Anthocyanin and Lycopene Contents Do Not Affect ß-Carotene Bioefficacy from Multicolored Carrots (Daucus carota L.) in Male Mongolian Gerbils.

BACKGROUND: Anthocyanins and carotenoids are phytochemicals that may benefit health through provitamin A carotenoid (PAC), antioxidant, and anti-inflammatory activities. These bioactives may mitigate chronic diseases. Consumption of multiple phytochemicals may impact bioactivity in synergistic or antagonistic manners. OBJECTIVES: Two studies in weanling male Mongolian gerbils assessed the relative bioefficacy of ß-carotene equivalents (BCEs) to vitamin A (VA) with simultaneous consumption of the non-PAC lycopene or anthocyanins from multicolored carrots. METHODS: After 3-wk VA depletion, 5-6 gerbils were killed as baseline groups. The remaining gerbils were divided into 4 carrot treatment groups; the positive control group received retinyl acetate and the negative control group was given vehicle soybean oil (n = 10/group; n = 60/study). In the lycopene study, gerbils consumed feed varying in lycopene sourced from red carrots. In the anthocyanin study, gerbils consumed feed varying in anthocyanin content sourced from purple-red carrots, and positive controls received lycopene. Treatment feeds had equalized BCEs: 5.59 ± 0.96 µg/g (lycopene study) and 7.02 ± 0.39 µg/g (anthocyanin study). Controls consumed feeds without pigments. Serum, liver, and lung samples were analyzed for retinol and carotenoid concentrations using HPLC. Data were analyzed by ANOVA and Tukey's studentized range test. RESULTS: In the lycopene study, liver VA did not differ between groups (0.11 ± 0.07 µmol/g) indicating no effect of varying lycopene content. In the anthocyanin study, liver VA concentrations in the medium-to-high (0.22 ± 0.14 µmol/g) and medium-to-low anthocyanin (0.25 ± 0.07 µmol/g) groups were higher than the negative control (0.11 ± 0.07 µmol/g) (P < 0.05). All treatment groups maintained baseline VA concentrations (0.23 ± 0.06 µmol/g). Combining studies, serum retinol had 12% sensitivity to predict VA deficiency, defined as 0.7 µmol/L. CONCLUSIONS: These gerbil studies suggested that simultaneous consumption of carotenoids and anthocyanins does not impact relative BCE bioefficacy. Breeding carrots for enhanced pigments to improve dietary intake should continue.

Inadequate Niacin Intake Disrupts Growth and Retinol Homeostasis Resulting in Higher Liver and Lower Serum Retinol Concentrations in Male Rats.

BACKGROUND: Niacin-derived nicotinamide adenine dinucleotide is an essential cofactor for many dehydrogenase enzymes involved in vitamin A (VA) metabolism. Several countries with high prevalence of VA deficiency rely on maize, a poor source of available niacin, as a dietary staple. OBJECTIVES: This study evaluated the interaction of dietary niacin on VA homeostasis using male Sprague-Dawley rats, aged 21 d (baseline body weight 88.3 ± 6.6 g). METHODS: After 1 wk of acclimation, baseline samples were collected (n = 4). Remaining rats (n = 54) were split into 9 groups to receive low tryptophan, VA-deficient feed with 3 different amounts of niacin (0, 15, or 30 mg/kg) and 3 different oral VA doses (50, 350, or 3500 nmol/d) in a 3 × 3 design. After 4 wk, the study was terminated. Serum, livers, and small intestine were analyzed for retinoids using high-performance liquid chromatography. Niacin and metabolites were evaluated with nuclear magnetic resonance. Plasma pyridoxal-P (PLP) was measured with high-performance liquid chromatography. RESULTS: Niacin intake correlated with serum retinol concentrations (r = 0.853, P < 0.001). For rats receiving the highest VA dose, liver retinol concentrations were lower in the 30-mg/kg niacin group (5.39 ± 0.27 µmol/g) than those in the 0-mg/kg and 15-mg/kg groups (9.18 ± 0.62 and 8.75 ± 0.07 µmol/g, respectively; P ≤ 0.05 for both). This phenomenon also occurred in the lower VA doses (P ≤ 0.05 for all). Growth and tissue weight at endline were associated with niacin intake (P ≤ 0.001 for all). Plasma PLP correlated with estimated niacin intake (r = 0.814, P < 0.001). CONCLUSIONS: Optimal niacin intake is associated with lower liver VA and higher serum retinol and plasma PLP concentrations. The extent to which vitamin B intake affects VA homeostasis requires further investigation to determine if the effects are maintained in humans.

Overlapping Vitamin A Interventions with Provitamin A Carotenoids and Preformed Vitamin A Cause Excessive Liver Retinol Stores in Male Mongolian Gerbils.

BACKGROUND: Vitamin A (VA) deficiency is a public health problem in some countries. Fortification, supplementation, and increased provitamin A consumption through biofortification are efficacious, but monitoring is needed due to risk of excessive VA intake when interventions overlap. OBJECTIVES: Two studies in 28-36-d-old male Mongolian gerbils simulated exposure to multiple VA interventions to determine the effects of provitamin A carotenoid consumption from biofortified maize and carrots and preformed VA fortificant on status. METHODS: Study 1 was a 2 × 2 × 2 factorial design (n = 85) with high-ß-carotene maize, orange carrots, and VA fortification at 50% estimated gerbil needs, compared with white maize and white carrot controls. Study 2 was a 2 × 3 factorial design (n = 66) evaluating orange carrot and VA consumption through fortification at 100% and 200% estimated needs. Both studies utilized 2-wk VA depletion, baseline evaluation, 9-wk treatments, and liver VA stores by HPLC. Intestinal scavenger receptor class B member 1 (Scarb1), ß-carotene 15,15'-dioxygenase (Bco1), ß-carotene 9',10'-oxygenase (Bco2), intestine-specific homeobox (Isx), and cytochrome P450 26A1 isoform α1 (Cyp26a1) expression was analyzed by qRT-PCR in study 2. RESULTS: In study 1, liver VA concentrations were significantly higher in orange carrot (0.69 ± 0.12 µmol/g) and orange maize groups (0.52 ± 0.21 µmol/g) compared with baseline (0.23 ± 0.069 µmol/g) and controls. Liver VA concentrations from VA fortificant alone (0.11 ± 0.053 µmol/g) did not differ from negative control. In study 2, orange carrot significantly enhanced liver VA concentrations (0.85 ± 0.24 µmol/g) relative to baseline (0.43 ± 0.14 µmol/g), but VA fortificant alone (0.42 ± 0.21 µmol/g) did not. Intestinal Scarb1 and Bco1 were negatively correlated with increasing liver VA concentrations (P < 0.01, r2 = 0.25-0.27). Serum retinol concentrations did not differ. CONCLUSIONS: Biofortified carrots and maize without fortification prevented VA deficiency in gerbils. During adequate provitamin A dietary intake, preformed VA intake resulted in excessive liver stores in gerbils, despite downregulation of carotenoid absorption and cleavage gene expression.

Mining maize diversity and improving its nutritional aspects within agro-food systems.

Agro-food systems are undergoing rapid innovation in the world and the system's continuum is promoted at different scales with one of the main outcomes to improve nutrition of consumers. Consumer knowledge through educational outreach is important to food and nutrition security and consumer demands guide breeding efforts. Maize is an important part of food systems. It is a staple food and together with rice and wheat, they provide 60% of the world's caloric intake. In addition to being a major contributor to global food and nutrition security, maize forms an important part of the culinary culture in many areas of Africa, the Americas, and Asia. Maize genetics are being exploited to improve human nutrition with the ultimate outcome of improving overall health. By impacting the health of maize consumers, market opportunities will be opened for maize producers with unique genotypes. Although maize is a great source of macronutrients, it is also a source of many micronutrients and phytochemicals purported to confer health benefits. The process of biofortification through traditional plant breeding has increased the protein, provitamin A carotenoid, and zinc contents of maize. The objective of this paper is to review the innovations developed and promoted to improve the nutritional profiles of maize and outcomes of the maize agro-food system.

Carrot Leaves Maintain Liver Vitamin A Concentrations in Male Mongolian Gerbils Regardless of the Ratio of α- to ß-Carotene When ß-Carotene Equivalents Are Equalized.

BACKGROUND: Carrots are an important horticultural crop that contain provitamin A carotenoids (PACs). Orange carrots have high concentrations of α-carotene, which upon central cleavage yields 1 retinal and 1 α-retinal molecule. The leaves of carrot plants are a source of PACs when consumed. OBJECTIVE: Male Mongolian gerbils aged 27-30 d were used to assess the bioefficacy of carrot leaves to maintain vitamin A (VA) status and investigate whether the ratio of α- to ß-carotene (α:ß-carotene) affected bioefficacy. METHODS: After 3 wk depletion, baseline gerbils were killed (n = 6) and the remaining gerbils (n = 60) were divided into 6 groups to receive 4 VA-deficient, carrot leaf-fortified feeds (1:1.4, 1:2.5, 1:5.0, and 1:80 α:ß-carotene ratio) equalized to 4.8 nmol/g ß-carotene equivalents (ßCEs), or VA-deficient feed with (VA+) or without (VA-) retinyl acetate supplements. Carrot-leaf powder from 4 carrot plants with differing α:ß-carotene ratios was used. After 4 wk, gerbils were killed and tissues were collected and analyzed for retinoids by HPLC. RESULTS: VA+ had higher total liver VA (means ± SD 0.91 ± 0.29 µmol) than all other groups (range: 0.40-0.62) (P ≤ 0.03), and the carrot leaf treatments did not differ from baseline (0.55 ± 0.09 µmol). VA- (0.40 ± 0.23 µmol VA/liver) did not differ from the leaf-fed groups, but 30% became VA deficient (defined as <0.1 µmol VA/g liver). α-Retinol accumulated in livers and lungs and was correlated to total α-carotene consumption (R2 = 0.83 and 0.88, respectively; P < 0.0001). Bioefficacy factors ranged from 4.2 to 6.2 µg ßCE to 1 µg retinol. CONCLUSIONS: Carrot leaves maintain VA status and prevent deficiency in gerbils regardless of the α:ß-carotene ratio. The bioconversion of PACs from carrot leaves to retinol is similar to what has been reported for other green leafy vegetables, making the consumption of carrot leaves a viable method to improve dietary PAC intake.