Denise Minger’s recent critical review of Dr. T. Colin Campbell’s The China Study has elicited a response from Dr. Campbell himself. Minger made a brilliant response that can be found here. I highly recommend reading it if you haven’t yet.
Minger’s review has generated new public debate over The China Study. In the process, Dr. Campbell and some other critics have made some comments about my original review as well as my recent blog post in which I argued that Denise Minger refuted the China Study once and for all. I will make a response to these comments below.
In a discussion on the “30 Bananas a Day” site, a paleontologist-in-training named Robert suggested that I used a particular rhetorical tactic common to creation scientists by “insinuating dishonesty” on the part of Dr. Campbell. The first example he cites is my suggestion that Dr. Campbell should have shared his findings that complete plant proteins promote cancer (in actuality, pre-cancerous lesions) as vigorously as animal proteins do in the third chapter of The China Study. The second example he cites is my finding it “curious” that Campbell stated that folate is derived exclusively from green leafy vegetables when in fact chicken liver contains five times as much folate as spinach.
Take his praise for Minger’s supposed “big reveal” about the rat studies. If you relied only on Masterjohn and Minger, you’d think Campbell had been hiding this from the public. It certainly seems to be the impression Masterjohn in particular wants his readers to walk away with.
Yet, Campbell revealed this information himself years ago, in his response to Mercola. He hasn’t ignored or tried to hide anything. The fact that his disclosure of this information is found in an obscure source has been used by Masterjohn and other critics to insinuate Campbell’s incompetence or deception. This is itself deceptive.
The Lysine Connection
Indeed, in September 2009, Dr. Campbell wrote a response to Dr. Joseph Mercola on VegSource.Com. After attempting to associate Dr. Mercola’s critique with mine and noting that I was a 24-year-old with no credentials (actually, I was 23 when my review first came out and when Dr. Campbell wrote his reply to Dr. Mercola I was 27), Campbell indeed revealed the lysine connection:
The adverse effects of animal protein, as illustrated in our laboratory by the effects of casein, are related to their amino acid composition, not to the effects of pasteurization, homogenization, or of the presence of hormones, pesticides, etc. . . . This focus on amino acid composition of proteins is important because animal based protein will be the same regardless [of] whether it is provided by grass-fed or feed lot fed animals. . . . There have been many different kinds of studies for well over a half century showing that the nutritional responses of different proteins are attributed to their differing amino acid compositions that have nothing to do with pasteurization, homogenization or contamination with foreign chemicals. These differences in nutritional response disappear when any limiting amino acids are restored. . . . Wheat protein, unlike casein for example, did not stimulate cancer development but when its limiting amino acid, lysine, was restored, it acted just like casein.
I was not aware of this response until tonight. However, the fact that Dr. Campbell has revealed the lysine connection in public is nothing new. Campbell published these findings in 1989 in the Journal of the National Cancer Institute. When I wrote that Dr. Campbell “should have informed us of the result,” I meant he should have informed us of this in chapter 3 of his bestselling book The China Study juxtaposed to his conclusion there that animal protein, but not plant protein, causes cancer.
I think it is quite clear that drawing attention to this fact in response to Dr. Mercola in a comparatively much more obscure source is not a substitute for drawing attention to it in his “Turning Off Cancer” chapter and integrating it into his conclusion. Indeed, Dr. Campbell mentioned it in the above context for the specific purpose of showing that it is animal protein itself and not the processing of animal protein that is responsible for the promotion of pre-cancerous lesions. Denise Minger is the first person I am aware of to put two and two together and point out that vegetarians eat a mix of proteins that would supply the lysine necessary to “Turn Cancer Back On.”
Did he try to hide it? I have no idea what Dr. Campbell’s intentions were in ommitting this fact from his book chapter. I do not know what lies within Dr. Campbell’s heart or mind and I think it would be inappropriately presumptuous on my part to try to guess. I do know, however, that the entire conclusion of chapter three rests on the claim that animal protein is unique in its ability to promote cancer and that chapter 4, “Lessons From China” is interpreted in the context of the experimental evidence put forth in chapter 3, “Turning Off Cancer.” I therefore believe that chapters 3 and 4 would conclude very differently if Dr. Campbell had allowed the lysine connection to influence their conclusions.
Folate — Whereforeart Thou in the Animal Kingdom?
Robert also made a statement about folate that I find just as “curious” as Dr. Campbell’s statement:
Although he doesn’t do it in this response, Masterjohn has also deliberately misinterpreted and misrepresented Campbell in the past. The most glaring example I know of — the one that stuck with me after all these years — is Masterjohn’s attack on Campbell regarding folic acid. Masterjohn took issue with Campbell’s statement that folic acid was derived exclusively from plant sources, noting that you can find folic acid in chicken and other meats. This is a deceptive tactic, relying on the fact that most people aren’t going to read very precisely. The key phrase in Campbell’s text was “derived from,” not “found in.” This is important, because it’s completely true that folic acid is only derived from plant sources; the reason it’s found in animal flesh is that those animals got it from the plants they ate. Folic acid is called folic acid precisely because it’s derived from plants; its root Latin word is “folium,” meaning “leaf.” Masterjohn knows this, or should. But he elided the distinction by using weasel words. This alone, IMO, invalidates anything else he says. He has violated a trust between researcher and reader, and is not a credible source.
First, that is not true. Folate is not ultimately derived exclusively from plant foods. Here is what the tenth edition of Modern Nutrition in Health and Disease has to say:
In 1931, Wills described responsiveness of “pernicious anemia of pregnancy,” now a misnomer, and “tropical anemia” to a component of a yeast preparation, Marmite. Day and colleagues indentified a response of a macrocytic anemia in monkeys to “vitamin M.” Other preprations were identified by properties such as support for growth of microorganisms, and the observation of such activity in spinach led to the name folic acid. Nutritional megaloblastic anemia was reversed by a component of liver unrelated to that curing cobalamin [vitamin B12] deficiency. The active component in all these preparations proved to be folate, once folic acid was purified and characterized.
Yeast, I believe we can all agree, is not a plant. However, perhaps the folate in liver comes only from leaves? Not according to the recent review in the British Journal of Nutrition entitled “Folic Acid in Ruminant Nutrition.” These authors write:
It is well known that the microbial activity and the ruminant population are influenced by the level of concentrates in the diet and the type of feed. As some bacterial species are able to synthesize folates and others need them, different amounts of folates can be synthesized and used in the rumen depending on the feed composition.
They conclude that part of a cow’s folate requirement is met by diet and part is met by synthesis of folate in the rumen, and that more study is needed to determine the factors that affect the proportions of each.
In other words, folate is not “exclusively derived from plant foods” no matter what definition of “derive” we use.
Even if it were true that folate only originates through plant synthesis, Campbell’s statement could still hardly be justified. This is what Dr. Campbell originally wrote:
In another study on Alzheimer’s, the risk of getting the disease was 3.3 times greater among people whose blood folic acid levels were in the lowest one-third range and 4.5 times greater when blood homocysteine levels were in the highest one-third. What are folic acid and homocysteine? Folic acid is a compound derived exclusively from plant-based foods such as green and leafy vegetables. Homocysteine is an amino acid that is derived primarily from animal protein. This study found that it was desirable to maintain low blood homocysteine and high blood folic acid. In other words, the combination of a diet high in animal-based foods and low in plant-based foods raises the risk of Alzheimer’s disease.
Usually when talking about human nutrition, the word “derive” means that humans derive a nutrient from a particular dietary source. Someone who wants to get technical might refer to this as proximate derivation rather than ultimate derivation.
In any case, Dr. Campbell’s conclusion is that we must eat a diet low in meat, the source of homocysteine, and rich in plant foods, the source of folate. Thus, I still find Dr. Campbell’s conclusion as “curious” as I did back in the spring of 2005 when, fast forward to July, 2010, chicken liver still has five times as much folate as spinach.
And unlike leafy greens — which have many benefits, no doubt — liver and other meats provide vitamin B12 in addition to folate. Vitamin B12 is necessary to assist folate in homocysteine metabolism, and one study found that 68% of vegetarians and 83% of vegans have elevated levels of methylmalonic aicd, indicating functional vitamin B12 deficiency. In the same study, high homocysteine was found in 16% of omnivores, 38% of vegetarians and 67% of vegans.
Besides all that, animal products provide the amino acid methionine. This is a “source of homocysteine” insofar as it is used for the vitally important process of methylating proteins. In the liver, when vitamin B6 is sufficient and the methylation process is proceeding adequately, rather than being converted back to methionine in a folate-dependent reaction, homocysteine is preferentially shuttled into the synthesis of glutathione, the master antioxidant of the cell and a principal molecule used for detoxification of drugs and environmental toxins. See this review for a reference.
Again, since liver is the king of all B vitamins, whether folate or B6, I fail to see based on basic physiology why we should avoid it for its methionine content in order to prevent Alzheimer’s disease. I propose that nutrition is more complex than “plant versus animal.”
Dr. Campbell Responds
After Denise Minger responded to Dr. Campbell’s post on Tynan.Net, Dr. Campbell responded to her on his web site as a Word document, with the response reprinted in html format on CampbellCoalition.Com and VegSource.Com. On the latter site, pictures of Minger and Campbell are posted side by side and the title reads in the spirit of civil discourse and scientific debate that “China Study Author Colin Campbell Slaps Down Critic Denise Minger.”
Unfortunately, Dr. Campbell does not seem to have read Minger’s response to his Tynan.Net post at all and does not seem to have read her original review very carefully either. He even accuses her of deleting a comment on her blog from an epidemiologist when in fact that comment can still be found together with Minger’s reply by going to her original review and scrolling down in the comments to the date 11/07/2010 (date/month/year) and looking for the third post on that day, which was entered by “rayna.” But I will leave these issues to the reader to decide after reading what both Campbell and Minger have to say by following the links above.
I do wish, however, to respond to several comments directed my way. First, Dr. Campbell attempts to link Minger with the Weston A. Price Foundation, which the editors of VegSource expand on by linking to my blog post about her review (by the way, this blog is authored in my name, and I’m not a foundation). In fact I was unaware of Minger’s blog until July 8, 2010 when several people forwarded me a link to her review. Since her review was brilliant, I wrote a blog post on it, but dozens of other bloggers beat me to it. A brief perusal of Minger’s writings about her negative experience with raw dairy seems to make it clear that she has a number of differences of opinion with WAPF. In the world of civil discussion and logical debate, someone’s views about one foundation or another have little to no impact on the strength of their arguments.
Second, Dr. Campbell seems to me to mischaracterize my original review:
Not only does Denise misrepresent and misunderstand the rationale for the science in The China Study, her choice of words do not facilitate what she hopes to achieve. Her overall message, often embellished with adjectives and subjective remarks, appeals to some questionable characters sympathetic to or subservient to the Weston A Price Foundation, a farm lobbying group whose advocates and apologists have accused me of being a “fraud”, a “liar”, a “buffoon” and (earlier) an associate of a “terrorist” organization. I doubt that this is what she wanted to achieve. These individuals, for much too long, have been carelessly using or even ignoring science to further their own interests, such as advocating for the use of a very high fat, high protein diet mostly consistent with the diet that has caused us so much difficulty.
I do not know where the words “fraud,” “liar,” or “buffoon” come from. Whoever, if anyone, used them, that is their choice and I do not condone such language used in public debate. The “terrorist” remark is a reference to a sentence included in my original review citing a Newsweek article linking Physician’s Committee for Responsible Medicine to PETA and another group, Stop Huntingdon Animal Cruelty, which the Department of Justice had listed as a terrorist organization. The intention behind this statement was never to accuse Dr. Campbell of having terrorist connections, but was to contrast the pro-meat and pro-dairy environment from which he came and his association with certain radical vegetarian groups to show the dramatic change of his positions over time.
When it became clear that many people were interpreting this as a suggestion that Dr. Campbell was himself tainted by this connection, I promptly removed this sentence from both versions of the review, the one on the WAPF site and the one on Cholesterol-And-Health.Com. Rather than hiding this fact, I explained this to Dr. Campbell in my response to his VegSource.Com comments, which can be found here.
Although there was nothing incorrect about the information, I removed it because it had so much as the potential appearance of an ad hominem attack, focusing on a person’s associations rather than the science and logic at hand.
What I find most disappointing about Dr. Campbell’s response is he did not once take any of Minger’s arguments seriously. It would have been respectful to at least address the argument of whether schistosomiasis infection could have confounded any of the correlations he presented, whether he believes it was a confounder or not.
Thus, while Dr. Campbell may be older and have far more credentials, I still believe the strength of the argument lies with Minger’s analysis. I still consider her the first person to have put together the implications of the lysine connection — that mixed plant proteins behave the same way as animal proteins in this cancer context — and I still believe that liver is a great source of folate.
Read more about the author, Chris Masterjohn, PhD, here.