Wednesday, May 02, 2007

EAT ZINC! Maybe it's time to reclassify iron filings as nutritional, too

This week, your friendly neighborhood GlobalSecurity.Org Senior Fellow has delved into the murky world of pet food production. And it's a bad and dim-looking place.

Imagine my astonishment to find that zinc oxide, an inert white dust used in paints, baby powder and other materials not considered good to eat, is sold as a food additive by one of the Chinese companies involed in the tainted pet food recall.

Imagine even greater astonishment when the same zinc oxide is found in dry cat and dog food formulations, as trace material.

The pet industry would seem to want consumers to think zinc oxide is necessary for good nutrition!

It isn't.

But DD became so confused he went into the kitchen to look at various goods to see if he had been eating zinc oxide himself!

Was there zinc oxide in Hebrew National Beef Franks? Apparently not, unless Hebrew National's fibbing.

No zinc oxide in the box of Triscuits or the box of organic cereal. No zinc oxide in the can of red chiles. No zinc oxide in Ragu's Mama's Meat Sauce.

Xuzhou Anying Biologic Technology Development Co. sells zinc oxide, right along side its protein powder, fresh carrots and ginger! Why, it almost looks like they'd want buyers to believe it's good for sprinkling on fresh veggies.

Xuzhou Anying wants people to believe zinc oxide is a good food additive. It's website devotes a page of useless information on the product, which I'll deal with in a moment.

But there's absolutely no common sense reason why zinc oxide would be considered a beneficial food additive.

Zinc ion is a critical component in a class of proteins known as metalloenzymes. And metalloenzymes are present within the vital biochemical pathways of life.

However, normal warm-blooded animals, including people, do not need to eat zinc oxide for their zinc requirements. The very idea is senseless. Dietary zinc is furnished in red meat, oysters, poultry, and plant proteins, among other things.

Many years ago DD worked closely with zinc-requiring metalloenzymes in the lab, purifying and characterizing them. Some experiments involved pulling the trace amounts of zinc out of the enzymes, noting the differences in activity that resulted, and then adding it back.

One example of a zinc-requiring protein was a phospho-glycero mutase found in wheat germ. Usually, the lab bought the wheat germ from a local health food store. The enzyme from the wheat germ was tested in the lab and compared with a counterpart found in human red blood cells.

So readers can see from this that trace amounts of zinc are found in common foods derived simply from nature. No need to eat an insoluble powder, zinc oxide, to add zinc to diets.

In fact, the idea of using it in such a way flies in the face of common sense and natural biochemistry.

However, somewhere along the line funny things started to happen in American food production.

Regulators apparently stopped paying attention. So did consumers.

People bought the silly idea that all kinds of things were good micronutrients, as long as -- and here's the good part -- the concentrations of the compounds in question fell below what was thought to be overtly harmful.

Let's put it another way.

You could eat a little bit of plastic, a little bit of baby powder in your food, and it probably wouldn't hurt. After years of it, who knows?

In any case, American agriculture has been spraying zinc on crops as part of its fertilization regimens, in the form of zinc sulfate, for many years. And it has expanded the use of zinc sulfate, with fertilizer companies making it available as a feed additive.

Zinc sulfate isn't good for you either. There's no reason to believe it is good for animals. But in very dilute trace form, it appears not to kill or chemically maim anyone.

Part of the reason for this is not one of healthful benefit. It's for the selling of zinc sulfate to make money.

It can be learned from the web that the market for zinc sulfate is essentially stagnant. It's only growth has occured in its addition as feed and fertilizer additive.

"Zinc sulfate's growth comes chiefly from fertilizer applications and animal feed supplements," writes one web page on business "innovation."

"It is especially applied on crops such as pecan, deciduous fruits, peanuts, cotton, corn, and citrus, and added to feeds for swine and poultry. Some of the fertilizer segment's gain in recent years came at the expense of zinc oxysulfate, produced from steel furnace fly ash. Fear of attendant undesirable heavy metals (e.g. chromium) resulted in some oxysulfate displacement in the fertilizer market." (Ummm, sounds good!)

"Agricultural uses will continue to provide modest growth for zinc sulfate, as zinc is an essential trace element for plant and animal life ... Other application areas are stagnant and are expected to remain so."

Zinc sulfate, as sold by a fertilizer company found on the web, contains a product spec sheet on toxicity. It is here.

Feed grade zinc sulfate, the brochure indicates, is a moderate health hazard. It is obviously not good to eat, as it causes symptoms in line with acute zinc toxicity --"kidney damage, liver damage and convulsions."

Keep in mind the fact that zinc requirement in diet is met by eating normally, not by eating zinc powders under the fool's-hall-of-fame idea that if it is sprinkled upon and into everything, after dilution in the food production chain, it will provide an essential ingredient. (In fairness, zinc sulfate isn't the only compound used in this idiotic manner.)

From this, it can be seen there is a market for zinc sulfate, no matter how unnecessary, in North America.

Enter a company like Xuzhou Anying Biologic Technology, a company now apparently caught, along with others, adding melamine to its protein additives shipped to US buyers in order to boost profits.

From Xuzhou Anying Biologic's webpage, a snapshot of its display on its "Zinc Oxide of Feedstuff."

Perhaps this looks reasonable to someone not versed in chemistry. It isn't. It's crap.

In fact, it makes crap look good.

Xuzhou's page compares its zinc oxide, a dubious product, to zinc sulfate, another dubious additive. It does this to apparently make a favorable impression, to persuade someone who does not -- perhaps -- have much in the way of brains, to buy it as a cheaper, better version of zinc sulfate.

"The cost of Zinc Oxide is lower ... " it reads. Yet zinc oxide and zinc sulfate, assuming one would want to buy zinc sulfate for this purpose, are something of apples and oranges. Zinc oxide is an insoluble-in-water powder. Zinc sulfate is soluble in water.

"Zinc Oxide is easier to be absorbed by animal than other Zinc," reads the Xuzhou Anying Biologic page.

Remember what I said about crap?

Zinc oxide is insoluble in water. Although it can be dissolved in acid, and would be expected to encounter some in the digestive system, eating zinc oxide -- in any quantity -- is in no way better than the normal way of getting trace amounts of zinc in the diet. Entertaining such a fancy is absurd.

In fact, in no biochemistry classes or books on proteins and enzymes does DD ever recall zinc oxide explained as biochemical source material.

Well, while times have surely changed since then DD is sure they haven't changed that much.

With further delving, one can find some information -- none of it particularly good -- on zinc in animal feeds.

"Long-term feeding of high zinc sulfate diets to lactating and gestating dairy cows," is the title of one paper found from the Journal of Dairy Science.

"Thirty dairy cows, fed a control diet consisting of silage and concentrates, were given either 0, 1000, or 2000 ppm of supplemental Zn (DM basis), from zinc sulfate monohydrate (ZnSO4.H2O) for most of a lactation," reads the abstract, a summary of the paper's purpose and findings.

"Feeding 2000 ppm Zn decreased milk yield and feed intake after several weeks. Some cows were affected more severely than others."

"Except for lower calf weights with 2000 ppm Zn, reproductive performance was not measurably affected by the dietary treatments. The 1000 ppm added Zn diet had no adverse effect on the cows in any parameter measured."

While it's not "terrible bad," unless you're doing a weird cost benefit analysis on how to decrease milk yield and lower feed consumption, spiking animal feeds with zinc salts appears to be undesirable, at best -- utterly pointless.

The original is here.

In another document from the web, entitled "Imported Cadmium-contaminated Zinc Sulfate Used in Fertilizer and Other Products," it is read: "In 1998, Washington became the first state in the nation to adopt standards for fertilizers. Two years later, when cadmium contamination was discovered in zinc sulfate from China used as ingredients in fertilizers . . . [it was] assumed the cadmium was added to the zinc sulfate. However, it is not clear if the zinc sulfate was deliberately contaminated or not."

Xuzhou Biologic's page on its "Zinc Oxide of Feedstuff" claims to not have much cadmium, lead or arsenic in it.

Hmmm, melamine.

The original is here.

In today's Los Angeles Times, it was said the FDA appointed a "food safety czar" to defend the food and "take into account increasing US dependence on food imports in a global econony."

"The development came as the agency saids its investigation of contaminated pet food ingredients from China had expaned to include feed eaten by millions of chickens that most likely have already been consumed in the US."

"We do not believe there is any significant threat to human health," was the saying of the day. Of course, it is right. Until it is found there is a signficant hazard to human health or it is found that an unlucky someone's kidneys or liver have had a hit put on them.

The original at the LATimes.


"The pet food industry loves to say that it’s more highly regulated than human food, but that’s just not true. Pet food exists in a bit of a regulatory vacuum; laws are on the books, but enforcement is another story. The FDA has nominal authority over pet foods shipped across state lines. But the real 'enforcers' are the feed control officials in each state," reads an interesting report on what's in pet food.

Read it here.

Yesterday, in Eat Zinc!

ChemNutra's PR blog on spiking of animal feeds.

MenuFoods, ChemNutra, Wilbur-Ellis, and the Chinese: Incidental agroterrorism.

Melamine, urea spiking in pet food recall at the WaPost.

Chinese melamine production for feed spiking -- in the New York Times.


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