随笔？杂谈？不，是杂论。它杂，任何题目都可以谈。但不像随笔，随手拈来，挥笔而下。它又论，论述一个观点，表达一个思想。有时它先叙后论，叙论结合。有时它有叙无论，论于读者心中。这，就是杂论。
October 3, 2006
September 30, 2006
Does SK-II have excess amount of chromium?
Recently, China’s General Administration of Quality Supervision, Inspection and Quarantine discovered trace amount of chromium and neodymium in SK-II skin care products. Then we saw all kinds of news about the refund and the unfair waiver form etc. I don’t know anything about this brand of cosmetics. But I happened to research the amount of chromium that’s needed by a human, for a completely different reason.
I found most vitamin and mineral supplements (e.g. Centrum) have chromium. A warning was posted on the label: diabetes or hypoglycemia patients need to consult doctor before taking the supplements. Why? I googled the web and seemed to have found the answer.
It is generally believed that chromium is an essential trace mineral for human body, while excess intake of chromium may have several undesired effects. However, different sources draw different conclusions.
UC Berkeley Wellness Letter presents a negative view about chromium [1]: There’s little evidence that chromium deficiency is widespread. Some very preliminary research suggests that chromium picolinate can reduce blood sugar in people with Type 2 diabetes, the most common form of the disease. But that’s a far cry from a reliable treatment for diabetes, which is not a chromium-deficiency disease. There is no good evidence backing chromium picolinate as a weight-loss aid, a muscle-builder, or a way to reduce blood cholesterol levels. This new evidence does suggest that it may have serious side effects. Nobody should take chromium picolinate, especially not young people.
However, other sources suggest differently. Briggs presents a double blind study in China [2]. The result indicates that daily intake of 1,000 mcg chromium have shown consistent improvement on type II diabetes. Similar results have been obtained by scientists at Agriculture Department’s Beltsville Human Nutrition Research Center. A chemical explanation is also presented [3]. Because chromium may potentially treat diabetes, it may interfere with other drugs. This explains the warning message on the bottle of supplements.
Different agencies cannot agree on the exact daily consumption amount as well. The FDA has not evaluated the daily intake value. The Food and Nutrition Board of the NRC has recommended a “safe and adequate” range for dietary chromium of 50 to 200 mcg per day [4]. But this number is argued by other agencies. Most supplements consider 80 to 150 mcg as 100% daily suggested value, with the amount for men less than women. Some research indicates the US population have chromium deficiency [2], while others conclude otherwise [1].
The absorption rate varies a lot for different forms of chromium. Again, different researches result differently. One research showed that 40% of chromium picolinate, 10% of chromium nicotinate, and 1% of chromium chloride can be absorbed [5]. It is very different from another research, which concludes that the absorption rate for chromium picolinate is only 4% [2]. Most mineral supplements have chromium chloride. It means even though one pill of supplement has about 100 mcg chromium chloride, the actual absorbed amount is only 1 mcg.
Another form of chromium, hexavalent chromium, is toxic. Fortunately, it does not exist in food.
Let’s get back to the cosmetics. It is discovered that several major brand of skin care products have between 0.5 mg to 5 mg chromium per kilogram of skin care products. That is equivalent to 0.5 mcg to 5 mcg chromium per gram, which is the normal consumption per day. This number is well below the US daily suggested value. As of now, I have not found any information about the type of chromium compound found in the cosmetics, nor is the amount regulated by Chinese administrations.
[1]: UC Berkeley Wellness Letter, Aug. 1996, June 1999, June 2003.
[2]: Chromium Steels the Body Against Diabetes, Nutrition Science News, Feb. 1999.
[3]: Coffee, Spice, Wine, Science News, May, 2004, Vol 165, No. 18, p. 282.
[4]: National Research Council. Recommended dietary allowances. 10th ed. Washington (DC): National Academy Press; 1989. p 241-2.
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September 24, 2006
Freestyle writing
Freestyle writing, as the name indicates, means to write at will with no specific topic. The writing may also be spontaneous, which means I will make more mistakes… Please remind me if you ever find one. Thanks in advance.
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