Low Vit Research Articles

DO LOW VITAMIN A LEVELS IN CHILDREN WITH CANCER INCREASE SUSCEPTIBILITY TO INFECTIONS AND INFLUENCE OUTCOME OF TREATMENT? 157

Introduction: Decreased vitamin A (Vit A) intake and low serum levels of retinal binding protein (RBP) have been associated with an increased incidence of some cancers and a shorter time before the recurrence of breast tumours respectively. Children in developing countries often have low Vit A serum levels and this has been associated with increased morbidity and susceptibility to respiratory and gastrointestinal infections.

Marginal vitamin A intake during pregnancy in Guinea pigs: effect on immune parameters in neonate

Chronic low vitamin A (vit A) intake by women of reproductive age can result in poor vit A status during pregnancy and may reduce transfer of vit A to the fetus. If vit A is required for the development of fetal immune mechanisms, immune function in the newborn could be impaired. To investigate this, female guinea pigs were fed a vit A-deficient diet for 1 mo before breeding. From the end of the depletion period until day 30 (d30) of pregnancy they were dosed orally once a week with 175 retinol equivalents (RE) vit A. From d30 until delivery (d68±2) they were dosed either at the same (175A) or a higher level, 700 (700A) or 1750 (1750A) RE/wk. After delivery neonatal lymphocytes from blood (whole blood cultures) and spleen (mononuclear cells) were tested for proliferative response by measuring incorporation of 3H-thymidine after stimulation with phytohemagglutinin (PHA). Responsiveness of splenic lymphocytes was not affected by treatment. However, blood lymphocytes from 175A neonates were more responsive than those from 1750A. Blood lymphocytes from 700A neonates did not differ from either the 175A or 1750A. Blood lymphocytes from female 175A neonates were less responsive to PHA than were those from males. Maternal liver vit A concentration increased with increasing dosage of vit A. Neonatal livers of 1750A contained significantly more vit A than the other two groups, which were close to the detection limit and did not differ. Although proliferation of splenic lymphocytes was not affected, the increased responsiveness of whole blood lymphocytes indicates that the immune system was affected by the low vit A intake of the dam.

682 PROSPECTIVE HIGH VS LOW CALCIUM AND PHOSPHORUS WITH FIXED LOW VITAMIN D CONTENT IN PARENTERAL NUTRITION (PN) IN INFANCY

Vit D 50 to 1000 IU/d in PN has been suggested for infants but prospective studies are lacking. Effects of high or low Ca and P on Ca metabolism have not been examined. We hypothesized that high Ca and P with low vit D in PN results in normal Ca, P and vit D metabolism in infants. 12 wt appropriate for gestation infants (3M,9F; 11W,1B); 32-41 wks; 1780-3630g at birth with surgical indications for PN received fixed ‘low’ 25 IU vit D2/dl and were randomized to either high Ca 60mg and P 46.5mg/dl, or low Ca 20mg and P 15.5mg/dl content. Measures were made at start, 10d, 3wks and 6wks. There were no differences in serum Ca, Mg, P, alkaline phosphatase, parathyroid hormone, calcitonin, and values were normal. Mean serum 25 hydroxyvit D (25OHD, protein binding) was 16-39 for high and 15-31ng/ml for low Ca,P grp. Mean serum 1,25 dihydroxyvitamin D (1,25(OH)2D, HPLC--binding) and tubular reabsorption P (TRP) in high Ca,P grp were stable 72-47pg/ml, and, 88-80% resp; values in low Ca,P grp were higher 78-127pg/ml and 75-99% (p<0.05 covariance, high v low). Urine Ca and Mg/Creatinine were not different between grps. 5 infants on PN for 71-175d with same vit and low Ca,P had normal 250HD with high TRP and 1,25(OH)2D. Thus, PN with 1) low 25IU vit D/dl maintains normal serum 25OHD for up to 6mos 2) high Ca,P similar to that absorbed from human milk results in stable serum 1,25(OH)2D and TRP. We speculate that low Ca, P intake results in adaptive increase in 1,25(OH)2D and TRP reflecting insufficient Ca and P intake; and high Ca and P my benefit bone mineralization in long term PN.

ULTRAVIOLET EXPOSURE AND 250H VITAMIN D IN BREAST-FED INFANTS IN BEIJING, CHINA

A high incidence of rickets among infants in the Peoples Republic of China has been reported, etiology unclear. The vit. D status of infants in China has not been investigated. The specific effect of sunshine (UV) exposure on D status in any infant is unstudied. We hypothesized that breast-fed infants in China have low vit. D status and UV exposure increases serum 25OH vit. D into the normal range. 54 breast-fed term infants 1 to 8 mos. without D supplements were randomly assigned into 2 grps. in a 2 mo. study, Sept. and Oct. (mos. of high UV exposure): controls with usual sun exposure; and experimental with 2 hr. sun/d. Infants received only human milk, rice soup, fruit juice and mashed vegetables and exposed mostly face and forearms. A 20 nurse team monitored UV exposure with diaries and a unique infant UV dosimeter. Only 100 μl blood samples were permissible in infants. Serum 25OHD was measured by protein binding assay after chromatography. (N 11 to 68 ng/ml). Mean maternal 25OHD was 22 ng/ml. Infant 25OHD correlated with mother's (r=0.48). Infant 25OHD ranged 3 to 61 ng/ml at entry with 20% <11 ng/ml. Mean ± SE 25OHD did not change for controls (21 ± 3 vs 18 ± 3 ng/ml, pre- vs. post- 2 mo.sun exposure 83 min./d) but increased significantly for experimental (28 ± 4 vs 40 ± 5 ng/ml, p<0.01, sun 144 min./d). Thus, infant 25OHD correlated with maternal 25OHD; although infants in Beijing may receive moderate sun exposure in fall, 20% of 25OHD are low and additional sun exposure for 2 mos. increases serum 25OHD towards normal.

Selenium and Vitamin E Deficiency in Pigs

The effect of dietary selenium (Se) and vitamin E (Vit. E) in pigs on Se and Vit. E in plasma and on Se in tissue from liver, heart, m. long, dorsi and m. psoas major was studied; and furthermore was the influence on the enzymes ASAT and ALAT studied. Two levels of Se were used, 0.03 and 0.06 mg Se per kg feed. Within each Se level 2 levels of Vit. E were used, 15 and 45 i. u. per kg feed. This resulted in 4 groups: 1. low Se and low Vit. E; 2. low Se and high Vit. E; 3. high Se and low Vit. E; 4. high Se and high Vit. E. Ten% of all pigs fed low Se, and 4% of the pigs fed low Se and high Vit. E diet died with severe symptoms of Se deficiency. None of the pigs fed the high Se diet died with such symptoms. Plasma Se determinations have been shown to indicate the Se status in pigs almost as accurately as liver Se determination. ASAT and ALAT enzyme determinations were not of any diagnostic value. There was a good agreement between dietary Vit. E level and the corresponding levels in plasma. Oxidized herring oil seems to enhance the Vit. E need.

Chlorotetracycline and Growth Promoting Effect of Beta Carotene and Vitamin A in Rats.

SummaryAddition of chlorotetracycline to a Vit. A-deficient diet was found to stimulate additional growth in Vit. A-deficient rats that received restricted intakes of beta carotene or Vit. A. Extent of additional growth depended on amount of the antibiotic incorporated in the basal diet and amount of the supplementary vitamin fed. Under the conditions of the experiments reported a diet that contained 1 g/kg of chlorotetracycline exerted the greatest growth-stimulating effect in rats that subsisted on a minimum maintenance intake of Vit. A or beta caratene. This increase in growth ranged from 200ioJo in the low Vit. A-intake animals to essentially no increase in growth rate of animals that received the higher doses of the vitamin. Food requirement per unit of weight increase was lower in the rats that received the chlorotetracycline-containing diets. Rats restricted to equal food intakes made greater gains in weight when the diet contained the antibiotic.

Effect of carbon tetrachloride injury on plasma and liver vitamin B12 levels.

Summary(1) Administration of carbon tetrachloride increased the serum level of vit. B12 of rats fed a casein diet. No similar increase was observed in rats previously offered a low vit. B12 diet. (2) Administration of carbon tetrachloride likewise increased the urinary excretion of parenterally administered vit. B12 or of absorbed vit. B12 following oral administration. (3) Physiological significances of these findings are discussed.

Metabolic interrelationship between folic acid, vitamin B12, and the citrovorum factor.

SummarySupplementing a low vit. B12-PGA chick diet with either increasing levels of vit. B12 (30 γ and 500 γ/kg) or increasing levels of PGA (2, 100, and 400 mg/kg) resulted in an increased capacity by the liver homogenates to convert added PGA to CF. The results further suggest that the 2 vitamins may influence the converting enzyme system through different mechanisms. In vitro addition of formate and vit. B12 to the liver homo-genate gave only a slight stimulation of PGA to CF conversion by the liver homogenate.