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Nutrients Jul 2022Vitamin A is a fat-soluble micronutrient necessary for the growth of healthy skin and hair. However, both too little and too much vitamin A has deleterious effects.... (Review)
Review
Vitamin A is a fat-soluble micronutrient necessary for the growth of healthy skin and hair. However, both too little and too much vitamin A has deleterious effects. Retinoic acid and retinal are the main active metabolites of vitamin A. Retinoic acid dose-dependently regulates hair follicle stem cells, influencing the functioning of the hair cycle, wound healing, and melanocyte stem cells. Retinoic acid also influences melanocyte differentiation and proliferation in a dose-dependent and temporal manner. Levels of retinoids decline when exposed to ultraviolet irradiation in the skin. Retinal is necessary for the phototransduction cascade that initiates melanogenesis but the source of that retinal is currently unknown. This review discusses new research on retinoids and their effects on the skin and hair.
Topics: Hair; Retinoids; Skin; Tretinoin; Vitamin A
PubMed: 35889909
DOI: 10.3390/nu14142952 -
Nutrition in Clinical Practice :... Dec 2019Vitamin A is a general term for retinoids. Vitamin A deficiency leads to a variety of cutaneous manifestations. It also functions as a hormone through retinoic acid... (Review)
Review
Vitamin A is a general term for retinoids. Vitamin A deficiency leads to a variety of cutaneous manifestations. It also functions as a hormone through retinoic acid receptors altering the activity of multiple cell lines. Pancreatic vitamin A levels are critical for retinoid signaling and normal pancreatic control of glucose. Vitamin A deficiency is more common during infection, and supplementation reduces severe morbidity and mortality from infectious diseases. Vitamin A modulates activities at the cellular level and, via its interrelationship with hormones such as thyroid, insulin, and corticosteroids, has diffuse metabolic effects on the body. It plays an important role in all stages of wound healing. Vitamin A is known for its ability to stimulate epithelial growth, fibroblasts, granulation tissue, angiogenesis, collagen synthesis, epithelialization, and fibroplasia. Local (topical) and systemic supplementation with vitamin A has been proven to increase dermal collagen deposition. There are numerous animal studies and limited human studies regarding physiologic effect of vitamin A on acute or chronic wounds via systemic or topical administration. The most common use of vitamin A supplementation is to offset steroids' effect. When considering supplementation, the potential benefits must be weighed against the risk of harm. Vitamin A toxicity can be critical and even result in death. The evidence for supplementation with vitamin A is currently limited to expert opinion and is not backed up by rigorous trials. There is an acute need for therapeutic trials with vitamin A supplementations.
Topics: Administration, Oral; Administration, Topical; Animals; Dietary Supplements; Humans; Vitamin A; Vitamin A Deficiency; Vitamins; Wound Healing; Wounds and Injuries
PubMed: 31697447
DOI: 10.1002/ncp.10420 -
Nutrition Research (New York, N.Y.) Nov 2021The gut microbiome plays important roles in the maintenance of host health and the pathogenesis of many diseases. Diet is a key modulator of the gut microbiome. There is... (Review)
Review
The gut microbiome plays important roles in the maintenance of host health and the pathogenesis of many diseases. Diet is a key modulator of the gut microbiome. There is increasing evidence that nutrients other than fermentable fiber affect the gut microbial composition. In this review, we discuss the effects of vitamins on the gut microbiome, and related gastrointestinal health, based on in vitro, animal and human studies. Some vitamins, when provided in large doses or when delivered to the large intestine, have been shown to beneficially modulate the gut microbiome by increasing the abundance of presumed commensals (vitamins A, B, D, E, and beta-carotene), increasing or maintaining microbial diversity (vitamins A, B, B, C, K) and richness (vitamin D), increasing short chain fatty acid production (vitamin C), or increasing the abundance of short chain fatty acid producers (vitamins B, E). Others, such as vitamins A and D, modulate the gut immune response or barrier function, thus, indirectly influencing gastrointestinal health or the microbiome. Future research is needed to explore these potential effects and to elucidate the underlying mechanisms and host health benefits.
Topics: Animals; Fatty Acids, Volatile; Gastrointestinal Microbiome; Humans; Microbiota; Vitamin A; Vitamins
PubMed: 34798467
DOI: 10.1016/j.nutres.2021.09.001 -
Biomolecules Nov 2023The skin is the most-extensive and -abundant tissue in the human body. Like many organs, as we age, human skin experiences gradual atrophy in both the epidermis and... (Review)
Review
The skin is the most-extensive and -abundant tissue in the human body. Like many organs, as we age, human skin experiences gradual atrophy in both the epidermis and dermis. This can be primarily attributed to the diminishing population of epidermal stem cells and the reduction in collagen, which is the primary structural protein in the human body. The alterations occurring in the epidermis and dermis due to the aging process result in disruptions to the structure and functionality of the skin. This creates a microenvironment conducive to age-related skin conditions such as a compromised skin barrier, slowed wound healing, and the onset of skin cancer. This review emphasizes the recent molecular discoveries related to skin aging and evaluates preventive approaches, such as the use of topical retinoids. Topical retinoids have demonstrated promise in enhancing skin texture, diminishing fine lines, and augmenting the thickness of both the epidermal and dermal layers.
Topics: Humans; Vitamin A; Skin Aging; Skin; Retinoids; Aging
PubMed: 38002296
DOI: 10.3390/biom13111614 -
International Journal of Molecular... Jan 2022Vitamin A is an essential fat-soluble vitamin that occurs in various chemical forms. It is essential for several physiological processes. Either hyper- or... (Review)
Review
Vitamin A is an essential fat-soluble vitamin that occurs in various chemical forms. It is essential for several physiological processes. Either hyper- or hypovitaminosis can be harmful. One of the most important vitamin A functions is its involvement in visual phototransduction, where it serves as the crucial part of photopigment, the first molecule in the process of transforming photons of light into electrical signals. In this process, large quantities of vitamin A in the form of 11--retinal are being isomerized to all--retinal and then quickly recycled back to 11--retinal. Complex machinery of transporters and enzymes is involved in this process (i.e., the visual cycle). Any fault in the machinery may not only reduce the efficiency of visual detection but also cause the accumulation of toxic chemicals in the retina. This review provides a comprehensive overview of diseases that are directly or indirectly connected with vitamin A pathways in the retina. It includes the pathophysiological background and clinical presentation of each disease and summarizes the already existing therapeutic and prospective interventions.
Topics: Gene Expression Regulation; Humans; Light Signal Transduction; Retinal Diseases; Signal Transduction; Vitamin A
PubMed: 35162940
DOI: 10.3390/ijms23031014 -
Nutrition in Clinical Practice :... Oct 2019Vitamin A is an essential micronutrient that comes in multiple forms, including retinols, retinals, and retinoic acids. Dietary vitamin A is absorbed as retinol from... (Review)
Review
Vitamin A is an essential micronutrient that comes in multiple forms, including retinols, retinals, and retinoic acids. Dietary vitamin A is absorbed as retinol from preformed retinoids or as pro-vitamin A carotenoids that are converted into retinol in the enterocyte. These are then delivered to the liver for storage via chylomicrons and later released into the circulation and to its biologically active tissues bound to retinol-binding protein. Vitamin A is a crucial component of many important and diverse biological functions, including reproduction, embryological development, cellular differentiation, growth, immunity, and vision. Vitamin A functions mostly through nuclear retinoic acid receptors, retinoid X receptors, and peroxisome proliferator-activated receptors. Retinoids regulate the growth and differentiation of many cell types within skin, and its deficiency leads to abnormal epithelial keratinization. In wounded tissue, vitamin A stimulates epidermal turnover, increases the rate of re-epithelialization, and restores epithelial structure. Retinoids have the unique ability to reverse the inhibitory effects of anti-inflammatory steroids on wound healing. In addition to its role in the inflammatory phase of wound healing, retinoic acid has been demonstrated to enhance production of extracellular matrix components such as collagen type I and fibronectin, increase proliferation of keratinocytes and fibroblasts, and decrease levels of degrading matrix metalloproteinases.
Topics: Humans; Receptors, Retinoic Acid; Retinoids; Retinol-Binding Proteins; Vitamin A; Wound Healing
PubMed: 31389093
DOI: 10.1002/ncp.10376 -
Alternative Therapies in Health and... Jul 2021Vitamins and their derivatives are used extensively in the field of dermatology to treat a range of conditions, both benign and malignant. Additionally, over the past... (Review)
Review
BACKGROUND
Vitamins and their derivatives are used extensively in the field of dermatology to treat a range of conditions, both benign and malignant. Additionally, over the past decade, vitamin supplements have been heavily advertised for improving overall health. Due to the widespread use of vitamins and their derivatives for dermatologic conditions, a comprehensive review of the evidence is needed.
OBJECTIVE
Here we review several of the well-established uses of vitamins A, B, C, and D in the management of dermatologic conditions ranging from acne vulgaris to malignant melanoma. Additionally, we examine the dermatologic consequences of both deficiency and excess of vitamins A, B, C, and D. Finally, we delve into newer applications for these vitamins and evaluate the evidence behind them.
CONCLUSION
Vitamins, in both topical and oral forms, play a key role in treating many dermatologic conditions. Some of the newer applications of vitamins, such as the use of vitamin B3 for non-melanoma skin cancer prevention, vitamin B6 for prevention of chemotherapy-induced alopecia, and vitamin C as an adjuvant treatment for malignant melanoma, appear promising. Further data is needed to validate these findings. Additionally, many people use vitamin B7 for hair, skin, and nail health. There is evidence that supports vitamin B7 supplementation in patients with uncombable hair syndrome, brittle nail syndrome, and seborrheic dermatitis. Some studies Some studies have also demonstrated a benefit in healthy individuals, although other studies have shown a neutral effect. Further randomized controlled trials are needed. Likewise, the use of vitamin D for the treatment of atopic dermatitis has conflicting results and requires further investigation. New research continues to emerge regarding vitamin supplementation, and it is an important topic for dermatologists.
Topics: Ascorbic Acid; Dermatologists; Dietary Supplements; Humans; Vitamin A; Vitamin D; Vitamins
PubMed: 33245705
DOI: No ID Found -
Ciencia & Saude Coletiva Mar 2019To evaluate the effect of vitamin A supplementation in postpartum infants and women on serum retinol levels and breast milk. The databases Medline, PubMed, Lilacs and...
To evaluate the effect of vitamin A supplementation in postpartum infants and women on serum retinol levels and breast milk. The databases Medline, PubMed, Lilacs and SciELO were consulted. The descriptors used were vitamin A, dietary supplement, child, postpartum period, infant and nutrition programs policies. Search found 7432 articles. After elimination of duplicity and application of eligibility criteria, 8 studies remained. All evaluated the effect of vitamin A supplementation on immediate postpartum, five studies used retinyl palmitate supplementation, one with retinyl palmitate and two did not specify the form of supplementation. Six studies evaluated colostrum and two included supplementation of children. It was found that supplementation in the puerperium increases the concentrations of serum retinol and breast milk, however, this result was in the short term and was relevant when the previous concentrations of the mother were low. When maternal serum concentrations are adequate, the retinol content in milk does not change, with little relevance for children. Further studies should be performed to evaluate the effect of megadoses supplementation on serum concentrations of children.
Topics: Colostrum; Dietary Supplements; Diterpenes; Female; Humans; Infant, Newborn; Milk, Human; Postpartum Period; Pregnancy; Retinyl Esters; Time Factors; Vitamin A; Vitamin A Deficiency
PubMed: 30892504
DOI: 10.1590/1413-81232018243.07112017 -
Nutrients Jan 2021Vitamin A is a fat-soluble vitamin that plays an important role in skin immunity. Deficiencies in Vitamin A have been linked to impaired immune response and increased... (Review)
Review
Vitamin A is a fat-soluble vitamin that plays an important role in skin immunity. Deficiencies in Vitamin A have been linked to impaired immune response and increased susceptibility to skin infections and inflammatory skin disease. This narrative review summarizes recent primary evidence that elucidates the role of vitamin A and its derivatives on innate immune regulators through mechanisms that promote skin immunity and sustain the skin microbiome.
Topics: Animals; Dermatitis; Humans; Immunity, Innate; Microbiota; Skin; Staphylococcus aureus; Tretinoin; Vitamin A; Vitamin A Deficiency
PubMed: 33494277
DOI: 10.3390/nu13020302 -
International Journal of Environmental... Sep 2019Rubella is a systemic virus infection that is usually mild. It can, however, cause severe birth defects known as the congenital rubella syndrome (CRS) when infection... (Review)
Review
Rubella is a systemic virus infection that is usually mild. It can, however, cause severe birth defects known as the congenital rubella syndrome (CRS) when infection occurs early in pregnancy. As many as 8%-13% of children with CRS developed autism during the rubella epidemic of the 1960s compared to the background rate of about 1 new case per 5000 children. Rubella infection and CRS are now rare in the U.S. and in Europe due to widespread vaccination. However, autism rates have risen dramatically in recent decades to about 3% of children today, with many cases appearing after a period of normal development ('regressive autism'). Evidence is reviewed here suggesting that the signs and symptoms of rubella may be due to alterations in the hepatic metabolism of vitamin A (retinoids), precipitated by the acute phase of the infection. The infection causes mild liver dysfunction and the spillage of stored vitamin A compounds into the circulation, resulting in an endogenous form of hypervitaminosis A. Given that vitamin A is a known teratogen, it is suggested that rubella infection occurring in the early weeks of pregnancy causes CRS through maternal liver dysfunction and exposure of the developing fetus to excessive vitamin A. On this view, the multiple manifestations of CRS and associated autism represent endogenous forms of hypervitaminosis A. It is further proposed that regressive autism results primarily from post-natal influences of a liver-damaging nature and exposure to excess vitamin A, inducing CRS-like features as a function of vitamin A toxicity, but without the associated dysmorphogenesis. A number of environmental factors are discussed that may plausibly be candidates for this role, and suggestions are offered for testing the model. The model also suggests a number of measures that may be effective both in reducing the risk of fetal CRS in women who acquire rubella in their first trimester and in reversing or minimizing regressive autism among children in whom the diagnosis is suspected or confirmed.
Topics: Autistic Disorder; Humans; Hypervitaminosis A; Liver; Liver Diseases; Rubella; Rubella Syndrome, Congenital; Rubella virus; Vitamin A
PubMed: 31546693
DOI: 10.3390/ijerph16193543