Emergent Fitness: Why I Have a Problem With Vegetarianism

Our quest to obliterate false dietary dogma continues!

....Well, not really, but, in this post, I do plan to add yet another piece of straw to the vegetarian camel's back.

"Why?" you ask.....Because I enjoy writing argumentative essays.

Now, to turn from my digression, let's continue with our breakdown of Denise Minger's article.

Point # 4 of Minger's Critique

According to Minger, Campbell makes the following claim in his book, The China Study -

Cardiovascular diseases are associated with lower intakes of green vegetables and higher concentrations of apo-B (a form of so-called bad blood cholesterol) which is associated with increasing intakes of animal protein and decreasing intakes of plant protein.

In short, Campbell claims that plant protein decreases, and animal protein increases, the amount of "bad cholesterol" (apo-B) circulating in one's blood. Since an increase in apo-B associates with cardiovascular disease (e.g. - heart attacks & coronary heart disease, problems from high blood pressure, and stroke), plant protein = good, and animal protein = no bueno. However, it seems once again that Campbell has jumped the gun with his conclusions; inferring causation when only weak, or often times non-existent, correlations abound.

In any event, how exactly did Campbell go about collecting data for this component of his argument? Questionnaires (oh boy). Let me just say this: WHEN SOMEONE STARTS INVOKING QUESTIONNAIRES AS EVIDENCE, I USUALLY STOP LISTENING. Questionnaires, in my opinion, serve as terrible sources of scientific data; especially when one plans to make practical recommendations based on said data.

Why?

Because people are people are people.....are people. Campbell, in order to determine if such a correlation between protein source and cardiovascular disease exists, asked people to indicate how many vegetables they ate per day, and over the course of the year. I can only speak for myself, but I doubt I could accurately answer either of these questions reliably (save if I had kept an accurate food journal). Questionnaires and surveys inescapably suffer from subjectivity. Given that science, at least purportedly, values objectivity as the highest of virtues, it seems fair to say that survey/questionnaire based data acquisition stands juxtaposed to the scientific method.

At any rate, let's assume Campbell's questionnaires yielded objective results. What do they tell us?

From the diet survey, green vegetable intake (average grams per day) has the following correlations:

Myocardial infarction (heart attack) and coronary heart disease: +5

Hypertensive heart disease (problems caused by high blood pressure): -4

Stroke: -8

From the questionnaire, green vegetable intake (times eaten per year) has the following correlations:

Myocardial infarction and coronary heart disease: -43**

Hypertensive heart disease: -36*

Stroke: -35*

In view of this data, Minger points out that reported yearly consumption of vegetables far exceeds, in protective value, that of daily vegetable consumption. What an interesting result, to say the least. In response to this data, I have the same questions as Minger - "Why the huge difference? Why would frequency be more protective than quantity? What accounts for this mystery?"

According to Minger, the reason for this discrepancy lies in geography -

The counties in China that eat greens year-round live in a particular climate and latitude—namely, humid regions to the south. The “Green vegetable intake, times per year” variable has a correlation of -68*** with aridity (indicating a humid climate) and a correlation of -60*** with latitude (indicating southerly placement on the ol’ map). Folks living in these regions might not eat the most green vegetables quantity-wise, but they do eat them frequently, since their growing season is nearly year-round.

In contrast, the variable “Green vegetable intake, grams per day” has a correlation of only -16 with aridity and +5 with latitude, indicating much looser associations with southern geography. The folks who eat lots of green veggies don’t necessarily live in climates with a year-round growing season, but when green vegetables are available, they eat a lot of them. That bumps up the average intake per day, even if they endure some periods where greens aren’t on the menu at all.

If green vegetables themselves were protective of heart disease, as Campbell seems to be implying, we would expect their anti-heart-disease effects to be present in both quantity of consumption and frequency of consumption. Yet the counties eating the most greens quantity-wise didn’t have any less cardiovascular disease than average. This tells us there’s probably another variable unique to the southern, humid regions in China that confers heart disease protection—but green veggies aren’t it.

Some of the hallmark variables of humid southern regions include high fish intake, low use of salt, high rice consumption (and low consumption of all other grains, especially wheat), higher meat consumption, and smaller body size (shorter height and lower weight). And...these southerly regions also had more intense sunlight exposure and thus more vitamin D—an important player in heart disease prevention.

In short, Campbell, in his vain attempts at reduction-ism, has failed to account for numerous, and more powerful, variables.

But What of Apo-B?

Despite the incredulity of Campbell's claims about plants, Minger notes the following -

Campbell is justified in noting the link between apolipoprotein B (apo-B) and cardiovascular disease in the China Study data, a connection widely recognized by the medical community today. These are its correlations with cardiovascular disease:

Myocardial infarction and coronary heart disease: +37**

Hypertensive heart disease: +35*

Stroke: +35*

And he’s also right about the negative association between apo-B and plant protein, which is -37*, as well as the positive association between apo-B and animal protein, which is +25* for non-fish protein and +16 for fish protein. So from a technical standpoint, Campbell’s statement (aside from the green veggie issue) is legit.

So, does Campbell yet come out on top? "Technically," yes. In reality, no.

When we look at the raw data, we get this -

Correlations between animal protein and cardiovascular disease:

Myocardial infarction and coronary heart disease: +1

Hypertensive heart disease: +25

Stroke: +5

Correlations between fish protein and cardiovascular disease:

Myocardial infarction and coronary heart disease: -11

Hypertensive heart disease: -9

Stroke: -11

Correlations between plant protein and cardiovascular disease (from the China Study’s “diet survey”):

Myocardial infarction and coronary heart disease: +25

Hypertensive heart disease: -10

Stroke: -3

Correlations between plant protein and cardiovascular disease (from the China Study’s “food composite analysis”):

Myocardial infarction and coronary heart disease: +21

Hypertensive heart disease: 0

Stroke: +12

As you can readily see, this data is quite erratic. As Minger states, animal and plant protein are "neck-and-neck." Moreover, Minger indicates that fish actually proves the most protective source of protein of all; meanwhile, plant protein actually seems most causative of heart attack!*

Now, you may yet note that animal protein looks fairly incriminated by this data (at least in view of hypertensive heart disease), however, when we break down the data further, according to more well defined sources of animal protein (fish included), we get this -

Correlations between specific animal foods and hypertensive heart disease:

Milk and dairy products intake: +30

Egg intake: -28

Meat intake: -4

Fish intake: -14

Dairy obviously looks rather bad in this data breakdown, but as Minger states in another article (A Closer Look at the China Study: Dairy and Disease) -

China’s dairy eaters don’t have significantly more cancers, myocardial infarction, stroke, and so forth than the dairy-free regions.

Dairy’s only significant mortality correlation, hypertensive heart disease, may be related to any number of variables we don’t have enough data to tweeze apart. (Lack of vegetables, excess sodium, high body weight, and high caloric intake, to name a few.)

Despite T. Colin Campbell’s findings with the milk protein casein spurring cancer in lab rats, there does not seem to be a correlation between high dairy consumption and cancer in the China Study data.

Here's a data chart from that article, just to give you an idea of the sparsity of information Campbell had to work with regarding dairy -

In my opinion, 2 data points hardly suffice to incriminate diary.

*Please realize that I do not think we ought to avoid eating ample amounts of veggies.

The Bottom Line

Campbell correctly demonstrates an association between apo-B and cardiovascular disease, however, the irreducible variables which lead to such an outcome only frustrate attempts to nail down a definite cause. As Minger states -

[T]o imply animal protein is causative of these diseases—and green vegetables or plant protein protective of them—is dubious at best. What factors cause both apo-B and cardiovascular disease risk to increase hand-in-hand? This is the question we should be asking.

That's it for today. If you missed the other 4 parts of this series, I have linked them below -