King Corn

KING CORN: A REVIEW

The film King Corn is a propaganda piece and full of misleading statements. 

First, the hair test that Dr Macko uses to estimate the percentage of corn in the diet, while useful for what it was intended, gives somewhat misleading results in this application.  First, a little background on this test. 

This test depends on the fact that in nature, some elements, such as carbon, have different forms with different weights, due to having differing numbers of neutrons in their nucleus, and thus slightly variable weights.  These differing weights of the same elements are called isotopes (from the Greek isos =equal+ topos=place).  Thus in the case of carbon, we have the normal isotope C12 with 6 protons and six neutrons for an atomic weight of 12, and we have isotope C13 with 6 protons and 7 neutrons for an atomic weight of 13.  In nature there is a mixture of these two isotopes, and plants take up and use both isotopes from the CO2 in the air to use in building plant tissue, and we have both isotopes in our body used interchangeably in our tissues and chemical reactions.

The test Dr. Macko is using to differentiate corn from other plant materials in the diets of humans and livestock utilizes the fact that a class of plants, called C4 plants, which includes corn, preferentially take up a different proportion of these two isotopes of carbon to make their tissues than do the class of C3 plants, which comprise the vast majority of other plants including forages..  These ratios of isotopes of carbon continue on in the food chain, and their proportions can be measured in the hair to determine which proportions of plants have been consumed, either C3 or C4 (assumed in the film to be corn).

What this film does not disclose however, is that livestock consume a number of other C4 plants in their rations other than corn.  Sorghum is also a C4 plant.  It is grown extensively throughout the West in dryer states such as Texas, Oklahoma, Kansas, Nebraska, and parts of Colorado.  In areas where it is grown it is used almost exclusively for livestock feeding.  Thus, the above test would be incapable of differentiating an atom of carbon as coming from livestock fed corn or sorghum. 

This same rationale would also apply to millet, which is also a C4 plant used for livestock feeding, grown in the northern central states, chiefly the Dakotas and Nebraska.

When we turn to plant foods directly consumed by humans, we also find a problem with the test used.  Sugar cane is also a C4 plant, and thus the sugar derived from it would be indistinguishable from corn in whatever form consumed as far as the hair test described.

These factors thus makes this test somewhat unreliable as a measure of exactly how much corn is in our diet, either directly or in the diets of the livestock we consume.

Next, I want to turn to their description of cattle feeding, and their reporting of its effects.  It is somewhat disappointing that the makers of this film did not avail themselves of the opportunity to educate themselves as to the facts regarding the cattle feeding industry when they had a good opportunity to do so.  First, as to their claim that feeding corn causes death within 120 days.  Curiously, their reference for this appears to be a random passer-by they met during filming.  The reality is quite different. 

Traditionally feeders take in either grass fed calves at 450 to 600 pounds, or grass fed yearlings (1 year old animals) at 550 to 800 pounds, and finish them out with a mixture of grains, protein supplements, roughage, and vitamin/mineral supplements to a slaughter weight of 1100 to 1400 pounds.  Cattle are usually fed an average of 177 days if started on feed as yearlings, and 237 days if started as calves, according to John D. Lawrence, extension livestock economist, with the article available at http://www.extension.iastate.edu/agdm/livestock/html/b1-35.html

The grain or energy component of the ration is balanced with whatever grain happens to be available and most cost effective locally.  In the Mid-west that would be corn.  In other parts of the western US, sorghum, millet or barley would be the energy component of choice, and in the eastern US soft wheat would often be the feed of choice.

Dairy cows are also fed a high concentrate ration required for high milk production.  They are feed high rates of grain over many milking cycles with obviously no early death, as a high value dairy cow obviously would not be fed such high grain diets if it would lead to early death.

The acidosis referred to in the movie certainly can become a problem.  It is caused by an overgrowth of lactic acid producing microorganisms in the rumen when high-carbohydrate foods are introduced too rapidly and abruptly.  It is easily controlled or prevented by introducing high-concentrate feeds gradually over a period of time, a common practice used in all feeding and dairy production situations. 

The idea that grain feeding is somehow unnatural is intimated at extensively in the movie.  Nothing could be further from the truth.  Cattle and other livestock have been given high-concentrate feed over historical times.  Even so called “Grass Fed” beef is almost always given a brief finishing feeding period with a higher concentrate finishing feed.  If all US livestock were to be exclusively pasture raised, as they obviously can not and will not be, due to the many many millions of additional acres required, meat would be many multiples of times more expensive, and meat would obviously be a specialty, seasonal food, as there obviously would not be any pastures available during the winter months.

There are actually some benefits to a more highly grass fed animal.  It has a lower fat content, and there is some evidence that it contains more omega-3 fatty acids.  These are actually only slight advantages, as the fat content of beef can be minimized by eating actual cuts of meat with close trimming.  Eating most of one’s beef in the form of hamburger is not a good practice, as quite a high content of the fat is not trimmed off and gets into the hamburger.  Meat is actually best viewed as not a good primary source of omega-3 fatty acids, which are more efficiently obtained in the diet through oils and supplementation. Grass fed beef will continue to be a boutique item demanded by a specialty clientele.  It is a good product, and some even prefer its unique flavor.

Now let us turn to the corn plant itself, which in the film is strangely attacked and demonized.  One of the most reprehensible parts of the film was the interview with the Harvard professor, who repeatedly made statements to the effect that corn is a non-food, is nutritionally empty, and has been deliberately bred to be so.  This is quite misleading.  This Harvard professor should know quite well (or maybe he doesn’t ?!) that corn, along with all plants domesticated by humanity over many millennia have been extensively selected for different varieties used for different purposes. 

In the case of corn, our North American native grain, it consists of a number of varieties hand selected both during prehistoric times and by many generations of traditional farmers.  We currently have 4 major types; sweet corn, used for eating fresh and canning, flour corn, used for milling into corn meal for human consumption, the well known popcorn, and dent corn, also know as field or feed corn. 

Field corn has been selected specifically to produce the energy source or carbohydrate portion of animal feeds.  Field corn typically contains 9% protein, 5% oil, with the remainder being carbohydrates. The latest USDA figures for 05-06 total corn utilization indicates 54% being used for animal feed, 20% being exported, 14% being used for ethanol, 5% being used for High Fructose Corn syrup, and 7% being used in various other human food products.

Corn is one of the handful of staple grains producing the main food source for human beings.  These grain staples, including corn, wheat, rice, barley and sorghum, produce collectively 90% of the calories required by human beings worldwide.  World civilization as we know it could not exist without these staple grains.  To say that carbohydrates, by far the greatest requirement in the human and animal diet and which are used for energy production, are “empty” calories is certainly a misstatement.  There are no “empty” calories or “bad” foods.  There are only good and bad diets. To expect that one food would have all the components of a healthy diet is naive.  This is the reason all responsible nutritionists continually speak of eating a variety of foods.

As for the cheap trick of trying to eat a mature cob of field corn, and saying it is a “non food” simply because it is not palatable and requires processing, the less said the better.  Simply take note that not one of the other staple grain crops that support 90 % of human nutrition, wheat, rough rice, barley, sorghum etc, would be edible in their raw state either.

Now let us address the issue of High Fructose Corn Syrup (HFCS).  Here I quite agree with the main thrust of their argument.  There is all kinds of good scientific evidence that a diet with a large percentage of HFCS has some deleterious effects, diabetes and obesity being among them.  Fortunately, it is actually quite easy to keep the majority of HFCS out of one’s diet.  The majority is to be found in two products, soda type drinks, and fruit juices with additional sweetener added.  The former really has no redeeming qualities, and should be eliminated from the diet, and the latter has many and increasing alternative choices on the shelf that either have no sugar added, or have natural sweeteners, this obviously in response to consumer demand.  There are other snack type foods with HFCS in them, but also many without.  There usually are many choices.  Obviously for those who are purists about absolutely no HFCS of any amount, this may take care.

To those with corn allergies, I can only say I feel the greatest sympathy.  I do hope you find good choices among all the many other food choices available.

I also want to comment on the lumping together of corn consumption in all its forms as being equally bad.  No doubt HFCS is not good nutrition, but to conflate that form of corn consumption, with consumption as meat products or other corn products is unconscionable.  There is not a shred of evidence that livestock fed corn as a feed carry the negative effects of HFCS.  Just ask the residents of Mexico, where corn is actually a staple, whether corn is a part of a healthy diet.  We in the US of course use wheat mainly as our staple source, either as bread or pasta. 

Finally, let me just briefly comment on the statements that the farm program has some conspiratorial part in encouraging corn overproduction.  First, the farm program has always tried to balance its provisions to be commodity neutral, that is, it endeavors to try to have farmers make planting decisions based on marketplace signals and good agronomic practices, rather than program provisions.  It is not always perfect in this regard, but that is its aim.

The idea that farmers will plant corn, or any other crop simply because of a relatively small government payment is woefully out of date.  The farm price of corn used in the movie was well under $2.00   This has not been the case for quite some time.  The last I checked, the price of corn was over $6.00.  I can assure you that farmers today do not make their main planting decisions at this point based upon a declining program payment.

In summary, to think that farmers here or in other countries will stop planting corn is quite unrealistic.  We have the lowest grain supplies worldwide today since the last days of World War II.  We will be planting more corn going forward, or at least we will try. 

Finally, I want to say I am neither involved in corn production nor cattle feeding.  I am a concerned person in traditional agriculture that tries to correct unfounded ideas whenever I can.  I salute these young college people for their idealism, and their concern for the HFCS issue.  I can only say that their credibility on this issue would not have been damaged quite so badly if they had stuck to the facts.

Comment by Richo — May 3, 2008 @ 12:55 pm