Dietary vitamin A regulates wingless-related MMTV integration site signaling to alter the hair cycle

    October 2014 in “Experimental Biology and Medicine
    Liye Suo, John P. Sundberg, Helen B. Everts
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    TLDR Eating vitamin A affects hair growth and health by changing cell signals in mice.
    The study found that dietary vitamin A activates hair follicle stem cells in mice in a dose-dependent manner, which induces the growth phase of the hair cycle and could make follicles more susceptible to autoimmune attack in alopecia areata. High levels of vitamin A were shown to increase WNT signaling within the hair follicle, with significant effects observed at doses as low as 4 IU vitamin A/g diet. The research suggests that retinoic acid regulates WNT signaling in developing hair follicles, and the authors aim to further explore this mechanism and establish a healthy range of retinoids for hair follicles, potentially aiding in the treatment of hair loss diseases. The study used doses of vitamin A 3-7 times higher than recommended for humans, which could be toxic, but are commonly consumed by mice and some Americans through supplements.
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