... we are essentially certain about these statements:

Cigarette smoking reduces risk of premature death

Some more things we know...

** The epidemic of vitamin D deficiency is killing more than 60,000 every year.

** Moderate exposure to UV light in a tanning bed eliminates a vitamin D deficiency.

** It is a myth that tanning bed use causes melanoma.

** The known benefits of tanning bed use outweigh any hypothetical risks.

** Slate is not the best news source for known knowns.

As for the unknown unknowns, "The only thing we have to fear is fear itself."

There is a lot of factual information on www.sunlightscam.com that, rightly, makes a lot of people uncomfortable. This information belongs in another category: unpublicized knowns.

One can not unring a bell.

Anonymous: Thank you for catching that. Text corrected. The lack of editing is both an advantage and a flaw of blogging. Jim: Interesting assertions. Could you please provide references that support them? I am unaware of the studies that generated the findings you discuss, and would like to learn more about the things you know. In particular, are the 60,000 vitamin D deficiency deaths in the developed world alone, or internationally (including areas with significant malnutrition)?

Rob's assertion that fluoridation of water is a net good is without basis. Please cite one independent study that demonstrates the safety of fluoride. Follow your curiosity and see the references at fluoridealert.org; there's study after study showing the negative effects of fluoridation. Do you really think that a drug as powerful as fluoride would not have effects beyond the teeth? Would you swallow sun screen to protect your skin? Google fluoride and thyroid gland and begin your education about fluoride. While you're at it, read The Fluoride Deception by Christopher Bryson.
http://quicksilverscreen.com/watch?video=43018

There are many things we choose to do or not to do for our health based on mere correlations. Is this wise? I think for the most part, yes. If people who eat carrots, for example, had a markedly higher incidence of cancer, I'd likely avoid carrots whether or not they actually caused the cancer and whether or not the carrots are good for us in other ways. BTW-there is not any actual correlation between carrots and cancer. Nothing is purely good or purely bad. Even the healthiest things can harm us in large doses so we have to weigh our options and make an informed decision. Will we sometimes get it wrong? Of course, but it is worth it to try and use some deductive reasoning. Tanning likley has some benefits. I for one feel psychologically happier after tanning and studies suggest a correlation between sunlight and increased seretonin levels. Tanning likely also has some risks. My father, a dermatologist, has shown me studies on those with lots of sun exposure resulting in burns, presenting with higher incidents of malignant melanoma. This isn't causality, but when Australia, a sun exposed region containing many fair skinned individuals has the highest rate of skin cancer in the world, you'd be a fool to ignore that kind of suggestion. Weigh the options. I'm not dark, but I'm not fair either. I can burn if I'm not careful. I tan outdoors sometimes, but I don't fry out in the sun all day. I think people want a black and white answer when they already have a gray one that makes perfect sense. It's like the alcohol. Good for you in moderation? Probably, but if you booze all day, it won't be beneficial to your health. It's not that complicated and neither is tanning.

Put one potted plant in the window with plenty of sunlight. Take a similar potted plant and put it in a cupboard, away from sunlight. Feed them both the same.
Come back one week later and put the plants side by side... what do you expect to see?

Children with rickets.... put them in sunlight for one week... no more rickets!

So? where is there NOT evidence. And those are just the easiest tests.

Think sunlight is bad?
Try living without it!

Mori
Toronto Canada

people can also learn to feed on sunlight.

Hate to burst your bubble, but there's loads of evidence that shows that fluoride does not reduce tooth decay. Fluoride delays eruption of teeth therefore making it appear that when the same aged children are compared that the fluoridated children have less tooth decay.
Actually, they've had their teeth a shorter period of time which makes them less likely to be as decayed at the time of examination.

Also, fluoride does harden tooth enamel which actually hides cavities. The enamel is microscopic rods. Cavity causing organisms can and does seep in between these rods to cause unseen cavities Dentists call these "fluoride bombs" because upon probing an otherwise sound-looking tooth "explodes" open to show a cavity, not big enough to appear on an x-ray.

All the studies that claim fluoride reduces tooth decay didn't use x-rays anyway. They just eyeballed it.

After 60 years of fluoridation and 50 years of fluoridated toothpaste and a glut of fluoridated products and foods on the market today, Americans children are fluoride-overdosed with up to 48% sporting dental fluorosis - white spotted, yellow, brown and/or pitted teeth.

Yet, tooth decay is a growing epidemic. Children in America are dying from untreated tooth decay. It's a crime!

i agree with these comments.

Fluoride does nothing for cavities. It's a poison

I just think it's pretty obvious that both claims about sunlight are true.

1.) Almost every animal species gets most of their vitamin D from the sun. Herbivores get all of their vitamin D from the sun, so as a vegetarian, I need to do that as well. Unnaturally avoiding sunlight for your entire life, unless you're allergic, is probably not a good idea.

2.) Constant exposure to the harmful sun rays throughout a lifetime definitely takes a toll on the skin. It may not cause fatal skin cancer, but it does speed up aesthetic problems with age. Repeated sunburn is also not a good idea. Therefore, it's a good idea to avoid sun sometimes, especially if you have light skin.

There is more than enough scientific literature to support those claims, which of course may be refined with further research. But fluoride benefits are a certainty and these aren't? Please!