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Abstracts

Abstracts

Cholesterol & Zinc

Cholesterol

Reduced zinc intake has been reported when cholesterol-lowering diets are adopted. Examined whether such diets compromise the zinc status of men with hypercholesterolemia.

For all subjects combined, mean fat and cholesterol intakes approached or met the guidelines of the National Cholesterol Education Program step 2 diet, with approximately 30 g fiber per day. Density (mg/1,000 kcal) of zinc intake was unchanged from the baseline value. Found a slightly positive relationship between fiber and zinc intakes; no relationship between fiber intake and plasma zinc level; no effect of supplement use (category included all types of supplements), alcohol use, or level of exercise on plasma zinc levels; and no difference by dietary assignment in zinc intake or plasma zinc levels.

Zinc status does not appear to be at risk in adult men who adopt cholesterol-lowering diets. These results may not be generalized to higher-risk population groups or situations in which dietary counseling is less comprehensive.

Zinc intake and plasma zinc level are maintained in men consuming cholesterol-lowering diets. Retzlaff-BM; Walden-CE; McNeney-WB; Dowdy-AA; Knopp-RH. J-Am-Diet-Assoc. 1995 Nov; 95(11): 1274-9.


Recent studies in animals and in vitro support the hypothesis that zinc, an essential micronutrient, possesses antioxidant properties. To determine whether zinc provides antioxidant protection in humans by decreasing low-density lipoprotein (LDL) oxidizability and the effect of zinc

No changes in the oxidizability of LDL or the plasma concentrations of total cholesterol, high-density lipoprotein (HDL) cholesterol and its subfractions, LDL cholesterol, or triacylglycerol were observed following zinc supplementation compared to placebo.

Plasma zinc concentrations were increased significantly, indicating that the lack of effect was not due to poor compliance. The antioxidant effect of zinc in relation to LDL was not demonstrated in humans at this dose, and higher doses are unlikely to be effective given the adverse interaction with copper metabolism and the potential decrease in the activity of superoxide dismutase, a free radical quenching enzyme.

Zinc provides little, if any, antioxidant protection against LDL oxidation in humans.

The effect of zinc supplementation on plasma lipids and low-density lipoprotein oxidation in males. Gatto-LM; Samman-S. Free-Radic-Biol-Med. 1995 Oct; 19(4): 517-21.

Copper therapy

Copper therapy

We review two newer treatments for Wilson's disease that each use an interaction of another metal with Cu to bring about therapeutic benefit. The two metals are Zn, in the form of the acetate salt, and Mo in the form of ammonium tetrathiomolybdate (TM). Zn, which blocks absorption of Cu in the intestine by inducing intestinal cell metallothionein, is used for maintenance therapy, treatment of the presymptomatic patient from the beginning, and treatment of the pregnant patient. TM, which complexes Cu in a tripartite complex with protein, is used for the initial treatment of neurologically presenting patients.

Interactions of zinc and molybdenum with copper in therapy of Wilson's disease. Brewer-GJ. Nutrition. 1995 Jan-Feb; 11(1 Suppl): 114-6.

Brewer-GJ: Interactions of zinc and molybdenum with copper in therapy of Wilson's disease. Nutrition. 1995 Jan-Feb; 11(1 Suppl): 114-6.

Endothelial function

Endothelial function

Zinc (Zn), an essential trace element, has antioxidant functions, stabilizes membranes and plays a role in the activity of a host of Zn metalloenzymes. Zn deficiency has been shown to increase erythrocyte fragility, decrease the Zn content of the erythrocyte membrane, and alter erythrocyte membrane fluidity.

Zn deficiency induced by various mechanisms disrupts endothelial barrier cell function in vitro and this was corrected with Zn supplementation.

Important implications for acute vascular processes, e.g., adult respiratory distress syndrome, and chronic vascular processes, e.g., atherosclerosis.

Zinc and endothelial function. McClain-C; Morris-P; Hennig-B. Nutrition. 1995 Jan-Feb; 11(1 Suppl): 117-20.

Growth & Zinc

Growth

We investigated the effects of zinc supplementation in case of moderate growth retardation in which GH treatment could not be used.

Suggest that zinc needs are increased in those children in this period of life.

Effects of zamic as a means for zinc supplementation in growing children. Fons-C; Brun-JF; Fedou-C; Fussellier-M; Bardet-L; Orsetti-A. Biol-Trace-Elem-Res. 1995 Apr; 48(1): 31-6.

Herpes labialis

Herpes labialis

Zinc sulfate as gel (Virudermin Gel) proved to be significantly more effective than the gel alone.

Symptoms were less marked and healing was faster. Due to the antiseptic properties of zinc sulfate superinfections can be prevented.

[Clinical double-blind trial of topical zinc sulfate for herpes labialis recidivans]. Kneist-W; Hempel-B; Borelli-S. Arzneimittelforschung. 1995 May; 45(5): 624-6.


The massive widespread use of a substance to treat HSV could lead to the spread of resistant HSV strains and hence to a failure of treatment in a vital indication. HSV treatments available over the counter (in Germany) are: Zinc sulfate, heparin and acyclovir.

Experiments show that heparin retains its activity even after 20 passages whereas acyclovir produces a completely resistant virus after only a single passage.

A combination of zinc sulfate and heparin would appear superior to zinc sulfate alone. The use of the genotoxic DNA polymerase inhibitor acyclovir should be restricted to severe cases.

[Zinc sulfate and heparin for local therapy of herpes. Antiherpetic drugs, not leading to selection of HSV variants] Kumel-G; Turley-H; Brendel-M. Fortschr-Med. 1995 May 30; 113(15): 235-8.

Immune function & Zinc

Immune function

Zinc and immune function relationship has been extensively studied. Both in experimentally induced mineral deficit and in genetically determined deficit observable in acrodermatitis enteropathica and in enteropathy of Danish A-46 cattle, a B and T dependent antibody response decrease, a T dependent cytolytic response decrease and a natural killer cytotoxic activity decrease are present noteviously. Serious reduction of the immune function is present, in proportion to the value of low zinc plasmatic level, in elderly patients, in malnourished and seriously zinc deficient children, in patients subjected to total parenteral supply, in HIV infections and especially in evident AIDS: in this condition the plasmatic zinc level can be considered, together with the CD4+ lymphocytes amount and the B2-microglobulin value, a disease progression marker. Zinc immunostimulating action mechanisms are complex, although thymic hormone (of which zinc is essential cofactor) stimulation seems to be most important. Zinc supplementation, also parenterally, can be useful in immunodeficiency (in the elderly, in the post-surgical patients, in genetically determined or alimentary induced deficit, in AIDS.

Zinc and immune function. Ripa-S; Ripa-R. Minerva-Med. 1995 Jul-Aug; 86(7-8): 315-8.

Infants & Zinc

Infants

Ten trace elements that are nutritionally essential include: zinc, copper, selenium, chromium, manganese, molybdenum, cobalt, fluoride, iodine, and iron. This article briefly reviews the biochemistry of these trace elements, describes clinical deficiency states, and provides a rationale for recommended enteral and parenteral intakes for preterm infants.

Trace elements in nutrition for premature infants. Zlotkin-SH; Atkinson-S; Lockitch-G. Clin-Perinatol. 1995 Mar; 22(1): 223-40.

Athletes & Zinc

Athletes

Mineral elements, including magnesium, zinc, and copper, are required for health maintenance. For athletes, adequate amounts of these minerals are required for physical training and performance.

Studies of athletes during training indicate the potential for increased losses of minerals in sweat and urine. Some studies report suboptimal intakes of minerals, particularly among athletes who are actively attempting to lose weight to meet standards for competition. However, most athletes consume diets that provide adequate amounts of minerals to meet population standards. Athletes should be counseled to consume foods with high nutrient density rather than to rely on mineral supplements. General use of mineral supplements can alter physiological function and impair health.

Micronutrients (magnesium, zinc, and copper): are mineral supplements needed for athletes? Lukaski-HC. Int-J-Sport-Nutr. 1995 Jun; 5 Suppl: S74-83.

Lactation & Zinc

Lactation

During lactation there is an increased maternal loss of essential trace element zinc that is secreted into milk. During the first six months of lactation a mean of approximately 1.1 mg d-1 of zinc is secreted into human milk, which decreases to 0.6 mg d-1 during the next six months of lactation.

The increased maternal need for zinc must be met through an increased dietary intake or homeostatic mechanisms which could compensate for the secretion of zinc into milk. These homeostatic mechanisms may include an increase in absorption, reduced excretion (urine and faecal endogenous losses) and the use of maternal pools of zinc, such as bone.

During lactation, homeostatic mechanisms partially compensate and need to be considered when dietary recommendations for zinc intake are made for lactating women.

Zinc needs and homeostasis during lactation. Moser-Veillon-PB. Analyst. 1995 Mar; 120(3): 895-7.

Overview

Overview

Zn deficiency in humans is widespread throughout the world. It is more prevalent in areas where the population subsists on cereal proteins. Conditioned Zn deficiency is seen in many disease states. Its deficiency during growth periods results in growth failure and lack of gonadal development in males. Other effects of Zn deficiency include skin changes, poor appetite, mental lethargy, delayed wound healing, neurosensory disorders, and cell-mediated immune disorders.

A clinical diagnosis of marginal Zn deficiency in humans remains problematic.

Zinc: an overview. Prasad-AS. Nutrition. 1995 Jan-Feb; 11(1 Suppl): 93-9.

Pregnancy & Zinc

Pregnancy

To evaluate whether zinc supplementation during pregnancy is associated with an increase in birth weight.

In all women, infants in the zinc supplement group had a significantly greater birth weight (126 g, P = .03) and head circumference (0.4 cm, P = .02) than infants in the placebo group.

Daily zinc supplementation in women with relatively low plasma zinc concentrations in early pregnancy is associated with greater infant birth weights and head circumferences, with the effect occurring predominantly in women with a body mass index less than 26 kg/m2.

The effect of zinc supplementation of pregnancy outcome. Goldenberg-RL; Tamura-T; Neggers-Y; Copper-RL; Johnston-KE; DuBard-MB; Hauth-JC. JAMA. 1995 Aug 9; 274(6): 463-8.

Preschoolers

Preschoolers

To assess vitamin and mineral intakes of Anglo-American and Mexican-American preschoolers.

Boys and Anglo-Americans had higher total nutrient intakes than girls and Mexican-Americans, respectively. Mexican-Americans had higher nutrient intakes per energy intake, which indicates a micronutrient-dense diet. When each nutrient was considered by the two thirds of the RDA criterion (66% of the RDA means adequate intake), the nutrients most likely to be inadequate were iron, zinc, vitamin D, vitamin C, and niacin. Mexican-American girls had significantly lower calcium intakes than the other gender and ethnic groups.

Parents and day care providers must ensure that preschoolers, especially girls and Mexican-Americans, eat nutrient-rich foods in adequate quantities that will achieve the recommended intakes.

Zive-MM et al: Vitamin and mineral intakes of Anglo-American and Mexican-American preschoolers [published erratum appears in J Am Diet Assoc 1995 May;95(5):533] J-Am-Diet-Assoc. 1995 Mar; 95(3): 329-35.

Recommended Dietary Allowances

Recommended Dietary Allowances

Forty-three menus that were to be used in a diet manual were designed to meet the requirements of a specific diet; provide 2,200 to 2,400 kcal, unless energy-restricted; meet the 1990 Dietary Guidelines for Americans; meet current recommendations for sodium (2g to 3 g/day), cholesterol (< or = 300 mg/day), and fiber (20g to 30 g/day); and meet or exceed the highest level for adults in the 1989 Recommended Dietary Allowances (RDAs). In addition, regular and low-fat, low-cholesterol menus for 1 week were collected from 11 hospitals throughout Arkansas. Menus were analyzed for energy, cholesterol, and 18 nutrients.

Only 11% of the menus met the RDA for zinc. Half of the menus did not meet the RDA for vitamin B-6 and one third did not meet the RDA for iron.

Regular and low-fat, low-cholesterol hospital menus had the same nutrient inadequacies because they did not differ in total servings from any food group. These data indicate that the public may have difficulty choosing a diet that meets both the Dietary Guidelines and the RDAs.

Problems encountered in meeting the Recommended Dietary Allowances for menus designed according to the Dietary Guidelines for Americans. Dollahite-J; Franklin-D; McNew-R. J-Am-Diet-Assoc. 1995 Mar; 95(3): 341-4, 347; quiz 345-6.

Requirements and toxicity

Requirements and toxicity

Early signs of toxicity of essential trace elements are important. Some trace elements are available over-the-counter (OTC) and/or are present at industrial waste sites. Physicochemically similar trace elements compete for ligands, impairing functions, which is exemplified by the zinc-copper antagonism described long ago by Van Campen, Hill and Matrone, and Klevay. Intestinal absorption of copper is inhibited by zinc. Thus risk of copper deficiency is increased when the molar ratio of zinc to copper (Zn:Cu) is high.

Manifestations of copper deficiency include decreased erythrocyte copper-zinc superoxide dismutase, increased low-density-lipoprotein cholesterol, decreased high-density-lipoprotein cholesterol, decreased glucose clearance, decreased methionine and leucine enkephalins, and abnormal cardiac function.

Calculation of a preliminary reference dose for OTC zinc that assumed high bioavailability and uncertain copper intakes established 9 mg as a safe amount for 60-kg adults.

Requirements and toxicity of essential trace elements, illustrated by zinc and copper. Sandstead-HH. Am-J-Clin-Nutr. 1995 Mar; 61(3 Suppl): 621S-624S.


In order to establish an adequate and safe dietary intake of zinc, several specific features of zinc metabolism have to be considered.

To translate physiological requirements to dietary requirement the availability of zinc has to be considered. From diets with a high content of phytate, less than 15% is typically absorbed while in refined animal protein based diets up to 40% is adsorbed. This means that that dietary requirement can very from < 5- > 15 mg d-1.

Zinc shows a low toxicity, but high doses of zinc interact with other trace elements, especially copper. (These interactions have already been observed at an intake of 50 mg.) Thus, the range between essential and potential deleterious intake of zinc is rather narrow.

Consideration in estimates of requirements and critical intake of zinc. Adaption, availability and interactions. Sandstrom-B. Analyst. 1995 Mar; 120(3): 913-5.

Smoking & Zinc

Smoking

Investigate the relationship between smoking and antioxidant nutrient intake and status.

Only the difference in Zn intake was statistically significant. There was no significant difference between smokers and non-smokers for either serum vitamin A (retinol) or vitamin E (alpha-tocopherol) level. The plasma vitamin C level of smokers was significantly lower than that of non-smokers. Smokers had significantly lower serum Cu (P = 0.04) and higher serum Zn levels (P = 0.003).

Smoking may cause an imbalance in antioxidant nutrient intake and status.

Relationship between smoking and antioxidant nutrient status. Faruque-MO; Khan-MR; Rahman-MM; Ahmed-F. Br-J-Nutr. 1995 Apr; 73(4): 625-32.

Status & Zinc

Status

Evaluated changes in zinc status in response to folic acid supplementation and the effect of zinc intake on folate utilization.

No differences in plasma zinc, erythrocyte zinc, urinary zinc, erythrocyte metallothionein or serum alkaline phosphatase, due to supplemental folic acid, were detected. Differences in the response to folic acid supplementation, due to the level of zinc intake, were not detected for serum, erythrocyte or urinary (labeled and unlabeled) folate.

Folic acid utilization was not influenced by level of zinc intake.

Zinc status is not adversely affected by folic acid supplementation and zinc intake does not impair folate utilization in human subjects. Kauwell-GP; Bailey-LB; Gregory-JF-3rd; Bowling-DW; Cousins-RJ. J-Nutr. 1995 Jan; 125(1): 66-72.

Uremia & Zinc

Uremia

Patients with chronic renal failure often have low plasma zinc (Zn) levels due to: low dietary Zn intake, a specific Zn transport defect, or absence of intestinal Zn ligand.

Zn supplementation and a Zn-chelating drug, diiodohydroxyquinolein (DQ), were used to assess these effects.
DQ, when given along with Zn sulfate supplements, causes a greater increase in plasma Zn levels than that caused by either drug given alone.

Effects of oral administration of zinc and diiodohydroxyquinolein on plasma zinc levels of uremic patients. Paniagua-R; Claure-R; Amato-D; Flores-E; Perez-A; Exaire-E. Nephron. 1995; 69(2): 147-50.

Weaning & Zinc

Weaning

Assessed the effect of fortification iron (reduced iron) on zinc absorption from a commercial vegetable-based weaning foo.

Values were not significantly different, thus iron fortification of the weaning food did not reduce zinc absorption.

Zinc absorption in infants fed iron-fortified weaning food. Fairweather-Tait-SJ; Wharf-SG; Fox-TE. Am-J-Clin-Nutr. 1995 Oct; 62(4): 785-9.

Respiratory Infection

Respiratory infection

Zinc supplements may treat respiratory infection as well as zinc deficiency. In a study, Indian infants and toddlers with zinc deficiency were administered either zinc or placebo. Among the zinc group, the deficiency dropped to 12%. Also, children taking zinc had 45% less respiratory infections.

Pediatrics 1998; 102:1-5

Common Cold

Common cold

Zinc lozenges may not be beneficial in treating the common cold among children and/or teenagers. In a trial based in Ohio, either zinc lozenges or placebo were administered to young participants with 24 hours of cold symptom onset. No significant changes were reported in either group. However, those taking zinc lozenges experienced bad taste, nausea, and throat irritation.

Macknin ML, Piedmonte M, Calendine C, Janosky J, Wald E: Zinc gluconate lozenges for treating the common cold in children: a randomized controlled trial, JAMA 1998 Jun 24;279(24):1962-7

Enhanced Performance and Growth

Enhanced performance and growth

In a clinical trial in China, young children from low-income families were treated with zinc, with or without micronutrients. Children taking zinc with micronutrients experienced better neuropsychologic performance and growth.

Allen LH: Zinc and micronutrient supplements for children, Am J Clin Nutr 1998 Aug;68(2 Suppl):495S-498S

Behavioral Changes

Behavioral changes

In this study, low birth-weight Brazilian infants were administered different concentrations of zinc supplements or placebo. No significant changes in mental or psychomotor development were reported. However, infants treated with 5 mg/day of zinc exhibited significant positive behavioral changes.

Ashworth A, Morris SS, Lira PI, Grantham-McGregor SM: Zinc supplementation, mental development and behaviour in low birth weight term infants in northeast Brazil, Eur J Clin Nutr 1998 Mar;52(3):223-7

Low Birth-Weight

Low birth-weight

Zinc supplementation with different doses may cause weight gain and may decrease incidences of diarrhea among infants. In a Brazilian trial, 28% decrease in diarrhea and significant weight changes in the fifth and sixth month were reported. Zinc supplement may be treated for low birth-weight.

Am J Clin Nutr 1998; 68:418S-424S

Stunted Growth

Stunted growth

Zinc supplements may not aid in increasing the height of stunted-growth infants, according to this study conduced on 6 to 9 month old Guatemalan infants. While the infants on zinc had increased the area of midarm muscle, no significant increase in length was noted.

Rivera JA, Ruel MT, Santizo MC, Lonnerdal B, Brown KH: Zinc supplementation improves the growth of stunted rural Guatemalan infants, J Nutr 1998 Mar;128(3):556-62

Skin Rash

Skin rash

Zinc supplementation may reduce incidences of skin rash and lower the hospitalization rate among children, according to this study conducted on infants. However, zinc supplementation may not increase length, height or head circumference among children. Unfortunately, children taking zinc had greater episodes of vomiting.

Meeks Gardner J, Witter MM, Ramdath DD: Zinc supplementation: effects on the growth and morbidity of undernourished Jamaican children, Eur J Clin Nutr 1998 Jan;52(1):34-9

Mortality & Zinc

Mortality

High doses of zinc may be associated with a greater mortality among young children. In this study based in Bangladesh, infants and toddlers having protein malnutrition were given zinc either at lower or higher doses. As a result, higher doses may increase mortality rate among these children. Zinc may only be used at low doses in order to treat infants' protein malnutrition.

Doherty CP, Sarkar MA, Shakur MS, Ling SC, Elton RA, Cutting WA: Zinc and rehabilitation from severe protein-energy malnutrition: higher-dose regimens are associated with increased mortality, Am J Clin Nutr 1998 Sep;68(3):742-8

Diarrhea

Diarrhea

Zinc supplementation may reduce the incidence of diarrhea. In a clinical study in Peru, children took either zinc supplement with or without additional vitamins or placebo. Overall, the results indicated that the incidence diarrhea over a few days dropped by 28% for those taking zinc only, and 33% for those taking zinc plus micro-nutrients. However, zinc supplements may only be effective among children with zinc deficiency.

Penny ME, et al.: Randomized, community-based trial of the effect of zinc supplementation, with and without other micronutrients, on the duration of persistent childhood diarrhea in Lima, Peru.
J Pediatr. 1999 Aug;135(2 Pt 1):208-17.

Low Birth Weight Infants

Low birth weight infants

Zinc supplements given to underweight infants may reduce their chance of succumbing to infectious disease, according to this randomized, double-blind, controlled study. Over 1100 full-term infants who were smaller than normal for their gestational age were given one of the following combinations (5 mL/day) from the time they were 30 to 284 days old: riboflavin; riboflavin and zinc; riboflavin, calcium, phosphorus, folate and iron; or riboflavin, zinc, calcium, phosphorus, folate, and iron. Zinc supplementation significantly reduced the number of infant mortalities due to infectious disease, while calcium, phosphorus, folate, and iron supplementation did not.
        
Sazawal S, Black RE, Menon VP, Dinghra P, Caulfield LE, Dhingra U, Bagati A: Zinc supplementation in infants born small for gestational age reduces mortality: a prospective, randomized, controlled trial, Pediatrics 2001 Dec;108(6):1280-6

Sickle Cell Disease & Zinc

Sickle cell disease

Young children with sickle cell disease may have zinc deficiency and therefore supplementation may improve their growth and body composition, according to this study. Researchers divided forty-two children, aged four to ten, into two groups and administered cherry syrup with elemental zinc to one group and plain cherry syrup to the other. They recorded height measurements, plasma zinc levels, and dietary intakes at the beginning of the study and at three, six, and twelve months. Evaluations of the 38 children who finished the study showed significant height differences between the zinc group and the control group. The children who were given zinc had greater average increases in height, sitting height, knee height, and arm circumference z scores. While the control group had decreases in their height-for-age and weight for age z scores, there were no major changes seen in these measurements for the zinc group.

Zemel BS, Kawchak DA, Fung EB, Ohene-Frempong K, Stallings VA: Effect of zinc supplementation on growth and body composition in children with sickle cell disease, Am J Clin Nutr 2002 Feb;75(2):300-7