Hypertension is one of the major risk factors for cardiovascular disease. Although various drugs for its treatment have been synthesized, the occurring side effects have generated the need for natural interventions for the treatment and prevention of hypertension. Dietary intervention such as the administration of prebiotics has been seen as a highly acceptable approach. Prebiotics are indigestible food ingredients that bypass digestion and reach the lower gut as substrates for indigenous microflora. Most of the prebiotics used as food adjuncts, such as inulin, fructooligosaccharides, dietary fiber and gums, are derived from plants. Experimental evidence from recent studies has suggested that prebiotics are capable of reducing and preventing hypertension. This paper will discuss some of the mechanisms involved, the evidence generated from both in-vitro experiments and in-vivo trials and some controversial findings that are raised.
Probiotics are live organisms that are primarily used to improve gastrointestinal disorders such as diarrhea, irritable bowel syndrome, constipation, lactose intolerance, and to inhibit the excessive proliferation of pathogenic intestinal bacteria. However, recent studies have suggested that probiotics could have beneficial effects beyond gastrointestinal health, as they were found to improve certain metabolic disorders such as hypertension. Hypertension is caused by various factors and the predominant causes include an increase in cholesterol levels, incidence of diabetes, inconsistent modulation of renin and imbalanced sexual hormones. This review discusses the antihypertensive roles of probiotics via the improvement and/or treatment of lipid profiles, modulation of insulin resistance and sensitivity, the modulation of renin levels and also the conversion of bioactive phytoestrogens as an alternative replacement of sexual hormones such as estrogen and progesterone.
The objective of this study was to evaluate the chemical, physicochemical, and functional properties of agrowastes derived from okara ( Glycine max), corn cob ( Zea mays sp.), wheat straw ( Triticum sp.), and rice husk ( Oryza sativa) for potential applications in foods. The fibrous materials (FM) were treated with alkali to yield fibrous residues (FR). Rice husk contained the highest ash content (FM, 8.56%; FR, 9.04%) and lowest lightness in color (FM, 67.63; FR, 63.46), possibly due to the abundance of mineral constituents. Corn cob contained the highest amount of soluble dietary fiber (SDF), whereas okara had the highest total dietary fiber (TDF). The high dietary fiber fractions of corn cob and okara also contributed to the highest water- and oil-holding capacities, emulsifying activities, and emulsion stabilities for both FM and FR samples. These results indicate that these agrowastes could be utilized as functional ingredients in foods.
Four strains of probiotics were evaluated for their alpha-galactosidase activity. Lactobacillus acidophilus FTCC 0291 displayed the highest specific alpha-galactosidase activity and was thus selected to be optimized in soy whey medium supplemented with seven nitrogen sources. The first-order model showed that meat extract, vegetable extract, and peptone significantly (P < 0.05) influenced the growth of L. acidophilus. The second-order polynomial regression estimated that maximum growth was obtained from the combination of 7.25% (w/v) meat extract, 4.7% (w/v) vegetable extract, and 6.85% (w/v) peptone. The validation experiment showed that response surface methodology was reliable with a variation of only 1.14% from the actual experimental data. Increased utilization of oligosaccharides and reducing sugars contributed to increased growth of L. acidophilus in the soy whey medium. This was accompanied by increased production of short-chain fatty acids and a decrease in pH.
Probiotics are live bacteria that could exert health beneficial effects upon consumption. In additional to their conventional use as gut modulators, probiotics are investigated for their role to prevent cancer. In-vivo and molecular studies have demonstrated encouraging outcomes, mainly attributed to its antimicrobial effects against carcinogen-producing microorganisms, antimutagenic properties, and alteration of the tumor differentiation processes. Prebiotics are indigestible food components that could promote the growth of beneficial bacteria including probiotics. Present studies have suggested that prebiotics also possess protective effect against colon carcinogenesis, mainly attributed to the production of short chain fatty acids upon its fermentation by gut microflora, and alteration of gene-expressions in tumor cells. Synbiotic (combination of probiotic and prebiotic) has been found to exert a synergistic effect in improving colon carcinogenesis compared to when both were used individually. This paper highlights the colon cancer preventive effects by probiotics, prebiotics and synbiotics. In addition, the controversial outcomes on the insignificant effect of these food adjuncts will be discussed.
The long history of safety has contributed to the acceptance of probiotics as a safe food adjunct. Consequently, many probiotic products and their applications have been granted GRAS (generally regarded as safe) status. However, this classification has been frequently generalized for all probiotic strains regardless of their application. Cases of probiotics from the genera Lactobacillus, Leuconostoc, Pediococcus, Enterococcus, and Bifidobacterium have been isolated from infection sites, leading to the postulation that these probiotics can translocate. Probiotic translocation is difficult to induce in healthy humans, and even if it does occur, detrimental effects are rare. Despite this, various reports have documented health-damaging effects of probiotic translocation in immunocompromised patients. Due to probiotics' high degree of safety and their morphological confusion with other pathogenic bacteria, they are often overlooked as contaminants and are least suspected as pathogens. However, the antibiotic resistance of some strains has increased the complexity of their eradication. Probiotic translocation and infection deserve further investigation and should become a facet of safety assessment so the negative effects of probiotics do not outweigh the benefits.
The aim of this study was to evaluate the effect of a synbiotic containing Lactobacillus acidophilus ATCC 4962, fructooligosaccharide, inulin and mannitol on plasma lipid profiles and erythrocyte membrane properties in hypercholesterolaemic pigs on high- and low-fat diets. Twenty-four white male Landrace pigs were randomly allocated to four treatment groups for 8 weeks (n 6). Treatment factors were the supplementation of synbiotic (with and without) and dietary fat (5 and 15 %). The supplementation of synbiotic reduced plasma total cholesterol (P = 0.001), TAG (P = 0.002) and LDL-cholesterol (P = 0.045) for both dietary fats. A higher concentration of esterified-cholesterol in HDL of pigs supplemented with synbiotic than the control regardless of dietary fat (P = 0.036) indicated that cholesterol was reduced in the form of cholesteryl esters. Reduced concentration of cholesteryl esters (P < 0.001) and increased concentration of TAG (P = 0.042) in LDL of pigs on synbiotic suggested that LDL-cholesterol was reduced via the hydrolysis of smaller and denser LDL particles. The erythrocytes of pigs without any synbiotic showed more prevalence of spur cells than those given the synbiotic, as supported by the higher cholesterol: phospholipid ratio in erythrocytes (P = 0.001). Also, membrane fluidity and rigidity were improved as supported by the decreased fluorescence anisotropies in the Hb-free erythrocyte membrane of pigs given synbiotic (P < 0.001). The administration of the synbiotic reduced plasma TAG, total cholesterol and LDL-cholesterol in hypercholesterolaemic pigs, possibly in the form of cholesteryl esters, via the interrelated pathways of lipid transporters (VLDL, LDL and HDL). The synbiotic also reduced deformation of erythrocytes via improved membrane fluidity and permeability.
The conventional use of probiotics to modulate gastrointestinal health, such as in improving lactose intolerance, increasing natural resistance to infectious diseases in the gastrointestinal tract, suppressing traveler's diarrhea, and reducing bloating, has been well investigated and documented. Most of the mechanisms reported to date are mainly caused by the suppression of pathogenic bacteria. Currently, the potential applications of probiotics are being expanded beyond alleviating gastrointestinal disorders to include benefits involving antihypertension, immunomodulation, improving serum lipid profiles, and the alleviation of postmenopausal disorders. Although they seem promising, most of these postulated benefits are based on in vitro evaluations, and the lack of in vivo evidence and/or incompatible outcomes between in vitro experiments and in vivo trials has led to inconclusive claims. This present review highlights some of the previous roles of probiotics on gut health and addresses several potential roles currently being investigated.