Showing papers in "Journal of The American College of Nutrition in 2002"

Omega-3 Fatty Acids in Inflammation and Autoimmune Diseases

Abstract: Among the fatty acids, it is the omega-3 polyunsaturated fatty acids (PUFA) which possess the most potent immunomodulatory activities, and among the omega-3 PUFA, those from fish oil— eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)—are more biologically potent than -linolenic acid (ALA). Some of the effects of omega-3 PUFA are brought about by modulation of the amount and types of eicosanoids made, and other effects are elicited by eicosanoid-independent mechanisms, including actions upon intracellular signaling pathways, transcription factor activity and gene expression. Animal experiments and clinical intervention studies indicate that omega-3 fatty acids have anti-inflammatory properties and, therefore, might be useful in the management of inflammatory and autoimmune diseases. Coronary heart disease, major depression, aging and cancer are characterized by an increased level of interleukin 1 (IL-1), a proinflammatory cytokine. Similarly, arthritis, Crohn’s disease, ulcerative colitis and lupus erythematosis are autoimmune diseases characterized by a high level of IL-1 and the proinflammatory leukotriene LTB4 produced by omega-6 fatty acids. There have been a number of clinical trials assessing the benefits of dietary supplementation with fish oils in several inflammatory and autoimmune diseases in humans, including rheumatoid arthritis, Crohn’s disease, ulcerative colitis, psoriasis, lupus erythematosus, multiple sclerosis and migraine headaches. Many of the placebocontrolled trials of fish oil in chronic inflammatory diseases reveal significant benefit, including decreased disease activity and a lowered use of anti-inflammatory drugs. Key teaching points:  In Western diets, omega-6 fatty acids are the predominant polyunsaturated fats. The omega-6 and omega-3 fatty acids are metabolically distinct and have opposing physiologic functions.  Eicosapentaenoic acid (EPA) is released to compete with arachidonic acid (AA) for enzymatic metabolism inducing the production of less inflammatory and chemotactic derivatives.  Animal and human studies support the hypothesis that omega-3 PUFA suppress cell mediated immune responses.  In experimental animals and humans, serum PUFA levels predict the response of proinflammatory cytokines to psychologic stress. Imbalance in the omega-6/omega-3 PUFA ratio in major depression may be related to the increased production of proinflammatory cytokines and eicosanoids in that illness.  The increased omega-6/omega-3 ratio in Western diets most likely contributes to an increased incidence of cardiovascular disease and inflammatory disorders.  Patients with autoimmune diseases, such as rheumatoid arthritis, inflammatory bowel disease and asthma, usually respond to eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) supplementation by decreasing the elevated levels of cytokines.

The Role of Tea in Human Health: An Update

Abstract: Tea is an important dietary source of flavanols and flavonols. In vitro and animal studies provide strong evidence that tea polyphenols may possess the bioactivity to affect the pathogenesis of several chronic diseases, especially cardiovascular disease and cancer. However, the results from epidemiological and clinical studies of the relationship between tea and health are mixed. International correlations do not support this relationship although several, better controlled case-referent and cohort studies suggest an association with a moderate reduction in the risk of chronic disease. Conflicting results between human studies may arise, in part, from confounding by socioeconomic and lifestyle factors as well as by inadequate methodology to define tea preparation and intake. Clinical trials employing putative intermediary indicators of disease, particularly biomarkers of oxidative stress status, suggest tea polyphenols could play a role in the pathogenesis of cancer and heart disease.

Selenocompounds in Plants and Animals and their Biological Significance

Abstract: There are several selenocompounds in tissues of plants and animals. Selenate is the major inorganic selenocompound found in both animal and plant tissues. Selenocysteine is the predominant selenoamino acid in tissues when inorganic selenium is given to animals. Selenomethionine is the major selenocompound found initially in animals given this selenoamino acid, but is converted with time afterwards to selenocysteine. Selenomethionine is the major selenocompound in cereal grains, grassland legumes and soybeans. Selenomethionine can also be the major selenocompound in selenium enriched yeast, but the amount can vary markedly depending upon the growth conditions. Se-methylselenocysteine is the major selenocompound in selenium enriched plants such as garlic, onions, broccoli florets and sprouts, and wild leeks.

Regulation of adiposity and obesity risk by dietary calcium: Mechanisms and implications

Abstract: Dietary calcium plays a pivotal role in the regulation of energy metabolism; high calcium diets attenuate adipocyte lipid accretion and weight gain during periods of overconsumption of an energy-dense diet and increase lipolysis and preserve thermogenesis during caloric restriction, thereby markedly accelerating weight loss. Intracellular Ca2+ has a key role in regulating adipocyte lipid metabolism and triglyceride storage, with increased intracellular Ca2+ resulting in stimulation of lipogenic gene expression and lipogenesis, suppression of lipolysis, and increased lipid filling and adiposity. Moreover, we have recently demonstrated that the increased calcitriol released in response to low calcium diets stimulates Ca2+ influx in human adipocytes and thereby promotes adiposity. Accordingly, suppressing calcitriol levels by increasing dietary calcium is an attractive target for the prevention and management of obesity. In support of this concept, transgenic mice expressing the agouti gene specifically in a...

Lithium: occurrence, dietary intakes, nutritional essentiality.

Abstract: Lithium is found in variable amounts in foods; primary food sources are grains and vegetables; in some areas, the drinking water also provides significant amounts of the element. Human dietary lithium intakes depend on location and the type of foods consumed and vary over a wide range. Traces of lithium were detected in human organs and fetal tissues already in the late 19th century, leading to early suggestions as to possible specific functions in the organism. However, it took another century until evidence for the essentiality of lithium became available. In studies conducted from the 1970s to the 1990s, rats and goats maintained on low-lithium rations were shown to exhibit higher mortalities as well as reproductive and behavioral abnormalities. In humans defined lithium deficiency diseases have not been characterized, but low lithium intakes from water supplies were associated with increased rates of suicides, homicides and the arrest rates for drug use and other crimes. Lithium appears to play an especially important role during the early fetal development as evidenced by the high lithium contents of the embryo during the early gestational period. The biochemical mechanisms of action of lithium appear to be multifactorial and are intercorrelated with the functions of several enzymes, hormones and vitamins, as well as with growth and transforming factors. The available experimental evidence now appears to be sufficient to accept lithium as essential; a provisional RDA for a 70 kg adult of 1,000 microg/day is suggested.

Fighting iron deficiency anemia with iron-rich rice.

Abstract: Objective: Iron deficiency is estimated to affect about 30% of the world population. Iron supplementation in the form of tablets and food fortification has not been successful in developing countries, and iron deficiency is still the most important deficiency related to malnutrition. Here we present experiments that aim to increase the iron content in rice endosperm and to improve its absorption in the human intestine by means of genetic engineering.Methods: We first introduced a ferritin gene from Phaseolus vulgaris into rice grains, increasing their iron content up to twofold. To increase iron bioavailability, we introduced a thermo-tolerant phytase from Aspergillus fumigatus into the rice endosperm. In addition, as cysteine peptides are considered major enhancers of iron absorption, we over-expressed the endogenous cysteine-rich metallothionein-like protein.Results: The content of cysteine residues increased about sevenfold and the phytase level in the grains about one hundred and thirtyfold, giving a ...

Feeding Behaviors and Other Motor Development in Healthy Children (2–24 Months)

Abstract: Objectives: To monitor infant’s gross, fine and oral motor development patterns related to feeding.Design: An incomplete block design was used with 57 to 60 (sample=98) mothers interviewed when their children were 2, 3, 4, 6, 8, 10, 12, 16 and 24 months (within ± 5 days of birth date). Each mother had 5 to 6 interviews.Setting: Selected developmental feeding behaviors were monitored using in-home interviews conducted by trained interviewers (n=2). At each interview, mothers reported the child’s age when behaviors first occurred, and anthropometric measurements were performed.Subjects: Subjects were healthy white children who lived mostly in homes with educated two-parent families of upper socioeconomic status.Results: Mean behavioral ages were within normal ranges reported in the literature, whereas individuals exhibited a wide diversity in reported ages. Examples of gross motor skills (age in months, ± SD) included sitting without help (5.50 ± 2.08) and crawling (8.00 ± 1.55). Mean ages for self-feeding ...

Calcium and weight: clinical studies.

Abstract: Data from six observational studies and three controlled trials in which calcium intake was the independent variable (and either bone mass or blood pressure the original outcome variable) have been reanalyzed to evaluate the effect of calcium intake on body weight and body fat. Analysis reveals a consistent effect of higher calcium intakes, expressed as lower body fat and/or body weight, and reduced weight gain at midlife. Similarly, studies relating nutrient intake to body composition report negative associations between calcium intake and body weight at midlife and between calcium and body fat accumulation during childhood. There is a fairly consistent effect size, with each 300 mg increment in regular calcium intake associated with approximately 1 kg less body fat in children and 2.5-3.0 kg lower body weight in adults. Taken together these data suggest that increasing calcium intake by the equivalent of two dairy servings per day could reduce the risk of overweight substantially, perhaps by as much as 70 percent.

Intake of refined carbohydrates and whole grain foods in relation to risk of type 2 diabetes mellitus and coronary heart disease.

Abstract: Recent survey data indicate that more than 50% of all adult Americans are overweight or obese. In parallel with this epidemic of weight gain in the general population, the incidence rate of type 2 diabetes mellitus (DM) is rapidly rising. Although their precise contributions are unclear, dietary factors are thought to affect body weight and the development of insulin resistance. Recent epidemiological data indicate that diets rich in high-fiber whole grains are associated with lower risk of coronary heart disease (CHD) and type 2 DM. These data are consistent with results from recent metabolic experiments, suggesting favorable lipid profiles and glycemic control associated with higher intake of whole grains, but not with refined grains. It seems prudent, therefore, to distinguish whole-grain rather than refined-grain cereal products for the prevention of chronic diseases.

Enhancing mineral content in plant food products

Abstract: Plant foods can serve as dietary sources of all essential minerals required by humans. Unfortunately, mineral concentrations are low in some plants, especially many staple food crops; thus, efforts are underway to increase the mineral content of these foods as a means to ensure adequate attainment of dietary minerals in all individuals. While these efforts have included classical breeding approaches in the past, it is clear that future progress can be made by utilizing the tools of biotechnology to effect directed changes in plant mineral status. Reviewed are the short- and long-distance mineral transport mechanisms responsible for the root acquisition and whole-plant partitioning of mineral ions in crop plants. This background is used to discuss different transgenic strategies with the potential to enhance mineral content in vegetative and/or reproductive tissues. Due to various constraints imposed by plant transport systems on whole-plant mineral movement, it is argued that modifications designed to inc...

Postprandial Thermogenesis Is Increased 100% on a High-Protein, Low-Fat Diet versus a High-Carbohydrate, Low-Fat Diet in Healthy, Young Women

Abstract: Objective: The recent literature suggests that high-protein, low-fat diets promote a greater degree of weight loss compared to high-carbohydrate, low-fat diets, but the mechanism of this enhanced weight loss is unclear. This study compared the acute, energy-cost of meal-induced thermogenesis on a high-protein, low-fat diet versus a high-carbohydrate, low-fat diet.Methods: Ten healthy, normal weight, non-smoking female volunteers aged 19-22 years were recruited from a campus population. Using a randomized, cross-over design, subjects consumed the high-protein and the high-carbohydrate diets for one day each, and testing was separated by a 28- or 56-day interval. Control diets were consumed for two days prior to each test day. On test day, the resting energy expenditure, the non-protein respiratory quotient and body temperature were measured following a 10-hour fast and at 2.5-hour post breakfast, lunch and dinner. Fasting blood samples were collected test day and the next morning, and complete 24-hour urin...

Risk for disordered eating relates to both gender and ethnicity for college students.

Abstract: Objective: To estimate the frequency of disordered eating behaviors among college students and associations by gender, ethnicity, participation in social organizations and college athletics and to determine whether responses to eight health behavior and attitude questions and body weight predicted a high score on the Eating Attitudes Test (EAT)-26, a screening instrument used to identify risks of developing an eating disorder.Methods: Subjects were a convenience sample of 1,899 college students (cleaned to 1620) who attended four classes, were members of 14 sororities or lived in five residence halls. Students reported height and weight and responded to the EAT-26 and eight items regarding health behaviors and attitudes.Results: Among women and men, 4.5% and 1.4%, respectively, reported previous treatment for an eating disorder, and 10.9% of women and 4.0% of men were at risk for eating disorders (scores ≥ 20 on EAT). Among African-Americans, 8.3% of women were at risk. One group of women who lived separa...

Beneficial effects of soybean isoflavone supplementation on bone metabolism and serum lipids in postmenopausal japanese women: a four-week study.

Abstract: Objective: The aim of this study was to determine the effects of soy isoflavones with weak estrogen-like activities both on bone metabolism and on serum lipids in perimenopausal women. Methods: Twenty-three healthy perimenopausal women were assigned randomly to either isoflavone or placebo groups. The isoflavone group (n = 12) received daily capsules of soy isoflavone extract (61.8 mg of isoflavones) and the placebo group (n = 11) received daily placebo capsules for four weeks. Urinary excretion of isoflavone was measured at weeks 0, 2 and 4. Urinary excretion of pyridinoline and deoxypyridinoline, bone stiffness and levels of serum cholesterol, triglyceride and cholesterol fractions were measured at weeks 0 and 4. Results: As compared to the placebo group, urinary isoflavone, primarily daidzein, excretion was increased at weeks 2 and 4 in the isoflavone group. Excretion of bone resorption markers was reduced significantly in the isoflavone group. Both total serum cholesterol and LDL cholesterol were decreased significantly in the isoflavone group. Other serum biochemical parameters were not changed in either group. Conclusion: Soy isoflavone supplementation for four weeks showed potentially beneficial effects on bone metabolism and on serum lipids in perimenopausal women. These effects could have the potential to reduce the risks of postmenopausal osteoporosis and of cardiovascular diseases in such women.

Effect on body weight of a free 76 Kilojoule (320 calorie) daily supplement of almonds for six months.

Abstract: Objective: Regular nut consumption is associated with lower rates of heart attack. However, as nuts are fatty foods, they may in theory lead to weight gain, although preliminary evidence has suggested otherwise. We tested the hypothesis that a free daily supplement (averaging 76 kJ) of almonds for six months, with no dietary advice, would not change body weight.Methods: Eighty-one male and female subjects completed the randomized cross-over study. During two sequential six-month periods, diet, body weight and habitual exercise were evaluated repeatedly in each subject. Almonds were provided only during the second period. The design was balanced for seasonal and other calendar trends.Results: During the almond feeding period, average body weight increased only 0.40 (kg) (p ∼ 0.09). The weight change depended on baseline BMI (p = 0.05), and only those initially in the lower BMI tertiles experienced small and mainly unimportant weight gains with the almonds. We estimated that 54% (recalls) or 78% (diaries) o...

Calcium effects on phosphorus absorption: implications for the prevention and co-therapy of osteoporosis.

Abstract: Objective: To evaluate the effect of calcium intake on absorption of dietary phosphorus, with special reference to typical calcium intakes and to those likely to be encountered in prevention and treatment of osteoporosis.Setting: Two academic health sciences centers; inpatient metabolic research unit.Methods: Evaluation of calcium and phosphorus balance data obtained in two data sets, the first, 543 studies of healthy women aged 35–65, and the second, 93 men and women aged 19–78; development of multiple regression models predicting fecal phosphorus (the complement of net absorbed phosphorus); data from the two centers analyzed separately as a check on the consistency of the findings.Results: Mean net absorption of phosphorus was 60.3% (±18.1) for data set 1 and 53.0% (±9.4) for data set 2. Just two variables, fecal calcium and diet phosphorus, were positively and independently associated with fecal phosphorus. These variables explained 73% of the variance in fecal phosphorus in data set 1 and 33% in data ...

High-Oleic and High-Stearic Cottonseed Oils: Nutritionally Improved Cooking Oils Developed Using Gene Silencing

Abstract: Gene technology and plant breeding are combining to provide powerful means for modifying the composition of oilseeds to improve their nutritional value and provide the functional properties required for various food oil applications. Major alterations in the proportions of individual fatty acids have been achieved in a range of oilseeds using conventional selection, induced mutation and, more recently, post-transcriptional gene silencing (PTGS). In particular, a number of high-oleic oils have been developed in order to provide high-stability cooking oils. These oils provide the opportunity to replace the current widespread use of saturated fats and hydrogenated oils that contribute significantly to increased risk of cardiovascular disease due to the effect of saturated and trans-fatty acids on elevating LDL cholesterol in the bloodstream. Similarly, oils with increased stearic acid content are being developed to enable the production of solid fats without the need for hydrogenation. We have recently applied hpRNA-mediated PTGS in cotton to down-regulate key fatty acid desaturase genes and develop nutritionally-improved high-oleic (HO) and high-stearic (HS) cottonseed oils (CSOs). Silencing of the ghFAD2-1 delta12-desaturase gene raised oleic acid content from 13% to 78% and silencing of the ghSAD-1 delta9-desaturase gene substantially increased stearic acid from the normal level of 2% to as high as 40%. Additionally, palmitic acid was significantly lowered from 26% to 15% in both HO and HS lines. Intercrossing the HS and HO lines resulted in a wide range of unique intermediate combinations of palmitic, stearic, oleic and linoleic contents. The oxidative stability, flavor characteristics and physical properties of these novel CSOs are currently being evaluated by food technologists.

To drink or not to drink: how are alcohol, caffeine and past smoking related to bone mineral density in elderly women?

Abstract: Objectives: To determine relationship between alcohol, caffeine, past smoking and bone mineral density of different skeletal sites in elderly women, accounting for other biological and life-style variables.Methods/Design: A cross-sectional study in 136 Caucasian women, mean ± SD age 68.6 ± 7.1 years, all healthy and free of medications affecting bones, including estrogen. Bone mineral density (BMD) of multiple skeletal regions and body composition were measured by dual X-ray absorptiometry. Serum vitamin D (25-OHD) and parathyroid hormone (PTH) were analyzed and used as confounders. Calcium (Ca) intake was assessed by food frequency questionnaire. Alcohol and caffeine consumption was assessed by questionnaires determining frequency, amount and source of each. There were no current smokers, but the history of smoking was recorded, including number of years and packages smoked/day. Past physical activity was assessed by Allied Dunbar National Fitness Survey and used as confounder. Statistical significance w...

The effect of high- and low-glycemic index energy restricted diets on plasma lipid and glucose profiles in type 2 diabetic subjects with varying glycemic control.

Abstract: Objective: To determine whether glycemic index (GI) differentially affects improved glucose and lipid profiles observed during weight loss in overweight subjects previously diagnosed with type 2 diabetes with variable glucose tolerance.Methods: Twenty-three female and twenty-two male overweight subjects participated in 12 weeks of energy restriction (average BMI 33.2 kg/m2, age 56.7 years, glycated hemoglobin (GHb) 6.7%). After a four-week run-in on a high saturated fat (SFA) diet (1540 kcal/day, 17% SFA), the free-living subjects were randomly assigned to either a high- (75 GI units) or low- (43 GI units) GI diet (1440 kcal/day, 60% carbohydrate, 5% SFA) for eight weeks. Weight, serum lipids, plasma glucose and glycated hemoglobin were measured every four weeks. An oral glucose tolerance test (OGTT) was also performed at baseline, weeks 4 and 12. From the baseline OGTT results subjects were divided into three groups of low, median and high glucose tolerance.Results: At baseline, BMI, age and glycated hem...

A glucomannan and chitosan fiber supplement decreases plasma cholesterol and increases cholesterol excretion in overweight normocholesterolemic humans

Abstract: Objective: Both chitosan and glucomannan have demonstrated hypocholesterolemic effects. A recent study in rats indicates that the combination of the two is also a potent hypocholesterolemic agent that increases fecal fat excretion. The objective of the present study was to determine the hypocholesterolemic effect of a supplement containing equal amounts of chitosan and glucomannan on blood lipid concentrations and fecal excretion of fat, neutral sterols and bile acids.Methods: Twenty-one overweight normocholesterolemic subjects (11 males and 10 females) were fed 2.4 g/day of a supplement containing equal amounts of chitosan and glucomannan. Prior to taking the supplement (initial period) and after 28 days (final period), blood was drawn for measurement of serum lipids and a three-day fecal sample collected for determination of fat, neutral sterol and bile acid excretion. Subjects maintained their normal dietary and activity patterns during the study.Results: Caloric intake and intake of fat and dietary fi...

The Development of the Surgical Treatment of Morbid Obesity

Abstract: Morbid obesity is defined as obesity with a body mass index ≥40, or ≥35 with secondary serious diseases. Conservative medical therapies in these individuals generally fail to sustain weight loss. Thus, surgical operations have evolved which are based on gastric restriction and/or malabsorption. Historically, the intestinal bypass operation was followed by the gastric bypass operation (in some instances combined with intestinal bypass) or by the gastric restriction operations (gastroplasty or gastric banding). Laparoscopic techniques are now being used for these operations, but require surgical expertise in both the bariatric operations and advanced laparoscopic skills. All operations may have complications, but these occur in a very small percent. Postoperative follow-up and nutritional surveillance are mandatory. The operations result in significant weight loss, and the current operations have a mean lasting weight loss of about 50 percent of excess body weight, with improvement or resolution of most obe...

"Healthy-start": outcome of an intervention to promote a heart healthy diet in preschool children.

Abstract: Objective: We evaluated the effects of a preschool nutrition education and food service intervention “Healthy Start,” on two-to-five-year-old children in nine Head Start Centers in upstate NY. The primary objective was to reduce the saturated fat (sat-fat) content of preschool meals to <10% daily energy (E) and to reduce consumption of sat-fat by preschoolers to <10% E.Methods: Six centers were assigned to the food service intervention and three to control condition. Food service intervention included training workshops for cooks and monthly site visits to review progress towards goals. Child dietary intake at preschool was assessed by direct observation and plate waste measurement. Dietary intake at home was assessed by parental food record and telephone interviews. Dietary data were collected each Fall/Spring over two years, including five days of menus and recipes from each center. Dietary data were analyzed with the Minnesota NDS software.Results: Consumption of saturated fat from school meals decreas...

Plasma vitamin D and 25OHD responses of young and old men to supplementation with vitamin D3.

Abstract: Objectives: This study was conducted to determine whether there are age differences in the plasma parent vitamin D and 25-hydroxyvitamin D (25OHD) responses to eight weeks of supplementation with 20 μg/day of vitamin D3.Methods: Twenty-five healthy young men (age 18–35) and 25 healthy older men (62–79) were randomly assigned to supplementation with 20 μg/day of vitamin D3 or to no intervention and followed for eight weeks. Plasma vitamin D3 was measured by high performance liquid chromatography and 25OHD was measured by competitive protein binding.Results: Both young and old men in the supplemented group had pronounced, rapid and similar increases in plasma vitamin D3, whereas vitamin D3 concentrations were stable in the control group. By the end of the eight-week adaptation period, plasma vitamin D3 of young and old men had increased by 4.3 and 6.2 nmol/L respectively. In the supplemented group, mean 25OHD concentrations of both the young and old men increased during the study, and the magnitude of the c...

Reducing diet and/or exercise training decreases the lipid and lipoprotein risk factors of moderately obese women.

Abstract: Objective: This study was designed to measure the influence of diet, exercise or both on serum lipids and lipoproteins in obese women.Methods: Obese subjects were randomly divided into one of four groups: diet alone (1,200–1,300 kcal/day, NCEP, Step I), exercise alone (five 45 minute sessions per week at 78.4 ± 0.5% maximum heart rate), exercise and diet, and controls. Maximal aerobic power, body composition, diet, serum lipids and lipoproteins were measured in all subjects at baseline and after a 12-week intervention period. Subjects included 91 moderately obese (45.6 ± 1.1 y, body mass index 33.1 ± 0.6 kg/m2) and 30 nonobese (43.2 ± 2.3 y, body mass index 21.4 ± 0.34 kg/m2) women who were recruited from the surrounding community. Independent t tests were used to compare obese and nonobese subjects at baseline. The 12-week intervention data from the obese groups were analyzed using a 4 × 2 repeated measures ANOVA design.Results: Cross-sectional comparisons at baseline showed obese subjects had significan...

Dietary calcium intake in lactose maldigesting intolerant and tolerant African-American women.

Abstract: Background: The relationship between lactose maldigestion, lactose intolerance, and calcium intake in premenopausal African American women is unknown.Objective: To determine how intolerance of lactose and dairy products affects intake of calcium in lactose maldigesting premenopausal African American women.Design: Dietary intake of calcium was assessed in 50 premenopausal lactose maldigesting African American women as determined by the breath hydrogen test. Twenty-six women were lactose intolerant and 24 were lactose tolerant by self-reports.Results: The average intake of calcium in lactose maldigesting and intolerant women was significantly lower than in lactose tolerant women (388 ± 150 mg/day vs. 763 ± 333 mg/day, p < 0.0001, t test). Neither group reached the newly established Dietary Reference Intake (DRI) for calcium (1,000 mg/day). Major source of dietary calcium in lactose tolerant women were milk and dairy products (45%), and mixed foods containing calcium from non-dairy sources (30%). In lactose ...

Food intake and electrolyte status of ultramarathoners competing in extreme heat.

Abstract: Objective: To relate changes in laboratory indices to dietary intake during extremely prolonged running and to determine if dietary intake influences the ability of runners to finish an 160 km trail race.Methods: We monitored intake and serum chemistries of 26 runners competing in an 160 km foot race in temperatures which peaked at 38°C. Blood was drawn pre-, mid- and post-race. Dietary intake and incidence of gastrointestinal distress or changes in mental status were determined by interview with runners approximately every 13 km. Twenty-three runners completed at least 88 kms and, of these 23 runners, 13 finished 160 km in a mean time of 26.2 ± 3.6 hours.Results: Finishers ingested nearly 30,000 J, 19.4 ± 8.1 L of fluid and 16.4 ± 9.5 g of sodium (Na). Sodium and fluid intake per hour was estimated to be 0.6 g/hour and 0.7 L/hour, respectively. Electrolyte intake during the first half of the race was similar between those that finished the race and those that did not. Finishers ingested fluid at a greate...

Pre-Menopausal Women, Classified as Hypo- or Hyper-Responders, do not Alter their LDL/HDL Ratio Following a High Dietary Cholesterol Challenge

Abstract: Background: Cholesterol is the dietary component that has elicited the most public interest in conjunction with coronary heart disease. However, the impact of excess dietary cholesterol intake on plasma cholesterol levels cannot be accurately predicted; therefore, its role in disease progression is not straightforward. Individual response variation can be due to factors such as ethnicity, hormonal status, obesity and genetic predisposition.Objective: The purpose of this study was to evaluate the differences that occur within the plasma compartment of normolipidemic pre-menopausal women, classified based on their response to a high dietary cholesterol challenge.Design: We recruited 51 pre-menopausal women (29 Caucasian and 22 of Hispanic origin) aged 18 to 49 years with initial plasma cholesterol concentrations ranging from 3.62 to 5.17 mmol/L. Using a cross-over research design, women were randomly allocated to an egg (640 mg additional dietary cholesterol per day) or placebo group (0 mg additional dietar...

Dietary Protein, Phosphorus and Potassium Are Beneficial to Bone Mineral Density in Adult Men Consuming Adequate Dietary Calcium

Abstract: Objective: The purpose of this study was to determine relationships of calcium (Ca), protein (Pr), phosphorus (P) and potassium (K) to measures of bone mineral density in adult men.Methods: Cross-sectional analysis of 57 men ages 39 to 42 years who were participants in an ongoing study. Dietary assessment was conducted using the Block food frequency questionnaire (FFQ). BMD of total body (TB), hip and lumbar spine (LS) were measured with dual X-ray absorptiometry (DXA).Results: Ca, Pr, P and K, as well as lean body mass (LBM), showed significant correlation with BMD at the total body, hip and lumbar spine. Stepwise forward regression selection method identified LBM, height and fat mass as significant predictors of TB-BMD, LBM and height as significant predictors of hip BMD, and LBM as a significant predictor of LS-BMD. As the nutrients tested correlated significantly with each other, only one nutrient was entered into the regression model at a time to accommodate the potential for multicollinearity. In re...

The influence of dietary composition on energy intake and body weight.

Abstract: We review evidence regarding the influence of dietary fat, fiber, the glycemic index and sugar on energy intake and body weight. Although data from comprehensive long-term studies are lacking, published investigations suggest that the previous focus on lowering dietary fat as a means for promoting negative energy balance has led to an underestimation of the potential role of dietary composition in promoting reductions in energy intake and weight loss. More randomized clinical trials are needed to examine the relative utility of different putative dietary factors in the treatment of obesity.

Obesity and Health Risks

Abstract: Childhood obesity is multi-factorial in etiology. Several factors contribute to the etiology of childhood obesity, and childhood obesity is itself associated with significant morbidity. This article focuses on the health risks of childhood obesity and on the prenatal and childhood influences that contribute to the genesis of childhood obesity.

Enhancement of vitamin E levels in corn.

Abstract: Vitamin E is the common name that describes eight naturally occurring compounds possessing alpha-tocopherol activity. These eight vitamin E compounds are collectively termed tocols, and all have antioxidant activity. There is natural variation among different corn breeding lines for levels of tocols. The two predominant isomers present in corn grain are gamma-tocopherol and alpha-tocopherol. Alpha-tocopherol is considered more desirable for human and animal consumption because it has higher biological activity than gamma-tocopherol. Most corn breeding lines naturally have much more gamma-tocopherol than alpha-tocopherol. Therefore a breeding goal is to increase levels of alpha-tocopherol relative to gamma-tocopherol. However, recent research suggests that gamma-tocopherol and compounds metabolized from it have properties important to human health that are unique from properties of alpha-tocopherol. Therefore it may be desirable to not only increase levels of alpha-tocopherol in corn grain, but also levels of gamma-tocopherol. Determination of levels of tocopherols in corn grain is very laborious, requires HPLC analysis and is too time consuming for use in routine commercial corn breeding programs. Therefore we are performing biotechnology enabled molecular marker mapping of chromosomal regions with genes that control levels and ratios of alpha- and gamma-tocopherol. Breeders can use molecular markers we have identified to expediently select for desirable alleles of genes that will improve levels of alpha- and gamma-tocopherol in corn grain, without having to perform laborious HPLC assays. Another biotechnology strategy we have initiated is genetic transformation of corn with the gamma-tocopherol methyl transferase gene to enhance conversion of gamma-tocopherol to alpha-tocopherol and thus increase levels of alpha-tocopherol. This transgenic strategy has been demonstrated in the model plant Arabidopsis, and we are now applying this approach to corn.