Proximate composition, minerals, fatty acids, and sterols were determined for eight species of shellfish commonly marketed in the Northwest. Moisture and total lipid content varied with the size of the species, with more variation in mollusca than in crustacea; total lipid content ranged from 0.7% in sea scallops to 3.1% in blue mussels but only from 1.2% in Dungeness crab to 1.3% in pink shrimp. The mineral content was highly variable; the mineral content of Northwest samples tended to be lower than that reported in other studies. Generally, shellfish are good sources of zinc, and Pacific oysters, blue mussels, and Manila clams are also good sources of iron. Five fatty acids (16:0, 16:1, 18:1, 20:5n-3, and 22:6n-3) represented from 60% to 84% of the fatty acid content. Palmitic acid ranged from 13% to 32% of the total fatty acids. Long-chain n-3 polyunsaturated fatty acids were predominant (37.6% to 54.3%), with sea scallops containing more than 50%; n-6 polyunsaturated fatty acids ranged from 1.5% to 6.5%. In crustacea, cholesterol was the primary sterol, and brassicasterol was the only other measurable sterol. In all mollusca except California squid, cholesterol averaged 37 mg/100 gm and ranged from 23% to 39% of the total sterols. In squid, cholesterol, at 231 mg/100 gm, was the only measurable sterol. We conclude that shellfish vary widely in their nutrient content but, in general, are valuable additions to the diet.

Chromatography, Gas↗

PubMed1989

The 1980s: a look at a decade of growth in dietetics through the pages of the Journal.

Explore the source record for details and available documents.

Aged↗

PubMed1989

The 10th edition of the Recommended Dietary Allowances: what's new in the 1989 RDAs?

Explore the source record for details and available documents.

Adolescent↗

PubMed1988

Weight loss leads to a marked decrease in nonresting energy expenditure in ambulatory human subjects.

The extent to which the resting and nonresting components of 24-hour energy expenditure decrease after weight reduction has not been prospectively assessed in ambulatory, weight-stable, reduced-obese humans. Accordingly, 24-hour energy expenditure was estimated as the weight-stabilizing (+/- 50 g/d) daily caloric intake of a defined liquid diet in a cross-sectional study of ten reduced-obese subjects after a 23.2% +/- 9.4% weight loss and 18 obese subjects at baseline weight. A regression analysis demonstrated an 18% decrease in the mean daily energy requirement of the reduced-obese subjects compared with that of subjects of the same relative body weight who had never dieted. Strong linear relationships were noted between estimated 24-hour energy expenditure and fat-free mass (FFM), and between resting metabolic rate (RMR) and FFM in the subjects at baseline weight. In six reduced-obese men, the 24-hour energy expenditure was only 75.7% +/- 5.6% of the value predicted by regression analysis for the decreased FFM. In these six subjects the RMR was 97.4% +/- 7.5% of that predicted for the decreased FFM, suggesting that essentially all the energy savings relative to FFM in the reduced-obese state occurred in nonresting energy expenditure. In a subsequent group of seven subjects studied longitudinally before and after a 21.5% +/- 2.3% weight loss, the decrease in nonresting energy expenditure accounted for 582 +/- 276 kcal/d or 71% of the decrease in estimated 24-hour energy expenditure. These data suggest a decrease in the nonresting energy expenditure of ambulatory reduced-obese individuals, which is greater than previously appreciated.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1988

Iron status of premenopausal women in a university community and its relationship to habitual dietary sources of protein.

Dietary intake and iron status was evaluated in 52 nonpregnant premenopausal women who were not using Fe supplements. Subjects were separated into three groups based on their habitual consumption of red meat (RM), fish and/or poultry (FP), or lacto-ovovegetarian (LV) sources of protein. No differences were observed among the groups in demographic characteristics (eg, age, height, weight, reported number of menstrual days per year) or total Fe intake. However, those women consuming red meat as their predominant source of protein demonstrated superior Fe status, especially reflected by higher serum ferritin concentrations (RM = 30.5 micrograms/L; FP = 15.6 micrograms/L; and LV = 19.1 micrograms/L). Thus, form rather than amount of dietary Fe appears to be most influential on Fe status; the basis for the distinctly lower Fe stores among heavy users of fish and/or poultry remains to be determined.

Adult↗

PubMed1988

Research methods in nutrition and dietetics: design, data analysis, and presentation.

Most problems in practice may be addressed through research. To show the applicability of research to all areas of nutrition and dietetics, seven types of research designs are discussed in this article: qualitative research; case series and surveys--both categorized as descriptive research; and experimental design, quasiexperimental design, cohort (follow-up) studies, and case-control studies--the four of which are categorized as analytical research because each design tests hypotheses of causal relationships. Sample size, subject selection, and statistical analysis and interpretation are discussed as appropriate to each research design. Numerous examples are presented, along with the basic research designs. Each section and subsection is numbered so that the article can serve easily as a reference and its component parts can be accessed readily. Research provides answers to questions and, generally, raises further questions that future research can address. Among the benefits of well-designed research are answers to clearly stated research questions, useful comparisons between options, information to guide evaluations of protocols, and data to document and support one's professional activities and one's staff.

Clinical Trials as Topic↗

PubMed1988

Iron nutrition and absorption: dietary factors which impact iron bioavailability.

Iron deficiency is widely observed worldwide, yet, paradoxically, iron is the most plentiful heavy metal in the earth's crust. Although absorption of iron from the gastrointestinal tract is strictly controlled, excretion is limited to iron lost from exfoliation of skin and gastrointestinal cells, customary and abnormal blood loss, and menses. Individuals highly vulnerable to iron deficiency have high iron needs, as during growth or pregnancy; high iron loss, as during marked hemorrhage or excessive and/or frequent menstrual losses; or diets with low iron content or bioavailability. Food iron is classified as heme or nonheme. Approximately half of the iron in meat, fish, and poultry is heme iron. Depending on an individual's iron stores, 15% to 35% of heme iron is absorbed. Food contains more nonheme iron and, thus, it makes the larger contribution to the body's iron pool despite its lower absorption rate of 2% to 20%. Absorption of nonheme iron is markedly influenced by the levels of iron stores and by concomitantly consumed dietary components. Enhancing factors, such as ascorbic acid and meat/fish/poultry, may increase nonheme iron bioavailability fourfold.

Ascorbic Acid↗

PubMed1985

Iron fortification of infant foods. A decade of change.

A survey of iron-fortified commercial foods commonly marketed for consumption by infants was conducted in 1972 and again in 1982. Positive changes had occurred in infant formulas and cereals during that decade, in availability of fortifying iron, level of fortification, and label information. Miscellaneous iron-containing products, cookies, and crackers were unreliable sources of dietary iron in both 1972 and 1982. Availability of fortifying iron in regular cereals had improved by 1982, though 10 percent lacked the label information. Fortified infant formulas and cereals contribute iron of high bioavailability to the typical infant diet in amounts equal to the USRDA. Food manufacturers need to continue to apply knowledge gained through research to sustain the lessened but still highly prevalent incidence of anemia in 1-2-year old children.

Biological Availability↗

PubMed1982

Iron status of elderly Americans.

Studies of iron nutriture in the elderly are limited and very few include observations on individuals over the age of 75. The two Health and Nutrition Examination Surveys carried out by the United States Department of Health, Education and Welfare demonstrate that the mean iron intake of Americans is adequate until the age of 75. However, with changes in the major food sources there is a decrease in iron derived from meat and a concomitant rise in the proportion supplied by breakfast cereals. Alterations in dietary iron bioavailability++ that may result from this have not been studied. Physiological data suggest that the elderly do not represent a target population for iron deficiency since iron requirements are no greater than those of adult men and lower than those of children and menstruating women. Furthermore, there is little direct evidence of a high prevalence of iron deficiency in the elderly, but the laboratory measurements that have proved useful in defining iron status in younger people have not been standardized for or extensively used in older people. Anemia is still the most important known consequence of significant iron deficiency. However, the application of Hb or hematocrit standards used in younger people to the elderly as well as the assumption that anemia can be equated with iron deficiency invalidates the conclusions of many surveys. Hb and hematocrit measurements are not suitable screening tests for iron deficiency in the elderly and there is an urgent need for a clearer understanding of the physiological and nutritional factors responsible for lower Hb values in older people, particularly older Blacks.

Adolescent↗

PubMed1982

Calculating dietary iron bioavailability: refinement and computerization.

Previous laboratory studies have shown that dietary iron during digestion forms two pools: heme and nonheme. Even though human beings absorb heme iron at a higher rate than nonheme iron, the major portion of food iron is nonheme (all grain and vegetable iron plus approximately 60 percent of the iron in meat, fish, and poultry). The absorption rate of nonheme iron can be increased markedly by concomitant consumption of ascorbic acid and/or meat/fish/poultry. These concepts have been incorporated into a model for estimating the quantity of bioavailable iron, the first trace mineral to be thus considered. This model has now been revised for easier and more refined application.

Ascorbic Acid↗

PubMed1979

Food iron absorption in human subjects. V. Effects of the major dietary constituents of semisynthetic meal.

Studies were performed in adult volunteer subjects to determine the effect on nonheme iron absorption of protein, carbohydrate, and fat. These constituents were administered as egg albumin, dextrimaltose, and corn oil, respectively, in a semisynthetic meal containing 700 kcal and 4.1 mg iron. Because any one of these ingredients are unpalatable when administered alone, their effect was determined by serially deleting or doubling their content in the basal semisynthetic meal. With both approaches, carbohydrate and fat had little influence whereas egg albumin had a significant inhibitory effect on the absorption of nonheme iron.

Absorption↗

PubMed1979

Priorities of nutritional concepts assigned by health professionals and students.

Medical faculty, practicing physicians, medical students, and dietitians/nutritionists rated nutritional concepts as to their importance for inclusion in the medical school curricula and indicated the best method of accomplishing this. Ten concepts were rated "essential." They related to biochemical and physiological aspects of nutrition; nutrition in pregnancy, lactation, growth, development, maturity, and old age; nutritional management in disease; drug and diet interrelationships; and critiques of popular dietary regimens. Ranked as "important" were eight concepts regarding sources of nutrition information; evaluation of nutritional status; recommended dietary allowances; and food additives, naturally occurring food toxins, and nutrient composition of foods. Based on results of this study, the authors make recommendations regarding nutritional concepts that should be included in medical school curricula and how these concepts should be incorporated.

Attitude of Health Personnel↗