(26-06-16)Research finds that 45 percent of common sunscreen ingredients interfere with the normal functioning of sperm cells

by S. Johnson

Researchers have found that a myriad of ultraviolet (UV) filtering chemicals in common sunscreens disrupt the functioning of normal sperm cells and mirror the effects of the female hormone progesterone.

Head author of the study Niels Skakkebaek, MD, DMSc, a professor at the University of Copenhagen, and colleagues tested the effects that 29 of 31 UV filters allowed in sunscreens had on human sperm cells. The researchers found that almost half of the UV filters acted as a hormone disruptor, thereby interfering with the normal functioning of sperm cells.

Although the intent of UV filters is to reduce the risk of skin cancer by cushioning the blow of UV rays, many sunscreens harbor cancer-causing chemicals, which get absorbed by the skin and into the blood stream.

In addition to being common in sunscreens, these chemicals are in several sunscreen-containing personal care products, including makeup, moisturizers and chap stick. It should therefore come as no surprise that previous studies have shown these chemicals are present in 95 percent of urine samples in the US, according to a press release from the Endocrine Society.

Sperm feel the burn
There are two different types of sunscreen: Physical sunscreens and chemical sunscreens. Physical sunscreens reflect UV rays with elements like zinc, whereas chemical sunscreens are loaded with synthetic chemicals to inhibit UV rays from reaching the skin. The results of the recent study suggest the chemical UV absorbers increase the risk of infertility.

The researchers tested sperm cells by submerging them in a buffer solution that mimicked the conditions in female fallopian tubes. In particular, the team assessed calcium signaling, a transduction mechanism whereby changes in the cell are produced by fluctuations in the concentration of calcium ions.

Calcium ions play a major role in sperm motility. The researchers discovered a specific ion channel that is the receptor for the female hormone progesterone. A host of calcium ions flood the sperm cells when they encounter progesterone, which hinders them from sufficiently fertilizing an egg.

Commenting on the widespread implications of the study, Skakkebaek said, "These results are of concern and might explain in part why unexplained infertility is so prevalent."

These calcium-signaling pathways are often launched by progesterone; however, the team found that 13 of the 29 UV filters, or 45 percent, triggered calcium signaling, even in low concentrations. "This effect began at very low doses of the chemicals, below the levels of some UV filters found in people after whole-body application of sunscreens," explained Skakkebaek.

This suggests that the UV filters mimic the activity of progesterone, thereby inhibiting the sperm from swimming correctly. Among the 13 UV filters, 9 of them mimicked the effects of progesterone. These findings imply that UV filters are endocrine disruptors, Skakkebaek added.

Some of the chemicals that have regulatory approval but have been shown to disrupt sperm cells include avobenzone, homosalate, meradimate, octisalate, octocrylene, oxybenzone and padimate. Previous research has shown that oxybenzone, a common sunscreen ingredient, is harmful to the planet's corals and coral reefs, according to the Daily Mail.

Beware of unnatural sunscreen products
With this background in mind, it is important that consumers read the list of ingredients of any sunscreen product. A typical sunscreen product consists of a cocktail of cancer-causing chemicals. Although sunscreen inhibits the skin from absorbing UV rays, it also inhibits the skin from producing vitamin D. This can lead to an onslaught of health problems in the long run. In fact, research has shown that sunscreen actually causes more cancer than it prevents.

This doesn't mean that consumers should banish sunscreen altogether. A pale person planning to spend several hours on a beach would benefit from some sort of protection from the sun with a natural sunscreen product. However, an informed consumer will recognize that moderate sun exposure, in addition to good nutrition, is healthy and necessary to activate vitamin D production in the skin.

Fortunately, there are ways to protect your skin naturally. You can better your internal skin resistance with what you eat. For instance, astaxanthin, an extremely powerful algae-based antioxidant, is known for boosting the skin's natural resistance to a sunburn. Fruits and vegetables chock full of antioxidants can help mitigate sunburns too, as they counter the effects of cancer-causing free radicals in the body spurred by UV rays.

The results of the recent study were presented at the 98th annual meeting of the Endocrine Society in Boston and are awaiting peer review. Nevertheless, they underscore the need for additional research about how these chemicals interact with the human body. Professor Skakkebaek is calling for future clinical studies to investigate the link between UV filters and human fertility.

"Our study suggests that regulatory agencies should have a closer look at the effects of UV filters on fertility before approval," he concluded.

Sources include:

NewsWise.com

DailyMail.co.uk

NaturalNews.com

NaturalNews.com

Science.NaturalNews.com

Fonte: NaturalNews

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In evidenza

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