Dietary vitamin A intakes of Filipino elders with adequate or low liver vitamin A concentrations as assessed by the deuterated-retinol-dilution method: implications for dietary requirements

Dietary vitamin A intakes of chinese children with adequate liver stores as assessed by the retinol isotope dilution technique

BACKGROUND

We attempted to estimate dietary vitamin A requirements based on dietary vitamin A intake in well-nourished Chinese children with adequate liver vitamin A reserves.

METHODS

A cross-sectional study was conducted in a kindergarten and an elementary school in Shiyan city, Hubei province of China from December 2009 to July 2010. After screening, 60 children (22 aged 4 ~ 6 y and 38 aged 7 ~ 9 y) were randomly subjected to a 3-d or 18-d deuterated-retinol-dilution (DRD) procedure to evaluate the vitamin A reserves in the body and liver. Dietary intakes of vitamin A were estimated from two (one in winter and one in summer) consecutive 3-day weighed food records and dietary recalls.

RESULTS

The dietary vitamin A intakes were significantly correlated with vitamin A stores in the body and liver, but not with the serum level of retinol. The dietary vitamin A intakes were 476.9 ± 196.7 µg retinol equivalent (RE) (or 377.7 ± 166.2 µg retinol activity equivalent (RAE)) / day for 4 ~ 6 y children and 529.1 ± 87.2 µg RE/d (or 464.0 ± 81.1 µg RAE/d) for 7 ~ 9 y children with adequate liver vitamin A reserves. The estimated liver stores of vitamin A derived from both time points (3-d and 18-d) were similar.

CONCLUSION

Adequate dietary vitamin A intakes among the well-nourished Chinese children were estimated to be 477 µg RE/d (95%CI 385 ~ 570) or 378 µg RAE/d (95%CI 304 ~ 441) for 4 ~ 6 y children and 529 µg RE/d (95%CI 500 ~ 560) or 464 µg RAE/d (95%CI 437 ~ 491) for 7 ~ 9 y children. Although it needs to be verified in a larger population of different regions in China, our results provide important data to establish the dietary requirement of vitamin A specifically for Chinese children.

Findings in 3 clinical trials challenge the accuracy of the Institute of Medicine's estimated average requirements for vitamin A in children and women

BACKGROUND

Vitamin A (VA) estimated average requirements (EARs) for women and children are extrapolated from rats and adult males. The retinol isotope dilution (RID) test can sensitively characterize VA status and intake requirements.

OBJECTIVES

These studies evaluated current EARs for children 4-8 y and women 19-30 y old.

METHODS

Zambian children (n = 133, ages 5-7 y), US women (n = 51, ages 19-27 y), and Indonesian women (n = 29, ages 19-30 y) were provided diets or supplements containing 30%-155% of VA EARs for 42-90 d. RID was performed before and after the intervention to quantify changes in total body VA stores (TBSs) and total liver VA reserves (TLRs). Linear regression was performed between VA intake and change in TBSs or TLRs.

RESULTS

Baseline mean ± SD TLRs were hypervitaminotic in Zambian children (1.13 ± 0.41 μmol VA/g liver), optimal in US women (0.46 ± 0.32 μmol/g VA/g liver), and deficient to marginal in Indonesian women (0.10 ± 0.08 μmol VA/g liver). VA intakes, resulting in no change in TBSs or TLRs, were 185 (95% CI: 18, 288) or 257 (95% CI: 124, 411) and 285 or 330 (CIs undefined) μg retinol activity equivalents (RAE)/d in the Zambian and US trials, respectively, but inconclusive in Indonesian women. The regression was not significant in either group of women.

CONCLUSIONS

Point estimates of VA intakes to maintain stores were below the current EARs of 275 (children) and 500 (women) μg RAE/d despite the TLRs being higher than the EARs were formulated to maintain (i.e., 0.07 μmol VA/g liver). Interventions based on these EARs may need to be scaled back. Lack of change in VA stores in women taking lower doses may result from physiological adaptation resulting in lower VA utilization. Longer, larger, and controlled studies are needed to accurately define EARs for VA.These trials were registered at Clinicaltrials.gov as NCT04123210 and NCT01814891.

Dietary vitamin A intakes among pregnant women attending antenatal care in health facilities in Dessie Town, North East Ethiopia

BACKGROUND

Vitamin A plays an important role in vision, cellular differentiation, embryonic development, reproduction, growth and the immune system. Women who live in developing countries face a risk of undernutrition during pregnancy as a result of poverty, poor diet quality and quantity, and a high fertility rate. This poor dietary problem could reflect the high risk of vitamin A deficiency in women. The present study aimed to determine the adequacy of vitamin A among pregnant women following antenatal care in health facilities of Dessie Town, Ethiopia, January 2017.

METHODS

Health facility-based cross-sectional study was conducted among 390 women who attended antenatal care in Dessie Town. Food groups from the Food and Agriculture Organization based on 24-h dietary recall were used to measure dietary intake of vitamin A and dietary diversity of women. Adequacy of vitamin A was determined from the nutrient adequacy ratio after obtaining reports of nutrient intake from food composition tables version III and IV in terms of B carotene and retinol equivalent, respectively, based on the estimated average requirement recommendation of vitamin A, 370 retinol equivalent day^-1 for pregnant women. Multivariable logistic regression analysis was performed to identify associated factors of vitamin A adequacy.

RESULTS

Adequacy of vitamin A among pregnant women was 41.8%, with an average nutrient adequacy ratio of 0.9. The mean dietary intake of vitamin A was 290.1 µg day^-1 . The predictors for adequacy of vitamin A were high and medium women diversity scores (adjusted odds ratio = 2.92; 95% confidence interval = 1.50-5.70) and (adjusted odds ratio = 1.87; 95% confidence interval = 1.11-3.16).

CONCLUSIONS

In the present study, adequacy of vitamin A was low and was affected by the dietary diversity score. A focus on food-based approaches, especially regarding educating pregnant women to diversify their diet, is crucial for reducing the risk of vitamin A deficiency. Vitamin A is crucial micronutrient for the health of women and fetus, being essential for morphological, ocular and functional developments, as well as fetal organ and skeletal growth. Its requirement is greater during pregnancy and its deficiencies lead to maternal and child mortality and development. The dietary intake of vitamin A among pregnant women remains below the current recommendation. Inadequate intake of vitamin A Pregnant women Heath facility Dessie, Ethiopia.

A Retinol Isotope Dilution Equation Predicts Both Group and Individual Total Body Vitamin A Stores in Adults Based on Data from an Early Postdosing Blood Sample

BACKGROUND

Retinol isotope dilution (RID) is used to determine vitamin A total body stores (TBS) after an oral dose of a vitamin A stable isotope. The generally accepted prediction equation proposed by Olson's group in 1989 (Furr et al. Am J Clin Nutr 1989;49:713-6) includes factors related to dose absorption and retention, isotope equilibration in plasma compared with stores, catabolism during the mixing period, and the optimal time for measuring plasma isotope enrichment.

OBJECTIVES

The objectives were 1) to develop a modified RID equation and identify an earlier sampling time for predicting TBS and 2) to improve prediction in individuals as well as groups.

METHODS

To develop a modified RID equation, we used results of model-based compartmental analysis [the Simulation, Analysis and Modeling software (WinSAAM version 3.0.8; http://www.WinSAAM.org)] of plasma [¹³C₁₀]retinol kinetic data from 32 previously studied, healthy young adults of European ancestry who had moderate vitamin A intakes and who ingested 2.95 μmol [¹³C₁₀]retinyl acetate.

RESULTS

We examined the time dependence of factors in the prediction equation related to absorption/retention (Fa) and isotope equilibration (S) and determined that 4 or 5 d postdosing was the optimal sampling time. TBS calculated by the equation TBS = Fa x S x (1/SA_p), where SA_p is plasma retinol specific activity (fraction of dose/μmol), were highly correlated with model-predicted TBS (r = 0.95 and 0.96 for 4 and 5 d, respectively; P < 0.001); predictions for individuals were also highly correlated (R_s = 0.94 and 0.94; P < 0.001).

CONCLUSION

The equation TBS ≈ 0.5 × (1/SA_p) accurately predicted vitamin A TBS in this group of 32 healthy young adults and its individual members with the use of data from 1 blood sample taken 4 d after isotope administration.

Vitamin A (retinoid) metabolism and actions: What we know and what we need to know about amphibians

Vitamin A status is an important consideration in the health of both wild and captive amphibians. Data concerning whole body vitamin A homeostasis in amphibians are scarce, although these animals have been used as experimental models to study the actions of vitamin A in vision, limb regeneration and embryogenesis. The available data suggest that many aspects of vitamin A biology in amphibians are similar to the canonical characteristics of vitamin A metabolism and actions established in mammals. This is consistent with the evolutionary conservation of these important biological processes. Amphibians must obtain vitamin A in their diet, with captive animals being prone to vitamin A deficiency. There is still much to be learned about vitamin A biology in amphibians that can only be achieved through rigorous scientific research. Improved understanding of amphibian vitamin A biology will aid the conservation of endangered amphibians in the wild, as well as the successful maintenance of ex situ populations.

Vitamin A isotope dilution predicts liver stores in line with long-term vitamin A intake above the current Recommended Dietary Allowance for young adult women

BACKGROUND

The Estimated Average Requirement (EAR) and Recommended Dietary Allowance (RDA) for vitamin A are 1.7 and 2.4 μmol/d (500 and 700 μg retinol activity equivalents/d), respectively, for nonpregnant, nonlactating women aged >19 y. This intake is presumed to maintain a minimally acceptable liver concentration of 0.07 μmol (20 μg) retinol/g; however, liver reserves have not been evaluated with respect to vitamin A intake in women of any age group defined in the Dietary Reference Intakes.

OBJECTIVE

This cross-sectional study examined vitamin A intake and liver reserves estimated by stable-isotope dilution testing.

DESIGN

Forty nonpregnant, nonlactating women (mean ± SD age: 22.4 ± 2.3 y) completed a Harvard food-frequency questionnaire (FFQ) and 3-d diet record (3DDR) before undergoing vitamin A status assessment by using a [(13)C2]retinol stable-isotope dilution test.

RESULTS

Vitamin A intake was 70% higher than the RDA by both dietary-assessment methods (P < 0.001). The mean (±SD) liver concentration of vitamin A was 0.45 ± 0.31 μmol/g (129 ± 89 μg/g) and ranged from 0.09 (26 μg/g) to 1.79 μmol/g (513 μg/g). Liver and total-body vitamin A were highly correlated with intake measured by FFQ (P ≤ 0.009), but 3DDR was not (P ≥ 0.22). Prediction equations were developed for 3- and 7-d data.

CONCLUSIONS

In this well-nourished population, vitamin A consumption was considerably higher than recommended, and liver reserves were consistent with intake. Because of their sensitivity, stable-isotope techniques can help to describe the vitamin A status and better characterize the intake needs of all groups defined in the Dietary Reference Intakes. Registration was not required for this trial.

Spirulina can increase total-body vitamin A stores of Chinese school-age children as determined by a paired isotope dilution technique

Spirulina is an alga rich in high-quality protein and carotenoids. It is unclear whether spirulina can improve the total-body vitamin A stores of school-age children in China with a high prevalence of vitamin A malnutrition. We aimed to evaluate the efficacy of spirulina in improving the total-body vitamin A stores of school-age children in rural areas of China when they consumed spirulina in their daily meals. A total of 228 children (6–11 years) were recruited and randomly divided into three groups supplemented with 4 g (containing 4·18 µg β-carotene), 2 g (containing 2·54 µg β-carotene) or 0 g spirulina 5 d/week for 10 weeks, respectively. Before and after the intervention period, each child was given 0·5 mg [²H₄]retinyl acetate and [²H₈]retinyl acetate, respectively. To assess vitamin A stores, blood samples (3 ml) were collected on the third and the twenty-first day after each labelled retinyl acetate dose for a retinol enrichment analysis using a GC mass spectrometer. The concentrations of retinol and β-carotene in serum samples were also determined by using HPLC. After the 10-week intervention, serum β-carotene concentrations of children with 2 or 4 g spirulina supplement increased by 0·160 and 0·389 µmmol/l, respectively. Total-body vitamin A stores increased significantly, with a median increase of 0·160 mmol in children taking 2 g spirulina and of 0·279 mmol in children taking 4 g spirulina. Spirulina is a good dietary source of β-carotene, which may effectively increase the total-body vitamin A stores of Chinese school-age children.

Ten-year trends in vitamin intake in free-living healthy elderly people: the risk of subclinical malnutrition

OBJECTIVE

To explore the trends of vitamin intake over a 10-year follow-up in a group of successfully aging elderly people.

DESIGN

Longitudinal study.

SETTING

City of Padua, Italy.

PARTICIPANTS

78 (34M/44F) free-living and still well-functioning survivors among the Italian participants in the SENECA multicenter project, aged 70-75 y at the baseline.

MEASUREMENTS

data were collected by means of a modified validated dietary history, both at baseline and then 10 y later. The dietary intake of vitamins B1, B2, A and C were considered, calculating the percentages of individuals with an intake below the lowest European Recommended Dietary Intake (RDI).

RESULTS

mean energy and macronutrient intake were consistent with dietary guidelines at both time points. There was no decline in total energy intake after a decade. At baseline, the intake of all vitamins exceeded the Lowest European RDI, with the exception of vitamin B1, for which 44% of the men and 60% of the women were already deficient. After a decade, the prevalence of vitamin B2 and vitamin A deficiencies rose to 50% of the sample. Vitamin C deficiencies rose in a decade from 3% to 6% in men and from 2.3% to 4.5% in women and it was the least prevalent.

CONCLUSION

despite an adequate nutritional/functional status and a total energy intake that could be expected to cover the recommendations for micronutrients too, a considerable proportion of our successfully aging elderly were already deficient in, or at high risk of becoming deficient in several essential vitamins. Multivitamin supplementation may be necessary, even in healthy individuals, to ensure an adequate micronutrient intake in the elderly.

Mathematical modeling of serum 13C-retinol in captive rhesus monkeys provides new insights on hypervitaminosis A

Hypervitaminosis A is increasingly a public health concern, and thus noninvasive quantitative methods merit exploration. In this study, we applied the (13)C-retinol isotope dilution test to a nonhuman primate model with excessive liver stores. After baseline serum chemistries, rhesus macaques (Macaca mulatta; n = 16) were administered 3.5 mumol (13)C(2)-retinyl acetate. Blood was drawn at baseline, 5 h, and 2, 4, 7, 14, 21, and 28 d following the dose. Liver biopsies were collected 7 d before and 2 d after dosing (n = 4) and at 7, 14, and 28 d (n = 4/time) after dosing. Serum and liver were analyzed by HPLC and GC-combustion-isotope ratio MS for retinol and its enrichment, respectively. Model-based compartmental analysis was applied to serum data. Lactate dehydrogenase was elevated in 50% of the monkeys. Total body reserves (TBR) of vitamin A (VA) were calculated at 28 d. Predicted TBR (3.52 +/- 2.01 mmol VA) represented measured liver stores (4.56 +/- 1.38 mmol VA; P = 0.124). Predicted liver VA concentrations (13.3 +/- 9.7 micromol/g) were similar to measured liver VA concentrations (16.4 +/- 5.3 micromol/g). The kinetic models predict that 27-52% of extravascular VA is exchanging with serum in hypervitaminotic A monkeys. The test correctly diagnosed hypervitaminosis A in all monkeys, i.e. 100% sensitivity. Stable isotope techniques have important public health potential for the classification of VA status, including hypervitaminosis, because no other technique besides invasive liver biopsies, correctly identifies excessive liver VA stores.

Physical activity, energy requirements, and adequacy of dietary intakes of older persons in a rural Filipino community

Background

Aging is a process associated with physiological changes such as in body composition, energy expenditure and physical activity. Data on energy and nutrient intake adequacy among elderly is important for disease prevention, health maintenance and program development.

Methods

This descriptive cross-sectional study was designed to determine the energy requirements and adequacy of energy and nutrient intakes of older persons living in private households in a rural Filipino community. Study participants were generally-healthy, ambulatory, and community living elderly aged 60–100 y (n = 98), 88 of whom provided dietary information in three nonconsecutive 24-hour food-recall interviews.

Results

There was a decrease in both physical activity and food intake with increasing years. Based on total energy expenditure and controlling for age, gender and socio-economic status, the average energy requirement for near-old (≥ 60 to < 65 y) males was 2074 kcal/d, with lower requirements, 1919 and 1699 kcal/d for the young-old (≥ 65 to < 75 y) and the old-old (≥ 75 y), respectively. Among females, the average energy requirements for the 3 age categories were 1712, 1662, and 1398 kcal/d, respectively. Actual energy intakes, however, were only ~65% adequate for all subjects as compared to energy expenditure. Protein, fat, and micronutrients (vitamins A and C, thiamin, riboflavin, iron and calcium) intakes were only ~24–51% of the recommended daily intake. Among this population, there was a weight decrease of 100 g (p = 0.012) and a BMI decrease of 0.04 kg/m² (p = 0.003) for every 1% decrease in total caloric intake as percentage of the total energy expenditure requirements.

Conclusion

These community living elderly suffer from lack of both macronutrient intake as compared with energy requirements, and micronutrient intake as compared with the standard dietary recommendations. Their energy intakes are ~65% of the amounts required based on their total energy expenditure. Though their intakes decrease with increasing age, so do their energy expenditure, making their relative insufficiency of food intake stable with age.

Vitamin A: is it a risk factor for osteoporosis and bone fracture?

Results from observational studies of the association between vitamin A intake or serum concentration and bone mineral density or fracture are mixed. The inconsistencies may be due, in part, to difficulties in obtaining an accurate assessment of vitamin A intake or status. Serum retinol is a poor measure of vitamin A status because it is subject to homeostatic control. Stable-isotope-dilution methodology gives a validated assessment of the total-body and liver vitamin A stores and is recommended in future studies on vitamin A status and osteoporosis. The potential for exacerbating an already serious public health problem with intakes of vitamin A currently considered safe indicates further research into this matter is warranted.

Carotene-rich plant foods ingested with minimal dietary fat enhance the total-body vitamin A pool size in Filipino schoolchildren as assessed by stable-isotope-dilution methodology

BACKGROUND

Strategies for improving the vitamin A status of vulnerable populations are needed.

OBJECTIVE

We studied the influence of the amounts of dietary fat on the effectiveness of carotene-rich plant foods in improving vitamin A status.

DESIGN

Schoolchildren aged 9-12 y were fed standardized meals 3 times/d, 5 d/wk, for 9 wk. The meals provided 4.2 mg provitamin A carotenoids/d (mainly beta-carotene) from yellow and green leafy vegetables [carrots, pechay (bok choy), squash, and kangkong (swamp cabbage)] and 7, 15, or 29 g fat/d (2.4, 5, or 10 g fat/meal) in groups A, B, and C (n = 39, 39, and 38, respectively). Other self-selected foods eaten were recorded daily. Before and after the intervention, total-body vitamin A pool sizes and liver vitamin A concentrations were measured with the deuterated-retinol-dilution method; serum retinol and carotenoid concentrations were measured by HPLC.

RESULTS

Similar increases in mean serum beta-carotene (5-fold), alpha-carotene (19-fold), and beta-cryptoxanthin (2-fold) concentrations; total-body vitamin A pool size (2-fold); and liver vitamin A (2-fold) concentrations were observed after 9 wk in the 3 study groups; mean serum retinol concentrations did not change significantly. The total daily beta-carotene intake from study meals plus self-selected foods was similar between the 3 groups and was 14 times the usual intake; total fat intake was 0.9, 1.4, or 2.0 times the usual intake in groups A, B, and C, respectively. The overall prevalence of low liver vitamin A (<0.07 mumol/g) decreased from 35% to 7%.

CONCLUSIONS

Carotene-rich yellow and green leafy vegetables, when ingested with minimal fat, enhance serum carotenoids and the total-body vitamin A pool size and can restore low liver vitamin A concentrations to normal concentrations.

Stable isotope dilution techniques for assessing vitamin A status and bioefficacy of provitamin A carotenoids in humans

Vitamin A deficiency is a major global public health problem. Among the variety of techniques that are available for assessing human vitamin A status, evaluating the provitamin A nutritional values of foodstuffs and estimating human vitamin A requirements, isotope dilution provides the most accurate estimates. Although the relative expense of isotope dilution restricts its applications, it has an important function as the standard of reference for other techniques. Mathematical modelling plays an indispensable role in the interpretation of isotope dilution data. This review summarises recent applications of stable isotope methodology to determine human vitamin A status, estimate human vitamin A requirements, and calculate the bioconversion and bioefficacy of food carotenoids.

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.