Vegetarians and Heart Disease: Will Ditching Meat Really Save Your Arteries?

Welcome to 2011! (Why don’t we have flying cars yet?) My new year’s blogolutions are to 1) write here more often and 2) actually answer emails. So far, I’m failing at both, but I’ve got 359 days left to clean up my act.

Sometimes, when I feel like I don’t have enough stress in my life and start craving a blood-pressure boost, I go to my old vegan haunts to read gems like these:

The only way meat can be digested is by putrefaction, our stomach acid is only 5% of that of a carnivore or omnivore so instead of being digested it basicly [sic] rots in your intestines which leaves toxic gases and waste to be absorbed into the blood. (From here.)

we know what’s happening. we’ve known for decades. however, we also have found that when we talk about the health detriments associated with eating the products of the corpse industries, people don’t believe us. (From here.)

[T]here is a single, sole cause to heart disease: cholesterol. If your total cholesterol is below 150 and LDL is below 70, you are essentially heart attack proof. What is the cause of high cholesterol? Saturated fat and animal products. (From here.)

Don’t you love this stuff? But I digress. What I want to talk about right now is one of the most oft-cited perks of being a vegetarian: an apparently lower risk of heart disease compared to omnivores. A recent paper called Chemistry Behind Vegetarianism sums it up by saying “Omnivores have a significantly higher cluster of cardiovascular risk factors compared with vegetarians, including increased body mass index, waist to hip ratio, blood pressure, plasma total cholesterol (TC), triacylglycerol and LDL-C levels, serum lipoprotein(a) concentration, plasma factor VII activity, ratios of TC/HDL-C, LDL-C/HDL-C and TAG/HDL-C, and serum ferritin levels.”

This is a trend that some folks translate as “meat causes heart disease”—a sentiment I saw plastered all over the veggie message boards during my most recent lurking spree. I assume this belief is bolstered by all the perfectly-preserved chunks bacon found in meat eaters’ arteries during heart biopsies. (more…)

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Hot Off the Press: A New “China Study” Links Wheat with Weight Gain

You’re going to hate me. This isn’t the wheat post, which means I’ve broken my “wheat is next” promise for the 80th time and should never be trusted with anything again ever. But during my nightly Pub(Med) crawl, I saw this nearly-new gem of a study glimmering in the dust and said to myself, “Wow. Wow! Wow.” By the third wow, a blog post was inevitable. So here it is. I promise this is truly interesting (not that me promising things matters anymore).

But first, some background.

A few years ago, a study hit the stands with the audacious title Vegetable-rich food pattern is related to obesity in China. The paper showed that among four diet patterns—“macho” (meat and alcohol), “sweet tooth” (sugary drinks and cake), “traditional” (rice, vegetables, pork, and fish), and “vegetable-rich” (vegetables, wheat, whole grains, and fruit)—only one had any relationship to obesity: the vegetable-rich pattern.

The study didn’t exactly receive a lot of press, probably because no one wants to think vegetables make people fat (including the researchers, who hummed and hawed their way to a half-baked conclusion—check out this post by Michael Eades). And as Stephan Guyenet explained, the study really showed a trend between wheat intake and weight gain, with the pounds rising as wheat replaced rice as a staple.

I mention this because the new study is actually a follow-up to the old one. It tracked changes in the participants’ weight over the span of five years, using the same method of divvying up food consumption into distinct diet patterns. In fact, here’s the table with their “factor loading” system, showing how various foods were weighted to determine adherence to each diet pattern. (Go ahead, click on it. You know you want to.)

I’m going to explain this study point-by-point before getting to the good stuff, because it’s a little complicated (but totally worth understanding).

Note that only two patterns use wheat as a factor: the “traditional” and “vegetable-rich” diets. The traditional pattern loaded inversely on wheat flour and positively on rice, whereas the vegetable-rich pattern loaded inversely on rice and positively on wheat. In simpler terms, that means the “traditional” pattern is rice based and the “vegetable-rich” pattern is wheat based. These two patterns are polar opposites in terms of their staple grain. The “macho” and “sweet tooth” patterns don’t take grain consumption into account.

After the researchers schemed up these diet patterns, they divided everyone into quartiles of adherence. Folks in the first quartile of any pattern had the lowest adherence to it, whereas folks in the fourth quartile ate diets most in line with that particular pattern. The paper only gives a detailed breakdown of the “traditional” diet quartiles and smaller summaries of the other three, but you can still see how food intake changes from quartile to quartile:

From the paper:

A clear increasing trend of the intake of fat was seen across quartiles of the ‘traditional’ pattern from low to high. Participants in the first quartile of this pattern had the highest intake of wheat flour and dietary fibre compared with the other groups. … There was a significant negative association between the ‘traditional’ pattern and energy density.

Darn right. The first quartile boasts an average wheat intake of 298 grams per day, versus only 21 grams in the fourth quartile. And fat intake rises from 75 to 87 grams per day from the first to fourth quartile. Energy density (calories per gram of food) also drops, although the researchers don’t mention that total energy intake (calories) is actually highest in the fourth quartile.

The researchers also note that “across quartiles of the ‘vegetable-rich’ pattern, the intake of energy, wheat flour and vegetable oil increased.” Most of that info didn’t make it into any tables, so we’ll just have to take their word for it.

Now here’s where it gets interesting.

The following table shows the five-year weight change for the different quartiles of each diet pattern. Remember that the “traditional” and “vegetable-rich” diets are the only ones defined—at least in part—by wheat consumption (or lack thereof). (A) is the traditional pattern, (B) is the macho pattern, (C) is the sweet-tooth pattern, and (D) is the vegetable-rich pattern.

What stands out here? How about this:

After adjustment for age, sex and baseline weight, the ‘traditional’ dietary pattern was inversely associated with weight gain, while the ‘vegetable-rich’ pattern was positively associated with weight gain. … No significant associations of the ‘macho’ and ‘sweet tooth’ patterns with weight gain were found.

What interests me is that the largest change in weight out of any of the graphs—1.4 kilograms—occurs between the first and second quartile in the “traditional” pattern. This corresponds with a drop in average wheat intake from 298 to 40 grams per day. (Without knowing the actual per-quartile numbers for the “vegetable-rich” pattern, it’s impossible to say how changes in wheat consumption match up with that graph, although the researchers already stated that wheat consumption rises throughout the quartiles.)

The inverse relationship between the “traditional” pattern and weight (and therefore wheat and weight) doesn’t seem to be confounded by other factors, either:

In the stratified multivariate analyses, an inverse association between the ‘traditional’ dietary pattern and weight gain was present in subjects aged < 40 years and ≥ 40 years, in non-smokers and smokers, in overweight and normal-weight subjects, in alcohol drinkers and non-drinkers, and in men and women. There were no significant interactions between any of the above factors and the ‘traditional’ dietary pattern with weight gain.

The connection between wheat and weight was so prominent in this study that the researchers (who carefully tiptoed around the subject in their 2008 writeup) couldn’t beat around the bush any longer. They slammed the “discussion” section with a giant wall of wheat text. Since I’m not sure how long the study will be available for free, I’ll quote the relevant parts right here (interspersed with some commentary):

A large difference in the intake of rice and wheat flour was found across quartiles of the ‘traditional’ dietary pattern. It represented two different sub-patterns with two different staple foods in inverse proportions, i.e. rice and wheat.

(No quibbles there. But the next part is where they try painfully hard to rationalize the wheat-weight connection.)

Rice is a low-energy food that contributes to the bulk of the traditional diet. Compared with wheat, rice absorbs more water when cooked. In addition, different cooking methods are used in preparing these two staple foods. For instance, steamed rice contains twice the amount of water and half of the energy compared with steamed bread(17). Thus, the energy density of the rice staple diet is usually lower than the one based on wheat.

(Regardless of energy density, the fourth quartile for both diet patterns show that the rice-based pattern had a higher average calorie intake than the wheat-based pattern, yet lower five-year weight gain—0.0 kilograms versus 1.6 kilograms.)

Since the content of wheat was only predominant in the first quartile of this dietary pattern, this may partly explain the negative association between the ‘traditional’ pattern and weight gain in the present study.

(Ding, ding, ding. But is it because wheat has lower water content, as they suggest, or does our favorite grain somehow wreak metabolic havoc? The weight changes in the “traditional” pattern echo wheat consumption more consistently than total energy intake.)

Also, this association could not be explained by fat intake, since a higher intake of the ‘traditional’ pattern was associated with a higher intake of fat. Intake of fibre was the highest among people in the first quartile of the ‘traditional’ pattern. Thus, the benefit of weight maintenance of the traditional dietary pattern was not related to dietary fibre.

(Blasphemy! How did such nonsense pass peer-review?)

The reason I find this so fascinating is that it perfectly corresponds with the patterns in the Oxford-Cornell China Study, which showed that wheat was the single biggest contributor to BMI out of any diet variable. Calories didn’t matter. Fat didn’t matter. Weight followed the wheat.

I recommend reading the full study before the Powers That Be shove it behind a pay wall (or before the wheat industry files a lawsuit). And I’d say my real wheat/heart disease post is coming up next, but I don’t want to jinx myself. It’s on the way, though. I promise (?).

Heart Disease and the China Study, Post #1.5

First of all: I’ve got some bad news, folks.

I just learned from a highly reliable source that I am not a “private blogger,” but rather, “very likely a large scale underground defamation campaign against Dr.Campbell.” As a result, all mention of my critique—AKA the Minger Scam—has been yanked from Wikipedia’s “The China Study” page by a vegan editor there. The rationale is as follows:

Just tell me, which “private fun blogger” is able, aside of her alleged full time work and study of “English literature”, to write 36 pages of scientific responses to a professor?!! And again and again??? Either “she” is some sort of very mighty – and very mad and crazy and hate filled – genius, which in itself would be something extremely rare and highly unlikely (really, why would a pretty young girl have so much reason for such a giant ordeal, fight, all that massive work, all that hate???) … Or “she” is in reality another underground [campaign].

Whoops—my bad! I forgot females aren’t supposed to think or write stuff; we’re here to take Home Ec and vacuum in stilettos and learn how to become Good Wives:

On behalf of Minger Scam, Inc., I apologize for any inconvenience we may have caused. 😉

Now onto business.

I’ve got graphs, graphs, graphs galore, but they aren’t really relevant to the upcoming wheat post, so I’m plopping them here instead. In my first China Study critique, I looked at some mortality differences between the five counties that ate the most animal foods and the five counties that ate the least. Here, I’m doing something similar—except this time I’ll be comparing the counties with the super-highest and ultra-lowest heart disease rates and seeing what they do differently in terms of diet.

One of the incredible things about China is the vast difference in heart disease mortality between regions. One county, Fusui, has only 1.5 per 100,000 deaths attributable to heart disease—whereas another county, Dunhuang, has a whoppin’ 184. That’s even more than the US’s figure of 106.

In case graphs freak you out, here’s a summary of what’s below:

  • The healthy-hearted regions almost universally had higher intakes of animal fat, animal protein, dietary cholesterol, and saturated fat than the heart-disease-prone regions.
  • The healthier regions generally had lower intakes of fiber, light-colored vegetables, plant protein, vegetable oil, and—big surprise—wheat flour.
  • Consumption of green vegetables didn’t differ significantly between the high and low heart disease regions. Neither did smoking rates, total cholesterol, or non-HDL cholesterol, although HDL cholesterol looks slightly higher in the regions with excellent heart health.

Does this “prove” anything about diet and heart disease? Nope—there’s the curse of epidemiology again. But we can make the observation that some regions in China exhibited astonishingly low rates of heart disease while eating more animal foods than the Chinese average. And the county with the absolute lowest consumption of animal foods, Longxian, had the second highest rate of heart disease mortality out of all the counties studied. (For the record, I used the China Study II data for this, all of which is available online.) (more…)

Brand-Spankin’ New Study: Are Low-Carb Meat Eaters in Trouble?

We interrupt your regularly scheduled wheat broadcast for an important announcement!

A few of you lovely readers emailed me today (thanks!) about the study Low-Carbohydrate Diets and All-Cause and Cause-Specific Mortality just published in the Annals of Internal Medicine. This paper compares mortality rates for folks eating a so-called “animal-based diet” versus a so-called “vegetable-based diet,” both of them so-called “low carbohydrate.” I finally got a chance to look at it, and indeed, a glance at the abstract looks a little spooky for any low-carb omnivores out there:

A low-carbohydrate diet based on animal sources was associated with higher all-cause mortality in both men and women, whereas a vegetable-based low-carbohydrate diet was associated with lower all-cause and cardiovascular disease mortality rates.

Oh noes! This abstract sounds vaguely China-Study-esque, with the conclusion that plant-based diets are healthier than ones featuring more animal foods. Was this study really comparing hardcore meat eaters with plant noshers, like the abstract implies? Is animal protein poison after all? Is it time to ditch the steaks and bow down in phytoestrogenic reverence to the almighty tofu? (more…)

The China Study, Wheat, and Heart Disease; Oh My!

(Not only is this woefully, frustratingly, absurdly belated, but it’s also not yet finished. But I hate being a blog tease, so here’s part one!)

If you’ve been following along with the previous China Study entries (and the wild drama that ensued), you know that I’ve been promising an entry on wheat for a while now, mostly because this little snippet snagged so many eyes:

Correlation between wheat flour and coronary heart disease: 0.67

That’s a value straight from the original China Study data. Could the “Grand Prix of epidemiology” have accidentally uncovered a link between the Western world’s leading cause of death and its favorite glutenous grain? Is the “staff of life” really the staff of death? Bwah ha ha.

(more…)

The China Study: A Formal Analysis and Response

Woefully belated. Endnoted up the wazoo. Marked lack of cutesy.

Click here for the HTML version, or head straight to the PDF:

“The China Study”: A Formal Analysis and Response

(Updated noon-ish PST on August 3rd with typo corrections)

If you haven’t done so yet, also read Campbell’s first response and Campbell’s second response, which this is in reply to.

I’ll see what I can do about getting this set up in blog-post form, but I really don’t have the mental capacity to work on it right now. Sorry. In the meantime, here’s the table of contents so you know what you’re getting yourself into:

Introduction

SECTION 1: Reiteration and Expansion of Criticisms

  1. Linkage of animal protein with cancer by way of cholesterol
  2. Misleading association of breast cancer with lipid intake and lipid intake with animal protein
  3. Supposition that plasma cholesterol increases liver cancer risk
  4. Misrepresentation of heart-protective effects of green vegetables, and the three-variable linkage between animal protein, apolipoprotein B, and cardiovascular disease
  5. Biased use of unadjusted univariate correlations to confer protective benefits of plant foods but not with animal foods
  6. Use of a three-variable chain to connect animal foods with “Western” diseases
  7. Unexplored role of blood glucose, insulin, and disease
  8. Dismissing relevant variables
  9. Errors in the extrapolation of casein to all animal protein

SECTION 2: Biological Models and Cited Papers

  1. Breast cancer
  2. Liver cancer
  3. Energy utilization
  4. Affluent-poverty diseases
  5. Summary

SECTION 3: Response to Points Raised by Campbell

  1. Wheat: confounded variable or legitimate concern?
  2. Selection of univariate correlations and confirmation bias
  3. Tuoli county and erroneous data
  4. Whole-food, plant-based diets versus whole-food diets with animal products
  5. Conclusion

And before anyone gets their knickers in a knot, listen up: Every time I employed a univariate correlation, it was because Campbell had done so first, under the same circumstances. Every. Time.

Also, this is sort of a pre-final version, and there may be typos (please point them out!) or orphaned punctuation (ditto). If I make any changes, I’ll post the updated version with a note.

Now if you’ll excuse me, I’m going to spend a very, very long time not staring at the computer screen, catching up on a couple weeks’ worth of sleep, and hopefully regrowing the little chunks of my soul that died while writing this. Adieu!

The China Study: My Response to Campbell

Alright folks, I’ll be honest. I was not expecting my China Study critique, which started as a nerdy personal project pursued in the wee hours of the morn, to generate much interest. Like most of my weird projects, I figured it would be briefly perused by a few number-lovers before fading quietly into the abyss of cyberspace.

Instead, it went viral and racked up 20,000 page views within 24 hours.

I’m surprised, but equally thrilled. My self-marketing skills are pretty dismal, and it was only by the grace of all the bloggers who featured my critique that this page-view boom occurred. Thank you to everyone who helped spread the word. I owe y’all!

This post is going to be quite long (no shocker there) and, in places, a bit more technical than the last. I know not everyone digs science mumbo-jumbo, so I’ll try to keep that to a minimum and explain things like journal quotes in simpler terms.

First, I’d like to address a couple points I’ve seen crop up in reader comments and emails I’ve received. (more…)

The China Study: Fact or Fallacy?

Disclaimer: This blog post covers only a fraction of what’s sketchy with “The China Study.” In the years since I wrote it, I’ve added a number of additional articles expanding on this critique and covering a great deal of new material. Pop over to my Forks Over Knives review for more information on what’s wrong with the conclusions drawn from Campbell’s casein/aflatoxin research, and if you’d rather look at peer-reviewed research than the words of some random internet blogger, see my collection of scientific papers based on the China Study data that contradict the claims in Campbell’s book. I’ve also responded to Campbell’s reply to my critique with a much longer, more formal analysis than the one on this page, which you can read here.

When I first started analyzing the original China Study data, I had no intention of writing up an actual critique of Campbell’s much-lauded book. I’m a data junkie. Numbers, along with tiny strawberries and Audrey Hepburn films, please me greatly. I mainly wanted to see for myself how closely Campbell’s claims aligned with the data he drew from—if only to satisfy my own curiosity as a long-time dietary inquisitor.

But after spending a solid month and a half reading, graphing, sticky-noting, and passing out at 3 AM from studious exhaustion upon my copy of the raw China Study data, I’ve decided it’s time to voice all my criticisms. And there are many.

First, let me put out some fires before they have a chance to ignite:

  1. I don’t work for the meat or dairy industry. Nor do I have a fat-walleted roommate, best friend, parent, child, love interest, or highly prodigious cat who works for the meat or dairy industry who paid me off to debunk Campbell.
  2. Due to food sensitivities, I don’t consume dairy myself, nor do I have any personal reason to promote it as a health food.
  3. I was a vegetarian/vegan for over a decade and have nothing but respect for those who choose a plant-based diet, even though I no longer limit myself to the vegetable kingdom. My goal, with the “The China Study” analysis and elsewhere, is to figure out the truth about nutrition and health without the interference of biases and dogma. I have no agenda to promote.

As I mentioned, I’m airing my criticisms here; this won’t be a China Study love fest, or even a typical balanced review with pros and cons. Campbell actually raises a  number of points I wholeheartedly agree with—particularly in the “Why Haven’t You Heard This?” section of his book, where he exposes the reality behind Big Pharma and the science industry at large. I admire Campbell’s philosophy towards nutritional research and echo his sentiments about the dangers of scientific reductionism. However, the internet is already flooded with rave reviews of this book, and I’m not interested in adding redundant praise. My intent is to highlight the weaknesses of “The China Study” and the potential errors in Campbell’s interpretation of the original data.

(more…)

Tuoli: China’s Mysterious Milk Drinkers

Important disclaimer: In light of new information, this post needs to be taken with a really whoppin’ huge grain of salt. It turns out Tuoli was “feasting” on the day the survey crew came for China Study I, so they were likely eating more calories, more wheat, more dairy, and so forth than they typically do the rest of the year. We can’t be completely sure what their normal diet did look at the time, but the questionnaire data (which is supposedly more reliable than the diet survey data) still suggests they were eating a lot of animal products and very little in the way of fruits or vegetables.

At any rate, I recommend not quoting this post or citing it as “evidence” for anything simply because of the uncertainty surrounding the Tuoli data in the China Study. Please see the following posts for more information on the issue of Tuoli’s accuracy:

http://rawfoodsos.com/2010/08/03/the-china-study-a-formal-analysis-and-response/

http://rawfoodsos.com/2010/07/16/the-china-study-my-response-to-campbell/

 

As I mentioned in the previous post on dairy consumption and disease in China, there’s a fascinating little county by the name of “Tuoli” situated in northwest China—a place quite worthy of nutritional study, due to their unique diet.

They live here:

Which looks like this:

Where they eat a lot of this:

But not a lot of this:

The Tuoli diet is so abnormal for China, in fact, that T. Colin Campbell et al omitted this county from analysis in several China Study papers—such as “Vitamin A and cartenoid status in rural China,” published in the British Journal of Nutrition:

One county (Tuoli County in Xinjiang Autonomous Region), composed primarily of an ethnic minority population of herdspeople, had disproportionately high values for retinol, lipid and protein intake due to an exceptionally high intake of animal foods. This ‘outlier’ was not included in the analysis, to characterize more accurately the average intakes of the rural Chinese population and to avoid the undue influence of one data point on the results.

Given the prevailing beliefs about nutrition and health—such as saturated fat and cholesterol as a cause of heart disease, the necessity of fiber for colon health, the immunity-boosting properties of fruits and vegetables, and the dangers of a diet high in animal fat—it would seem the Tuoli should showcase the health woes that come from breaking every rule in the diet book.

But is that the case? (more…)