beta-carotene and Hypervitaminosis-A

Vitamin A (VA) deficiency is a public health problem in many countries. The World Health Organization recommends high-dose VA supplements to children aged 6-59 months based on unequivocal evidence that supplements decreased mortality risk. VA supplements were meant as a temporary intervention until more sustainable approaches could be implemented. Fortification of processed foods with preformed VA is a means to improve VA status. The most recent addition of retinyl palmitate to cooking oil in countries that may also fortify margarine and milk will undoubtedly have a positive impact on VA status. However, quantitative measures have not been used to assess the underlying VA status of the groups who have adopted widespread fortification. The addition of preformed VA to otherwise adequate diets in VA may cause excessive total body stores. Monitoring population status will require accurate VA assessment to ensure that hypervitaminosis does not prevail. This perspective describes a cohort of rural Zambian children who have adequate diets in VA, mostly as provitamin A carotenoids; who were given high-dose VA supplements till the age of 5 years; who have access to VA-fortified sugar; and whose mothers had access to VA-fortified sugar throughout pregnancy and lactation. Many of these children turned orange during mango season, and this phenomenon occurred at estimated liver reserve concentrations >1 μmol retinol equivalents/g liver. It will be necessary to continue to monitor VA status, including all sectors of the population that have access to successful interventions, to optimize health with the intent to lower retinol content of fortified foods or better target VA supplementation to areas of most need.

Topics: beta Carotene; Child, Preschool; Diet; Dietary Supplements; Diterpenes; Dose-Response Relationship, Drug; Evidence-Based Medicine; Food, Fortified; Humans; Hypervitaminosis A; Infant; Mangifera; Nutritional Status; Recommended Dietary Allowances; Retinyl Esters; Rural Population; Seasons; Skin; Vitamin A; Zambia

Vitamin A has the unique distinction of being readily available over the counter, yet conferring significant toxic and teratogenic potential. Although vitamin A deficiency is relatively rare in the United States, globally it is the most common cause of blindness. The following is a review of the various forms and derivatives of vitamin A and their associations with potential adverse perinatal outcomes.. Obstetricians & Gynecologists, Family Physicians.. After participating in this CME activity, physicians should be better able to identify sources of Vitamin A, distinguish between toxic and non toxic forms of Vitamin A and counsel patients regarding the dosages of Vitamin A that are tolerable during pregnancy.

Topics: Abnormalities, Drug-Induced; beta Carotene; Clinical Trials as Topic; Dietary Supplements; Dose-Response Relationship, Drug; Female; Humans; Hypervitaminosis A; Infant, Newborn; Nonprescription Drugs; Perinatal Care; Pregnancy; Pregnancy Complications; United States; United States Food and Drug Administration; Vitamin A; Vitamin A Deficiency; Vitamins

High doses of synthetic antioxidative vitamins: A, E, C and β-carotene are often used on long-term basis in numerous preventive and therapeutic medical applications. Instead of expected health effects, the use of those vitamins may however lead to cases of hypervitaminosis and even to intoxication. The article points out main principles of safety which are to be observed during supplementation with antioxidative vitamins. Toxic effects resulting from erroneous administration of high doses of those substances on organs and systems of the organism are also discussed. Attention is drawn to interactions of antioxidative vitamins with concomitantly used drugs, as well as intensification of adverse effects caused by various exogenous chemical factors. Moreover, the article presents the evaluation of supplementation with these vitamins, which was performed in large studies.

Topics: Antioxidants; Ascorbic Acid; beta Carotene; Dietary Supplements; Dose-Response Relationship, Drug; Food-Drug Interactions; Humans; Hypervitaminosis A; Vitamin A; Vitamin E

The decreased dietary diversity wrought from the adoption of the settled, agrarian system to replace the hunter-gather and pastoralist lifestyles assured a stable supply of protein and calories from grains and tubers while creating a vulnerability for humans to suffer micronutrient deficiencies. The vitamin A from animal tissue is more bioavailable to humans than the provitamin A in the matrix of green plants. Provitamin A carotenes achieve a dietary vitamin A efficacy nearly equivalent to that of the preformed vitamin only in the context of an oily matrix. The homeostatic regulation of carotene bioconversion by the intestine, moreover, prevents any excess toxic accumulation of vitamin A from provitamin A sources. The efficacy and safety of the palm fruit (genus Elaeis) as a source of vitamin A, in addition to its cultural recognition as a food, are more consistent with the gentler concept of "alleviation" of the public health problem of hypovitaminosis A, then the more aggressive, medical model of "eradication" with its greater potential for risk and collateral damage. The palm fruit and its derivatives achieve new opportunities for creative contribution and sustained use in formats of supplementation (prophylactic in children and women, for lactation), food-to-food fortification (in bakery goods and snacks, as condiments), and even in food diversification strategies. Experience in India, South Africa, and Guatemala begins to define and delineate the opportunities and limitations for the palm fruit to contribute to the alleviation of endemic vitamin A deficiency.

Topics: beta Carotene; Biological Availability; Humans; Hypervitaminosis A; Nutritive Value; Palm Oil; Plant Oils; Public Health; Safety; Vitamin A; Vitamin A Deficiency

Toxicity has been associated with abuse of vitamin A supplements and with diets extremely high in preformed vitamin A. Consumption of 25,000-50,000 IU/d for periods of several months or more can produce multiple adverse effects. The lowest reported intakes causing toxicity have occurred in persons with liver function compromised by drugs, viral hepatitis, or protein-energy malnutrition. Certain drugs or other chemicals may markedly potentiate vitamin A toxicity in animals. Especially vulnerable groups include children, with adverse effects occurring with intakes as low as 1,500 IU.kg-1.d-1, and pregnant women, with birth defects being associated with maternal intakes as low as approximately 25,000 IU/d. The maternal dose threshold for birth defects cannot be identified from present data. An identifiable fraction of the population surveyed consumes vitamin A supplements at 25,000 IU/d and a few individuals consume much more. beta-Carotene is much less toxic than vitamin A.

Topics: Abnormalities, Drug-Induced; Animals; beta Carotene; Carotenoids; Dose-Response Relationship, Drug; Drug Synergism; Humans; Hypervitaminosis A; Liver Diseases; Vitamin A

In this case report, the authors describe a 48-year-old male who complained to his primary care physician of abdominal discomfort and yellow/orange skin discoloration. Physical examination was normal except for some mild mid-abdominal discomfort (no observed skin color changes). An abdominal CT scan indicated a colon that was full of stool. Laboratory studies indicated elevated liver enzymes. Upon further questioning, the patient reported ingesting 6-7 pounds of carrots per week to facilitate his dieting effort. The patient was diagnosed with constipation, hypercarotinemia, and possible vitamin A toxicity. Following the cessation of excessive carrot ingestion, his liver enzymes normalized within 1 month.

Topics: beta Carotene; Constipation; Daucus carota; Diet; Feeding and Eating Disorders; Humans; Hypervitaminosis A; Male; Middle Aged; Tomography, X-Ray Computed

Topics: beta Carotene; Diet; Hand; Humans; Hypervitaminosis A; Male; Middle Aged; Obesity; Pigmentation Disorders

Topics: beta Carotene; Diet; Hand; Humans; Hypervitaminosis A; Pigmentation Disorders

Topics: Adolescent; Anorexia Nervosa; beta Carotene; Daucus carota; Feeding Behavior; Female; Foot Dermatoses; Hand Dermatoses; Humans; Hypervitaminosis A

Topics: Adult; Aged; beta Carotene; Cornea; Corneal Diseases; Diet, Vegetarian; Female; Humans; Hypervitaminosis A; Pigmentation Disorders

Topics: beta Carotene; Carotenoids; Child; Humans; Hypervitaminosis A; Respiratory Syncytial Virus Infections; Vitamin A

In previous reports, deficiencies in serum vitamin A were considered a frequent finding in persons with Down's syndrome. Based on this assumption, the regular determination of both serum carotene and vitamin A has been recommended for the preventive care of this population. In the author's preventive medicine clinic for children with Down's syndrome, we have checked these items routinely in 44 fasting patients (aged 14 months to 19 years). The author was surprised to find no patient with either a deficiency of carotene or vitamin A, but 14 patients had hypercarotenemia. Any known aetiology of this finding, such as excessive ingestion, diabetes mellitus or hypothyroidism, could not be verified. It has to be mentioned that the previous reports on serum carotene levels were based on determinations by conventional spectrophotometric methods (normal range: 50-670 micrograms/dl), whereas the author applied an improved method of high-performance liquid chromatography with a much lower normal range (50-750 micrograms/l). Further investigations are to be performed to verify these findings and to evaluate probable mechanisms of hypercarotenemia in persons with Down's syndrome.

Topics: Adolescent; beta Carotene; Carotenoids; Child; Child, Preschool; Down Syndrome; Female; Humans; Hypervitaminosis A; Infant; Male; Reference Values; Vitamin A