The China Study

If you already know about The China Study then you will know how important a milestone it is for nutritional research. It’s such an important study that I thought it would be worth taking a quick look at its background, method and conclusions.

Background

Protein Consumption in Rats

Professor T Colin Campbell observed a relationship between the amount of dietary protein consumed and the promotion of cancer in rats. The animal protein used was casein (the main protein in milk and cheese), along with a variety of plant proteins. Distinct differences between the effects of animal vs. plant-based protein were observed:

  • animal protein tended to promote disease conditions
  • plant protein tended to have the opposite effect

Early 1970’s in China

The Chinese premier Zhou Enlai was dying of cancer. He had organised a survey called the Cancer Atlas which gathered details on about 880 million people. The survey revealed cancer rates across China to be geographically localised, suggesting dietary/environmental factors—not genes—accounted for differences in disease rates.

1983-1984 Survey

Dr. Campbell with researchers from Cornell University, Oxford University, and the Chinese government, conducted a major epidemiological study (i.e. a study of human populations to discover patterns of disease and the factors that influence them). This was called The China Project (from which the book The China Study derived some of its data). Researchers investigated the relationship between disease rates and dietary/lifestyle factors across the country.

Why China?

  • large population of almost one billion
  • very little migration within China
  • rural Chinese mostly lived where they were born
  • strict residential registration system existed
  • food production was very localised
  • the Cancer Atlas had revealed diseases were localised and so dietary and environmental factors (not genes) would be likely to account for disease rate variation by area (whether affluent and eating Western diet, or rural and eating traditional plant-based diet)

Method

Research Questions

1. Is there an association between environmental factors, like diet and lifestyle, and risk for chronic disease?

2. Would the patterns observed in a human population be consistent with diet and disease associations observed in experimental animals?

Hypothesis

Researchers hypothesised generally that an association between diet/lifestyle factors and disease rates would indeed exist. A specific hypothesis was that animal product consumption would be associated with an increase in cancer and chronic, degenerative disease.

Hypothesis Testing

6,500 adults in 65 different counties across China were surveyed in the 1983-4 project. These counties represented the range of disease rates countrywide for seven different cancers. The survey process with each participant included:

  • three-day direct observation
  • comprehensive diet and lifestyle questionnaires
  • blood and urine samples
  • food samples from local markets analysed for nutritional composition
  • survey of geographic factors

1989-1990 Survey

  • same counties and individuals resurveyed plus a survey of 20 additional new counties in mainland China and Taiwan.
  • 10,200 adults surveyed
  • socioeconomic information collected
  • data combined with new mortality data for 1986-88

Analysis of Data from both 1983-1984 & 1989-1990 Surveys

  • data was analysed at approximately two dozen laboratories around the world to reduce chances of error in data analysis
  • researchers could be confident that if results were consistent, then they would be correct

Conclusion

  • diseases more common in Western countries clustered together geographically in richer areas of China
  • diseases in richer areas of the world were thus likely to be attributed to similar “nutritional extravagance”
  • diseases in poorer areas of the world were likely to be attributed to nutritional inadequacy/poor sanitation
  • blood cholesterol (strongly associated with chronic, degenerative diseases) was higher in those consuming more animal foods
  • lower oestrogen levels in women (associated with fewer breast cancers) related to increased plant food consumption
  • higher intake of fibre (found only in plants) associated with lower incidence of colon and rectal cancer

The consistency of the results led the researchers to make the overall conclusion that the closer people came to an all plant-based diet, the lower their risk of chronic disease.

Published Data

  • The data on both the 1983-1984 survey and the 1989-1990 survey can be seen in more detail here.
  • More detail on the experimental study design of the China Project (covered in Appendix B) plus a full copy of The China Study in pdf format is available here.
  • Professor T Colin Campbell’s complete CV (including published papers analysing data from the China Project) is available here.

Plant Protein vs Animal Protein Webinar from Professor T Colin Campbell

If you have any comments or require further information on this topic, please let me know.


Bibliography:

  1. Chen J, Campbell TC, Li J, Peto R. Diet, Life-Style and Mortality in China: A Study of the Characteristics of 65 Chinese Counties. Oxford, UK: Oxford University Press; 1990.
  2. Chen J, Peto R, Pan W-H, Liu B-Q, Campbell TC, Boreham J, Parpia B. Mortality, Biochemistry, Diet and Lifestyle in Rural China: Geographic Study of the Characteristics of 69 Counties in Mainland China and 16 Areas in Taiwan. Oxford, UK; Ithaca, NY; Beijing, PRC: Oxford University Press, Cornell University Press; People’s Medical Publishing House, 1990.

 

How To Analyse the Health Claims Made for Dietary Supplements

critical thinking.jpg

How do you decide whether dietary supplement health claims are factual or phoney?

In this article I would like to apply critical thinking to one such claim that I came across at random on Amazon.co.uk.

These are the sort of questions we are going to ask:

  1. What is the health claim that is being promoted about the supplement?
  2. Is the health claim “evidence-based” (that is, based on research results)?
    • Does it include any research references or citations ? (Be wary of reports that only contain personal testimonials.)
    • Are the research and/or citation from a reputable source?
  3. Who is funding the research?
  4. Who are the researchers and/or authors? Consider the following:
    • What are their credentials or qualifications?
    • Are they currently or have they previously been funded by industry?
  5. Are the conclusions well-reasoned and warranted by the evidence (that is, for the health claim/s listed in question #1)? Consider the following:
    • Claims that sound too good to be true.
    • Recommendations that promise a quick fix.
  6. What might be some important consequences of accepting these conclusions (for individuals, society, the environment,etc.)?

Swanson Beta Carotene Vitamin A – 10,000IU, 250 Softgels

Offered for sale on Amazon.co.uk

1) What is the health claim being promoted with the supplement?

They state in a bullet-point list at the start of the advertisement the following: “A powerful source of antioxidant protection for the whole body” and “Delivers a healthy dose of essential vitamin A nutrition”. Neither of these claims is directly linked to the product since they are simply general statements and there is no definition or clarification of terms such as “healthy dose” or “essential”. It would be reasonable to assume that readers of this advertisement might consider that the seller was making these health claims about the softgel product itself.

The third bullet-pointed statement “Each convenient softgel provides 10000 IU of antioxidant nourishment” clearly links the softgel product with the claim; however, there is no immediate clarity about what “antioxidant nourishment” actually means, nor is there any supporting explanation or data related to the claim.

In the Product Description, further down the page, the seller makes additional statements:

  1. “Get vitamin A for healthy vision and antioxidant protection for your whole body with beta- carotene!” and
  2. “A natural plant pigment that can be converted into vitamin A by the body as needed, beta-carotene also acts as a powerful antioxidant in its own right.”

Again there is a lack of clarity about whether the above statements directly relate to the benefits of the softgel product being sold.

The exclamatory general statement in A. could be interpreted in one of two ways: firstly, that their softgel product offers these benefits or, secondly, that beta-carotene in general offers these benefits.

The general statement in B. could also be interpreted in one of the above two ways.

The lack of clarity in both the initial bullet-pointed list and in A. and B. above raise the issue of whether or not legal responsibility is being accepted for implied claims regarding the benefits of the softgel product being sold.

2) Is the health claim (as stated above) “evidence-based” (that is, based on research results)?

No. Such words as “Sources”, “References” or “Evidence” do not appear.

– Does it include any research references / citations?

No citations are used.

– Are the citations from a reputable source?

N/A

3) Who is funding the research?

There are no references to research data. A look at the seller’s website revealed no additional research-based evidence for the implied/stated claims on advertisement. And the following general statement made under the Our Guarantee tab provides no additional links to research data: “We know how important your health is to you and your loved ones. That’s why we’re focused on delivering only high quality products you can trust at the best value. Our lab evaluates every product to make sure it’s compliant with strict standards and government regulations, and we fully believe in and stand behind our products. If you’re dissatisfied for any reason, we’ll give you a full refund and pay return shipping.”

4) Who are the researchers and/or authors?

There are no researchers or authors mentioned.

– What are their credentials or qualifications?

N/A in view of the lack of information on researchers.

– Are they currently or have they previously been funded by industry?

They are a company that advertises, sells and distributes supplements to the general public. I assume they are self-funded by their own business profits. There is no indication from my research that they are in receipt of additional funding from any other source.

5) Are the conclusions well reasoned and warranted by the evidence (for the health claim listed in question #1)? Consider the following:

– Claims that sound too good to be true.

The statements they make are rather general and, on the face of it, do not seem “too good to be true”. However, because of the lack of referenced research or evidence of any sort within the advertisement there is no way of assessing the validity of their implied/stated claims for the softgel product without reference to external sources. Their general statements about the benefits of beta-carotene for healthy vision and as an antioxidant for the whole body, and for vitamin A as being in some sense “essential”, seem reasonable on the face of it. There is no mention of research suggesting the harmful effects of beta-carotene (such as can be found here and here), nor of the biochemical relationship between beta-carotene as a precursor for vitamin A except for the generalised statement that beta-carotene is a “…natural plant pigment that can be converted into vitamin A by the body as needed”. The term “natural” when applied to a vitamin supplement containing isolated beta-carotene is something that is not justified and might mislead the reader to suspect that supplementation is as natural a way of acquiring beta-carotene as deriving it from diet.

– Recommendations that promise a quick fix.

“Delivers a healthy dose of essential vitamin A nutrition” and “Each convenient softgel provides 10000IU of antioxidant nourishment” appears to be offering a solution to a problem – viz. the problem of not having sufficient vitamin A nutrition and/or sufficient antioxidant nourishment. I think it would be reasonable to suspect that the average reader would consider this to be a quick fix for a perceived deficiency in vitamin A nutrition and/or sufficient antioxidant nourishment – whatever these terms do or do not imply or actually mean when put under scrutiny.

6) What might be some important consequences of accepting these conclusions (for individuals, society, the environment, etc.)?

In terms of consequences for individuals purchasing and taking this supplement, there are potentially significant implications. Whenever unsupported health claims are made in relation to health supplements, there is a danger of individuals being misled. When a supplement is fairly innocuous and has no associated published evidence included with it to suggest inherent dangers associated with its use, issues of reliability of claims and value for money are perhaps the most relevant issues involved. However, when the supplement being sold has been shown in published literature to have associated dangers, this is something that might raise much greater concern. In this case, I believe that there is ample research data on the negative effects of vitamin A / beta-carotene supplements to raise the question of whether or not the seller should be legally allowed to advertise this product without some printed warning being included in the advert.

As Professor T Colin Campbell asks “Did you know, for example, that vitamin A at higher levels of intake, actually can increase, not decrease, cancer risk?”

In terms of environmental consequences, I can see none.

In terms of societal consequences, there is the wider issue of how much responsibility should be taken by governments and organisations (such as Amazon – the website advertising this product) for allowing companies like Swanson vitamins to sell products without any health warnings or reference to evidence in support of implied or stated health claims for the product in question.


Final Comment

So, I hope you found this example of critical thinking of some interest. I would suggest that it is a good idea to apply similar analytical approaches to anything you come across, written or verbal, that makes claims about your health.

You only have one life, and I hope you do all you can to live it to the fullest, healthiest and happiest…seeing through the empty promises of organisations and individuals who would sell you anything just to make a quite profit.

A Fat to Forget

Eating cakes and biscuits appears to impair memory.

Research (1.) suggests that there is relationship between consumption of dietary trans-fats and word-memory.

1018 individuals were given word recall tests that were scored and matched against the amount of trans-fats consumed by each individual.

The results are worth remembering next time you reach for the cookie jar. Every gram of dietary trans-fats consumed per day was associated with an estimated 0.76 fewer words recalled.

Is this causation or just correlation? The researchers consider that the pro-oxidant (2.) and energetic detriments of dietary trans-fats (3.) are evidence of causation. They used triangulation (4.) with other evidence to ensure that other causal factors were not being mistakenly included. (See charts below if you are interested in the statistical data).

Trans-fats are found in many biscuits, cakes and other processed foods. They are made by pumping hydrogen into liquid vegetable oil so that the oil becomes more solid. Food manufacturers do this in order to increase the shelf life of the products and to improve flavour and texture. You will know that they are present in products if you see the words “partially hydrogenated oils” on the ingredients list.

The leader of this study, Dr Beatrice Golomb, said: “Trans fats were most strongly linked to worse memory, in young and middle-aged men, during their working and career building years…From a health standpoint, trans fat consumption has been linked to higher body weight, more aggression and heart disease…As I tell my patients, while trans fats increase the shelf life of foods, they reduce the shelf life of people.” (5.)

What does this mean for our love affair with biscuits and cakes?

Well, it appears that we love them but they don’t love us. Maybe the best thing to do is to forget about eating them before they make us forget that we have eaten them…

 


References, Definitions & Data

1. Beatrice Alexandra Golomb, Alexis K. Bui. https://doi.org/10.1371/journal.pone.0128129. June 17, 2015. A Fat to Forget: Trans Fat Consumption and Memory.
2. Pro-oxidants are substances that accelerate the oxidation of another substance. This process can produce free radicals which are associated with many chronic health problems such as cardiovascular and inflammatory disease, cataract, and cancer. Antioxidants prevent free radical induced tissue damage by preventing the formation of radicals, scavenging them, or by promoting their decomposition. Berries are a great source of antioxidants.
3. Ascherio A, Willett WC. Am J Clin Nutr. 1997 Oct;66(4 Suppl):1006S-1010S. Health effects of trans fatty acids.
4. Triangulation means using more than one method to collect data on the same topic. This is a way of assuring the validity of research through the use of a variety of methods to collect data on the same topic, which involves different types of samples as well as methods of data collection.
5. https://www.medpagetoday.com/primarycare/dietnutrition/52263.

Is all scientific research equally valid?


I don’t know about you, but I often get into discussions with people and end up citing research that backs up my claims. It is not uncommon for the other person to say something like “Yea, but I bet there’s other research that says the opposite” or “I don’t trust any research – it’s all biased one way or another…”

So, if you do consider that some research is worthy of respect but get a bit frustrated trying to find research that you can really trust, where do you go to find it?

Some of my usual favourites for nutritional research are PubMed, Nutritionfacts.org, Physicians Committee for Responsible Medicine, Centre for Nutrition Studies, British Journal of Nutrition, There are also lots of nutrition journals, such as The British Journal of Nutrition, Food and Nutrition Sciences, Nutrition Journal, and the Journal of Human Nutrition and Food Science.

But, and it’s a big BUT…There are times when bias can be detected in some of the research that we come across.

For instance, we might discover that the research was funded by an organisation that wanted to see an outcome which was favourable for their purposes – whether academic or financial. Also, it is quite possible that individual researchers within the studies may have had personal or professional bias. And whilst the process of peer-review is meant to ensure a high level of transparency and honesty with the reviewed research, this is sadly not always the case.

However, there is an interesting organisation called the USPSTF (United States Preventive Services Task Force) that I would like to talk about with you. I am not stating any opinion about individual research projects that they have covered, nor am I claiming that they are the gold standard in research that everyone should trust implicitly; however, they have a really interesting method of reviewing current research findings on a given subject and it is this that I want to share with you.

It is their function to review all available published research and then publish a paper that states, in their considered opinion, whether the overall results found (for instance, on the effectiveness of mammograms or prostate cancer screening) suggest that current medical/health practices are helpful, harmful or neutral in their impact on individuals in particular and on society in general. Based on this, they then make recommendations to governments, organisations and individuals.

Their way of doing this is as close to people-power (that is, the empowerment of the average person in the street) as I have found recently in this academic field. This is how it works (cartoons are my addition!):

Recommendations Development Process: A Graphic Overview

Step 1. Topic Nomination

Anyone can nominate a new topic or an update to an existing topic at any time, via the Task Force Web site. The Task Force prioritises topics based on several criteria, including the topic’s relevance to prevention and primary care, importance for public health, potential impact of the recommendation, and whether there is new evidence that may change a current recommendation.

Step 2. Draft and Final Research Plans

Once a topic is selected, the Task Force and researchers from an Evidence-based Practice Centre (EPC), develop a draft research plan for the topic. This plan includes key questions to be answered and target populations to be considered. The draft research plan is posted on the Task Force’s Web site for four weeks, during which anyone [that includes you and me] can comment on the plan. The Task Force and the EPC review all comments and consider them while making any necessary revisions to the research plan. The Task Force then finalises the plan and posts it on its Web site.

Step 3. Draft Evidence Review and Draft Recommendation Statement

Using the final research plan as a guide, EPC researchers gather, review, and analyse evidence on the topic from studies published in peer-reviewed scientific journals. The EPC then develops one or more draft evidence reviews summarising the evidence on the topic. Members discuss the evidence reviews and use the information to determine the effectiveness of a service by weighing the potential benefits and harms. Members then develop a draft recommendation statement based on this discussion. The draft evidence review and draft recommendation statement are posted on the Task Force Web site for four weeks.

Step 4. Final Evidence Review and Final Recommendation Statement

The Task Force and EPC consider all comments on draft evidence reviews and the Task Force considers all comments on the draft recommendation statement. The EPC revises and finalises the evidence reviewed and the Task Force finalises the recommendation statement based on both the final evidence review and the public comments.

All final recommendation statements and evidence reviews are posted on the Task Force’s Web site. The final recommendation statement and a final evidence summary, a document that outlines the evidence it reviewed, are also published in a peer-reviewed scientific journal.

Interesting eh?

Final Comment

Never underestimate the tactics used by both organisations and individuals to misrepresent information in order to mislead the public for their own agendas.

If you come across conflicting and troubling opinions about nutrition (whether expressed by friends and family, in newspapers and magazine, on the TV or internet sites, in research papers or books), you can send me links to the information and I will take a look at it and help you to analyse it in a way that allows you to form your own opinion about the validity of the claims made.

There’s no better way to ensure that you have the motivation to continue with the optimal WFPB dietthan when you know intellectually that your nutrition and lifestyle decisions are backed-up by solid and reliable scientific research.

In future posts, I will outline and review various research methods, as well as introduce some intriguing alternative opinions about nutritional research as expressed by Prof. T Colin Campbell.