Vitamin-mineral supplement use and nutritional status of athletes.

Dietary, anthropometric, and chronic disease risk factors (CDRF) including blood lipids and blood pressure (BP), were measured in 91 vitamin-mineral supplement users (SU) and nonusers (NU) representing a wide range of athletic interests. Supplements were used by 46 (51%) subjects; 100% of female athletes and 51% of male athletes used supplements while none of a group of 15 control female subjects currently used supplements. Both dietary intake and energy expenditure were measured using 7-day records. Adiposity was determined from body weight, body mass index, and skinfolds. Total cholesterol, high-density lipoprotein cholesterol, serum ferritin, hemoglobin, hematocrit, zinc, copper, and vitamin C were based on 12-hour fasting blood samples. Dietary intake (excluding supplements) for SU tended to be greater than NU for vitamin C, thiamin, riboflavin, niacin, B6, B12, folate, calcium, iron and magnesium. Plasma vitamin C levels were significantly higher among SU than NU of both gender groups (p < 0.05). Although SU may exhibit additional healthy lifestyle practices, lipid profiles for many of these athletes were unfavorable with regard to CDRF.     

Seasonal changes in female athletes' diets.

Dietary intakes of 24 female athletes in various sports were compared inseason and postseason to those reported by 24 nonathletes during the same time period. Diets were analyzed for energy, carbohydrate, fat, protein, vitamins A and C, thiamin, riboflavin, niacin, folacin, calcium, and iron. During the study, the athletes' and nonathletes' diets were similar. Their energy intakes were lower than recommended while their iron and calcium intakes were marginal (less than 70% of the recommended dietary allowance). Although few dietary changes were observed, the nonathletes' diets changed more than those of the athletes during the study. Both groups reduced their energy intakes but only the nonathletes' reduction was significant. Initially many subjects were dieting. More subjects reported dieting during the second recording period. These results suggest that the desire to be thin may influence dietary intakes of female athletes more than changes in exercise training.     

Sweat iron and zinc losses during prolonged exercise

The purpose of this study was to examine the effects of a 2-hour exercise bout on sweat iron and zinc concentrations and losses in males and females. Nine male and 9 female recreational cyclists exercised at approximately 50% VO(2peak) in a temperate environment (Ta = 23 degrees C, RH = 51%). Sweat samples were collected for 15 min during each of four 30-min exercise bouts. No significant differences were observed between males' and females' sweat iron or zinc concentrations or losses. Sweat iron concentrations decreased significantly between 60 and 90 min of exercise. Sweating rates increased significantly from 30 to 60 min and remained constant during the second hour. Sweat iron losses were significantly lower during the second hour (0.042 mg/m2/h) than the first hour of exercise (0.060 mg/m2/h). Sweat zinc concentrations also decreased significantly over the 2-hour exercise bout. Dietary intakes of iron and zinc were not significantly correlated to sweat iron and zinc concentrations. Sweat iron and zinc losses during 2 hours of exercise represented 3% and 1% of the RDA for iron and 9% and 8% of the RDA for zinc for men and women, respectively. These results suggest a possible iron conservation that prevents excessive iron loss during prolonged exercise.     

Vitamin and mineral supplementation to athletes.

Vitamin and mineral supplements are frequently used by competitive and recreational athletes. Dietary deficiencies of most vitamins are not very common among athletes except in those who restrict their food intake in order to maintain body weight. Vitamins most likely to be deficient in the diet are folate, B6, B12, and E. Biochemical evidence of vitamin deficiencies in some athletes have been reported for thiamine, riboflavin, and B6. When the diet is deficient, vitamin supplements may improve performance but are not likely to be effective if the dietary intake is adequate. Some female athletes' diets are low in calcium, iron, and zinc. Low calcium intake may reduce peak bone mass in young women. Iron deficiency may impair performance and needs to be corrected with an iron supplement. Zinc supplements that exceed the RDA interfere with the absorption of copper and lower HDL-cholesterol.     

Selected Mineral Intakes of Adult African-Americans in the Washington, DC Area

The objective of this study was to assess daily self-selected mineral intake of free-living African-American adults using the duplicate portion collection technique coupled with direct chemical analysis. A duplicate sample of every food and beverage consumed was collected by each subject. The collection period was for 3 days (Sunday, Tuesday, and Thursday) of 1 week in 1986. The chemical analysis included calcium, phosphorus, magnesium, sodium, potassium, manganese, iron, copper, zinc, and phytate. Forty adult African-Americans (20 females and 20 males) living in the Washington, DC area volunteered to participate. They were apparently healthy, ranging in age from 21 to 65 years, with a median age of 38.5 years. The analytical data from the daily food and beverage intake were compared with the Recommended Dietary Allowances (RDA)/ Estimated Safe and Adequate Daily Dietary Intakes (ESADDI). The results were also compared with data from the National Health and Nutrition Examination Survey (NHANES) III and USDA's Continuing Survey of Food Intakes by Individuals(USDA-CSFII 1989–91). Compared with the RDA/ESADDI, for women, the median intakes of less than two-thirds the recommendations were : calcium (54%), magnesium (65%), iron (61%), copper(60%), zinc (61%), and potassium (50%) as determined by chemical analysis. For the men, applying the same criteria, the minerals and percentages are: calcium (64%), magnesium (56%), copper (60%), zinc (61%), and potassium (58%). The phytate:zinc and phytate × Ca:Zn molar ratios suggested no general inhibition of zinc bioavailability despite some higher than suggested limiting molar ratios found in a few individual daily diets. Although limited in scope, these results suggest that African-American adults are selecting diets that are frequently low in specific minerals. Some of these essential nutrients have been implicated in chronic health problems prevalent in this ethnic group; e.g., hypertension and cardiovascular diseases. Therefore, nutritionists and other health professionals should emphasize the need for a wider selection of foods to prevent specific mineral deficits. These foods might include acceptable dairy products, meats/seafood, and mineral-fortified cereals/breads and juices.     

Mineral balances of men and women consuming high fiber diets with complex or simple carbohydrate

Calcium, copper, iron, magnesium, manganese, and zinc balances of 20 men, 19 premenopausal women, and 12 postmenopausal women were determined while they consumed self-selected diets or high fiber diets with either complex or simple carbohydrate. Self-selected intakes of calcium, magnesium, copper and zinc were generally below RDA levels. Iron intakes of premenopausal women were less than two-thirds RDA. Balances during the self-selected intake period of calcium in men and women and of magnesium and zinc in women were negative, but lower-than-usual intakes could have contributed to this. High fiber diets did not adversely affect zinc, copper, manganese or iron balances. Calcium and magnesium balances were generally negative, especially in women, even though intakes were adequate. Excretion of copper was increased in premenopausal women consuming the simple carbohydrate diet. The levels of magnesium and especially calcium needed to maintain balance when consuming a high fiber diet may be above present RDA levels.     

Snacking patterns and nutrient density of snacks consumed by southern girls

We obtained information on the snacking patterns and nutrient contributions that snacks made to the total diet of 1224 adolescent girls living in eight southern states. We examined the data according to age (12-, 14-, and 16-year-old girls), race (black and white), and family per capita income (low, middle, and high). Snacking was common, with afternoon snacking at home occurring more frequently than snacking at other times or places regardless of race, age, or income group. Snack nutrient densities (amounts of nutrients per 1000 kcal) were generally lower than those of meals, but snacks contributed 52%, 43%, and 39% of the respective Recommended Dietary Allowance (RDA) for riboflavin, vitamin C, and thiamin and notable amounts of other vitamins, minerals, proteins, carbohydrates, and fats. The nutrients that snacks provided in the lowest amounts relative to RDA were folacin (8%), vitamin D (9%), zinc (10%), and iron (11%).     

Dietary intake and thiamin, iron, and zinc status in elite Nordic skiers during different training periods.

This study evaluated how different training periods affect dietary intake and biochemical indices of thiamin, iron, and zinc status in elite Nordic skiers. Subjects were 17 skiers and 39 controls, ages 18-38 yrs. Dietary data were collected by 7-day food records at 3-month intervals. Coefficient of variation (CV) was used to indicate magnitude of seasonal changes. Energy intake for the year (28 food record days) was 3,802 kcal/day (CV 19.1%) in male skiers, 2,754 kcal/day (CV 3.7%) in male controls, 2,812 kcal/day (CV 9.1%) in female skiers, and 2,013 kcal/day (CV 5.9%) in female controls. CVs for thiamin, riboflavin, vitamin C, calcium, magnesium, iron, and zinc intake were 14.1-23.9% (male skiers), 2.9-15.0% (male controls), 4.8-24.5% (female skiers), and 4.3-11.5% (female controls). Seasonal changes in energy, carbohydrate, and micronutrient intakes reflected energy expenditure in male endurance athletes particularly. Erythrocyte transketolase activation coefficients and serum ferritin and zinc concentrations did not differ between skiers and controls. Seasonal variations in these biochemical indices of nutritional status were of the same magnitude in skiers and controls, despite large changes in skiers' physical activity.     

The effect of nutrition education on the nutritional status of pregnant filipino women in Hawaii

The effect of nutrition education on the nutritional status of 43 pregnant women of Filipino ancestry in Hawaii was studied. Subjects were assigned to a control or experimental group: the latter received a series of nutrition education lessons. Dietary and anthropometric assessments were conducted during the first or second trimester and again, during the third trimester. The majority of women from both groups had poor diets at the initial interview: only vitamins A and C met the Recommended Dietary Allowance (RDA). At the initial interview, more than 40% of women in both groups had intakes (without supplements) that fell below 2/3 of the RDA in calories, zinc, phosphorous and magnesium. Additionally, in the control group, iron, calcium, thiamin and vitamin A were below 2/3 of the RDA in more than 40% of women. During the final interview, there was an improvement of the diet in both groups but it was greater in the experimental group as compared to the control group, but the difference was not statistically significant. The greater improvement in the experimental group may be due to the nutrition education sessions held by the nutritionist.     

Race-, gender- and age-specific differences in dietary micronutrient intakes of US children

Race-, gender- and age-specific differences in dietary micronutrient intakes of 1- to 10-year-old US children were evaluated. Three-day, dietary intakes from the US Department of Agriculture's Continuing Survey of Food Intakes by Individuals were evaluated. Data from 1895 children (967 males, 928 females; 1,540 Whites, 355 Blacks) who resided in the 48 conterminous states were analyzed. Micronutrient intakes, intakes as percent of the Recommended Dietary Allowance (RDA) and percent of children who consumed < or =67% of the RDA were computed. Black males compared with White males, Black females compared with White females and White females compared with White males had significantly lower dietary intakes for several micronutrients. More Black males than White males had intakes < or =67% of the RDA for vitamin E, calcium and zinc. Blacks and female children were at a greater risk for vitamin A, vitamin E, calcium, iron and zinc deficiency.     

The effect of ethanol consumption on trace mineral status in elderly rats

The effect of ethanol consumption on trace mineral status in 23-month old female rats was investigated. Ethanol was isocalorically substituted for dextrin at 35% of the calories in a liquid diet. Tissue trace minerals were determined by atomic absorption spectrophotometry. Compared to controls, rats consuming ethanol for 30 days had decreased liver concentrations of zinc, iron and magnesium. Other tissues examined were unaffected. Tissue concentrations of copper and manganese and hemoglobin, hematocrit and plasma ceruloplasmin were not different. Histological liver examination revealed fatty infiltration in ethanol treated rats. Decrease of liver concentrations of zinc, iron and magnesium in the absence of cirrhosis is attributed to the effect of ethanol and was not due to lower dietary intake of these minerals in the ethanol consuming animals compared to the controls.     

Contribution of food products and drinking water to the intake of minerals by elderly

The aim of this paper was to assess the contribution of food product groups and drinking water to mineral and trace elements supply. On the basis of 3-day record data it was found that the intake of calcium and copper by 75-80 years old elderly living in Warsaw area (Poland) was insufficient. The same for iron among women and zinc among men was observed. The RDA for energy was covered in 90% by men's diets and in 78% by women's diets. Dairy products were the main source of calcium (48%), cereals were the main source of magnesium (29%), while iron came mainly from cereals (31%) and meat products (21%). Two latter groups of products also significantly contributed in zinc intake by the elderly (29% and 25% respectively). Cereals (33%) and potatoes (16%) were the main sources of copper. Drinking water had significant share only in calcium (14%) and zinc (9%) intake. Cereals, vegetables, dairy and meat products gave relatively more minerals to men's diets, while potatoes, fruits, eggs and other products (fats, sugar, sweets etc.)--to women's diets.     

Nutrient intake of low-income pregnant women: laboratory analysis of foods consumed

Nutrient intake of a group of 22 young, mainly black, low-income pregnant women was evaluated by use of data resulting from laboratory analysis of foods prepared and consumed in the home over a 24-hour period. Magnesium, zinc, and folacin were the nutrients least well supplied in the foods consumed. Analyzed values for daily intake of the three were below 50% of the RDAs. Mean energy intake was considerably lower than recommended allowances, even though mean gain in weight was somewhat greater than that recommended for normal pregnancy, a finding like that of other investigators. The wide range in daily intake of energy and various nutrients among subjects is comparable with that found in a number of other studies, which showed that many individuals have marked deviations in intake from day to day. Analyzed diets also were examined in terms of nutrient density. Mean nutrient density for protein, calcium, phosphorus, vitamin A, thiamin, riboflavin, niacin, and ascorbic acid compared favorably with that of the RDAs, in contrast with the poor nutrient density for zinc, magnesium, and folacin. Laboratory analysis of the diets had the advantage of providing information about nutrient content of foods as prepared and consumed in the home. The analysis had particular advantage in the evaluation of content of zinc, magnesium, and folacin, as data for the three nutrients in food composition tables are limited.     

The nutrient intakes of pregnant and lactating mothers of good socio-economic status in Cambridge, UK: some implications for recommended daily allowances of minor nutrients

1. Forty-two mothers from social classes I, II and III non-manual and twenty-one from social classes III manual M), IV and V were studied longitudinally. The mean daily nutrient intakes in months 4-9 of pregnancy, months 2-4 of lactation and 3 and 6 months post-lactation are presented and are compared with the UK and the US recommended daily allowances (RDA). 2. The quality of the diets (nutrients per 4184 kJ (1000 kcal] was found to be better than that of other adult female populations studied in the UK, except for a group of dietitians. 3. The mean daily intakes of nutrients for which there are UK RDA were almost all greater than 100% of the RDA. The exceptions were iron, which in the manual group (social classes IIIM, IV and V) was 85% of the RDA in pregnancy and 75% post-lactation, and vitamin D. 4. Among the nutrients for which there are US, but not UK RDA, only phosphorus and vitamin B12 intakes were greater than 100% of the RDA in both groups at all stages of the study. Intakes of other nutrients were below the RDA: pantothenate 70-91, vitamin B6, zinc, vitamin E and copper 40-72, folate 21-44, and biotin less than 20% of the RDA. 5. The bases of the RDA for adult women were examined; for most nutrients the information is limited. It was concluded that the RDA for magnesium, vitamin E and pantothenate are probably higher than necessary and that deficiency is unlikely; that zinc, copper, vitamin B6 and folate are probably 'marginal' nutrients for 'at risk' groups; and that information on biotin is insufficient even roughly to assess the dietary requirement.     

学龄前儿童缺铁性贫血的研究——Ⅰ.北京市学龄前儿童缺铁性贫血的调查研究

我们用光电比色法和微量毛细玻璃管法,测定了血红蛋白含量,红细胞数和血球压积等,了解北京市城区托幼机构、散居和郊区(半山区)的学龄前儿童缺铁性贫血发病情况,发现郊区儿童缺铁性贫血患病率明显高于市区托幼机构及散居的儿童。从各年龄组来看,7个月至2岁患病率最高。市区二个托儿所三天称重法膳食调查结果,儿童铁的摄取量平均为8.6mg,达不到供给量标准,而一幼儿园用记帐法膳食调查表明,这些儿童铁的平均摄取量超过供给量标准,达12.8mg,其贫血发病率显著下降。因此,北京市学龄前儿童尤其婴幼儿贫血的发生,膳食中铁供给不足可能是主要原因。     

Interactions among dietary fat, mineral status, and performance of endurance athletes: a case study

In a pilot study, performance measures and mineral metabolism were assessed in 3 male endurance cyclists who consumed isoenergetic, isonitrogenous diets for 28-day periods in a randomized, crossover design in which dietary carbohydrate, polyunsaturated, or saturated fat contributed about 50% of daily energy intake. Peak aerobic capacity [62 ml/(kg á min)] was unaffected by diet. Endurance capacity at 70-75% peak aerobic capacity decreased with the polyunsaturated fat diet. Copper retention tended to be positive only with saturated fat. Less iron and zinc were retained (intake - losses), and fecal losses of these minerals increased with the polyunsaturated fat. Blood biochemical measures of trace element nutritional status were unaffected by diet, except serum ferritin, which tended to decrease during consumption of the polyunsaturated fat diet. These preliminary results suggest that diets high in polyunsaturated fat, particularly linoleic acid, impair absorption and utilization of iron and zinc, and possibly magnesium, and may reduce endurance performance.     

Changes in vitamin and mineral intakes and serum concentrations among free-living men on cholesterol-lowering diets: the Dietary Alternatives Study

Nutritional adequacy of diets with 18-30% of calories from fat was investigated in men with elevated serum cholesterol (n = 396) at the end of diet classes and 1 and 2 y later. On 4-d food records, intakes of vitamin A, beta-carotene, folate, vitamin C, magnesium, vitamin B-6, iron, thiamin, and riboflavin increased from baseline whereas niacin, selenium, vitamin E, and zinc decreased. Median zinc intake, 80% of the recommended dietary allowance (RDA) at baseline, decreased to approximately 75% of the RDA, most markedly when intakes of meat, fish, and poultry were limited to 85 g/d. Nutrient densities generally increased. Of the serum nutrients measured, median beta-carotene and vitamin C increased, whereas vitamin B-6, iron, and zinc were unchanged. Below-normal values were fewer for vitamin C and magnesium. Diets similar to the National Cholesterol Education Program Step-Two Diet [less than 7% saturated fatty acids, less than 200 mg cholesterol/d] appeared to provide increased levels of most micronutrients both short and long term to men receiving comprehensive dietary counseling.     

Mineral content of foods and total diets: the Selected Minerals in Foods Survey, 1982 to 1984

The 234 foods of the FDA's Total Diet Study were collected four times per year form mid-1982 to mid-1984 and analyzed for 11 essential minerals. Daily intakes of the minerals were estimated for eight age-sex groups of the U.S. population. Levels of calcium, magnesium, iron, zinc, copper, and manganese were low (less than 80% of the RDA or below the low end of the Estimated Safe and Adequate Daily Dietary Intake range) for some or all age-sex groups. Those most at risk of low intakes were young children, teenage girls, adult women, and older women. Non-discretionary sodium intake exceeded the upper Estimated Safe and Adequate Daily Dietary Intake range for two age-sex groups, and iodine was considerably above the RDA for all age-sex groups. Levels of potassium, phosphorus, and selenium were adequate for all groups.     

Zinc, gravida, infection, and iron, but not vitamin B-12 or folate status, predict hemoglobin during pregnancy in Southern Ethiopia

The etiology of anemia during pregnancy in rural Southern Ethiopia is uncertain. Intakes of animal-source foods are low and infections and bacterial overgrowth probably coexist. We therefore measured the dietary intakes of a convenience sample of Sidama women in late pregnancy who consumed either maize (n = 68) or fermented enset (Enset ventricosum) (n = 31) as their major energy source. Blood samples were analyzed for a complete blood count, vitamin B-12 and folate status, plasma ferritin, retinol, zinc, albumin, and C-reactive protein (CRP). The role of infection and gravida was also examined. Dietary intakes were calculated from 1-d weighed records. No cellular animal products were consumed. Of the women, 29% had anemia, 13% had iron deficiency anemia, 33% had depleted iron stores, and 74 and 27% had low plasma zinc and retinol, respectively. Only 2% had low plasma folate (< 6.8 nmol/L) and 23% had low plasma vitamin B-12 (< 150 pmol/L), even though 62% had elevated plasma methylmalonic acid (MMA) (> 271 nmol/L). None had elevated plasma cystathionine or total homocysteine (tHcys). Women with enset-based diets had higher (P = 0.052) plasma vitamin B-12 concentration and lower (P < 0.05) cell volume, plasma cystathionine, and retinol than women consuming maize-based diets, but mean hemoglobin, plasma ferritin, MMA, tHcys, and folate did not differ. Plasma zinc, followed by CRP (< or = 5 mg/L), gravida (< or = 4), and plasma ferritin (> or = 12 microg/L) status were major positive predictors of hemoglobin. Despite some early functional vitamin B-12 deficiency, there was no macrocytic anemia. Consumption of fermented enset may have increased vitamin B-12 levels in diet and plasma.     

Estimated intake and food sources of vitamin A, folate, vitamin C, vitamin E, calcium, iron, and zinc for Guamanian children aged 9 to 12

This study describes the nutrient intake and food sources of select vitamins and minerals for children on Guam. Food records (n = 954) from public school students aged nine to twelve of all regions on Guam were analyzed for nutrient content and compared to Recommended Dietary Allowances (RDA). Individual foods were condensed into 194 food aggregates and food lists representing 84% to 91% of the major vitamins and minerals in the diet of the children were developed by frequency analysis. Median intake of calcium, vitamin E, folate were less than 50% of the Recommended Dietary Allowance (RDA) and mean intake of these nutrients was 60% RDA or less. Mean and median vitamin A intake was 107% and 76% RDA, respectively. Both mean and median intake of Vitamin C, iron and zinc were present at levels above 100% RDA. Rice, meat, fruit drink from powder, milk, and fortified cereals are foods that provide substantial contributions to the vitamin and mineral content of the diets. Traditional, nutrient dense foods, such as fish, yams, papaya, and mango had minor contributions because of low frequently of consumption. Information from this study can be used to develop specific diet assessment instruments and culturally appropriate nutrition education.