I'm now well into my stage 2 study of Diseases of Affluence from Dr T Colin Campbell's Certificate in Plant Based Nutrition and it's really ramping up. But here's another installment of the thought-provoking discussion from the first stage, Nutrition Fundamentals. These discussions are really making me get my stories straight.
Significant design differences between the China Project and the Harvard Nurses' Health Study led researchers to some very different conclusions. Controversy reigns at the highest levels of scientific inquiry. Describe to a confused acquaintance how you evaluate contradictory science to guide your dietary choices.
These days, you can find a study that says ANYTHING about food and health. You will hear countless experts with the secret to your health problems, and they will cite the studies to prove it. Lots of people I know have just given up trying to find any answers. “Everything causes cancer.” “There are no bad foods; I just use moderation.”
I believe that food affects your health profoundly, and I believe we already know the answers to the major health problems in Western society. How am I so certain with all those contradictory studies out there? The media loves to give you the latest sensation. Well, after 15 years I have a few guidelines when I hear the “latest” about nutrition.
Who did it?
A laboratory is just a laboratory, but who is running the study? What is their professional history and what are their credentials in nutrition? Most importantly, are they independent health researchers, or are they employees of some sector of industry? A cynical fact is that if there is food industry money behind a study, there is a bias toward a study result that favours the industry.
A classic example is the study on cholesterol level and eggs; used to “prove” that eggs don’t raise cholesterol when in fact they are a major contributor (along with other animal foods) to existing high cholesterol levels.
Who confirmed the results?
For most studies, the press release comes before any independent review. Instead, look for peer-reviewed studies, where peer experts of the researchers examine the methodology and results. These peers have a responsibility to report biases and mistakes in the study.
The doctors I trust: Dr Campbell, Dr McDougall, Dr Ornish, and more, all have multiple peer-reviewed studies in respected journals. Other qualified doctors who promote dietary advice which contradicts the plant-based diet never have peer-reviewed studies supporting them.
How many studies?
One study is one study – it returns results for the particular variables under inspection, and that’s all.
For example, the Nurses’ Health Study indicated that reducing animal fat in the diet did not improve breast cancer rates. This has widely been quoted as “fat levels make no difference to breast cancer,” which contradicts all epidemiological evidence about fat consumption but is reassuring to people who want to sell high-fat foods or eat them.
Yet more accurately and importantly, this study established that eating the same or more total animal food (with its protein and cholesterol), even with lower fat levels, contributed to breast cancer. And that result matches Dr Campbell’s own laboratory research on animal protein promoting cancer.
For me, the media darlings, the “groundbreaking” studies that contradict all previous evidence, are automatically suspect. If all previous studies say X, and a new study says Y, odds are the new study is biased or mistaken.
Experts I trust like Dr Campbell and Dr McDougall believe that science’s preference for isolating and studying individual elements can lead to misunderstandings for nutrition in real people.
- studies that involve isolated nutrients (e.g., a vitamin or a type of fat) and
- studies on diets made up of foods that are composed of refined food elements instead of whole foods
often return unhelpful or even misleading results (see Nurses’ Health Study) in the context of nutrition and health. However, studies like the China Health Study show consistent results for dietary health. These results can also be reliably applied to individual patients, as Dr McDougall and Dr Ornish do, with verifiable success.
Say no to drugs
Lots of health news is about amazing new drugs to treat the sad variety of disease we suffer from. While drugs can be effective, and sometimes necessary, remember that the media release will never discuss the side effects that all powerful drugs cause along with their stated purpose.
I already know through verified studies that a plant-based diet is more successful at treating heart disease, cancer, stroke, and diabetes than any drug, with no side effects. I already know from personal experience that it is an effective longterm weight loss strategy (which no drug is).
There may be more to learn from dietary research, but I don’t need to wait around for it. I know enough to improve my health now.