Green leafy vegetables in diets with a 25:1 omega-6/omega-3 fatty acid ratio modify the erythrocyte fatty acid profile of spontaneously hypertensive rats.

BACKGROUND: In addition to the actual composition of the diet (i.e. nutrient composition, food groups), the omega-6/omega-3 fatty acid ratio has been demonstrated to influence the tissue fatty acid profile and subsequently the risk for cardiovascular and other diseases. Likewise, the consumption of green leafy vegetables (GLVs) may favorably reduce the risks associated with disease. Although an ~ 3:1 omega-6/omega-3 fatty acid ratio (ω-6/ω-3 FAR) is recommended, the typical American diet has an ~ 25:1 ω-6/ω-3 FAR. Previous research affirms the ability of collard greens (CG), purslane (PL), and sweet potato greens (SPG) to improve the hepatic profile of spontaneously hypertensive rats (SHRs). The aim of the present study was to determine the influence of GLVs, incorporated (4%) into diets with a 25:1 ω-6/ω-3 FAR, on the erythrocyte fatty acid profile of male SHRs. METHODS: SHRs (N = 50) were randomly assigned to one of five dietary groups - standardized control (AIN-76A), Control (25:1 ω-6/ω-3 FAR), CG (25:1 ω-6/ω-3 FAR + 4% CG), PL (25:1 ω-6/ω-3 FAR + 4% PL) or SPG (25:1 ω-6/ω-3 FAR + 4% SPG). Following 6 weeks consumption of diets, SHRs erythrocyte fatty acid profiles were determined by gas-liquid chromatography. RESULTS: Significantly lower percentages of total saturated fatty acids (p < 0.05) and greater percentages of polyunsaturated fatty acids were present among SHR erythrocytes following the consumption of diets containing CG, PL and SPG. Total polyunsaturated fatty acids were greatest among SHRs consuming diets containing purslane. CONCLUSIONS: The present study demonstrates the ability of GLVs to mitigate the potential effects of an elevated ω-6/ω-3 FAR, which may contribute to an atherogenic fatty acid profile, inflammation and disease pathogenesis. Dietary recommendations for disease prevention should consider the inclusion of these GLVs, particularly among those consuming diets with an ω-6/ω-3 FAR that may promote disease.

Diets containing traditional and novel green leafy vegetables improve liver fatty acid profiles of spontaneously hypertensive rats.

BACKGROUND: The consumption of green leafy vegetables (GLVs) has been demonstrated to reduce the risks associated with cardiovascular and other diseases. However, no literature exists that examines the influence of traditional and novel GLVs on the liver fatty acid profile of an animal model genetically predisposed to developing hypertension. The aim of the present study was to examine the effects of diets containing 4% collard greens, purslane or sweet potato greens on the liver fatty acid profiles of four-week old male spontaneously hypertensive rats (SHRs, N = 44). Following four weeks consumption of the diets, liver fatty acid profiles were determined by gas-liquid chromatography of transesterified fatty acid methyl esters. RESULTS: SHRs consuming the control diet had greater percentages of liver saturated fatty acid and less omega-3 fatty acid percentages. SHRs consuming the diets containing vegetables had significantly greater liver concentrations of γ- linolenic, docosahexaenoic and docosahexaenoic acids, as well as lower levels of lauric, palmitic and arachidonic acids. SHRs consuming the control diet had significantly greater percentages (p < 0.05) of oleic; significantly less γ-linolenic and docosahexaenoic acids. CONCLUSIONS: This study demonstrates the ability of GLVs to modulate liver fatty acid composition, thus providing protection against elevations in atherogenic fatty acids, which may be involved in CVD pathogenesis. Consequently, dietary recommendations for the prevention of CVD should consider the possible cardioprotective benefits and the subsequent alterations in fatty acid profiles afforded by diets containing collard greens, purslane and sweet potato greens.

Polyphenol-rich sweet potato greens extract inhibits proliferation and induces apoptosis in prostate cancer cells in vitro and in vivo.

Sweet potato (Ipomoea batatas) leaves or greens, extensively consumed as a vegetable in Africa and Asia, are an excellent source of dietary polyphenols such as anthocyanins and phenolic acids. Here, we show that sweet potato greens extract (SPGE) has the maximum polyphenol content compared with several commercial vegetables including spinach. The polyphenol-rich SPGE exerts significant antiproliferative activity in a panel of prostate cancer cell lines while sparing normal prostate epithelial cells. Mechanistically, SPGE perturbed cell cycle progression, reduced clonogenic survival, modulated cell cycle and apoptosis regulatory molecules and induced apoptosis in human prostate cancer PC-3 cells both in vitro and in vivo. SPGE-induced apoptosis has a mitochondrially mediated component, which was attenuated by pretreatment with cyclosporin A. We also observed alterations of apoptosis regulatory molecules such as inactivation of Bcl2, upregulation of BAX, cytochrome c release and activation of downstream apoptotic signaling. SPGE caused DNA degradation as evident by terminal deoxynucleotidyl transferase-mediated dUTP-nick-end labeling (TUNEL) staining of increased concentration of 3'-DNA ends. Furthermore, apoptotic induction was caspase dependent as shown by cleavage of caspase substrate, poly (adenosine diphosphate-ribose) polymerase. Oral administration of 400 mg/kg SPGE remarkably inhibited growth and progression of prostate tumor xenografts by ∼69% in nude mice, as shown by tumor volume measurements and non-invasive real-time bioluminescent imaging. Most importantly, SPGE did not cause any detectable toxicity to rapidly dividing normal tissues such as gut and bone marrow. This is the first report to demonstrate the in vitro and in vivo anticancer activity of sweet potato greens in prostate cancer.

Sweet potato leaves: properties and synergistic interactions that promote health and prevent disease.

Sweet potato (Ipomoea batatas) leaves provide a dietary source of vitamins, minerals, antioxidants, dietary fiber, and essential fatty acids. Bioactive compounds contained in this vegetable play a role in health promotion by improving immune function, reducing oxidative stress and free radical damage, reducing cardiovascular disease risk, and suppressing cancer cell growth. Currently, sweet potato leaves are consumed primarily in the islands of the Pacific Ocean and in Asian and African countries; limited consumption occurs in the United States. This comprehensive review assesses research examining the nutritional characteristics and bioactive compounds within sweet potato leaves that contribute to health promotion and chronic disease prevention. Research has affirmed the potential cardioprotective and chemopreventive advantages of consuming sweet potato leaves, thus indicating that increased consumption of this vegetable should be advocated. Since reducing the prevalence of chronic diseases is of public health concern, promoting the consumption of sweet potato leaves warrants further and more intensive research investigation.

Trans fat intake lowers total cholesterol and high-density lipoprotein cholesterol levels without changing insulin sensitivity index in Wistar rats.

Epidemiologic studies have demonstrated that trans fat intake increases the risk of some chronic diseases. We hypothesize that trans fat intake would increase the risk of cardiovascular disease and type 2 diabetes mellitus by changing the lipid profile in plasma, the secretion of adipokines in adipose tissue, and the insulin sensitivity. Accordingly, the major objective of present study was to investigate the effect of dietary intake of trans fat on lipid profile, insulin sensitivity, and adipokine levels in plasma. Two groups of Wistar rats were fed a diet containing 4.5% trans fat or a control diet containing no trans fat for 16 weeks. Fasting glucose level was monitored every 2 weeks. At the end of feeding experiment, blood, heart, kidney, liver, omental adipose tissue, and semitendinosus muscle were collected. The trans fat content in organs, lipid profile, adipokine, insulin, and glucose levels in plasma were analyzed. The trans fat content in adipose tissue, heart, kidney, liver, and muscle of rats fed trans fat were 169.9, 0.6, 1.2, 1.7, and 2.5 mg/g samples, respectively. The trans fat content in these organs contributed to 15.9%, 1.2%, 2.3%, 4.3%, and 6.1% of the total fat, respectively. The plasma glucose level, insulin level, and insulin sensitivity index were not significantly different between the trans fat and control groups. The results indicated that trans fat intake might not be related to insulin resistance. However, lipid profile and plasma adipokine levels were significantly changed after trans fat feeding. The trans fat fed group showed significantly lower total cholesterol and high-density lipoprotein cholesterol levels than the control group. The decreased high-density lipoprotein cholesterol level may indicate the detrimental effect of trans fat intake on lipid profile. Adiponectin and resistin levels were significantly higher in the trans fat group than the control group. Leptin levels were significantly lower in the trans fat group than the control group. The results indicated that dietary intake of trans fat can significantly change the adipokine levels, but the possible links between adipokine level change caused by trans fat intake and metabolic effects of this change need further investigations.

Use of focus groups to understand African-Americans' dietary practices: Implications for modifying a food frequency questionnaire.

OBJECTIVE: To generate information about dietary practices, food preferences and food preparation methods from African-Americans in Macon County, Alabama, as a precursor to an intervention designed to modify an existing dietary health questionnaire (DHQ). METHOD: African-American males (30) and females (31) ages 20 to 75 years participated in eight focus groups in Macon County Alabama between June and July, 2007. RESULTS: The core topics identified were dietary practices; food preferences; food preparation methods; fast food practices; and seasonal/specialty foods. The younger focus group participants reported consuming mostly fast foods such as hamburgers for lunch. Fruits, vegetables, salads, fish, chicken and sandwiches were the most common lunch foods for the older males and females. Across the groups, rice, cornbread and potatoes were reportedly the most commonly consumed starchy foods at dinner. Frying and baking were the most common cooking methods. Fewer participants reported removing the skin when cooking chicken versus those who did not remove. Traditional foods including fried green tomatoes and cracklings were selected for addition to the modified DHQ, while those not commonly consumed, were deleted. CONCLUSIONS: Participants described high-fat traditional food preferences, common frying and addition of salted meats to vegetables, which informed the modification of a DHQ.

Total phenolics and antioxidant capacity of indigenous vegetables in the southeast United States: Alabama Collaboration for Cardiovascular Equality Project.

Collard greens, mustard greens, kale, okra, green onion, butter beans, butter peas, purple hull peas, rutabagas, and eggplant are frequently consumed by African Americans in the southeast United States. Sweet potato greens and purslane are two novel vegetables in this region. The objective of this study was to analyze total phenolics and antioxidant capacity in these indigenous vegetables. The total phenolic content was analyzed using the Folin-Ciocalteu method and ranged from 7.4 to 53.5 mg gallic acid equivalents per gram of dried sample. The antioxidant capacity was analyzed using the radical DPPH(•) scavenging capacity assay and oxygen radical absorbance capacity assay (ORAC). At a concentration of 10.0 mg dried vegetable equivalent/ml, the extract of these vegetables was able to quench 13.2-88.5% DPPH(•) radical in 30 min. The ORAC value ranged from 2.5 to 100.7 µmoles of trolox equivalents per gram of dried sample. The antioxidant capacity of the vegetable samples was highly related to their total phenolic content. The results suggest that these indigenous vegetables consumed by African Americans in the southeastern United States are good sources of the phenolic compounds, which might provide anti-oxidative protection against free radicals in the human body. Consumption of these vegetables might reduce the risk of chronic diseases.

Bioavailability of calcium from sweetpotato and soy flour supplemented diets in hamsters.

The bioavailability of calcium from two varieties of sweetpotatoes and supplementation of sweetpotatoes with soy flour was investigated in hamsters using plasma calcium concentration and femur calcium content as indicators. Five different diets were fed to five groups of animals for 28 days. There was no significant difference in plasma calcium concentrations of hamsters in all the diet groups. However, the femur calcium content of hamsters with transgenic sweetpotato flour (TSPF) and parent nontransgenic (from which transgenic was produced) sweetpotato flour (NTSPF) diets was significantly higher than that of the transgenic sweetotato flour supplemented with soy flour (TSPF + SF) and parent nontransgenic sweetpotato flour supplemented with soy flour (NTSPF + SF) diets. The relative bioavailability of calcium from the control (100%), TSPF+SF (30%), NTSPF+SF (23%), TSPF (57%) and NTSPF (46%) indicated that sweetpotatoes could be the better source of calcium, however, supplementation with soy flour might reduce the bioavailability of calcium.

Nutritional assessment of transgenic sweetpotato on body weight, lipid, and protein status in hamsters.

The objectives of the present study were to evaluate the nutritional quality of genetically modified sweetpotato (genotype PI318846-3) on growth, lipid metabolism, and protein metabolism of hamsters. Three different diets made with transgenic and nontransgenic sweetpotato protein flour including a control diet with casein were fed to male Golden Syrian hamsters for 28 days. The protein efficiency ratio (1.35 +/- 0.01) of the transgenic sweetpotato protein diet was significantly higher (p<0.05) than the nontransgenic sweetpotato and control diets. Plasma albumin and plasma total protein concentrations of hamsters fed the sweetpotato diets were significantly lower (p<0.05) than that of the control. The casein diet (control) produced hypercholesterolemia in hamsters, whereas sweetpotato diets maintained lower plasma and liver total and LDL-cholesterol concentrations in hamsters. Sweetpotatoes contain less amount of protein to maintain the normal animal growth; however, transgenic sweetpotato has good quality protein that supported the growth of hamsters better than nontransgenic sweetpotato.

Storage Conditions and Microbial Quality of Smoked Dry Herring in Ghana.

A microbial profile of smoked dry herring stored under various storage conditions for up to 6 months at ambient temperature was determined. The fish were stored in polyethylene bags, polyethylene bags with desiccant, the traditional oven storage, modified storage structure, and freezer (control) storage. The fish stored in polyethylene bags with or without desiccant spoiled rapidly. Microbial counts were also very high. The microbial counts of fish stored in the traditional oven and the modified structure were small, even less than that stored in freezer. The storage losses were only 4% for the modified structure while the traditional oven storage was 29%. The major pathogenic bacterium found in smoked dry herring was Staphylococcus aureus .

Survey of the Microbial Quality of Dry Fish, Cassava and Okra in Ghana.

A microbial profile of dry foods in Ghana including smoke dried herrings, salt dried tilapia, salt dried trigger fish, gari, kokonte and okra was evaluated. Okra had the highest aerobic count of 42 × 106, followed by kokone 16-20 × 104, smoke dried herrings 0.2-4 × 104, salt dried tilapia 3-4 × 103, salt dried trigger fish 3- 44 × 102 and gari 3-34 × 102. Anaerobic count was low for all the samples except smoke dried herrings 7-9.5 × 102. Differences in mold count was not evident ranging from 2 × 102 to 39 × 103 for all samples. Aspergillus and Penicillium were the predominant molds. Coliform count was low for salt dried fish and gari, but higher for smoke dried herrings 2-25 × 102, kokonte 11-29 × 102 and okra 31 - 47 × 102.