May 22, 2023

The China Study and Cherry Picking Science

The China Project was a groundbreaking study that amassed a large amount of data on diet and its potential correlation to mortality. But is The China Study book based on this raw data, or a case of cherry-picking science to suit one’s agenda? We take a look at what the research really says about animal-based protein and disease.

What is the China Study?

In 1983, a groundbreaking collaborative research project was undertaken by researchers from Cornell University and Oxford University, along with the government of China. This comprehensive nutritional study was referred to as the China Project, and it was the first of its kind.

Throughout the 1980s, the project studied the diets of approximately 6,500 rural Chinese citizens, drawing conclusions between what they ate and the diseases most often experienced in these same communities.1

Why China?

China, specifically rural China, was chosen as a preferred location for the study because rural China spans diverse geography, hence diverse food resources. What’s more, the residents tend to spend their whole lives in one location, thus eating the same local foods over the course of their entire lives.

The geographical-based variation offered researchers a unique opportunity to see if certain diets correlated with certain diseases or mortality rates. For example, data showed death rates from seven types of cancer varied significantly among the selected rural Chinese counties.

Nutritional studies in humans are notoriously difficult to undertake as it is challenging to control the variables. The China Project seemed to offer a means of examining the relationship between diet and health in a holistic way. Also, it potentially allowed for a comparison between the primarily plant-based, real-food diets of the rural East and the standard diet of the West.

The groundbreaking China Project offered a never-before-seen depth of data on the relationship between what we eat and instances of diseases such as cancer, diabetes, heart disease, and osteoporosis.

The China Study vs The China Project Research

Several bloggers, including Denise Minger, Anthony Colpo and others have written extensively on the discrepancies between the actual data found within the China Project research and The China Study book.

It appears some data was omitted because it did not align with the recommended vegan diet. Other data was grossly misinterpreted in a classic case of mistaking correlation for causation. Primarily, the book claims lack of animal protein in the Chinese diet is the cause of good health, but the Chinese counties with the lowest incidence of disease also ate little to no processed food, bread, or sugars and may have benefited from social and environmental conditions that promoted greater health.

In support of veganism, the book makes two bold, primary claims. The first is about cholesterol and the other is about casein, a protein found in dairy.

Cholesterol

The China Study has infamously written that “eating foods that contain any cholesterol above 0 mg is unhealthy.” The research mentioned in support of this, however, doesn’t stand up to scrutiny.

For a primer on how to better understand nutritional science facts by reviewing the underlying research, look no further than Dr. Jaquish’s book, Weight Lifting is a Waste of Time. In it, he cites a study on red meat and cholesterol as an example of confusing correlation with causation.

In the study referenced, red meat consumption correlated with increased BMI, decreased exercise time per week, and increased alcohol consumption and smoking. Nonetheless, researchers and the journalists who reported on the study chose to highlight red meat alone as the cause of high cholesterol.2

Similarly, The China Study often fails to adjust for additional risk factors when coming to conclusions. But, as several critics have pointed out, even if the correlation between disease and cholesterol remained after other risk factors were omitted, there’s still no correlation in the data between animal-based proteins and an increased incidence of disease.

In fact, in the original China Project data, cancer was more likely to be associated with plant protein than animal protein, although neither showed a statistically significant correlation.

Casein

Campbell uses his own research on casein and cancer rates to conclude that a plant-based diet (which does not include casein) is healthier than an animal-based diet (which might include casein). But again, when looking at the raw data, his logic appears flawed.

Campbell did find that rats on a 20% casein diet developed cancer at much higher rates than rats on a 5% casein diet. Using that information, he concludes that no animal-based protein is safe for human consumption because casein is an animal-based protein. Aside from the absurd jump from casein alone to all animal-based protein, he fails to mention that despite higher rates of cancer, the 20% of casein rats lived much longer lives. As it turns out, the rats consuming less dairy-based protein simply weren’t living long enough to develop the disease.3

In the China Project, there were two outlying counties where dairy consumption was high. Here, cancer was not more prevalent, but hypertensive heart disease was. However, these counties also consumed much more salt, wheat, and snuff tobacco.

From the data, one would be hard-pressed to draw conclusions about the health of all animal-based proteins. Curiously, the China Study authors used this data to judge all animal-based proteins as harmful.

The Latest Protein Science

Researchers continue to learn more about nutrition, but old myths and beliefs die hard. Especially, when it comes to cholesterol, fat, and animal versus plant-based protein. Most of the claims made by The China Study were debunked when the book was first published in 2005.

Since the latest 2016 edition, these claims seem even more out of touch with the latest scientific understanding, especially as it relates to protein. We take a closer look at a few:

Myth: Animal-Based Protein Causes Cancer

Truth: A diet high in carbohydrates, sugar, and fiber correlates with cancer mortality at nearly seven times the rate that diets high in animal protein do. What’s more, total fat as a percentage of daily calories is negatively correlated with cancer mortality.4

Myth: If Less of Something is Good, None of It is Better

Truth: In The China Study, the authors concluded that if the Chinese were healthier despite consuming less animal protein as a percentage of their total daily calories, then no animal protein must be better. This assumption, however, fails to consider a large amount of protein many communities were getting from organ meats and shellfish. These foods were providing essential nutrients such as zinc and B12, despite accounting for a few of one’s daily calories. Eliminating all animal-based foods would deny communities these beneficial nutrients.

Myth: Plant-Based Protein is Healthier

Truth: Plant-based protein is often assumed to be healthier because it is low in fat and cholesterol. But the latest research on cholesterol leaves much room for doubt regarding its relationship to cardiovascular disease.5 Plant-based protein is also high in carbohydrates and offers limited essential amino acids.6 For those interested in building or maintaining muscle, studies find that animal protein is more effective.7

The Value of Critical Thinking

In sticking tight to a predetermined agenda, that of promoting veganism, The China Study also does a great disservice by completely omitting discussion of that which might be a bigger cause of mortality, wheat.

When it comes to disease, the original China Project research shows no statistically significant differences between the mostly plant-based communities and those who eat more animal-based protein. However, there is a significant correlation between wheat consumption and disease. This is not mentioned at all in the book.

Perhaps the biggest lesson learned here is that thanks to the volume of nutritional research, nearly anyone can pick and choose from studies to come to the conclusion they’d like.

What’s important then, is applying a healthy dose of doubt to the information you receive while learning how to find and read the original sources of data. Finally, simplifying your own diet will make it easier to pinpoint what’s working best in your own body.

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