Plasma response to oral beta-carotene in Guatemalan schoolchildren

Red Palm Oil in the Maternal Diet Improves the Vitamin A Status of Lactating Mothers and Their Infants

Improvement of the vitamin A status of lactating mothers and their nursing infants following maternal palm oil consumption was comparable to that following supplementation with purified β-carotene. Mothers who consumed β-carotene as red palm oil had 2.1- and 2.5-fold increases in their serum and milk β-carotene concentrations, respectively, and 2.8- and 3.2-fold increases in their serum and milk α-carotene concentrations, respectively. Infant serum retinol concentrations were significantly increased following maternal supplementation with red palm oil or β-carotene. Maternal intake of red palm oil or β-carotene supplements did not alter infant serum carotenoids, maternal serum retinol, or milk retinol. Because the local diet includes foods prepared with oil, the possibility that red palm oil could provide a significant source of provitamin A carotenoids for Honduran women and children should be further investigated.

β-Cryptoxanthin- and α-carotene-rich foods have greater apparent bioavailability than β-carotene-rich foods in Western diets

β-Carotene (BC), β-cryptoxanthin (CX) and α-carotene (AC) are common carotenoids that form retinol. The amount of retinol (vitamin A) formed from carotenoid-rich foods should depend chiefly on the bioavailability (absorption and circulation time in the body) of carotenoids from their major food sources and the selectivity and reactivity of carotene cleavage enzymes towards them. The objective of the present study was to estimate the apparent bioavailability of the major sources of provitamin A (AC, BC and CX) from the diet by comparing the concentrations of these carotenoids in blood to their dietary intakes. Dietary intakes were estimated by FFQ (three studies in this laboratory, n 86; apparent bioavailability calculated for six other studies, n 5738) or by food record (two studies in our laboratory, n 59; apparent bioavailability calculated for two other studies, n 54). Carotenoid concentrations were measured by reversed-phase HPLC. Apparent bioavailability was calculated as the ratio of concentration in the blood to carotenoid intake. Then apparent bioavailabilities for AC and CX were compared to BC. Eating comparable amounts of AC-, CX- and BC-rich foods resulted in 53 % greater AC (99 % CI 23, 83) and 725 % greater CX (99 % CI 535, 915) concentrations in the blood. This suggests that the apparent bioavailability of CX from typical diets is greater than that of BC. Thus, CX-rich foods might be better sources of vitamin A than expected.

beta-Carotene deficiency in cholestatic liver disease of childhood is caused by beta-carotene malabsorption

BACKGROUND

: Depletion of beta-carotene (b-c) has not been extensively studied in children with chronic cholestatic liver disease.

PATIENTS AND METHODS

: We assessed b-c serum concentration in 53 children with cholestatic liver disease: 19 patients operated on for biliary atresia, 12 with Alagille syndrome, and 22 with progressive familial intrahepatic cholestasis. To test b-c absorption, 6 children with chronic cholestasis received a load of 10 mg b-c/kg body weight.

RESULTS

: We found decreased b-c concentrations in 45 patients. The absorption of b-c was not detectable in 5 of 6 children studied.

CONCLUSIONS

: b-c depletion is a common problem of chronic cholestatic liver disease in childhood that can be attributed to disturbed intestinal absorption.

Use of the deuterated-retinol-dilution technique to monitor the vitamin A status of Nicaraguan schoolchildren 1 y after initiation of the Nicaraguan national program of sugar fortification with vitamin A

BACKGROUND

Nicaragua initiated a national program of vitamin A fortification of its domestic sugar supply starting with the 1999-2000 sugarcane harvest.

OBJECTIVE

This study was conducted to document any change in the vitamin A status of a cohort of children during the first year of the program.

DESIGN

The vitamin A status of 21 Nicaraguan schoolchildren (mean age: 6.7 y; range: 5.3-9.3 y) was assessed in March 2000 and in March 2001. Total-body vitamin A stores and liver vitamin A concentrations were estimated with the deuterated-retinol-dilution (DRD) technique at a dose of 5 mg [(2)H(4)]retinyl acetate at baseline and 5 mg [(2)H(8)]retinyl acetate during the repeat test 1 y later. Plasma retinol and carotenoids were measured by HPLC.

RESULTS

Median total-body vitamin A stores increased from 0.33 to 0.72 mmol (P = 0.0001), liver vitamin A concentrations from 0.52 to 0.78 mumol/g (P = 0.0003), and plasma retinol concentrations increased from 0.97 to 1.17 mumol/L (P = 0.01).

CONCLUSION

The vitamin A status of Nicaraguan schoolchildren improved during the year after the initial distribution of vitamin A-fortified sugar in Nicaragua.

Comparison of the effects of supplemental red palm oil and sunflower oil on maternal vitamin A status

BACKGROUND

Conflicting results have been reported on the ability of dietary carotenoids to improve vitamin A status in lactating women. Red palm oil is one of the richest dietary sources of beta-carotene.

OBJECTIVE

We aimed to determine the efficacy of red palm oil in increasing retinol and provitamin A status in pregnant and lactating women.

DESIGN

Ninety rural, pregnant Tanzanian women from 3 randomly selected villages were recruited during their third trimester to participate in 3 dietary intervention groups: a control group, who were encouraged to maintain the traditional practice of eating staples with dark-green leafy vegetables, and 2 study groups, who were given either sunflower or red palm oil for use in household food preparations. The intervention lasted 6 mo. Plasma samples were collected at the third trimester and 1 and 3 mo postpartum, and breast-milk samples were collected 1 and 3 mo postpartum.

RESULTS

Supplementation with red palm oil, which is rich in provitamin A, increased alpha- and beta-carotene concentrations significantly (P < 0.001) in both plasma and breast milk. Plasma retinol concentrations were similar in all dietary groups. Breast-milk retinol concentrations tended to decrease from 1 to 3 mo postpartum in the control group, but were maintained in both oil groups. The difference in change in breast-milk retinol concentration between the red palm oil group and the control group was significant (P = 0.041).

CONCLUSIONS

Consumption of red palm oil increases concentrations of alpha- and beta-carotene in both breast milk and serum and maintains breast-milk retinol concentrations. Sunflower oil consumption seems to conserve breast-milk retinol similarly to consumption of red palm oil. Breast-milk retinol might be maintained through increased dietary intake of these vegetable oils and use of mild cooking preparation methods (such as the addition of oil at the end of cooking and avoidance of frying).

Serum carotenoid depletion follows first-order kinetics in healthy adult women fed naturally low carotenoid diets

Dietary intakes of carotenoids are highly variable in human populations as are serum carotenoid concentrations. However, there are few controlled data relating carotenoid intake to concentration. Most of the data that are available are from measurements of the absorption and decay of large pharmacologic doses of carotenoids, and are therefore of unknown physiologic relevance. Our objective was to determine the half-life (t(1/2)) of the most abundant carotenoids in blood serum from healthy adult women living under controlled conditions. As part of two carotenoid isotopic studies, we measured serum concentrations of beta-carotene, alpha-carotene, lutein, zeaxanthin, beta-cryptoxanthin and lycopene in 19 healthy young adult women that were fed controlled low carotenoid diets for approximately 10 wk. All other nutrients (vitamins A, E and C) were provided at 100-150% of the 1989 U.S. recommended dietary allowance levels. Exercise and activities were controlled throughout the studies to simulate usual activity patterns. Carotenoid concentrations were measured by reversed-phase HPLC. Serum carotenoid concentration decreases during depletion followed first-order kinetics. The half-lives determined in decreasing order were as follows: lutein (76 d) > alpha-carotene (45 d) = beta-cryptoxanthin (39 d) = zeaxanthin (38 d) = beta-carotene (37 d) > lycopene (26 d). Half-lives were unrelated to physical or demographic characteristics such as body mass, body fat, racial background or age in these relatively homogeneous groups. Carotenoids decreased by similar first-order mechanisms, although the rates differed for individual carotenoids.

Tissue stores of beta-carotene are not conserved for later use as a source of vitamin A during compromised vitamin A status in mongolian gerbils (Meriones unguiculatus)

Vitamin A (VA) deficiency remains a serious problem in the world today. Current approaches to preventing or treating VA deficiency, including dietary intervention with provitamin A compounds, rely on the body converting ingested beta-carotene (betaC) to VA. However, it is not known whether betaC that is already in the tissues can be used as a source of VA to prevent deficiency. The objectives of these studies were to determine whether tissue betaC stores are converted to VA when the Mongolian gerbils have low VA status and whether previously fed betaC is retained in the tissues for later conversion to VA. In the first study, gerbils were prefed diets with betaC (20.3 +/- 6.2 nmol/g diet) (+betaC) or without betaC (-betaC), and with VA [2.4 +/- 1.5 nmol/g diet (+betaC diet) or 12.0 +/- 4.2 nmol/g diet (-betaC diet)] for 7 d, and then depleted of both betaC and VA for up to 84 d. On d 0 after the prefeeding period, hepatic betaC stores were 13.3 +/- 9.1 nmol. These stores were significantly lower after 28d of consuming the -VA/-betaC diet (2.16 +/- 1.7 nmol), even though the hepatic VA concentrations did not change. In the second study, the gerbils were prefed a -VA/+betaC diet (74.3 +/- 19. 7 nmol betaC/g diet) for 7 d, and then fed a betaC-free diet either with (7.1 +/- 1.4 nmol/g) or without VA for up to 34 d. Hepatic betaC stores after the 7-d prefeeding period were 38.1 +/- 20.6 nmol, and were significantly higher than after 7d of consuming either a +VA/-betaC (12.4 +/- 10.8 mmol) or -VA/-betaC diet (11.4 +/- 8.0 nmol). The results from both studies suggest that a substantial amount of hepatic betaC is rapidly lost when betaC is eliminated from the diet and therefore is not conserved to meet later VA needs. The presence of VA in the diet (Study 2) did not affect the rate of betaC loss from the serum and tissues. Moreover, no evidence was found that the stored betaC was utilized for VA. The data suggest that there may be two pools of hepatic betaC, one that is lost rapidly and another that is lost more slowly over time, but losses are not affected by VA status.

Effect of heat treatment on the biological value of beta-carotene added to soybean cooking oil in rats

Vitamin A deficiency is one of the major nutritional problems in the world, most common in developing countries. Food fortification is a recognised approach to supply vitamins and minerals to needed populations. Vegetable cooking oils were previously suggested by us as a carrier for vitamin A fortification. Fortification of cooking oil with beta-carotene could also be a strategy to prevent vitamin A deficiency. The objective of this article is to start studies on the use of cooking soya oil as a vehicle for synthetic carotene, to evaluate its stability to heat treatment, and to test its bioavailability and bioconversion to vitamin A in rats. Batches of carotene-fortified soybean oil were prepared, containing 2, 4 and 8 RE/g of diet. Some of them were heated to test its stability. At 100 degrees C there was no loss of carotene, at higher temperature carotene retention was 65%. The bioavailability and bioconversion of beta-carotene added to soybean oil was measured through feeding nursing rats and their pups method. Weight gain was good and plasma vitamin A increased significantly in all groups. Liver vitamin A values of rats fed diets with fortified soybean oil heated at 100 degrees C was similar to the 4 RE non-heated fortified oil group (0.72 +/- 0.06 and 0.64 +/- 0.08 mumol/g, respectively). Heated at 170 degrees C the liver total vitamin A value was reduced (0.45 +/- 0.04 mumol/g), but kept bioavailable vitamin A equivalent to 2 RE (0.47 +/- 0.09 mumol/g). Bioconversion of beta-carotene to vitamin A was validated by the plasma and liver findings. beta-carotene added to soybean oil showed good stability to heat and its bioconversion to vitamin A was shown in rat assays. beta-carotene mixed well with edible soybean oil and the fortified cooking oil showed potential as a carrier to be used for the prevention of vitamin A deficiency.

The plasma beta-carotene response to a single meal of carrots in Guatemalan schoolchildren

Plasma samples were obtained before, and 8 and 24 h after the ingestion of an ad libitum amount of cooked carrots by 23 school children from a peri-urban community in Guatemala City. The single-meal consumption of cooked carrots ranged from a low 122 g to a high of 961 g (mean: 370.5 +/- 237.2 g; median: 268.4 g). The measured beta-carotene content of the carrots was 10.1 mg per 100 g of edible portion; therefore, the range of intake of beta-carotene was 12.4 to 97.0 mg (mean: 37.4 +/- 24 mg; median: 27.1 mg). Changes in plasma beta-carotene levels at 8 h ranged from a decrement of -0.32 mumol/l (-16.98 micrograms/dl) to an increment of 0.79 mumol/l (42.44 micrograms/dl), with a mean of 0.11 +/- 0.24 mumol/l (5.97 +/- 12.82 micrograms/dl). Changes at 24 h were less dramatic than those at 8 h. A regression of the 8-h changes in plasma beta-carotene on the amount of carrot carotene consumed (corrected by body weight) had an r-value of 0.12. Baseline levels of plasma retinol were poor predictors of the plasma beta-carotene response with this sample size (r = 0.10). The magnitude of the plasma response to beta-carotene from carrots appears to be lower than that observed with pure, powdered, crystalline carotenes; moreover, the variability of the post-carrot response seems to be greater--and its association to dosage appears to be weaker--than with the pharmacological beta-carotene.

Blood retinol and beta-carotene levels in rural Guatemalan preschool children

Plasma retinol and beta-carotene levels were measured in 502 preschool Guatemalan children from five rural hamlets. Their ages ranged from 6 to 78 months (mean: 42.9 +/- 19.2 months); 45% males and 55% females. The mean retinol value in the whole group was 0.9 +/- 0.4 mumol/l (range: 0.1 to 8.4 mumol/l). There was no significant difference between sexes in retinol mean values nor in the incidence of retinol values less than 0.7 mumol/l (22% in males, 18% in females). When grouped by age and community, significant low retinol mean values were found in two hamlets in the youngest age group (12 to 23 months) as compared to the other age-groups (p < 0.05). In the other two hamlets, there were no significant differences among retinol means by age-group. The highest prevalence of deficient retinol values by age-group was in the 12 to 23 months group (40%), and decreased as age increased. The mean value for beta-carotene in the whole group was 0.13 +/- 0.18 mumol/l (range: 0.01 to 2.23 mumol/l). There were no significant differences in beta-carotene means between sexes in the whole group. Stratifying the beta-carotene data by age-groups and community, values were significantly higher in the 48-59 months and 72-83 months groups, as compared with the other age groups in two of the communities (p < 0.05). Significant differences across communities for beta-carotene were found only in the 12 to 23 months group.

Plant sources of provitamin A and human nutriture

Hypovitaminosis A is a problem in many parts of the developing world. Beyond the stop-gap measures of capsule distribution and food fortification, increased consumption of accessible sources of vitamin A, specifically of the carotenoid provitamin A in yellow, orange, and green plants, has been promoted as the sustainable, long-term solution. However, a search of the available literature reveals few examples of human studies to support the effectiveness of this solution. Evidence from feeding studies shows an almost universally poorer uptake of intact carotenoids from plant sources as opposed to pure, chemical sources. With notable exceptions, the bioconversion of plant carotenoids to preformed vitamin A also seems to be inefficient. Epidemiologic observations in poor Third World populations and in vegetarians in an industrialized nation indicate a relatively greater potency for animal sources of vitamin A. In developing countries, low fat intakes, intestinal roundworms, recurrent diarrhea, and tropical enteropathy all may contribute to reduced utilization of plant provitamin A. The accepted 6:1 equivalency of beta-carotene to preformed vitamin A must be challenged and reexamined in the context of dietary plants. The consequences of operating on a miscalculation could be serious indeed for public health programs designed to alleviate and eradicate hypovitaminosis A.