College of Human Ecology Faculty Publications » Human Nutrition

Effects of Dietary Fiber and Its Components on Metabolic Health

Nate — Thu, 22 Sep 2011 20:12:38 +0000

Dietary fiber and whole grains contain a unique blend of bioactive components including resistant starches, vitamins, minerals, phytochemicals and antioxidants. As a result, research regarding their potential health benefits has received considerable attention in the last several decades. Epidemiological and clinical studies demonstrate that intake of dietary fiber and whole grain is inversely related to obesity, type two diabetes, cancer and cardiovascular disease (CVD). Defining dietary fiber is a divergent process and is dependent on both nutrition and analytical concepts. The most common and accepted definition is based on nutritional physiology. Generally speaking, dietary fiber is the edible parts of plants, or similar carbohydrates, that are resistant to digestion and absorption in the small intestine. Dietary fiber can be separated into many different fractions. Recent research has begun to isolate these components and determine if increasing their levels in a diet is beneficial to human health. These fractions include arabinoxylan, inulin, pectin, bran, cellulose, ß-glucan and resistant starch. The study of these components may give us a better understanding of how and why dietary fiber may decrease the risk for certain diseases. The mechanisms behind the reported effects of dietary fiber on metabolic health are not well established. It is speculated to be a result of changes in intestinal viscosity, nutrient absorption, rate of passage, production of short chain fatty acids and production of gut hormones.

Lycopene and apo-12’-lycopenal reduce cell proliferation and alter cell cycle progression in human prostate cancer cells

Nate — Thu, 04 Aug 2011 13:44:27 +0000

Lycopene is associated with a reduced risk of prostate cancer. However, lycopene may not be wholly responsible for the effects seen in vivo or in cell culture systems. Apo-lycopenals or other lycopene metabolites, whether produced by cleavage enzymes within the body or consumed with tomato products, can be found in tissues at concentrations equivalent to physiological retinoid concentrations. Therefore, it is plausible that lycopenoids, like retinoids, are bioactive within tissues. Androgen-independent DU145 prostate cancer cells were treated with lycopene, apo-8′-lycopenal, or apo-12′-lycopenal. DU145 cell proliferation was significantly reduced by supra-physiological levels of lycopene and apo-12′-lycopenal, in part, through alteration of the normal cell cycle. Levels of the gap junction protein, connexin 43, were unaltered by lycopene or apo-lycopenal treatment while cell apoptosis rates significantly decreased. We further confirmed that connexin 43 protein levels were unaltered by lycopene treatment in mouse embryonic fibroblasts, or in Dunning R3327-H rat prostate tumor. The present data indicate that lycopene and apo-12′-lycopenal reduce the proliferation of prostate cancer cells, in part, by inhibiting normal cell cycle progression.

Nutrition-Related Practices and Attitudes of Kansas Skipped-Generation(s) Caregivers and Their Grandchildren

Nate — Mon, 07 Mar 2011 16:26:32 +0000

Despite growing numbers, the nutrition practices and attitudes of skipped generation(s) kinship caregivers regarding feeding the dependent children in their care have not been examined. In this qualitative study, transcriptions of semi-structured interviews with 19 female and four male skipped-generation(s) Kansas caregivers (ages 47 to 80, 92% non-Hispanic whites, 83% female, 78% grandparents and 22% great-aunt or great grandparent caregivers; caring for a range of one to four children, ages three to 18, for an average of nine years) were content analyzed for how their nutrition-related practices and attitudes had changed since parenting the first time. Sub-themes regarding practices included: being more nutrition and food safety conscious now, and shifting their child feeding style. The children seemed to be adversely affected by an on-the-go lifestyle and the use of more electronics. Caregivers described their sources for child feeding advice as being based mostly on information from their mothers, physicians, and their past parenting experiences. Sub-themes for attitudes included opinions that nutrition and safe food handling are important and that nutritious food is expensive. They preferred printed or video nutrition education materials and wanted to receive information through organizations they trusted. This population could benefit from education on: infant, child, adolescent, and sports nutrition; feeding “picky eaters”; healthful recipes, “fast foods” and packaged foods; quick, inexpensive meals and snacks low in fat, sugar, and salt; limiting sedentary time; family meals; using food thermometers; and intergenerational gardening and cooking.

Malnutrition: Risks & Concerns in Dysphagia Management

Nate — Tue, 04 Jan 2011 19:41:31 +0000

Malnutrition, particularly undernutrition, negatively affects health outcomes. Risk of malnutrition, often identified by a Registered Dietitian as part of a patient’s dietary assessment, increases greatly in the presence of dysphagia. Patient characteristics that may be linked to malnutrition include advanced age, medical diagnoses, level of diet tolerated, actual calorie and protein intake, need for feeding assistance, weight changes, and quality of life issues. Many older adults may be malnourished at the time of their hospital admission or become so during the course of their medical care. Poor physical condition from malnutrition could negatively impact a patient’s rehabilitation potential. This article highlights possible causes and effects of undernutrition and the importance of nutrition strategies to patient care through a case study illustration.

Lignan Biosynthesis Enhancement in Transgenic Wheat

Nate — Tue, 04 Jan 2011 19:38:15 +0000

Phytochemical lignans are phenylpropane dimers linked by β-β bonds with a 1,4-diarylbutane structure. They are biosynthesized in the cell cytoplasm through action of enzymes of the phenylpropanoid pathway, in which phenylalanine ammonia lyase (PAL) catalyzes the initial step of the secondary metabolism and pinoresinol laciresinol reductases (PLR) accelerates the final steps of biosynthesis of lignans. Lignans not only present abundantly in flaxseed but also in various grains such as wheat. Epidemiological and clinical studies have shown a correlation between the consumption of lignan-rich whole grain products and a reduced cancer risk. In animal models, lignans have been shown to have cancer preventive activities. Our previous studies demonstrated that the contents in lignans in various wheat cultivars were significantly associated with antitumor activities in APC^min mice. This review article covers updated aspect of lignans with emphasis on our recent lignan biosynthesis enhancement via transgenic engineering in wheat by over-expressing PLR gene. To develop a stably expression and more efficient transformation, a future study in genetically engineered wheat with pathway transformation by over-expressing both the PAL and PLR enzymes will be further discussed.

Cytostatic inhibition of cancer cell growth by lignan secoisolariciresinol diglucoside

Nate — Tue, 04 Jan 2011 19:33:00 +0000

Our previous study demonstrated that lignan metabolites enterolactone and enterodiol inhibited colonic cancer cell growth by inducing cell cycle arrest and apoptosis. However, the dietary lignans are naturally present as glycoside precursors, such as secoisolariciresinol diglucoside (SDG), which have not been evaluated yet. This study tested the hypothesis that dietary SDG might have a different effect than its metabolites in human colonic SW480 cancer cells. Treatment with SDG at 0 to 40 µmol/L for up to 48 hours resulted in a dose- and time-dependent decrease in cell numbers, which was comparable to enterolactone. The inhibition of cell growth by SDG did not appear to be mediated by cytotoxicity, but by a cytostatic mechanism associated with an increase of cyclin A expression. Furthermore, high-performance liquid chromatography analysis indicated that SDG in the media was much more stable than enterolactone (95% of SDG survival vs 57% of enterolactone after 48-hour treatment). When the cells were treated with either enterolactone or SDG at 40 µmol/L for 48 hours, the intracellular levels of enterolactone, as measured by high-performance liquid chromatography–mass spectrometry/electron spray ionization, were about 8.3 × 10^-8 nmol per cell; but intracellular SDG or potential metabolites were undetectable. Taken together, SDG demonstrated similar effects on cell growth, cytotoxicity, and cell cycle arrest when compared with its metabolite enterolactone. However, the reliable stability and undetectable intracellular SDG in treated cells may suggest that metabolism of SDG, if exposed directly to the colonic cells, could be different from the known degradation by microorganisms in human gut.

Loss of Purkinje cells in the PKCγ H101Y transgenic mouse

Nate — Mon, 29 Nov 2010 19:53:46 +0000

Spinocerebellar ataxia type 14 (SCA14) is an autosomal, dominant neurodegenerative disorder caused by mutations in PKCγ. The objective of this study was to determine effects of PKCγ H101Y SCA14 mutation on Purkinje cells in the transgenic mouse. Results demonstrated that wild type PKCγ-like Purkinje cell localization of HA-tagged PKCγ H101Y mutant proteins, altered morphology and loss of Purkinje cells were observed in the PKCγ H101Y SCA14 transgenic mouse at four weeks of age. Failure of stereotypical clasping responses in the hind limbs of transgenic mice was also observed. Further, PKCγ H101Y SCA14 mutation caused lack of total cellular PKCγ enzyme activity, loss of connexin 57 phosphorylation on serines, and activation of caspase-12 in the PKCγ H101Y SCA14 transgenic mouse. Results clearly demonstrate a need for PKCγ control of gap junctions for maintenance of Purkinje cells. This is the first transgenic mouse to our knowledge which models a human SCA14 mutation.

Food safety educational intervention positively influences college students’ food safety attitudes, beliefs, knowledge, and self-reported practices

Nate — Wed, 20 Oct 2010 19:21:15 +0000

In this study, the authors evaluated college students’ food safety attitudes, beliefs, knowledge, and self-reported practices and explored whether these variables were positively influenced by educational intervention. Students (n = 59), were mostly seniors, health or non-health majors, and responsible for meal preparation. Subjects completed a food safety questionnaire (FSQ) prior to educational intervention, which consisted of three interactive modules. Subjects completed module pre-, post-, and post-posttests. The FSQ was also administered after exposure to intervention and five weeks later to determine changes in food safety attitudes, beliefs, knowledge, and self-reported practices. Students’ FSQ attitude scores increased from 114 to 122 (p ≤ .001); FSQ belief and knowledge scores improved from 86 to 98 (p ≤ .001) and from 11 to 13 (p ≤ .001), respectively. Food safety knowledge was also measured by module pre- and posttests, and improved significantly after intervention for all students, with health majors having the greatest increase. Intervention resulted in improved food safety self-reported practices for health majors only The educational intervention appeared effective in improving food safety beliefs and knowledge. For health majors, attitudes and some self-reported practices improved. For all areas, the strongest effects were seen in health majors.

Beef and soy-based food supplements differentially affect serum lipoprotein-lipid profiles because of changes in carbohydrate intake and novel nutrient intake ratios in older men who resistive-train

Nate — Mon, 04 Oct 2010 16:12:16 +0000

Objective: We examined if the predominant source of dietary protein influenced the lipoprotein-lipid profile in older men who performed resistive exercise training (RT).
Design: This is a 14-week, randomized, repeated-measures study with a 12-week period of RT with supplementation of different sources of dietary protein (beef and soy).
Setting: Nutrition, Metabolism, and Exercise Laboratory, Central Arkansas Veteran’s Healthcare System, North Little Rock, Ark.
Subjects: Twenty-six healthy men were recruited, and 21 men (age 65 ± 5 years, body mass index 28.2 ± 2.6 kg/m²) completed the study.
Interventions: For 14 weeks, all men were counseled to self-select a lacto-ovo-vegetarian diet. For 2 weeks (baseline), all men also consumed 0.6 g-protein/kg per day from portioned quantities of soy-based texturized vegetable protein foods. For the next 12 weeks, 11 men were randomized to continue with texturized vegetable protein foods (VEG group), whereas 10 men were randomized to receive 0.6 g-protein/kg per day from portioned quantities of beef (BEEF group) and continue their otherwise lacto-ovo-vegetarian diet. All men participated in RT 3 d/wk during this 12-week period. Assessments of upper and lower body muscle strength and power, serum lipoproteinlipid profile, and dietary nutrient intakes were made at baseline and week 12 of RT (POST).
Results: The BEEF and VEG groups increased (P < .05) overall muscle strength and muscle power with RT, with no differences between groups. From baseline to POST, the BEEF group had increased concentrations of high-density lipoprotein cholesterol (P = .025; HDL-C), low-density lipoprotein cholesterol (P = .027; LDL-C), and total cholesterol (P = .015: CHOL), with no changes (P > .05) in triacylglycerol (TG), the CHOL/HDL-C ratio, or the TG/HDL-C ratio. The VEG group did not experience within-group changes (P > .05) in any lipoprotein-lipid parameter. At POST, the concentrations of HDL-C, LDL-C, and CHOL were greater in the BEEF group compared with the VEG group. There were significant interaction effects for HDL-C (P = .004) and the TG/HDL-C ratio (P = .022). Multiple regression analysis determined that, regardless of intervention, change in the saturated fat/fiber ratio (SF/fiber) predicted CHOL (adjusted R² = 0.34); the SF/fiber ratio predicted LDL-C (adjusted R² = 0.36); the cholesterol/fiber intake ratio predicted HDL-C (adjusted R² = 0.26), and the change in carbohydrate intake predicted the CHOL/HDL-C ratio (adjusted R² = 0.37) and TG (adjusted R² = 0.44).
Conclusions: These results suggest that the lipoprotein-lipid profile in these older men was differentially affected by supplementation with beef versus soy-based foods during RT. Regardless of group, the lipoprotein-lipid changes were predicted by differences in the SF/fiber ratio and cholesterol/fiber ratio and increases in carbohydrate intake over time.

Calcium-fortified beverage supplementation on body composition

Nate — Mon, 04 Oct 2010 15:34:43 +0000

Background: We investigated the effects of a calcium-fortified beverage supplemented over 12 months on body composition in postmenopausal women (n = 37, age = 48–75 y).
Methods: Body composition (total-body percent fat, %Fat_TB; abdominal percent fat, %Fat_AB) was measured with dual energy x-ray absorptiometry. After baseline assessments, subjects were randomly assigned to a free-living control group (CTL) or the supplement group (1,125 mg Ca⁺⁺/d, CAL). Dietary intake was assessed with 3-day diet records taken at baseline and 12 months (POST). Physical activity was measured using the Yale Physical Activity Survey.
Results: At 12 months, the dietary calcium to protein ratio in the CAL group (32.3 ± 15.6 mg/g) was greater than the CTL group (15.2 ± 7.5 mg/g). There were no differences from baseline to POST between groups for changes in body weight (CAL = 0.1 ± 3.0 kg; CTL = 0.0 ± 2.9 kg), %Fat_TB (CAL = 0.0 ± 2.4%; CTL = 0.5 ± 5.4%), %Fat_AB (CAL = -0.4 ± 8.7%; CTL = 0.6 ± 8.7%), or fat mass (CAL = 1.3 ± 2.6 kg; CTL = 1.3 ± 2.7 kg).
Conclusion: These results indicate that increasing the calcium to protein ratio over two-fold by consuming a calcium-fortified beverage for 12 months did not decrease body weight, body fat, or abdominal fat composition in postmenopausal women.