Tuesday, April 16, 2013
The much hyped resveratrol fails under test among humans
Another failure to generalize from rodents
It’s been touted as a cure-all for diabetes, dementia, heart disease and even hearing loss, but the miraculous health benefits of red wine cannot be reaped if you are obese, say researchers.
Resveratrol, the active compound found in the skins of red grapes and cocoa, is an antioxidant produced by plants to help protect them from extreme environments and block the effects of ultraviolet sunlight, infections and temperature changes.
The research, published in journal Diabetes, found that although test-tube studies had suggested that resveratrol had an effect on obesity, diabetes, high blood-pressure and blood cholesterol, it had no effect on 24 obese, but otherwise healthy men.
The study, carried out by Aarhus University Hospital in Denmark, gave 12 men high-dose supplements of the substance and 12 men a placebo for four weeks.
Over this period the participant’s insulin sensitivity, blood pressure, cholesterol, and resting energy expenditure were monitored.
Researchers found that there was an insignificant decrease in insulin sensitivity and no change in blood pressure, cholesterol and resting energy expenditure.
‘The lack of effect disagrees with [previous] data obtained and raises doubt about the justification of resveratrol as a human nutritional supplement, said the scientists.
The research contradicts previous data showing that the life of lab rodents - including old, fat, and even diabetic mice – could be extended by supplementing the diet with the chemical.
It was presumed that the chemical could work in the same way for humans.
When government cries wolf
There was some confusion a few days ago about whether certain kinds of licorice are legal in California. I had pointed out that an out-of-state firm was unwilling, because of Proposition 65, to ship its licorice to California. That does not mean that the licorice is illegal in California. It is not. But, under Proposition 65, it must be accompanied by a warning label saying that certain ingredients may cause cancer.
Presumably, the firm was not willing to add such a label. Why? Think about the rest of the U.S. market outside California, which would probably be over 85% of the market. Californians have learned to ignore Proposition 65 labels because they are white noise: they don't communicate anything about degrees of danger or probabilities. But if people in those other states see such a warning, many of them might get nervous.
There does seem to be a simple solution: add a Proposition 65 warning label only for shipments to California. Why doesn't the company do it? I don't know. It's possible that the California market is much smaller than 15% of the market and that it just isn't worth it.
The point about warnings as white noise does, though, raise a more-serious issue. Within a few miles of where I live in coastal California is Monastery Beach, where the undertow is particularly severe. Many people have drowned at the beach. I remember one time in the last 10 years when a whole visiting family drowned.
Notice the word "visiting." Almost all the people who drown there are tourists. Why is that relevant?
The locals tend to know about the undertow. Outsiders do not. On the beach for well over 15 years has been a big sign warning of the undertow. I think many tourists simply think the sign is typical government overstatement. When I went through the San Jose airport Saturday morning in a long line at TSA, we passengers were subjected to John Pistole's warning, on an infinite loop, of the dangers of terrorism. We've all seen enough to know that it's not that dangerous. So we tend to ignore government warnings. So when there really is a high-probability threat and the government warns us, we tend to dismiss that too. Government cries wolf way too often.
It's a kind of a Gresham's law of warnings: warnings about low-probability threats drown out, rather than drive out, warnings about high-probability threats.
One last example. In 1982, when I was working in the Reagan administration, my friend Harry Watson came to town and we rented two kayaks. I had never been in a kayak in my life. We tried them out on the placid C&O canal beside the Potomac River and then went to put them in the Potomac. "WARNING: DANGEROUS CANOE PUT-IN." said the sign. "Yeah, right," we thought. There goes government crying wolf again.
Wrong. Within 50 yards of having put in our kayaks, we were using all our physical energy to navigate down a very rough river. Within less than 2 minutes, I was worn out and all I had left was adrenaline. After I got to my first bit of calm, I relaxed slightly and immediately tipped over. I was heading for the next big set of rapids. Fortunately, a seasoned kayaker appeared out of nowhere, told me to hold on to the strap on his kayak, and towed me to shore. I was lucky. Those people at Monastery Beach were not.
Good information is just too important for us to allow government to drive it out with bad information.
Posted by jonjayray at 12:24 AM