Discovery and biological relevance of 3,4-didehydroretinol (vitamin A) in small indigenous fish species and its potential as a dietary source for addressing vitamin A deficiency.

Discovered in the late 1920s, 3,4-didehydroretinol (DROL, vitamin A) plays a significant biological role in freshwater fish. The functions of this vitamin have been investigated but to a far lesser extent than those of retinol (ROL, vitamin A). A recent study indicating all-trans DROL has 119-127% vitamin A biological activity compared to that of all-trans ROL suggests the significance of DROL for addressing vitamin A deficiency (VAD) in comparison to ROL may be currently overlooked.

Consumption of canned citrus fruit meals increases human plasma β-cryptoxanthin concentration, whereas lycopene and β-carotene concentrations did not change in healthy adults.

Several studies suggest that β-cryptoxanthin has a greater plasma response from its common food sources than other carotenoids such as β-carotene and lycopene. The hypothesis of this study is that changes in plasma β-cryptoxanthin concentrations will be greater than changes in plasma β-carotene or lycopene concentrations even if these carotenoids are fed in a similar food matrix, such as citrus fruit. We tested this hypothesis by measuring changes in plasma concentrations of β-cryptoxanthin, lycopene, and β-carotene after feeding measured amounts of canned tangerines and pink grapefruit to healthy nonsmoking adult humans.

Absorption, metabolism, and functions of β-cryptoxanthin.

β-Cryptoxanthin, a carotenoid found in fruits and vegetables such as tangerines, red peppers, and pumpkin, has several functions important for human health. Most evidence from observational, in vitro, animal model, and human studies suggests that β-cryptoxanthin has relatively high bioavailability from its common food sources, to the extent that some β-cryptoxanthin-rich foods might be equivalent to β-carotene-rich foods as sources of retinol. β-Cryptoxanthin is an antioxidant in vitro and appears to be associated with decreased risk of some cancers and degenerative diseases.

Red palm oil-supplemented and biofortified cassava gari increase the carotenoid and retinyl palmitate concentrations of triacylglycerol-rich plasma in women.

Boiled biofortified cassava containing β-carotene can increase retinyl palmitate in triacylglycerol-rich plasma. Thus, it might alleviate vitamin A deficiency. Cassava requires extensive preparation to decrease its level of cyanogenic glucosides, which can be fatal.

Beta-cryptoxanthin as a source of vitamin A.

Beta-cryptoxanthin is a common carotenoid that is found in fruit, and in human blood and tissues. Foods that are rich in beta-cryptoxanthin include tangerines, persimmons and oranges. Beta-cryptoxanthin has several functions that are important for human health, including roles in antioxidant defense and cell-to-cell communication.

Bioavailability of iron, zinc, and provitamin A carotenoids in biofortified staple crops.

International research efforts, including those funded by HarvestPlus, a Challenge Program of the Consultative Group on International Agricultural Research (CGIAR), are focusing on conventional plant breeding to biofortify staple crops such as maize, rice, cassava, beans, wheat, sweet potatoes, and pearl millet to increase the concentrations of micronutrients that are commonly deficient in specific population groups of developing countries. The bioavailability of micronutrients in unfortified staple crops in developing regions is typically low, which raises questions about the efficacy of these crops to improve population micronutrient status. This review of recent studies of biofortified crops aims to assess the micronutrient bioavailability of biofortified staple crops in order to derive lessons that may help direct plant breeding and to infer the potential efficacy of food-based nutrition interventions.

Gastric digestion of raw and roasted almonds in vivo.

Almonds are an important dietary source of lipids, protein, and α-tocopherol. It has been demonstrated that the physical form of almond kernels influences their digestion and absorption, but the role of thermal processes on the digestion of almonds has received little attention. The objectives of this study were to examine the gastric emptying and nutrient composition of gastric chyme from pigs (used as a model for the adult human) fed a single meal of either raw or roasted almonds over a 12-h postprandial period (72 pigs total, 6 pigs at each diet-time combination).

Assessment of tissue distribution and concentration of β-cryptoxanthin in response to varying amounts of dietary β-cryptoxanthin in the Mongolian gerbil.

There is a general lack of knowledge regarding the absorption and tissue storage of the provitamin A carotenoid β-cryptoxanthin. The present study investigated the whole-body tissue distribution of β-cryptoxanthin in an appropriate small animal model, the Mongolian gerbil (Meriones unguiculatus), for human provitamin A carotenoid metabolism. After 5 d of carotenoid depletion, five gerbils were euthanised for baseline measurements.

The effects of daily consumption of β-cryptoxanthin-rich tangerines and β-carotene-rich sweet potatoes on vitamin A and carotenoid concentrations in plasma and breast milk of Bangladeshi women with low vitamin A status in a randomized controlled trial.

Background: The potential of β-cryptoxanthin (CX)-rich foods to form vitamin A (VA) in humans in not well understood.

Objective: We measured the effects of consuming CX- and β-carotene (BC)-rich foods on plasma and breast milk VA and carotenoids in lactating women with low VA status.

Design: Participants were randomly assigned to 4 groups (n = 34, 34, 34, and 33, respectively) receiving orange-fleshed sweet potatoes (OFSPs) (12 mg BC/d), tangerines (5.

Biofortified cassava increases β-carotene and vitamin A concentrations in the TAG-rich plasma layer of American women.

Biofortification of cassava with the provitamin A carotenoid β-carotene is a potential mechanism for alleviating vitamin A deficiency. Cassava is a staple food in the African diet, but data regarding the human bioavailability of β-carotene from this food are scarce. The objective of the present study was to evaluate provitamin A-enhanced cassava as a source of β-carotene and vitamin A for healthy adult women.

Modelling potential β-carotene intake and cyanide exposure from consumption of biofortified cassava.

Vitamin A (VA) deficiency causes disability and mortality. Cassava can be crossbred to improve its β-carotene (BC) content; typical white cassava contains negligible amounts of BC. However, cassava contains cyanide and its continued consumption may lead to chronic disability.

Release and bioaccessibility of β-carotene from fortified almond butter during in vitro digestion.

The objective of this study was to determine the release and bioaccessibility of β-carotene from fortified almond butter using in vitro digestion models. Two types of fortifiers were investigated: β-carotene oil (oil) and whey protein isolate (WPI)-alginate-chitosan capsules containing β-carotene oil (capsule). Shaking water bath and Human Gastric Simulator (HGS) digestion models assessed the impact of gastric peristalsis on the release of β-carotene.

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.

Absorption estimates improve the validity of the relationship between dietary and serum lycopene.

Objective: Studies show low correlations between dietary intake and serum concentrations of lycopene, which make it difficult to assess the effectiveness of dietary interventions with this phytonutrient. We hypothesized that 1) combining food-frequency questionnaires (FFQs) and 3-d diet records (3D-DRs) by the triads method would improve the validity of this relation and 2) correcting dietary information for differences in lycopene absorption from food matrices would further improve validity.

Methods: We measured dietary intakes of lycopene from 49 adults by 3D-DR and FFQ.

A minute dose of 14C-{beta}-carotene is absorbed and converted to retinoids in humans.

Our objective was to quantify the absorption and conversion to retinoids of a 1.01-nmol, 3.7-kBq oral dose of (14)C-beta-carotene in 8 healthy adults.

Tangerine tomatoes increase total and tetra-cis-lycopene isomer concentrations more than red tomatoes in healthy adult humans.

Lycopene, or the foods that contain it, may prevent prostate cancer. Studies suggest that some cis-lycopene isomers are more bioavailable than the trans-lycopene isomer. We hypothesized that tangerine tomatoes, which predominantly contain the tetra-cis isomer, should be a good source of bioavailable lycopene.

Effects of chronic ethanol ingestion and folate deficiency on the activity of 10-formyltetrahydrofolate dehydrogenase in rat liver.

Background: We recently observed that ethanol feeding impairs 10-formyltetrahydrofolate (10-FTHF) dehydrogenase (EC 1.5.1.

Extraction and chromatography of carotenoids from pumpkin.

Vitamin A deficiency is a health problem in Southeast Asia that can be corrected by feeding orange fruits and vegetables such as mango. Pumpkin is a traditional Korean food that is easy to store and is already believed to have health benefits. We extracted carotenoids from pumpkin by liquid-liquid extraction and by supercritical fluid extraction.

The triacylglycerol synthesis enzyme DGAT1 also catalyzes the synthesis of diacylglycerols, waxes, and retinyl esters.

The final step of triacylglycerol biosynthesis is catalyzed by acyl CoA:diacylglycerol acyltransferase (DGAT) enzymes. The two known DGATs, DGAT1 and DGAT2, are encoded by unrelated genes. Although both DGAT1 and DGAT2 knockout mice have reduced tissue triacylglycerol contents, they have disparate phenotypes, prompting us to investigate whether the two enzymes have unrecognized functional differences.

Kinetic parameters and plasma zinc concentration correlate well with net loss and gain of zinc from men.

The search for a reliable, convenient indicator of Zn status was the focus of research for several decades. Plasma Zn concentration is still the most widely used clinical measurement, despite the known problems of interpretation. More recently, researchers suggested that isotopically determined kinetic parameters, such as the exchangeable Zn pool (EZP), may more accurately and reliably reflect body Zn status.

Carotenoid and retinoid metabolism: insights from isotope studies.

Use of isotopes as tracers has had an important role in elucidating key features of vitamin A and retinoid metabolism in animal models and humans. Their use has shown that beta-carotene absorption is variable, and that the appearance of beta-carotene and its metabolites in the blood by time since dosing follows characteristic patterns. Retinol formed from beta-carotene shows a different pattern, as does lutein.

Measurements of the major isoforms of vitamins A and E and carotenoids in the blood of people with spinal-cord injuries.

We used reversed-phase HPLC with diode array detection to simultaneously measure the major isoforms of vitamins A, E, and the carotenoids in serum from 55 healthy people with spinal cord injuries. Typically, the method measured retinol (vitamin A), alpha-tocopherol (vitamin E) and beta-carotene, alpha-carotene, lutein, lycopene, and cryptoxanthin (carotenoids). gamma-Tocopherol (vitamin E), 25-hydroxycalciferol (vitamin D), and the carotenoid zeaxanthin could also be measured when they were present in high concentrations.

Dietary intakes and serum concentrations of vitamin E and total carotenoids of healthy adults with severe physical disabilities are lower than matched controls.

Millions of people worldwide have severe chronic physical disabilities (e.g., polio, spinal cord injury).

Variability in conversion of beta-carotene to vitamin A in men as measured by using a double-tracer study design.

Background: The vitamin A activity of beta-carotene is variable and surprisingly low in women. The reasons for this are not well understood. The vitamin A activity of beta-carotene in men is still uncertain.

DGAT1 is not essential for intestinal triacylglycerol absorption or chylomicron synthesis.

Dietary triacylglycerols are a major source of energy for animals. The absorption of dietary triacylglycerols involves their hydrolysis to free fatty acids and monoacylglycerols in the intestinal lumen, the uptake of these products into enterocytes, the resynthesis of triacylgylcerols, and the incorporation of newly synthesized triacylglycerols into nascent chylomicrons for secretion. In enterocytes, the final step in triacylglycerol synthesis is believed to be catalyzed primarily through the actions of acyl-CoA:diacylglycerol acyltransferase (DGAT) enzymes.