It happens almost without fail. Foreign friends who go to the United States for a visit come back with observations about how hideously obese we Americans are.

We may munch a lot of twinkies, and nosh on too many chips, but we Americans also seem surprisingly picky about what we stick in our mouths. Or so it might appear from reaction to an article I wrote this past week. The article, available here, is about how China has largely cornered the global market for vitamin C, and lots of other vitamins and basic drugs, like penicillin.

The article got a lot of attention within McClatchy’s 31 newspapers. And readers reacted strongly. Following on the heels of the pet food scandal, in which Chinese suppliers added a chemical to an ingredient in pet food that has left thousands of dogs and cats dead, many Americans don’t seem to be willing to trust China to produce their vitamins safely.

There’s a lot of tricky waters and cross-currents in this “food scare” business, and both China and the United States are reacting in radically different fashions. China on Thursday said a significant quantity of food it imports from the United States is ridden with salmonella and other contaminants. And it came out this week that two U.S. companies have also been using melamine, the implicated chemical, to bulk up animal feed.

In any case, this is all fertile ground for spinmeisters and PR people, and let me tell you a lot of work needs to be done. To wit: Read these comments posted to a version of my story printed Friday on the front page of the Sacramento Bee in California. They don’t seem to be happy at all about swallowing Chinese-made vitamin C.

A reader -- “Beggar” -- wrote a comment that 10 people ranked as positive. It said:

“China is a corrupt nation with no national concern for its own people nor anybody else. The communist party (you *do* realize it's communist totalitarian state, right?) cares only for its own perpetuation and the moneyed elite care only for their continued wealth.

“Corruption is rampant and there workers are poorly treated and don't particularly care about the products that they're producing.

“Remember how the US was in that 1880-1930 time range? That's China.

“Wake up people.

“BOYCOTT CHINA

“(To our legislators -- thanks for getting us into a sole-source situation... and not even telling us that the stuff we're eating comes from the Chinese cesspool).”

Then a reader, identified as TupacGoldstein, added his own comment:

“I want to know where stuff comes from. If you wanna eat crap from China or some other corrupt and unsanitary nation that’s your choice. Ah, I forgot. You don't have a choice.

Then reader Karly wrote:

“Demand Point of origin labels from our legislators

“I read labels. I didn't realize China had the corner on drugs & supplements. Our government needs to mandate point of origin on all labels! I agree, Boycott Chinese Products. Thankfully, none of my cats ingested any of the contaminated cat food. Today I am dumping out the tylenol in my medicine cabinet including vitamin supplements. We will be eating More from my garden and locally grown, organic, fruits & vegetables for me - how else are we going to know what we're consuming? Message to Diane Feinstein, Barbara Boxer, Dennis Cardoza - take action NOW to inform & protect us!

This, of course, was all too much for some the-less-government-the-better folks. Buddell wrote:

"Karly, why are you asking government officials to protect you? Is it the cradle-to-grave mentality of dem. Californicos? You want to blame someone for this scenario with China, blame unionized labor. It has driven a large manufacturing segment of our society to China. Basic economics 101: those who make good products at reasonable prices will survive and prosper.