β-Carotene Is an Important Vitamin A Source for Humans (2025)

Related papers

-Carotene Is an Important Vitamin A Source for Humans

Tilman Grune

Journal of Nutrition, 2010

Experts in the field of carotenoids met at the Hohenheim consensus conference in July 2009 to elucidate the current status of b-carotene research and to summarize the current knowledge with respect to the chemical properties, physiological function, and intake of b-carotene. The experts discussed 17 questions and reached an agreement formulated in a consensus answer in each case. These consensus answers are based on published valid data, which were carefully reviewed by the individual Hohenheim Consensus Conference "Beta-Carotene as an Important Vitamin A

View PDFchevron_right

A review of vitamin A equivalency of β-carotene in various food matrices for human consumption

wGertjan Schaafsma

British Journal of Nutrition, 2014

Vitamin A equivalency of β-carotene (VEB) is defined as the amount of ingested β-carotene in μg that is absorbed and converted into 1 μg retinol (vitamin A) in the human body. The objective of the present review was to discuss the different estimates for VEB in various types of dietary food matrices. Different methods are discussed such as mass balance, dose–response and isotopic labelling. The VEB is currently estimated by the US Institute of Medicine (IOM) as 12:1 in a mixed diet and 2:1 in oil. For humans consuming β-carotene dissolved in oil, a VEB between 2:1 and 4:1 is feasible. A VEB of approximately 4:1 is applicable for biofortified cassava, yellow maize and Golden Rice, which are specially bred for human consumption in developing countries. We propose a range of 9:1–16:1 for VEB in a mixed diet that encompasses the IOM VEB of 12:1 and is realistic for a Western diet under Western conditions. For a ‘prudent’ (i.e. non-Western) diet including a variety of commonly consumed v...

View PDFchevron_right

-Carotene Conversion to Vitamin A Decreases As the Dietary Dose Increases in Humans

Journal of Nutrition, 2010

It has been suggested that high doses of 8-carotene limit its conversion to vitamin A, yet this effect has not been well established in humans. A feeding study was conducted in a randomized crossover design in which volunteers consumed 2 doses of deuterium-labeled /3-carotene on 2 occasions, with /3-carotene and vitamin A response assessed by plasma area under the concentration time curve (AUC). Seven volunteers (4 men, 3 women) consumed each of 2 doses of /3-carotene-d8 and provided serial blood samples for 37 d after each dose. /3-Carotene doses were 20 and 40 mg. Plasma /3-carotene-d8 was assessed by H PLC-MS. Plasma retinol (ROH)-d4, which was derived from the f3-carotene-d8, was evaluated by GC-MS after saponification to convert retinyl esters to ROH prior to the formation of the trimethylsilylether. The plasma AUC for f3-carotene-d8 increased 2-fold from the 20-mg dose to the 40-mg dose. The plasma AUC for ROH-d4 increased 36% from the 20-mg dose to the 40-mg dose. These results establish that, in humans, /3-carotene conversion to vitamin A decreases as the dietary dose increases. J. Nutr. 140: 915-918, 2010.

View PDFchevron_right

Optimal nutrition: vitamin A and the carotenoids

Christine Clewes

Proceedings of the Nutrition Society, 1999

View PDFchevron_right

An LC/MS/MS method for stable isotope dilution studies of -carotene bioavailability, bioconversion, and vitamin A status in humans

John Hesketh

The Journal of Lipid Research, 2014

View PDFchevron_right

Bioequivalence of β-carotene and retinol

D. Thurnham

Journal of the Science of Food and Agriculture, 2007

For many years it was accepted that 6 mg of β-carotene were required to produce 1 mg of vitamin A in the form of retinol. The equivalence was based on the assumptions that two-thirds of dietary β-carotene are not absorbed, while in the metabolism of the remaining third 1 mol of β-carotene is converted to 1 mol retinol. Recently, the bioequivalence was raised to 12 mg β-carotene and 1 mg retinol. The objective of this review was to reexamine the data that were used to support the new equivalence ratio, especially since some of these data were obtained in developing countries where infestation with gut parasites and exposure to other infections is common, yet the influence of inflammation on plasma carotenoid and retinol concentrations is frequently ignored. Bioequivalence studies examined in this review include those done in developing and developed countries, depletion and repletion studies, feeding with vegetable sources of β-carotene or pure supplements, influence of helminths, carotenoid interactions and matrix effects and studies using stable isotopes (SI). SI studies show the bioefficacy of β-carotene conversion to retinol is generally poor even for pure β-carotene unless the dose is small and fed regularly until equilibration is reached. Retinol formation appears to be inversely influenced by previous vitamin A intake, the amount of material given and current vitamin A status. In spite of technical complexities, more SI studies where liver reserves of vitamin A are determined pre and post intervention are needed to evaluate β-carotene bioefficacy of different vegetable sources.

View PDFchevron_right

Vitamin A equivalency of beta-carotene in healthy adults: limitation of the extrinsic dual-isotope dilution technique to measure matrix effect

Paul J M Hulshof

The British journal of nutrition, 2009

Data on the vitamin A equivalency of beta-carotene in food are inconsistent. We quantified the vitamin A equivalency (microg) of beta-carotene in two diets using the dual-isotope dilution technique and the oral-faecal balance technique. A diet-controlled, cross-over intervention study was conducted in twenty-four healthy adults. Each subject followed two diets for 3 weeks each: a diet containing vegetables low in beta-carotene with supplemental beta-carotene in salad dressing oil ('oil diet') and a diet containing vegetables and fruits high in beta-carotene ('mixed diet'). During all 6 weeks, each subject daily consumed a mean of 55 (sd 0.5) microg [13C10]beta-carotene and 55 (sd 0.5) microg [13C10]retinyl palmitate in oil capsules. The vitamin A equivalency of beta-carotene was calculated as the dose-corrected ratio of [13C5]retinol to [13C10]retinol in serum and from apparent absorption by oral-faecal balance. Isotopic data quantified a vitamin A equivalency of [13...

View PDFchevron_right

Studies on the bioconversion of β-carotene to active vitamin A in underprivileged Guatemalan children

carmen lopez

The Journal of Nutritional Biochemistry, 1997

The mechanism by which the rate of P-carotene conversion to active vitamin A in the enterocyte is poorly understood. It is postulated that body vitamin A status plays a very important role. Until recently, it has not been possible to detect and quantify the product of p-carotene bioconversion, i.e., retinal, in the gut, and retinyl ester, in the circulation. This study aimed at confirming that a rise in plasma retinyl palmitate concentration would occur after administration of P-carotene to underprivileged Guatemalan schoolchildren. Twenty rural children, aged 7 to I I years, received 30 mg of pure, crystalline P-carotene in oral capsules in the fasting state. Thirteen peri-urban poor children participated as controls; each received capsules of cellulose. Standard meals with low vitamin A levels were served during the observation period. Plasma levels of p-carotene, retinal, and retinyl palmitate were determined by HPLC at baseline, 2 hr, and 24 hr after ingestion of capsules. Anthropometric and biochemical characteristics were similar in both groups at baseline. An average increase of 0.15 2 0.05 FmoWL in retinyl esters was observed in the supplemented group at 2 hr, with a return to baseline levels at 24 hr; whereas in the control group no retinyl esters were detected at all at any time. A tendency of a greater retinyl ester response with a lower baseline circulating retinol level was observed. This is the first instance in which p-carotene bioconversion to retinyl palmitate has been quantified in children. We propose that the rise in retinyl esters after oral administration of p-carotene could be used to examine the factors that influence the rate of bioconversion of p-carotene to active vitamin A. (J. Nutr. Biochem. 8:623-628. 1997) 0 Elsevier Science Inc. 1997

View PDFchevron_right

Bioconversion of Carotenoids in Five Fruits and Vegetables to Vitamin A Measured by Retinol Accumulation in Rat Livers

Armando Carrillo López

American Journal of Agricultural and Biological Sciences, 2010

Problem statement: Vitamin A deficiency is one of the most prevalent and major nutritional problems in developing countries, especially in young children. In many countries, a substantial proportion of dietary vitamin A is commonly derived from pro-vitamin A carotenoids obtained from colored fruits and orange or green vegetables. However, the bioavailability of retinol derived from carotenoids from these plant sources is not well known. Approach: The present study analyzed β-Carotene and Total Carotenoids (TC) composition of carrots (Daucus carota), parsley (Petroselinum crispum), Spinach (Spinacea oleracea), mangoes (Mangifera indica) and papayas (Carica papaya) and determined the bioconversion of their carotenoids to vitamin A by monitoring the levels of retinol accumulated in liver and plasma of Wistar rats (Rattus norvegicus). Products were freeze-dried, β-Carotene content analyzed by HPLC and TC by Spectrophotometry. Results: Carrots presented the highest content of β-carotene followed by parsley with 32.8 and 19.6 mg 100 g −1 , respectively. Spinach had the highest content of TC followed by parsley with 60.7 and 56.7 mg 100 g −1 , respectively. Four-week-old male Wistar rats received a standard diet as an adaptation period, a diet free of Carotenoids and Vitamin A (CVA-diet) as depletion period and finally a Fruit or Vegetable (FoV) based diet as repletion period. The highest β-carotene bioconversion was for mango and the lowest for parsley, whereas the highest TC bioconversion was for carrots and the lowest for parsley. There were no significant differences in plasma retinol between treatments. Conclusion/Recommendations: There was no relation between carotenoids content in FoV-based diet and retinol status in plasma. Furthermore, the employment of a general retinol conversion factor is regarded as not appropriate. So, it is recommended to consider specific conversion factors for groups of horticultural crops, for example, a factor for green leafy vegetables and other factor for fruits or roots.

View PDFchevron_right

β-Carotene absorption and cleavage in rats is affected by the vitamin A concentration of the diet

Martje Van Vlissingen

Journal of Nutrition

The purpose of this study was to examine whether intestinal /3-carotene cleavage activity, mea sured with the dioxygenase assay, is affected by vitamin A intake and whether this in vitro activity is a deter minant of /8-carotene cleavage in vivo, measured in lymph-cannulated rats. Six groups of 10-20 rats were fed a diet with a low, normal or high retinyl palmitate concentration (120 RE, 1200 RE and 12,000 RE per kg, respectively) for 14 to 18 wk, either supplemented or not with 50 mg /^-carotene/kg in the last 6 wk. In testinal dioxygenase activity was 90% higher (P < 0.05) in the animals fed the unsupplemented low vitamin A diet than in the animals fed the unsupplemented high vitamin A diet, whereas in /^-carotene-supplemented rats intestinal dioxygenase activity was significantly lower than in unsupplemented rats. The molar ratio between retinyl esters and jà ¶-carotene in lymph col lected over 8 h after a single intestinal dose of /j-carotene (250 fig) to /8-carotene-unsupplemented rats fed the three levels of vitamin A was correlated with in testinal dioxygenase activity (r = 0.66, P = 0.003). Dioxygenase activity in the liver was not affected by the vitamin A concentration of the diet but was 70% higher in the /3-carotene-supplemented rats. Based on the difference in liver vitamin A contents between ßcarotene-supplemented and unsupplemented rats we estimated /^-carotene conversion factors of 9:1 for the rats fed the high vitamin A diet and 4:1 for the rats fed the normal and low vitamin A diets. Intestinal /^-caro tene cleavage activity is higher in vitamin A-déficient rats than in rats with a high intake of either vitamin A or /^-carotene. The intestinal dioxygenase activity as measured in vitro is an adequate indicator of in vivo /icarotene cleavage activity.

View PDFchevron_right

β-Carotene Is an Important Vitamin A Source for Humans (2025)
Top Articles
Latest Posts
Recommended Articles
Article information

Author: Aron Pacocha

Last Updated:

Views: 6306

Rating: 4.8 / 5 (68 voted)

Reviews: 83% of readers found this page helpful

Author information

Name: Aron Pacocha

Birthday: 1999-08-12

Address: 3808 Moen Corner, Gorczanyport, FL 67364-2074

Phone: +393457723392

Job: Retail Consultant

Hobby: Jewelry making, Cooking, Gaming, Reading, Juggling, Cabaret, Origami

Introduction: My name is Aron Pacocha, I am a happy, tasty, innocent, proud, talented, courageous, magnificent person who loves writing and wants to share my knowledge and understanding with you.