Vitamin a and e
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The Role of Vitamins A and E: Insights from Recent Research
Vitamin A and E Supplementation in Newborns
Importance of Vitamins A and E in Infants
Vitamins A and E are crucial antioxidants that play significant roles in immune function, growth, and development, especially in newborns. A study focusing on breast-fed term infants revealed that supplementation with 3000 IU of vitamin A and 5 IU of vitamin E over three months significantly increased the plasma levels of these vitamins compared to a placebo group1. This indicates that early supplementation can enhance the nutritional status of newborns, potentially supporting better health outcomes.
Mechanisms and Functions of Vitamins A and E
Vitamin A: Transcriptional Regulator and Indirect Antioxidant
Vitamin A, through its metabolite all-trans-retinoic acid, acts as a potent transcriptional regulator, influencing the expression of numerous genes involved in the body's antioxidant responses. Despite common misconceptions, vitamin A functions more as an indirect antioxidant by regulating gene expression rather than directly neutralizing free radicals2.
Vitamin E: Direct Antioxidant and Metabolic Influencer
Vitamin E, primarily in the form of α-tocopherol, is a direct antioxidant that protects polyunsaturated fatty acids in cell membranes from oxidative damage. Additionally, it influences metabolic pathways and gene expression profiles, although it does not act as a transcriptional mediator like vitamin A2.
Metabolism and Transfer of Vitamins A and E
Absorption and Transport
Both vitamins A and E are fat-soluble and require specific carrier proteins for their intracellular transport. Vitamin A is transported by retinoid-binding proteins, which are essential for its metabolism and signaling. Vitamin E is transported by α-tocopherol transfer protein (α-TTP) in hepatic cells, and defects in this protein can lead to vitamin E deficiency and associated neurological disorders4.
Transfer to Offspring
During gestation and lactation, adequate transfer of vitamins A and E from mother to offspring is critical. These vitamins support immunity, growth, and development in early life stages. Their absorption, blood transport, tissue uptake, and storage are complex processes that ensure sufficient supply to the young3.
Interrelationship Between Vitamins A and E
Protective and Sparing Effects
Vitamin E plays a significant role in preserving vitamin A by protecting it from oxidation. This interdependence is evident in dietary studies where vitamin E enhances the storage of vitamin A in the liver and prevents its depletion5 6. In experimental settings, vitamin E supplementation has been shown to increase the absorption of large doses of vitamin A, further highlighting their synergistic relationship9.
Clinical Applications and Therapeutic Potential
Immune Function in the Elderly
Supplementation with vitamins A, C, and E has been shown to improve cell-mediated immune function in elderly patients. This includes increases in T cell counts and lymphocyte proliferation, suggesting that these vitamins can enhance immune responses in older adults8.
COVID-19 and ICU Patients
A clinical trial is investigating the impact of vitamins A, B, C, D, and E on the severity and mortality rates of ICU patients with COVID-19. The hypothesis is that these vitamins can improve clinical outcomes by supporting immune function and reducing inflammation7.
Arthritis Treatment
The effectiveness of vitamins A, C, E, and selenium in treating arthritis has been explored, with mixed results. While some studies suggest that vitamin E may be as effective as diclofenac in managing symptoms, the overall evidence remains inconclusive due to methodological weaknesses in the trials10.
Conclusion
Vitamins A and E are essential nutrients with significant roles in immune function, growth, and development. Their supplementation can enhance health outcomes in newborns, support immune function in the elderly, and potentially improve clinical outcomes in ICU patients. However, more robust clinical trials are needed to fully understand their therapeutic potential in conditions like arthritis.
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Most relevant research papers on this topic
Vitamin A and E Supplementation in Breast-Fed Newborns
Supplementation with 3000 IU vitamin A and 5 IU vitamin E for 3 months increases circulating vitamin levels in newborn term babies compared to nonsupplemented infants.
RCTVitamin A and Vitamin E: Will the Real Antioxidant Please Stand Up?
Vitamin A is an indirect antioxidant that regulates genes, while vitamin E is a direct antioxidant that protects polyunsaturated fatty acids in membranes.
Literature Review
Highly CitedVitamins A and E: metabolism, roles and transfer to offspring
Vitamins A and E play crucial roles in immunity, tissue damage prevention, reproduction, growth, and development, and their transfer to offspring during gestation and lactation is crucial for their survival.
Highly CitedIntracellular Transport of Fat‐Soluble Vitamins A and E
Intracellular transport of fat-soluble vitamins A and E is crucial for their proper metabolism and function in the human body.
Highly CitedInterrelationship of Vitamins A and E
Vitamin E has a significant interdependence with vitamin A, preserving it in oil solutions and increasing its store in the liver of rats, with varying effects on growth in young rats depleted of vitamin A.
Non-RCT
Animal StudyINTERRELATIONS BETWEEN VITAMINS A AND E.
Vitamin E protects vitamin A from oxidation and has a sparing effect on it and carotenoids, ensuring that deficiency symptoms in one vitamin do not compound those in the other.
Impact of vitamins A, B, C, D, and E supplementation on improvement and mortality rate in ICU patients with coronavirus-19: a structured summary of a study protocol for a randomized controlled trial
Vitamin A, B, C, D, and E supplementation significantly improves the severity and mortality rate in ICU patients with COVID-19.
RCT
Very Rigorous JournalThe effect of dietary supplementation with vitamins A, C and E on cell-mediated immune function in elderly long-stay patients: a randomized controlled trial.
Dietary supplementation with vitamins A, C, and E can improve cell-mediated immune function in elderly long-stay patients.
RCTHighly CitedVitamin E supplements and the absorption of a massive dose of vitamin A.
Vitamin E supplements can increase the intestinal absorption of vitamin A, but do not significantly affect its retention in children.
Non-RCTThe antioxidant vitamins A, C, E and selenium in the treatment of arthritis: a systematic review of randomized clinical trials.
There is no convincing evidence that selenium, vitamin A, vitamin C, or the combination product selenium ACE is effective in treating any type of arthritis.
Systematic Review
Rigorous JournalHighly Cited