Context is king.
In the field of population health statistics (i.e. epidemiology), context allows scientists/medics to confidently assign explanation(s) for the trends they discover. Context is needed in all research fields, but is especially important in epidemiology. Otherwise we could mistakenly conclude that everyone who gets gum disease tends to have teeth, so teeth cause gum disease, as an extreme example.
From the start of modern epidemiology to the surveys on the effects of a vegan (plant-based) diet, context remains crucial.
John Snow, the recognised founder of modern epidemiology (i.e. population health statistics), famously tracked down the spread of a cholera pandemic down to the usage of a single London water pump in the 19th century . As a sceptic of the prevailing “bad air” theory of contagious disease transfer, John Snow gave some context to the “germ theory” of disease by determining that the cholera patients all fetched water from a potentially contaminated source. Officially the theory of “miasma” (bad air) was the recognised cause of the outbreaks at the time, despite John Snow’s analysis. It is thought that the fear of political consequences from letting the general public know that their trusted water source had been contaminated by human faeces could have led to a delayed acceptance of John Snow’s work by the relevant authorities.
The study on “Diet, Lifestyle and Mortality in China” showed an association with a mainly plant-based, traditional Chinese diet (essentially a vegan diet) and protection from cancer and cardiovascular disease . When the China study was published (i.e. 1990) other studies that had similar observations [3, 4], and several experiments provided a contextual precedent to attribute protective properties to a plant-based diet , following the principles outlined by Sir Austin Bradford Hill .
Were there any hidden factors in the “China study” that were the real cause of protection from chronic disease? Maybe people who ate mainly whole plants exercised more, for example? Even when the possible contribution of factors like exercise were mathematically “removed” or “accounted for”, a clear statistical link (i.e. correlation) still indicated that a plant-based diet conveyed protection from cancers and cardiovascular disease. In other words, additional known factors like exercise were unlikely to be the hidden cause of the diet-disease correlation observed. Multiple diet and lifestyle factors, including exercise in certain chronic diseases, have been associated with a lowered risk of death .
The proper context of epidemiology studies is to find statistical links (i.e. correlations) to build a hypothesis/theory. Experimental evidence, like a dietary intervention for sick patients, is needed to prove causation. But robust correlations are too significant to ignore, and deserve proper exploration. Otherwise, before we have sturdy experimental data, we chase the hypothesis of “miasma” during a cholera pandemic and ignore relevant, solid studies of a contemporary “John Snow”.
In recent times, the plant-based diet has now been tested and proven effective at the level of population studies and diet intervention trials for protection from many cancers [8, 9, 10], cardiovascular [11, 12] and metabolic diseases [11, 13, 14]. A comparison of studies involving over 1.6 million participants highlighted that, when tested, the “plant-based”/vegan diet is associated with the highest protection from risk of death, diabetes, cardiovascular disease and overall cancer incidence . “Plant-based studies” have evolved even further to indicate that specific plant foods are effective protection against specific chronic diseases:
· Brazil nuts have broad efficacy and potential in inflammatory conditions . (Please note: high antioxidant intake in the form of plant foods is associated with reduced risk of death by lymphoma , respiratory diseases  and risk of developing Parkinson’s disease , alongside other benefits [17, 19]).
· Blueberries appear to double the number of circulating, cancer cell-attacking natural killer cells .
· Sweet potatoes may protect against renal (kidney) cancer .
The book “How Not to Die” by Michael Greger and Gene Stone thoroughly details an impressive amount of scientific data behind plant-based health .
Confidence in the plant-based diet’s protective nature against many chronic diseases is bolstered in the context of all the experimental evidence that confirms it. Diet and health have many confounding variables, especially if you factor in lifestyle and psychological influences. But whether you are healthy or not, another day alive is another dice roll at life, statistically speaking. Why not “load the dice” and pile on all the dietary factors you can (at your own pace) to improve your chances at good health?
Disclaimer: If you have medical concerns, please consult your doctor before implementing the opinions in this article.
N. Baiden PhD.
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