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Nutrients Mar 2022Lung cancer is one of the most common neoplasms globally, with about 2.2 million new cases and 1.8 million deaths annually. Although the most important factor in... (Meta-Analysis)
Meta-Analysis Review
Lung cancer is one of the most common neoplasms globally, with about 2.2 million new cases and 1.8 million deaths annually. Although the most important factor in reducing lung cancer risk is lifestyle change, most patients favour the use of supplements, for example, rather than quitting smoking or following a healthy diet. To better understand the efficacy of such interventions, a systematic review was performed of data from randomized controlled trials concerning the influence of beta-carotene supplementation on lung cancer risk in subjects with no lung cancer before the intervention. The search corpus comprised a number of databases and eight studies involving 167,141 participants, published by November 2021. The findings indicate that beta-carotene supplementation was associated with an increased risk of lung cancer (RR = 1.16, 95% CI = 1.06-1.26). This effect was even more noticeable among smokers and asbestos workers (RR = 1.21, 95% CI = 1.08-1.35) and non-medics (RR = 1.18, 95% CI = 1.07-1.29). A meta-regression found no relationship between the beta-carotene supplementation dose and the size of the negative effect associated with lung cancer risk. Our findings indicate that beta-carotene supplementation has no effect on lung cancer risk. Moreover, when used as the primary chemoprevention, beta-carotene may, in fact, increase the risk of lung cancer.
Topics: Antioxidants; Dietary Supplements; Humans; Lung Neoplasms; Smoking; beta Carotene
PubMed: 35405977
DOI: 10.3390/nu14071361 -
ELife Sep 2020Carotenoids are essential in oxygenic photosynthesis: they stabilize the pigment-protein complexes, are active in harvesting sunlight and in photoprotection. In plants,...
Carotenoids are essential in oxygenic photosynthesis: they stabilize the pigment-protein complexes, are active in harvesting sunlight and in photoprotection. In plants, they are present as carotenes and their oxygenated derivatives, xanthophylls. While mutant plants lacking xanthophylls are capable of photoautotrophic growth, no plants without carotenes in their photosystems have been reported so far, which has led to the common opinion that carotenes are essential for photosynthesis. Here, we report the first plant that grows photoautotrophically in the absence of carotenes: a tobacco plant containing only the xanthophyll astaxanthin. Surprisingly, both photosystems are fully functional despite their carotenoid-binding sites being occupied by astaxanthin instead of β-carotene or remaining empty (i.e. are not occupied by carotenoids). These plants display non-photochemical quenching, despite the absence of both zeaxanthin and lutein and show that tobacco can regulate the ratio between the two photosystems in a very large dynamic range to optimize electron transport.
Topics: Photosynthesis; Plants, Genetically Modified; Nicotiana; Xanthophylls; beta Carotene
PubMed: 32975516
DOI: 10.7554/eLife.58984 -
Acta Ophthalmologica Dec 2022The aim of this paper is to summarize all available evidence from systematic reviews, randomized controlled trials (RCTs) and comparative nonrandomized studies (NRS) on... (Review)
Review
The aim of this paper is to summarize all available evidence from systematic reviews, randomized controlled trials (RCTs) and comparative nonrandomized studies (NRS) on the association between nutrition and antioxidant, vitamin, and mineral supplements and the development or progression of age-related macular degeneration (AMD). The Cochrane Database of Systematic Reviews, Cochrane register CENTRAL, MEDLINE and Embase were searched and studies published between January 2015 and May 2021 were included. The certainty of evidence was assessed according to the GRADE methodology. The main outcome measures were development of AMD, progression of AMD, and side effects. We included 7 systematic reviews, 7 RCTs, and 13 NRS. A high consumption of specific nutrients, i.e. β-carotene, lutein and zeaxanthin, copper, folate, magnesium, vitamin A, niacin, vitamin B6, vitamin C, docosahexaenoic acid, and eicosapentaenoic acid, was associated with a lower risk of progression of early to late AMD (high certainty of evidence). Use of antioxidant supplements and adherence to a Mediterranean diet, characterized by a high consumption of vegetables, whole grains, and nuts and a low consumption of red meat, were associated with a decreased risk of progression of early to late AMD (moderate certainty of evidence). A high consumption of alcohol was associated with a higher risk of developing AMD (moderate certainty of evidence). Supplementary vitamin C, vitamin E, or β-carotene were not associated with the development of AMD, and supplementary omega-3 fatty acids were not associated with progression to late AMD (high certainty of evidence). Research in the last 35 years included in our overview supports that a high intake of specific nutrients, the use of antioxidant supplements and adherence to a Mediterranean diet decrease the risk of progression of early to late AMD.
Topics: Humans; Antioxidants; Ascorbic Acid; beta Carotene; Dietary Supplements; Macular Degeneration; Vitamins
PubMed: 35695158
DOI: 10.1111/aos.15191 -
Biochimica Et Biophysica Acta.... Nov 2020Vitamin A is an essential nutrient, critical for proper embryonic development in mammals. Both embryonic vitamin A-deficiency or -excess lead to congenital malformations... (Review)
Review
Vitamin A is an essential nutrient, critical for proper embryonic development in mammals. Both embryonic vitamin A-deficiency or -excess lead to congenital malformations or lethality in mammals, including humans. This is due to the defective transcriptional action of retinoic acid, the active form of vitamin A, that regulates in a spatial- and temporal-dependent manner the expression of genes essential for organogenesis. Thus, an adequate supply of vitamin A from the maternal circulation is vital for normal mammalian fetal development. Provitamin A carotenoids circulate in the maternal bloodstream and are available to the embryo. Of all the dietary carotenoids, β-carotene is the main vitamin A precursor, contributing at least 30% of the vitamin A intake in the industrialized countries and often constituting the sole source of retinoids (vitamin A and its derivatives) in the developing world. In humans, up to 40% of the absorbed dietary β-carotene is incorporated in its intact form in chylomicrons for distribution to other organs within the body, including the developing tissues. Here, it can serve as a source of vitamin A upon conversion into apocarotenoids by its cleavage enzymes. Given that β-carotene is carried in the bloodstream by lipoproteins, and that the placenta acquires, assembles and secretes lipoproteins, it is becoming evident that the maternal-fetal transfer of β-carotene relies on lipoprotein metabolism. Here, we will explore the current knowledge about this important biological process, the cross-talk between carotenoid and lipid metabolism in the context of the maternal-fetal transfer of this provitamin A precursor, and the mechanisms whereby β-carotene is metabolized by the developing tissues. This article is part of a Special Issue entitled Carotenoids recent advances in cell and molecular biology edited by Johannes von Lintig and Loredana Quadro.
Topics: Animals; Carotenoids; Embryonic Development; Female; Humans; Lipoproteins; Maternal-Fetal Relations; Placenta; Pregnancy; Vitamin A; Vitamin A Deficiency; beta Carotene
PubMed: 31863969
DOI: 10.1016/j.bbalip.2019.158591 -
Food and Chemical Toxicology : An... Jun 2021β-Carotene oxidation products have newly discovered bioactivity in plants and animals. Synthetic fully oxidized β-carotene (OxBC) has application in supporting...
β-Carotene oxidation products have newly discovered bioactivity in plants and animals. Synthetic fully oxidized β-carotene (OxBC) has application in supporting livestock health, with potential human applications. The safety of synthetic OxBC has been evaluated. An Ames test showed weak-to-moderate mutagenicity in only one cell line at high concentrations. A mouse micronucleus assay established a non-toxic dose of 1800 mg/kg body weight, and no bone marrow micronuclei were induced. Plant sources of β-carotene inevitably contain varying levels of natural OxBC. Vegetable powders and dried forages can be especially rich. Intakes of natural OxBC for humans and livestock alike have been estimated. The exposure range for humans (1-22 mg/serving) is comparable to the safe intake of β-carotene (<15 mg/d). In livestock, OxBC in alfalfa can contribute ~550-850 mg/head/d for dairy cattle but in forage-deficient poultry feed much less (~1 ppm). Livestock intake of supplemental synthetic OxBC is comparable to OxBC potentially available from traditional plant sources. Human intake of synthetic OxBC in meat from livestock fed OxBC is similar to a single serving of food made with carrot powder. It is concluded that consumption of synthetic OxBC at levels comparable to natural OxBC is safe for humans and animals.
Topics: Animals; Cats; Cattle; Dietary Exposure; Dogs; Escherichia coli; Humans; Mice; Micronucleus Tests; Oxidation-Reduction; Poultry; Salmonella typhimurium; Swine; beta Carotene
PubMed: 33891992
DOI: 10.1016/j.fct.2021.112207 -
Food and Chemical Toxicology : An... Oct 2022Spontaneous oxidation of β-carotene yields a polymer-rich product (OxBC) together with minor amounts of many apocarotenoids. OxBC's activity extends β-carotene's...
Spontaneous oxidation of β-carotene yields a polymer-rich product (OxBC) together with minor amounts of many apocarotenoids. OxBC's activity extends β-carotene's benefits beyond vitamin A, finding utility in supporting health in livestock, pets, and humans. Although the naturally occurring form of OxBC is consumed in foods and feeds, a direct demonstration of synthetic OxBC's safety provides additional support for its usage. A toxicological study in rats showed a maximum tolerated single oral dose of 5000 mg/kg, an LD of more than 10,000 mg/kg, and a NOAEL of 1875 mg/kg body weight. A repeat-dose 90-day oral toxicity study showed no adverse physiological or pathological effects. A study of OxBC uptake by mice over 2-5 days showed OxBC already was naturally present. The highest levels were in liver, lung, and hamstring. Dosing did not increase levels in liver, kidney, lung, and muscle. Increases occurred in urine, intestinal content, plasma, feces, spleen, and cecum with preferential elimination of polymer, consistent with processing of OxBC. Compared to the 4:1 polymer: apocarotenoid ratio of OxBC, polymer was enriched in liver and spleen and depleted in lung, kidney, hamstring, and abdominal muscle. The apparent control of OxBC in major tissues further supports its safety.
Topics: Animals; Biological Transport; Humans; Liver; Mice; Polymers; Rats; Vitamin A; beta Carotene
PubMed: 36041660
DOI: 10.1016/j.fct.2022.113387 -
Molecules (Basel, Switzerland) Oct 2022β-cyclocitral (βCC), a main apocarotenoid of β-carotene, increases plants' resistance against stresses. It has recently appeared as a novel bioactive composite in a... (Review)
Review
β-cyclocitral (βCC), a main apocarotenoid of β-carotene, increases plants' resistance against stresses. It has recently appeared as a novel bioactive composite in a variety of organisms from plants to animals. In plants, βCC marked as stress signals that accrue under adverse ecological conditions. βCC regulates nuclear gene expression through several signaling pathways, leading to stress tolerance. In this review, an attempt has been made to summarize the recent findings of the potential role of βCC. We emphasize the βCC biosynthesis, signaling, and involvement in the regulation of abiotic stresses. From this review, it is clear that discussing compound has great potential against abiotic stress tolerance and be used as photosynthetic rate enhancer. In conclusion, this review establishes a significant reference base for future research.
Topics: beta Carotene; Plants; Diterpenes; Aldehydes; Stress, Physiological; Gene Expression Regulation, Plant
PubMed: 36296438
DOI: 10.3390/molecules27206845 -
Nature Communications May 2022The endoperoxides of β-carotene (βCar-EPOs) are regarded as main products of the chemical deactivation of O by β-carotene, one of the most important antioxidants,...
The endoperoxides of β-carotene (βCar-EPOs) are regarded as main products of the chemical deactivation of O by β-carotene, one of the most important antioxidants, following a concerted singlet-singlet reaction. Here we challenge this view by showing that βCar-EPOs are formed in the absence of O in a non-concerted triplet-triplet reaction: O + β-carotene → βCar-EPOs, in which β-carotene manifests a strong biradical character. Thus, the reactivity of β-carotene towards oxygen is governed by its excited triplet state. βCar-EPOs, while being stable in the dark, are photochemically labile, and are a rare example of nonaromatic endoperoxides that release O, again not in a concerted reaction. Their light-induced breakdown triggers an avalanche of free radicals, which accounts for the pro-oxidant activity of β-carotene and the puzzling swap from its anti- to pro-oxidant features. Furthermore, we show that βCar-EPOs, and carotenoids in general, weakly sensitize O. These findings underlie the key role of the triplet state in determining the chemical and photophysical features of β-carotene. They shake up the prevailing models of carotenoid photophysics, the anti-oxidant functioning of β-carotene, and the role of O in chemical signaling in biological photosynthetic systems. βCar-EPOs and their degradation products are not markers of O and oxidative stress but of the overproduction of extremely hazardous chlorophyll triplets in photosystems. Hence, the chemical signaling of overexcitation of the photosynthetic apparatus is based on a chlorophyll-β-carotene relay, rather than on extremely short-lived O.
Topics: Carotenoids; Chlorophyll; Oxygen; Photosynthesis; Reactive Oxygen Species; beta Carotene
PubMed: 35513374
DOI: 10.1038/s41467-022-30095-z -
Molecules (Basel, Switzerland) Dec 2020Carotenoids are vital antioxidants for plants and animals. They protect cells from oxidative events and act against the inflammatory process and carcinogenesis. Among... (Review)
Review
Carotenoids are vital antioxidants for plants and animals. They protect cells from oxidative events and act against the inflammatory process and carcinogenesis. Among the most abundant carotenoids in human and foods is β-carotene. This carotenoid has the highest level of provitamin A activity, as it splits into two molecules of retinol through the actions of the cytosolic enzymes: β-carotene-15,15'-monooxygenase (β-carotene-15,15'-oxygenase 1) and β-carotene-9',10'-dioxygenase (β-carotene-9',10'-oxygenase 2). The literature supports the idea that β-carotene acts against type 2 diabetes mellitus, cardiovascular diseases, obesity, and metabolic syndrome. Due to the many processes involved in β-carotene biosynthesis and metabolic function, little is known about such components, since many mechanisms have not yet been fully elucidated. Therefore, our study concisely described the relationships between the consumption of carotenoids, with emphasis on β-carotene, and obesity and type 2 diabetes mellitus and its associated parameters in order to understand the preventive role of carotenoids better and encourage their consumption.
Topics: Animals; Antioxidants; Diabetes Mellitus, Type 2; Humans; Insulin Resistance; Lipid Metabolism; Obesity; Oxidative Stress; beta Carotene
PubMed: 33316948
DOI: 10.3390/molecules25245803 -
Biochimica Et Biophysica Acta.... Nov 2020Atherosclerotic cardiovascular disease (ASCVD) is the principal contributor to myocardial infarction, the leading cause of death worldwide. Epidemiological and... (Review)
Review
Atherosclerotic cardiovascular disease (ASCVD) is the principal contributor to myocardial infarction, the leading cause of death worldwide. Epidemiological and mechanistic studies indicate that β-carotene and its vitamin A derivatives stimulate lipid catabolism in several tissues to reduce the incidence of obesity, but their roles within ASCVD are elusive. Herein, we review the mechanisms by which β-carotene and vitamin A modulate ASCVD. First, we summarize the current knowledge linking these nutrients with epidemiological studies and lipoprotein metabolism as one of the initiating factors of ASCVD. Next, we focus on different aspects of vitamin A metabolism in immune cells such as the mechanisms of carotenoid uptake and conversion to the vitamin A metabolite, retinoic acid. Lastly, we review the effects of retinoic acid on immuno-metabolism, differentiation, and function of macrophages and T cells, the two pillars of the innate and adaptive immune response in ASCVD, respectively. This article is part of a Special Issue entitled Carotenoids recent advances in cell and molecular biology edited by Johannes von Lintig and Loredana Quadro.
Topics: Atherosclerosis; Biological Transport; Humans; Lipid Metabolism; Macrophages; Obesity; Vitamin A; beta Carotene
PubMed: 31978554
DOI: 10.1016/j.bbalip.2020.158635