Vitamin A and thyroid are crucial for good eyesight in humans
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I know I will get hatemail again due to mentioning again the benefits of vitamin A, but the results of the study below are hard to argue with. It appears, vitamin A (retinoic acid) is required for the first step of retinal cell differentiation during fetal development, and thyroid hormone is required for the second one. The role of vitamin A in eyesight has been known for quite some time, to the point that the US Navy ran human experiments during the Cold War with a vitamin A analog trying to get humans to be able to see in the dark like nocturnal animals. Thyroid hormone’s role is less known, but considering the retina is part of the central nervous system and the latter is extremely sensitive to metabolic disturbances, the fact that good thyroid function is required for good vision is not really all that surprising. Ray did recommend thyroid and vitamin A to people with poor eyesight, especially the elderly, as well as serotonin antagonists. Since serotonin is the primary “brake” on oxidative metabolism in the central nervous system, his recommendations make perfect sense, and match the findings of the study below.
https://www.pnas.org/doi/10.1073/pnas.2510799123
https://hub.jhu.edu/2026/02/18/retina-organoids-human-vision/
“…The Johns Hopkins team concluded the distribution of cones in the foveola results from a coordinated process of cell fate specification and conversion during early development. Initially, a sparse number of blue cones are present in the foveola at weeks 10 through 12. But, by week 14, they transform into red and green cones. The patterning occurs by way of two processes, the new study shows. First, a molecule derived from vitamin A called retinoic acid is broken down to limit the creation of blue cones. Second, thyroid hormones encourage blue cones to convert into red and green cones. “First, retinoic acid helps set the pattern. Then, thyroid hormone plays a role in converting the leftover cells,” Johnston said. “That’s very important because if you have those blue cones in there, you don’t see as well.” The findings offer a different perspective to the prevailing theory that blue cones migrate to other parts of the retina during development. Instead, the data suggest that these cells convert to achieve optimal cone distribution in the foveola. “The main model in the field from about 30 years ago was that somehow the few blue cones you get in that region just move out of the way, that these cells decide what they’re going to be, and they remain this type of cell forever,” Johnston said. “We can’t really rule that out yet, but our data supports a different model. These cells actually convert over time, which is really surprising.” The insights could pave the way for new therapies for vision loss.”
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@haidut Those who tout Vitamin A is a poison have no understanding of immunity, eye health, testosterone or ceruloplasmin.
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@bio3nergetic
We must remember that vit.A , retina/brain/LRAT require phospholipids/lecithin
Lecithin forms cell mambranes and we lose it while aging
Perhaps some forms of vit.A "toxicity" could be a lecithin deficiency
AI
Lecithin supplementation has shown potential in supporting retinal function, primarily through its role in enhancing the bioavailability of nutrients essential for eye health and as a component of specialized medical treatments. Lecithin, particularly in the form of lecithin-bound iodine (LBI) or phosphatidylcholine, is associated with improvements in retinal pigment epithelium (RPE) health, tear film stability, and the reduction of oxidative damage in the retina.Key Findings on Lecithin and Retinal Function:
Retinal Pigment Epithelium (RPE) Protection: Lecithin-bound iodine (LBI) has been used in Japan to treat retinal diseases, including central serous chorioretinopathy. In studies, LBI was shown to prevent hypoxic damage to RPE cells and suppress inflammatory responses (such as CCL2 secretion), suggesting a protective effect on the retinal structure.
Retinal Degeneration and Function: In animal models of retinal degeneration, a lecithin-containing diet improved retinal function, as evidenced by higher b-wave amplitude in electroretinography (ERG) tests compared to control groups. It was found to reduce the invasion of macrophages into the retina and decrease inflammatory markers.
Enhancing Nutrient Absorption: Lecithin acts as an emulsifier that helps the body absorb and utilize fat-soluble vitamins, including Vitamin A, which is crucial for producing visual pigments in the retina and maintaining photoreceptor function.
Exudative Age-Related Macular Degeneration (AMD): Research into the use of iodized lecithin tablets for exudative AMD indicated a potential positive impact, with studies reporting improved visual acuity and reduced retinal thickness in treated groups compared to control groups.
Tear Film Stability (Dry Eye Disease): Sunflower lecithin supplementation has been shown to improve dry eye disease (DED) symptoms. As a rich source of phosphatidylcholine, it may enhance the lipid secretions from the meibomian glands, stabilizing the tear film.
Retina Protection against Toxicity: Studies on rat retinas indicate that lecithin can help maintain the structural integrity of retinal proteins (specifically α-helix and β-sheet ratios) when exposed to oxidative stress, potentially reducing damage from, for example, chemotherapeutic agents like ifosfamide.Important Context:
Lecithin-Retinol Acyltransferase (LRAT): Lecithin:retinol acyltransferase is an enzyme crucial for the metabolism of Vitamin A in the retina. It helps convert all-trans retinol to all-trans retinyl ester, a key step in the visual cycle.
Limitations: While promising, some uses of lecithin, specifically lecithin-bound iodine, have limited clinical trials outside of Japan, and many findings are based on preclinical or older studies.In summary, lecithin supplementation, particularly when containing iodine or as a source of phosphatidylcholine, may support retinal function by improving structural integrity, reducing inflammation, and increasing the absorption of necessary nutrients, according to research.