiency during growth induced an increase in BP from day 30 of the experimental period, leading to hypertension on day 60. Animals that were fed the zinc-deficient diet had lower urinary excretion levels of nitrates and nitrites and higher intensity of spontaneous luminescence on day 60. At the end of the experiment, zinc-deficient rats showed decreased NADPH diaphorase activity in endothelium and smooth muscle of the thoracic aorta and intestinal arterioles and decreased activity of NOS in thoracic aortic tissue. An imbalance in zinc bioavailability during postnatal and growing periods may be may be a risk factor in development of cardiovascular alterations in adult life. The mechanisms involved may include an impaired vascular NO system as a result of decreased NOS activity and higher systemic oxidative stress. Moderate and marginal zinc deficiency is by far more common than severe deficiency, especially in infants, children, and pregnant women in developing and developed countries, as a result of imbalances between intake and increased requirements (1,2). Zinc is an essential trace element required by all living organisms for many physiologic functions, including growth, development, and reproduction (3). Zinc has been documented to act as an antioxidant, to have membranestabilizing properties, to block apoptotic cell death, and to be essential for endothelial integrity (4 -6). Intracellular zinc is associated with proteins, primarily via complex interactions with cysteines, acting as an integral component of numerous metalloenzymes, structural proteins, and transcription factors (1,7).There is increasing interest in possible involvement of trace elements such as zinc in the pathogenesis of cardiovascular diseases (8). Many enzymes that are involved in the regulation of arterial blood pressure (BP), such as nitric oxide (NO) synthase (NOS), angiotensin-converting enzyme, and neutral endopeptidases, contain zinc in their structure (9 -11). The NOSs are a family of enzymes that catalyze the synthesis of NO and L-citrulline from L-arginine in the presence of NADPH and O 2 . The NOS family consists of three isoforms that are expressed in many tissues, including endothelium and vascular

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The aim of this study was to evaluate the influence of diets with different types of fibres on Ca bioavailability and metabolic parameters in growing Wistar rats. Twenty four male Wistar rats were fed with 3 different diets: control (C), polydextrose (PD), and extruded whole maize (M) during a 60 day period. Apparent Ca absorption percentage (%Ca Abs), total skeleton bone mineral content (t BMC), total bone mineral density (t BMD), femur (F), spine (S) and tibia (T) BMD, cecum weight, and pH were evaluated. Malondialdehyde (MDA) and lipid (TG and cholesterol) contents in serum and liver were also evaluated. The results showed that rats fed with M and PD had the same cecum weight, but higher than that of C (1.53 ± 0.02 vs. 0.94 ± 0.01). There was moderate acidification of the cecal content in rats fed with M compared to C (pH 5.93 vs. 6.98) and the fecal weight was 1.06 ± 0.02, 3.07 ± 0.03 and 4.81 ± 0.05 for PD, M and C, respectively. There were significant differences in %Ca Abs between PD and C (87.57 ± 1.20 vs. 71.10 ± 1.11). The PD group had the highest values of F-BMD, S-BMD, and T-BMD, but there were no differences between M and C groups. Regarding lipids, there was a significant lowering effect in the M liver triglycerides content. Moreover, liver MDA levels significantly decreased with M and PD diets. The consumption of PD and grain fibres can exert some beneficial gastrointestinal effects such as lowering of the pH, hepatic TG and MDA content related to fibre colon fermentation.

Purpose. To evaluate the effect of polydextrose (PDX) on Ca bioavailability and prevention of loss of bone mass. Methods. Twenty-four two-month-old ovariectomized rats were fed three isocaloric diets only varied in fiber source and content up to 60 days (FOS group, a commercial mixture of short- and long-chain fructooligosaccharide, OVX group fed AIN 93 diet, and PDX group). A SHAM group was included as control. Apparent Ca absorption percentage (%ABS), changes in total skeleton bone mineral content (tsBMC) and bone mineral density (BMD) and femur BMD, % Bone Volume, Ca and organic femur content, caecal weight, and pH were evaluated. Results. %ABS and caecum weight of PDX and FOS were higher, and caecum pH was lower compared to OVX and SHAM. PDX reached a higher pH and lower caecum weight than FOS possibly because PDX is not completely fermented in the colon. Changes in tsBMC and femur BMD in FOS and PDX were significant lower than SHAM but significantly higher than OVX. % Bone Volume and femur % of Ca in PDX were significantly higher than OVX and FOS but lower than SHAM. Conclusions. PDX increased Ca absorption and prevented bone loss in OVX rats.

Modifications of nutritional properties (amino acids, available lysine, protein digestibility, fatty acids, fiber, inositol phosphate (IPs), free and bound phenolics, and antioxidant properties) of whole rice ingredients processed by soaking, germination, and/or extrusion cooking were evaluated. Soaking and germination reduced proteins by lixiviation and hydrolysis, respectively. Lysine was the limiting amino acid. Polyunsaturated fatty acids increased after germination. Protein digestibility was 100% for germinated rice, decreased to 75% after the extrusion process. Fiber content decreased around 73% after the extrusion of soaked and germinated flours. Soaking‐extrusion combined processes produces >50% IPs reduction. Germination‐extrusion produced flours with the highest antioxidant capacity (54 µmol trolox g−1), which was in accordance with the highest content of free and bound phenolics (66 and 69 mg GA 100 g−1, respectively). Grain treatments changed nutritional properties of flours resulting in low antinutrient whole grain ingredients, which could be used to develop whole grain‐based foods. Practical applications Phytic acid (PA) is an antinutrient having negative effects on mineral bioavailability and protein digestibility. There are processes such as soaking, germination, and extrusion, which alone or combined can decrease PA. However, nutritional composition and functionality of flours can change. We observed PA was highly reduced by soaking or germination combined with extrusion and antioxidant capacity and phenolic content increased in germinated and germinated‐extruded flours compared to the other treatments. These modified whole grain rice flours low in anti‐nutrients could be used in the production of expanded products or pre‐cooked ingredients to develop whole grain based foods nutritionally improved.