International Units Of Vitamin Research Articles

Vitamin D Supplementation Increases Serum Levels of Soluble Receptor for Advanced Glycation End Products Among Women With Polycystic Ovary Syndrome [30

INTRODUCTION: To examine the effect of vitamin D3 supplementation on the changes in serum receptor for advanced glycation end products (sRAGE) and serum anti-Müllerian hormone (AMH) among vitamin D–deficient women with polycystic ovary syndrome (PCOS). METHODS: A total of 136 women with (n=68) or without (age-matched control; n=68) PCOS who were diagnosed with vitamin D deficiency were studied. All participants received supplemental oral vitamin D3 (50,000 international units/wk) for 8 weeks, followed by 1,000 international units vitamin D3 supplementation for 16 weeks. All women provided blood samples for the measurements of sRAGE, AMH, and other analytes at baseline and at the end of supplementation (24 weeks). RESULTS: In all participants, there was a negative correlation between body mass index and serum sRAGE levels (r=−0.46, P=.003). In women with PCOS, but not in those in the control group, vitamin D3 supplementation increased serum sRAGE (P<.001) and decreased serum AMH levels (P<.001). The increases in serum sRAGE were positively correlated with the increases in serum 25-hydroxyvitamin D after vitamin D3 supplementation in women with PCOS (r=0.72, P<.001). CONCLUSION: Vitamin D3 supplementation in women with PCOS showed a protective effect against the inflammatory action of advanced glycation end products by enhancing the circulating sRAGEs. The normalization in serum AMH induced by vitamin D3 therapy indicates a possible improvement in folliculogenesis.

Prevalence of Vitamin D Insufficiency in Adult Hematopoietic Cell Transplant (HCT) Patients with Documented Osteopenia or Osteoporosis after Steroid Exposure: A Quality Assurance Study

Background: Steroid exposure is a known risk factor for osteopenia and osteoporosis. Vitamin D insufficiency is a known factor that contributes to bone loss. Low concentrations of vitamin D are associated with impaired calcium absorption, negative calcium balance and a compensatory rise in parathyroid hormone, which results in excessive bone resorption. Historically at Seattle Cancer Care Alliance, adult allogeneic HCT patients treated with steroids routinely have a Dual Energy X-ray Absorptiometry (DEXA) scan at departure. While many patients were found to have osteopenia or osteoporosis, it was unknown how many of these patients were additionally vitamin D deficient. Objective: The aims of this quality assurance study were: 1) to identify the prevalence of vitamin D insufficiency in adult HCT patients with osteopenia or osteoporosis post-HCT and 2) to evaluate the need to change standard practice guidelines at our center to assess for vitamin D insufficiency more regularly in at-risk groups. Design: We identified all allogeneic HCT patients with postHCT steroid exposure and documented osteopenia or osteoporosis on departure DEXA scan over a six month period. A serum 25-OH vitamin D level was drawn on patients meeting these criteria. Results: 40 adults met inclusion criteria: 22 males and 18 females. All patients were receiving 1500 mg calcium and 800 international units vitamin D3 daily with combination of diet, multivitamin and/or supplements per standard practice guidelines at Seattle Cancer Care Alliance. All patients were counseled by a registered dietitian to ensure adequate calcium and vitamin D intake. 4 patients had deficient 25-OH vitamin D levels (25-OH vitamin D 30 ng/mL). The prevalence of insufficiency or deficiency was 73% (29/ 40). Stratified by age, the prevalence of insufficiency or deficiency was:

The effect of vitamin D supplementation on arterial stiffness in an elderly community–based population

Vitamin D deficiency may lead to impaired vascular function and abnormalities in central arterial stiffness. We compared the effects of two different doses of vitamin D3 on arterial stiffness in an elderly population with deficient serum 25–hydroxy–vitamin D levels. A total of 119 known vitamin D deficient (<50 nmol/L) subjects were randomized to receive either 50,000 international units (IU) or 100,000 IU single intramuscular vitamin D3. In the group that received 100,000 IU vitamin D, median pulse wave velocity decreased from 12.2 m/s (range, 5.1–40.3 m/s) to 11.59 m/s (range, 4.3–14.9 m/s) after 8 weeks (P = .22). A mean decrease of 3.803 ± 1.7 (P = .032) in augmentation index (a measure of systemic stiffness) was noted. Only 3/51 (5.8%) who received 100,000 IU vitamin D reached levels of sufficiency (>75 nmol/L). A significant decrease in augmentation index was seen in the group that received 100,000 IU vitamin D. Serum levels of 25–hydroxy–vitamin D were still deficient at 8 weeks in the majority of patients, which may be attributable to impaired bioavailability.

Safety of Vitamin D Replacement in Patients with Primary Hyperparathyroidism and Concomitant Vitamin D Deficiency

To evaluate the safety of vitamin D replacement in patients with vitamin D deficiency and primary hyperparathyroidism. Retrospective chart review of 35 patients from our endocrine clinic, age 22 to 89 years, diagnosed with primary hyperparathyroidism and vitamin D deficiency, and treated with either 1,000 to 2,000 international units (IU) of vitamin D daily or 50,000 IU of vitamin D weekly for 5 months. Data were collected before and after treatment on serum calcium, 25-hydroxyvitamin D (25-OH D), intact parathyroid hormone (iPTH), phosphorus, alkaline phosphatase, nephrolithiasis, fractures, and osteoporosis. 25-OH D increased significantly, from a baseline of 14.65 ± 6.57 ng/mL to 42.17 ± 12.98 ng/mL after weekly treatment with 50,000 IU of vitamin D (P<.0001), and from 22.42 ± 5.47 ng/mL to 33.33 ± 6.39 ng/mL following daily treatment with 1,000 to 2,000 IU of vitamin D (P<.0001). Pre- and posttreatment unadjusted serum calcium remained stable in the high-dose group (10.80 ± 0.43 mg/dL vs. 10.72 ± 0.67 mg/dL; P = .47), but decreased slightly in the low-dose group (10.76 ± 0.58 mg/dL vs. 10.11 ± 0.54 mg/dL; P = .0007). After adjusting for age, sex, vitamin D, and PTH levels, the small calcium difference in the low-dose group became statistically insignificant. Treatment with either high or low doses of vitamin D did not significantly change iPTH levels. Creatinine remained stable in all patients, and no new cases of nephrolithiasis were reported. Replacing vitamin D in mild primary hyperparathyroidism is safe, effective, and does not increase calcium to dangerous levels.

Effects of egg and vitamin A supplementation on hemoglobin, retinol status and physical growth levels of primary and middle school students in Chongqing, China.

Lack of protein and vitamin A influences the growth of student in impoverished mountain areas. The aim of the study was to assess the effects of egg and vitamin A supplementation on hemoglobin, serum retinol and anthropometric indices of 10-18 years old students of a low socioeconomic status. A total number of 288 students from four boarding schools were randomly selected by using cluster sampling method in Chongqing, and they were assigned into supplement group and control group non-randomly. Students in supplement group received a single 200,000 international units vitamin A and 1 egg/day (including weekends) for 6 months. The control group did not receive any supplementation. We measured hemoglobin, serum retinol and height and weight at baseline and after supplementation. The supplementation increased the mean hemoglobin concentration by 7.13 g/L compared with 1.38 g/L in control group (p<0.001), the mean serum retinol concentration by 0.31 μmol/L compared with 0.09 μmol/L in the control group (p=0.005), the mean height-for-age z score by 0.05 compared with 0.03 in the control group (p=0.319), the mean weight-for-age z score by 0.05 compared with -0.12 in the control group (p<0.001). Our results revealed that egg and vitamin A supplementation is an effective, convenient, and practical method to improve the levels of hemoglobin, serum retinol and prevent the deterioration of growth in terms of weight for primary and middle school students from outlying poverty-stricken areas. Our intervention did not have a beneficial effect on linear growth.

A Comparison of Oral and Topical Vitamin A Supplementation in African Foam-Nesting Frogs (Chiromantis xerampelina)

Vitamin A is essential for a variety of functions, including cellular differentiation, morphogenesis, growth, vision, immune response, and reproduction. A captive population of African foam-nesting frogs (Chiromantis xerampelina) with a known history of vitamin A deficiency had higher than expected incidence of sudden death, bacterial osteomyelitis, and stunted growth. Due to the high prevalence and untreatable nature of the diseases in the population, euthanasia of the population was recommended. Before euthanasia, the population was entered into a study to compare oral dietary supplementation of vitamin A to topical treatment with water-miscible vitamin A palmitate (AQUASOL A Parenteral, Mayne Pharma Inc., Paramus, New Jersey 07652, U.S.A.). Eighty-four frogs, weighing 2-7 g, were divided into a control and three treatment groups of 21 frogs per group, with normalized weight distribution. The control group received standard daily nutrition of crickets dusted with a supplement containing 342,000 international units (IU) vitamin A/kg. The treatment groups consisted of oral supplementation with crickets dusted with a fortified supplement containing 822,510 IU vitamin A/kg; topical vitamin A palmitate 50 IU every other day; and topical vitamin A palmitate 50 IU once a week. After 30 days, all frogs were euthanized, and 12 frogs from each group were analyzed for whole-body vitamin A levels. The control and treatment groups 1, 2, and 3 had average whole-body vitamin A levels of 1371.4 IU/kg (SE 284.4), 908.7 IU/kg (SE 186.5), 6385.9 IU/kg (SE 675.9), and 3521.8 IU/kg (SE 575.1), respectively. These results suggest that oral supplementation using a product high in vitamin A may be ineffective at raising whole-body vitamin A levels above those achieved with standard nutrition. Topical administration of vitamin A on an every other day and once a week dosing schedule achieved levels 4.5- and 2.5-fold higher than standard nutrition, respectively.

Vitamin C and E Supplementation to Prevent Spontaneous Preterm Birth

To estimate whether maternally administered vitamins C and E lower the risk of spontaneous preterm birth. This is a secondary analysis of a randomized, double-masked, placebo-controlled trial in nulliparous women at low-risk administered 1,000 mg vitamin C and 400 international units vitamin E or placebo daily from 9 to 16 weeks of gestation until delivery. Outcomes include preterm birth attributable to premature rupture of membranes (PROM) and total spontaneous preterm births (spontaneous preterm birth attributable to PROM or spontaneous labor). Of the 10,154 women randomized, outcome data were available for 9,968 (4,992 vitamin group and 4,976 placebo group). A total of 1,038 women (10.4%) delivered preterm, of whom 698 (7.0%) had spontaneous preterm birth. A spontaneous preterm birth occurred in 356 women (7.1%) assigned to daily vitamin C and E supplementation and in 342 (6.9%) assigned to placebo. There were 253 women (2.5%) who delivered after preterm PROM and 445 (4.5%) after a spontaneous preterm labor. In women supplemented with vitamins C and E, births attributed to preterm PROM were similar at less than 37 and 35 weeks of gestation, but births were less frequent before 32 weeks of gestation (0.3% compared with 0.6%, adjusted odds ratio 0.3-0.9). However, total spontaneous preterm births across gestation in women supplemented with vitamins C and E or a placebo were similar. Maternal supplementation with vitamins C and E beginning at 9 to 16 weeks of gestation in nulliparous women at low risk did not reduce spontaneous preterm births. ClinicalTrials.gov, www.clinicaltrials.gov, NCT00135707. I.

Administration of RRR-α-tocopherol to pregnant mares stimulates maternal IgG and IgM production in colostrum and enhances vitamin E and IgM status in foals

This study assessed the effect of a vitamin E supplement given to pregnant mares on immunoglobulins (Ig) levels in foals. In addition, the fatty acid (FA) content and composition of the mares' milk was assessed. Milk α-tocopherol concentrations were compared between pregnant Danish Warmblood mares (n = 17) given a daily oral supplement of 2500 international units (IU) RRR-α-tocopherol in the last 4 weeks of pregnancy and a group of unsupplemented mares (n = 17) receiving 170-320 IU vitamin E daily originating from the feed. Milk α-tocopherol was higher in supplemented mares (36.7, 12.4 and 9.8 μmol/l respectively) in relation to control mares (13.1, 6.4 and 5.8 μmol/l on days 1, 2 and 3 respectively; p < 0.001). Milk IgG was higher on days 2 and 3 post-partum (PP) in supplemented mares (1.03 and 0.73 mg/ml respectively) in relation to control mares (0.79 and 0.56 mg/ml respectively; p < 0.05). Milk IgM was higher on days 2 and 3 post-partum (PP) in supplemented mares (0.19 and 0.17 mg/ml) in relation to control mares (0.13 and 0.11 mg/ml respectively; p < 0.05). Plasma α-tocopherol in foals was higher from supplemented mares on days 1, 2 and 3 (5.7, 14.8 and 19.2 μmol/l respectively) in relation to foals from control mares (3.6, 6.1 and 7.6 respectively; p < 0.001). Foal plasma IgM was higher from supplemented mares on day 3 (0.50 mg/ml) in relation to foals from control mares (0.32 mg/ml; p < 0.001). The total FA content in milk was highest on day 1 (21.6 g FA/kg milk) in relation to days 2 and 3 (13.6 and 13.5 g FA/kg milk respectively; p < 0.001). In conclusion, a daily oral supplement of 2500 IU RRR-α-tocopherol increased α-tocopherol content in mare milk and foal plasma, IgG and IgM in mare milk and IgM in foal plasma.

Vitamin A in diets for Nile tilapia

Dietary vitamin supplementation decrease stress caused by high stocking density, and boosts immunological system of farmed fish. A studied was carried out to determine vitamin A requirements of Nile tilapia (Oreochromis niloticus) in an all male group (13.8 ± 1.2 g) and a mixed sex population (9.8 ± 2.3 g). Fish stocked in 100-L plastic aquaria (26.0 ± 1.0ºC) were fed to near satiety, twice a day, seven days a week, during 75 days with vitamin A-free, semi-purified diets supplemented with 0; 600; 1,200; 1,800; 2,400; 3,000; 3,600; 4,200; 4,800 and 5,400 International Units (IU) of retinyl palmitate (30% vitamin A) per kg of diet in a completely randomized experimental design, factorial arrangement 2c10 (n = 4). Deficiency signs of vitamin A were observed in fish fed 0 to 1.200 IU vitamin A kg-1 diet; moderate signs were observed in fish fed diets with 1.800 to 3.600 IU vitamin A kg-1 diet; no interactions group*level (p &lt; 0.05) were detected. Dietary levels of vitamin A up to 5.400 IU kg-1 influenced final weight and weight gain of fish (p &lt; 0.05), but did not influence feed consumption (p &gt; 0.05). A group effect was observed regarding all performance variables (p &lt; 0.0001). Quantification of hepatic retinol (HPLC) detected vitamin A only in fish fed 5.400 IU retinol kg-1 of diet, therefore characterizing that dietary retinol was used and stored. The quantity of 5.400 IU of retinol kg-1 of diet is recommended for adequate nutrition of Nile tilapia.

Vitamin D: Cancer Prevention's Sunny Future?

C ould preventing cancer be as easy as taking a vitamin supplement? For decades, studies have suggested that sunlight and vitamin D decrease the risk of some nonskin cancers. In the past few years, there has been a crescendo in the research, including results from the first randomized, controlled trial to show that vitamin D can lower cancer risk. The Canadian Cancer Society thinks that vitamins might be one way to prevent some cancers. In June 2007, the national organization recommended that adults living in Canada consider taking vitamin D supplements of 1,000 international units (IU) a day in the fall and winter. Those at high risk of low vitamin D levels should take it year round. The move was a break from the Canadian government’s daily intake recommendation of 200 – 600 IU, which is aligned with the U.S. Institute of Medicine’s adequate intakes. Then, in October, the Canadian Cancer Society wrote a letter to North American research granting agencies, including the National Institutes of Health, lobbying for a large-scale clinical trial that tests at least 1,000 IU of vitamin D. The goal: to fi gure out what dose prevents cancer. Although making a recommendation and asking for more research at the same time may seem contradictory, Heather Chappell, senior manager of cancer control policy for the Canadian Cancer Society, said that this approach struck a balance between two health issues. One is geographic location — 90% of vitamin D comes from the sun when ultraviolet rays convert a precursor in the skin to vitamin D, but during fall and winter at higher latitudes, no vitamin D synthesis occurs. Findings from a conference on vitamin D and health, sponsored by the cancer society and the National Cancer Institute of Canada, concluded that overall vitamin D levels may be low in the general population and that “vitamin D may have benefi cial effects on some types of cancer.” The other issue is reminding Canadians to protect themselves from the sun. Tanning salons in Canada were advertising indoor tanning as a venue to get your vitamin D, which most scientists consider dangerous because of the skin cancer risk. “Taking a supplement is a safer alternative for Canadians than indoor tanning,” Chappell said. “That recommendation is only based on what we know to date.” What the society does know is based on a combination of the conference fi ndings (which brought together 14 national health organizations) and a review of about 60 studies, mostly o b s e r v a t i o n a l , Chappell said. But making recommendations before there have been many randomized, controlled trials concerns some researchers. Several research conferences and organizations have looked at the many questions that still need to be answered about vitamin D and cancer risk. “When you fi nd something in observational studies, the interventions are rarely, rarely as positive or as powerful as the observations,” said Wake Forest University professor Gary Schwartz , Ph.D., who has been examining the vitamin D link to prostate cancer for two decades. “It is an open question whether vitamin D supplementation will reduce the risk of cancer. The questions are how much vitamin D, when, and what cancer.” Ecologic, epidemiologic, and laboratory studies have provided evidence linking higher vitamin D exposures to lower risk of colon, breast, and prostate cancers. But a U.S. National Cancer Institute conference in May 2007 determined that there are many gaps in the research. The conference was spurred by the “sunshine vitamin” getting a lot of attention in the lay press, for which pace picked up after results from a randomized trial were published.

Host–pathogen evolution: Implications for the prevention and treatment of malaria, myocardial infarction and AIDS

Humans have evolved complex immune systems to protect against infection by pathogens. However, pathogens possess a remarkable genetic versatility that allows them to gain new vigour and so escape such population immunity. Conflicting pathogen-host objectives, therefore, lead to the evolutionary equivalent of an "arms race". Typically, in this struggle, pathogens attempt to deplete their host of specific nutrients that are essential for immune system function. After infection, the resulting deficiency of nutrient(s) may cause many of the disease symptoms and sequela. In malaria, Plasmodium falciparum, for example, depletes its host of Vitamin A, possibly resulting in blindness in some cases. However, 200,000 International Units of Vitamin A, given to children every three months can reduce significantly their susceptibility to malaria. This would seem to be a minimum child dosage for the treatment of the disease. In contrast, the Coxsackie B virus causes a selenium deficiency that may result in myocardial infarction or Keshan disease. However, table salt fortified with 15ppm anhydrous sodium selenite can cause dramatic drops in the incidence of Keshan disease, while selenium supplementation also reduces re-infarction rates. HIV-1 depletes its host of four nutrients: selenium, cysteine, glutamine and tryptophan, resulting in symptoms known as AIDS. Open and closed clinical trials in South Africa, Zambia and Uganda, involving daily adult doses of 600mcg l-selenomethione, and some 500mg l-glutamine, hydroxytryptophan and N-acetyl cysteine, however, have shown that such supplementation can reverse the symptoms of AIDS and prevent HIV-1 infected patients declining into this disease. It is obvious, therefore, that supplementation of diet with specific nutrients can reduce infection by particular pathogens. In addition, if infection still occurs, their use as a treatment may prevent many of the symptoms and sequela commonly associated with diseases such as malaria, myocardial infarction and AIDS.

Fluorescent Lipid Oxidation Products and Heme Spectra Index Antioxidant Efficacy in Kidney Tissue of Hamsters

Studies ranging from epidemiological to molecular suggest that dietary antioxidants protect against chronic diseases. The hypothesis was investigated that hamster kidney homogenates are better protected against induced oxidative damage after animals were fed a purified vitamin E deficient diet supplemented with 30 international units (IU) vitamin E/kg (30 IU diet) than fed the minimum required 3 IU vitamin E/kg (3 IU diet). The addition of 200 mg (+)-catechin to the 3 IU diet may offer protection. The effects of dietary (+)-catechin and α-tocopherol on tissue oxidizability were investigated by measuring (i) fluorescent products in lipid extracts, (ii) heme protein oxidation and (iii) heme destruction. A rapid initial increase of oxidation markers was measured over the 4 h incubation period for iron + ascorbate induced oxidation and a constant increase for lipoxygenase catalyzed products. Analysis of covariance over time and comparison at specific incubation times showed that iron + ascorbate induced homogenates from hamsters fed the 30 IU diet generated less fluorescent products and oxidized heme proteins than homogenates from the 3 IU or the 3 IU plus (+)-catechin fed animals. Incubation with lipoxygenase produced more lipid fluorescent products and heme protein oxidation in the 3 IU than in the 30 IU vitamin E group. In conclusion, supplementary dietary vitamin E but not supplementary (+)-catechin in a diet containing the minimum requirement of vitamin E for the species enhances oxidative resistance of kidney tissue.

Dietary vitamin e in an atherogenic hamster model

Regular consumption of fruits, vegetables and cereals moderates development of coronary heart disease and atherosclerosis in humans, possibly as a result of antioxidants present in these foods. The aim of this study was to develop a hamster model sufficiently sensitive to test the effects of nutritional rather than pharmacological amounts of food components on the development of atherosclerosis. The effect of vitamin E on aortic lipid deposition was investigated in hamsters fed a hypercholesterolemic diet containing per kilogram 2 g cholesterol, 90 g butterfat, 35 g vitamin E-stripped corn oil, 25 g fish oil and either the minimum requirement of 3 international units (IU) vitamin E or 30 IU. After 30 weeks, lipoprotein cholesterol fractions did not differ between groups, and the 6:1 LDL-cholesterol : HDL-cholesterol ratio was atherogenic. Early atherosclerosis was measured by lipid staining of aortic arch sections with oil red O and quantified by a photomicroscopy color-scanning technique. The area of lipid deposits in the 30 IU vitamin E group (7.9 ± 1.3%, mean ± SEM) was 58% less than in the 3 IU vitamin E group (18.7 ± 4.4%, p < 0.03). Hamsters fed a mixture of saturated and n-6 and n-3 polyunsaturated fatty acids plus cholesterol became hypercholesterolemic and were sensitive to vitamin E with respect to development of atherosclerosis. This model provides a tool to test atheroprotective effects of individual food components in vivo.

Retinitis pigmentosa: unfolding its mystery.

Retinitis pigmentosa: unfolding its mystery.

Effects of vitamin A and ethanol on liver plasma membrane fluidity.

To study possible mechanisms whereby vitamin A and ethanol may affect liver plasma membranes, rats were fed liquid diets containing either 6 international units of vitamin A per kcal or 5 times more, with or without ethanol (36% of total energy as isocaloric substitution for carbohydrate). Vitamin A supplementation resulted in 2- to 3-fold increases of liver plasma membrane free retinol (p less than 0.005) and retinyl esters (p less than 0.001), particularly esters of palmitate and oleate, whereas cholesterol esters did not change. The fluorescent probe 1,6-diphenyl-1,3,5-hexatriene revealed decreased fluidity as measured by an increase in fluorescence polarization which correlated significantly with retinyl palmitate plus oleate content in membranes. In rats fed ethanol chronically, we first verified our previous observation of a decrease in liver plasma membrane fluorescence polarization. We now find this effect to be associated with (and possibly due to) an increase of cholesterol ester content. In linear regression analysis, the change in fluorescence polarization correlated positively with vitamin A (p less than 0.02) and negatively with cholesterol ester contents (p less than 0.001). Ethanol feeding partially offset the effect of vitamin A supplementation on fluorescence polarization. We conclude from these observations that liver plasma membranes contain a significant amount of vitamin A, that vitamin A supplementation increases membrane fluorescence polarization and that chronic ethanol administration can interfere with this effect.

Selenium/Vitamin E: Role in Disease Prevention and Weight Gain of Neonatal Calves1,2

A 3×2 factorial arrangement of treatments comparing 0, 1, or 2 injections of a selenium/vitamin E preparation and feeding of starter commencing at 14 or 28 days of age was used to examine effects of supplemental selenium/vitamin E on health and growth of neonatal calves. Dosage per injection was .078mg selenium and 5.4 international units of vitamin E per kg body weight. Neither a single injection at birth nor two injections (birth and day 14) reduced incidence of respiratory diseases or improved weight gains in unstressed calves. Calves first offered starter at 14 days as compared with 28 days gained more weight in the 56 days. A single injection of selenium/vitamin E at birth increased selenium of blood serum at day 14 by 87%, and a second injection increased selenium of blood serum at day 28 an additional 10%. Selenium of blood serum of calves not given an injection decreased linearly from birth to day 56. Calves first fed starter at day 14 had lower concentrations of selenium of blood serum from day 28 to 42 than calves first offered starter at day 28. Glutathione peroxidase activity of erythrocytes was higher in calves receiving one or two injections of selenium/vitamin E than in control calves; however, a lag of 4 to 5 wk occurred between injections and elevation of glutathione peroxidase activity.

Use of reversed-phase high-performance liquid chromatographic analysis for the determination of provitamin A carotenes in tomatoes

The usual methods of provitamin A evaluation of foods convert the total pigment amout, determined spectrophotometrically, into vitamin A units. Since the totally inactive lycopene is the major carotenoid in the tomato, such readings result in erroneously high provitamin A values. In view of the recent development of chemically bonded, reversed-phase, microparticulate packings and their use in high-performance liquid chromatography which combines highly accurate and reproducible resolution with the speed and ease of operation, a new method using such a system was developed to isolate carotenoid pigments from tomato samples. A 15-min column separation was thus achieved, dramatically decreasing the analysis time of the classical open column chromatographic procedures, which often result in unresolved and altered fractions due to long-term exposure to oxygen, ligh, solvents and sometimes adsorbent. β-Carotene and lycopene were determined and quantitated in six tomato samples. β-carotene, 100% vitamin A-active, was expressed in International Units of vitamin A. The newly developed method gives a more reliable evaluation of the fruit potency in vitamin A than the methods of the Association of Official Analytical Chemists currently used for food composition tables.

Chronic Hypervitaminosis A

A case of chronic hypervitaminosis A in a 51-year-old female is discussed. The patient was ingesting 27,500--35,000 international units of vitamin A daily for 30 years. The patient displayed the classic symptoms of the disease, including skin and hair changes, esophageal varices and extensive liver disease. Vitamin A products were discontinued and the patient's dietary intake of the vitamin was minimized. Previous reports and studies of hypervitaminosis A are reviewed. Social factors causing increased consumption of vitamin A and regulations governing the sale of vitamin A are discussed. By being aware of the factors influencing vitamin A consumption, hypervitaminosis A can be detected and prevented more readily.

Inhibition of Lysosomal Enzymes by Dapsone

The possible inhibition of lysosomal enzymes by dapsone (diaminodiphenylsulfone) was studied. Experimentally induced hypervitaminosis A in rabbits results in loss of chondroitin sulfate from cartilage matrix through the release of lysosomal enzymes. In this study, thinning and decreased toluidine blue and Alcian blue staining of tracheal and articular cartilage produced by the administration of 500,000 international units of vitamin A daily were inhibited by the administration of dapsone. These findings strongly suggest that dapsone inhibits lysosomal enzyme activity. Inhibition of lysosomal enzyme activity may play a role in the therapeutic effects of dapsone on certain diseases such as dermatitis herpetiformis.

Vitamin A-induced nonspecific resistance to infection.

The effect of vitamin A on resistance to infection was evaluated. Mice treated with four consecutive daily injections of 3,000 international units of vitamin A palmitate and then challenged with either a gram-negative bacterium (Pseudomonas aeruginosa), a gram-positive bacterium (Listeria monocytogenes), or a fungus (Candida albicans), showed a significant decrease in total mortality or mortality rate compared with control animals. Five hours after challenge with P. aeruginosa, the mice treated with vitamin A had sterile blood, whereas the control animals showed persistent bacteremia until death. However, the clearance of colloidal carbon or aggregated human serum albumin by the reticuloendothelial system was unaltered by treatment with vitamin A. In addition, vitamin A did not affect in vitro growth of the three challenge organisms. These studies demonstrate that vitamin A induces nonspecific resistance to infection in mice.