Question: What are freckles? What biochemical processes cause them to form? Are there positive or negative health aspects of freckles?

Answer: Freckles are brown, tan or dark, dots or spots that appear on the face and other areas of the body. More specifically, freckles are skin cells that contain a pigment called melanin. This pigment is a chemical synthesized by skin cells called melanocytes. Freckles or melanin function by absorbing and reflecting ultraviolet rays emitted from the sun. When ultraviolet rays from the sun contact the skin, the melanocytes activity increases causing freckles to appear and darken. There are three basic types of melanin: eumelanin, pheomelanin, and neuromelanin. The most common is eumalinin. Eumalinin polymers are composed of many cross-linked 5,6-dihydroxyindole and 5,6-dihydroxyindole-2-carboxylic acid polymers.

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https://en.wikipedia.org/wiki/Melanin

UVA radiation causes DNA damage to melanocytes. Someone over exposed to UV rays is at risk of damaging their melanocytes and developing skin cancer.  Researches say UV radiation generates reactive oxygen and nitrogen that energizes an electron in melanin. “That energy causes DNA lesions which can lead to cancer causing mutations.”

Dr. Doug E Brash from the Yale School of Medicine says, “You have two opposing things happening at the same time: Melanin protecting you and melanin damaging you,” explained Dr. Doug E. Brash, a skin cancer researcher at the Yale School of Medicine. “You’ve got this race going on between melanin blocking and protecting you.”

Incidence of freckles is related to genetic make-up. Someone who has parents with freckles is more likely to have freckles themselves. Also, someone with a lighter skin complexion is more prone to have a freckled phenotype than someone with darker skin tone.

People with fair skin complexion have less melanin. Melanin is what causes someone’s skin tissue to be darker or tanner. When the ultraviolet rays from the sun reach a person with a lighter skin tone, the melanin produced from melanocytes can develop as freckles instead of an evenly distributed tan.

By, Nathan Monsein

References:

  1. org/wonder/what-causes-freckles
  2. http://www.healthline.com/health-news/melanin-protects-us-from-and-can-cause-skin-cancer-021915
  3. https://en.wikipedia.org/wiki/Melanin
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