A watchdop group has called on the US Food and Drug Administration to shed some light on sunscreens. The government agency has failed to finalize standards for testing and labeling sunscreens, says a report by the Washington, DC-based nonprofit Environmental Working Group. The report also concludes that 85% of sunscreens on the market either contain potentially toxic ingredients or fail to provide enough protection from both UVB and UVA radiation. Most products shield the skin from UVB rays, which cause sunburn as well as DNA damage associated with skin cancer.

A study published yesterday in the journal of the Federation of American Societies for Experimental Biology (FASEB), provides details to support the idea that UVB rays are more likely to cause cancer. However, research published in May suggests that the deeper-penetrating UVA rays that cause skin aging also suppress the immune system, compromising the body’s ability to protect itself against the development and spread of skin cancer.

The FDA is currently considering sunscreen labeling changes to help consumers make better choices, but in the meantime, the American Academy of Dermatology offers this advice: Use broad spectrum sunscreen products of SPF 15 that protect against UVA and UVB rays. Lather it on everyday and wear protective clothing.

Image by Daquella manera

Yesterday’s Washington Post ran an article that I found really provocative, linking the drop in crime in recent decades to… um, lead poisoning.

The general idea is that children who are exposed to lead are more prone to committing violent crime as adolescents presenting, according to the article, “a unifying new neurochemical theory for fluctuations in the crime rate.”

Sounds really good. Too good, in fact. I’m wary of “unifying theories” with such sweeping implications.

There is apparently a lot of literature linking lead exposure to aggressive behavior. But it’s a big step from that to linking crime rates across the world to lead levels.

The article is based on the work of economist Rick Nevin, who looked at nine countries with different abortion rates, police strategies, demographics and economic conditions and found that up to 90% of the variation in violent crime in these countries could be explained by lead.

In the U.S., for example, children were exposed to lead — in household paint at the turn of the 20th century and in gasoline fumes after World War II — and in each case, violent crime peaked roughly 20 years later. Much of the lead in gasoline was eliminated by the mid-1980s explaining, according to Nevin, the drop in crime in the 1990s (what do you have to say that, Rudy Giuliani?), and because this had the biggest impact on inner-city neighborhoods, Nevin says, violent crime in those neighborhoods has declined faster than the overall crime rate.

I know the writer, Shankar Vedantam, and deeply respect his journalistic abilities, so I’m sure he checked out the credibility of this research. But I would have felt better if pretty much the only other expert quoted in the article hadn’t been the editor of the journal, Environmental Research, in which Nevin has published most of his work. The article says Nevin’s work, and the other research that supports this hypothesis, hasn’t received much attention. If it’s good science, why ever not??

Seafood lovers, pregnant women and lobbyists for the fishing industry heard some startling news this week from a study in The Lancet.

Offspring of women who ate a lot of seafood during pregnancy scored higher on tests of verbal and social ability than offspring of women who at little or none—despite concerns about high mercury levels in seafood. Even the study’s authors were surprised.

The take-home message of the study may seem positive, but it comes with ominous undertones: “The benefits of eating seafood outweigh the risks.” Somehow, I’m not fully comforted.

What the study did not address was how the seafood-reared children would have fared if their mothers had eaten mercury-free fish—a thing about as rare as coelacanth caviar. It’s a tough question, but it’s worth asking — given that mercury at the concentrations found in many fish is likely harmful to fetal development, as The National Academy of Sciences has concluded.

The new study didn’t take the bite out of mercury — it just suggests that omega-3 fatty acids and other substances in seafood are really good for the developing nervous system. The findings will certainly put pressure on US regulatory agencies to change their advisories limiting fish intake for vulnerable populations. Pregnant women in the study had to eat more than the level advised by the agencies, 340 grams per week, for the beneficial effect.

So what is fish lover to do — believe this one study and start chowing down on tuna fish sandwiches? Carefully parse lists of fish species with high and low mercury content, or just eat a lot of omega-3 containing flax seed?

There’s only one sure way to make things simpler — and safer. And that is to get rid of mercury in our waterways.

The Bush administration is notoriously backward on this front. The US Environmental Protection Agency — the same agency that issues advisories on fish consumption — has ruled that coal-fired power power plants have almost 20 years to cut their emissions by 70 percent. That stands in contrast to an overturned Clinton-era ruling calling for a 90 percent reduction by 2008.

The EPA has received hundreds of thousands of letters protesting the Bush-era ruling — so a single study from The Lancet is unlikely to change anything. But those letters show how strongly people feel that there should be only benefit, but no risk, to eating a basic food item.