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Sunscreen Not So Good for You?
j-beda writes "Don't like sunscreen? Maybe that tan is good for you. It looks like people are rethinking the common wisdom of avoiding sun exposure... "research suggests that vitamin D might help prevent 30 deaths for each one caused by skin cancer". Maybe if Kurt Vonnegut ever does address MIT grads, he will say something else..."
In Australia, we have much higher UV levels than you do in the northern hemisphere. Skin cancer is a real concern. I have several friends that have had cancerous growth removed while they were in their twenties. Certainly vitamin D deficiencies can be a problem, however this can easily fixed with very low exposure levels. If you ever visit Australia use sunscrean or become a lobster in 15 minutes.
Actually, if you're thinking of getting some vitamin D by lying without sunscreen on the beach near the sea, you'de probably be much better of eating seafood ! Many fishes contain vitamin D, sardines, mackerels, salmon... + you don't get skin cancer.
\u262D = \u5350
I live in Queensland, Australia. Thousands of people a years die from skin cancer, in fact we have the highest rate of skin cancer in the world. Only stupid people go out in the sun exposed here. Most people in their 50s or older who spenmt their childhood in the sun before the skin cancer campains of the 70s have had skin cancers cut out.
But put it on after you've been out in the sun for a few minutes, rather than before going out into the sun. Your body needs very little time exposed to UV-B light to produce sufficient amounts of Vitamin D. Far less time than it takes to get a tan (or in my case, a burn. I couldn't tan, even if I wanted to).
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If you bothered to read the article, you would be aware that there are different forms of vitamin D, and that most pills contain a different form than that produced by sunbathing (and also not very much of it).
It also noted that excessive vitamin D from pills can lead to a build-up of calcium in the body (not a good thing), which is not an issue with sunbathing.
Vitamin pills shouldn't be necessary at all - if you need them, then there's something wrong with your diet and/or lifestyle.
The study says you should get about 10 to 15 minutes of sun exposure a day. Sun screen is still good for you, and it's not an excuse to lay on the beach for hours tanning. Basically you just need to go for a short walk outside every day, which is good for you for other reasons, and you'll be ok.
-matt
"In many [western] countries, peoples' diet changed substantially in the second half of the twentieth century, generally with increases in consumption of meat, dairy products, vegetable oils, fruit juice, and alcoholic beverages, and decreases in consumption of starchy staple foods such as bread, potatoes, rice, and maize flour. Other aspects of lifestyle also changed, notably, large reductions in physical activity and large increases in the prevalence of obesity."[18]
"It was noted in the 1970s that people in many western countries had diets high in animal products, fat, and sugar, and high rates of cancers of the colorectum, breast, prostate, endometrium, and lung; by contrast, individuals in developing countries usually had diets that were based on one or two starchy staple foods, with low intakes of animal products, fat, and sugar, and low rates of these cancers."[18]
"These observations suggest that the diets [or lifestyle] of different populations might partly determine their rates of cancer, and the basis for this hypothesis was strengthened by results of studies showing that people who migrate from one country to another generally acquire the cancer rates of the new host country, suggesting that environmental [or lifestyle factors] rather than genetic factors are the key determinants of the international variation in cancer rates."[18]
See also:
Scientists estimate that most cancers are associated with factors related to how we live, called lifestyle factors. Evidence reviewed by the American Cancer Society suggests that about one-third of the 550,000 cancer deaths that occur in the United States each year is due to dietary factors (for example, excess calories, high fat, and low fibre). Another third is due to cigarette smoking. Other lifestyle factors which increase the risk for cancer include drinking heavily, lack of regular physical exercise, promiscuous sexual behavior,
Ron Paul
The problem isn't science, but things that masquarade as science.
Science is about repeatable controlled experiments that yield consistent results. Repeatable means that you need to understand what exactly is going on in your experimental setup so that somebody else can reproduce it. Controlled means you account for all variables and only vary one at a time.
The problem is that doing all this correctly with people costs a LOT of money. So, instead we settle for sloppy studies that aren't well-controlled, then everybody starts talking about how useless science is when five people do the "same" study and come up with different conclusions. Some of the common flaws:
The only really effective way to these kinds of tests on people is with placebo-controlled clinical trials. Take 2000 people, split them into a few groups which are as similar as possible in makeup, and make them all spend 15 minutes a day blindfolded in a tanning booth, and make them all take pills. Some groups don't actually get any UV, but the experience is simulated so that they don't realize this. Some groups do get the UV. Some groups get various vitamin D supplements (with or without vitamin A), and some groups get placebos. At least one group gets neither UV or a supplement. Then follow the group over 50 years and see what the results are. Such an experiment should be both conclusive and repeatable.
Of course, most scientists want their results next year and have limited budgets, so they're not going to start a 50-year study that they won't even be alive to see the end of. Instead, they just look at random dead people and try to guess how much time they spent in the sun and what pills they have taken.
Even modern drug clinical trials have all kinds of issues (clearly seen in recent high-profile drug recalls) - these trials are very carefully controlled trials subject to all kinds of review and which cost hundreds of millions of dollars to perform.
So, the problem isn't a failure in science. The problem is that sometimes we aren't patient enough or resourceful enough to use science, and instead resort to something else and call it "science". Science isn't very practical when dealing with people - they live a long time, you can't just put them in cages, you have to pay them, and you can't do much in the way of manipulating them. Most real biological science uses other animals as a result (Need some subjects with cancer? Just breed them to be prone to it.)...
It's also important to know your genetic predisposition. For example, if you have type I (very fair skin), getting skin cancer eventually at some point in your life is inevitable: all you need is to live long enough and get enough sun. The type of skin cancer you will get from such chronic UVB exposure is most likely a basal cell carcinoma (not fatal) and 30% of these occur on the nose. As another example, if you have the dysplastic nevus syndrome (DN), you'll will have a higher incidence of malignant melanoma. This type of cancer is related more to acute sunburn than chronic exposure and is much more deadly: if you detect them early they are 100% curable, too late and they are 0% curable. Have a nice summer!
From personal experience I can also add that the sun in the Northern Hemisphere never seemed as hot or burning as the sun in Australia. I could walk around in the summer sun in Boston and barely get even a touch of colour. In Australia I would be burnt in less than an hour - probably quicker. Sun screen is very important in Australia as is a hat and a shirt.
It's the latitude. Boston is around 42 N. Australia is mostly between 16 S (Cairns) and 34 S (Sydney). In the northern hemisphere, you should be comparing yourself to somewhere in Mexico or North Africa, not the northern USA.
Mary Schmich is the original author.
Kurt Vonnegut is a novelist. My top recommendation for a book to read by him would be Slaughterhouse Five. It's an account of the fire bombing of Dresden (which he witnessed, as a US soldier) near the end of World War II. Fantastic prose. So it goes.
HDL or LDL is not actually cholesterol. They are what they say they are: lipoproteins. Cholesterol is cholesterol. All living creatures (ok, let's just say vertebrates, I am not very sure here) incorporate cholesterol into their cell walls to make cells waterproof. Because cholesterol is insoluble in water and thus also in blood, it is transported in our blood inside spheric particles composed of fats (lipids) and proteins, the so-called lipoproteins. Lipoproteins are easily dissolved in water because their outside is composed mainly of water-soluble proteins. The inside of the lipoproteins is composed of lipids, and here are room for water-insoluble molecules such as cholesterol. Like submarines, lipoproteins carry cholesterol from one place in the body to another. The main task of HDL is to carry cholesterol from the peripheral tissues, including the artery walls, to the liver. Here it is excreted with the bile, or used for other purposes, for instance as a starting point for the manufacture of important hormones. The LDL submarines mainly transport cholesterol in the opposite direction. They carry it from the liver, where most of our body's cholesterol is produced, to the peripheral tissues, including the vascular walls. When cells need cholesterol, they call for the LDL submarines, which then deliver cholesterol into the interior of the cells. Most of the cholesterol in the blood, between 60 and 80 per cent, is transported by LDL and is called "bad cholesterol". Only 15-20 percent is transported by HDL and called "good" cholesterol. A small part of the circulating cholesterol is transported by other lipoproteins. So you see, bad cholesterol is actually good at something very important. Of course, excess is bad. Bad eating habits stimulate the overproduction of cholesterol, much more then what the body needs. So much more that the HDL cannot "recycle" back to the liver, so the excess gets stuck on the artery walls. So the parent is right, cholesterol IS necessary for the body to function. If you magically got rid of all your LDL "bad cholesterol", you'd be dead.
Just buying it might not be enough. You might want to take the next step and drink it as well.
The real debate underlying this article surrounds the appropriate "dose" of vitamin D. The current recommendations in the US (400 IU per day) are entirely based on requirements for maintaining normal bone mineral composition. This has absolutely no relation to other biological effects of vitamin D (cellular differentiation, immune cell activity).
Whereas you can get 400 IU per day by drinking vitamin D fortified milk, full-body exposure to solar ultraviolet radiation can produce as much as 10,000 - 40,000 IU of vitamin D. In the winter and at high latitudes vitamin D production from solar UV can drop to zero. Between diet, supplements, and sun exposure, the ideal combination and target dose for cancer prevention has not been established. It is almost certainly considerably above the 400 IU that you need to maintain healthy bones.
1) Milk ISN'T good for you, period, [sic]
Actually, it all depends on who you mean by "you," and what your underlying assumptions are about resources, technology, etc. If you are lactose intolerant, then by all means stay away from milk. That doesn't mean you can't have cheese and yogurt, though. It is a well-accepted theory that the lactose tolerance mutation of northern European populations is one of the factors that enabled their success (and by success, I mean they didn't all die out). It is also true that Mongolian tribesmen may not have the resources to eat fresh kale to get their calcium, or to buy soy "milk" from their local organic grocery store. However, goats, sheep, and cows can digest grasses and produce milk with--guess what--calcium! But in fact, it's the casein in milk that supplies the protein, and many vegetarian cultures have relied on dairy products for a large part of their protein consumption.
2) humans weren't supposed to drink another animals milk [sic]
You should be careful when using words like "supposed" because you imply you have some sort of insight into the Way the Universe Should Be. Bullshit. You can't say humans weren't supposed to drink milk anymore than you can say humans weren't meant to jump rope. No other animal does that, either. No other animal writes poetry, or commits suicide, or contemplates philosophy. Just because humans differ from other animals does NOT imply any should or ought, so shut your mouth unless you have some Divine Insight. I would like to point out that other animals may not drink milk after infancy, but they do eat organ meat, entrails, eyeballs, and all sorts of other nutrient-rich animal parts that we tend to discard, these days--including partially digested food in the animal's intestinal tract. Maybe you'd prefer eating tripe to drinking milk?
3) This is ignoring the pitfalls falls of todays production techniques whereby they pump growth hormones into the cows so they produce milk far longer than they are normally capable of. [sic]
This is your single valid point, and it is only valid for milk from a regular dairy. Those same organic grocery stores that sell soy milk also sell milk from cows without all those hormones and (though you didn't mention it) antibiotics. But you're tangling the issues, here. That is an argument for better treatment of dairy cattle, not an argument against milk itself. I have a problem eating hot dogs, these days, but that doesn't make all meat repulsive to me.
Maybe someday it will be proven that milk is the poison you make it out to be. But now, the evidence is far from conclusive, and you obviously don't know your milk history. As it stands, milk was probably responsible for my ancestors' survival, and your burden of proof is pretty high. Oh, and a better grasp of English grammar and spelling might help you be more persuasive, in the future. It would be comical that you have a sentence "Milk ISN'T good for you period," ending in a comma, except that I'm pretty sure you didn't intend that.
Si la vida me da palo, yo la voy a soportar Si la vida me da palo, yo la voy a espabilar
Yeah, people need to RTFA:
In late May 1997, Chicago Tribune metro columnist (and "Brenda Starr" writer) Mary Schmich was walking to work along Lake Shore Drive, wondering what she was going to write about that day. It occurred to her that it was near graduation time and she thought she would write a column that read like a commencement address. As she wondered what advice she might offer, she saw a woman sunbathing on the shore of Lake Michigan.
"I hope she's wearing sunscreen," thought Schmich, 45, "because I didn't at that age."
And that's how newspaper columns are born.
A couple of months later, the column became an Internet hoax when a prankster - never identified except as "Culprit Zero" - copied it, labeled it as "Kurt Vonnegut's commencement address at MIT,"