Mark OReilly investigates the link between animal produce and cardiovascular disease
Modern medicine has improved our protections against acute and chronic diseases, but has found no reliable preventative measures for cardiovascular disease (CVD). Cumulative data is pointing towards lifestyle as the key factor, but which aspect of it?
Putting aside environmental issues, we are largely left with exercise, sleep and diet. There is agreement that we need more exercise and sleep, but the general public is often confused by the messages it receives on diet. A lot of this confusion stems from conflation of objectives. Weight management, muscle development and energy gain are often the immediate rewards of a specific diet, and lowered carbohydrates frequently deliver in these areas, so it is tempting to conclude that a meat-based, fat-rich diet is 'natural' for humans - the key to survival for our hunting ancestors.
This logic is false. For most of our evolutionary history, we were plant-eating primates. Meat-eating probably contributed to our dominance, and hunters, crippled by inflammatory diseases or cancer at 50, were nevertheless able to pass on brain-enhancing DNA. However, species success is independent of long-term personal health and can be cruel on the individual unit. It's hard to find land-based, heavy meat-eaters with lifespans comparable to our own.
There is plenty of evidence to show that high-fat, low-carb diets have a negative impact on long-term health. One of the reasons for the obscuring of this fact is confusion around the nature of carbohydrates in plant food. Most of us should avoid too many refined carbs, such as white flour and white rice, but a true low-carb diet would also exclude many vegetables - which are essential to our health.
The whole food, plant-based diet
Research to date is favouring the 'whole plant' diet as protection against CVD. The main feature of such a diet is avoidance of animal produce and any plant element that has been isolated, such as refined carbohydrates and refined fats. Government and medical bodies do not push these diets, mindful of food industry counter-attacks and the danger of turning consumers off - but what if they work? Five categories of evidence have led to the formulation of the whole plant diet as a protective measure against CVD:
Autopsies: More than 70% of a sample of 500 US soldiers killed in the Korean War were found to have nascent CVD. Native Korean soldiers - at a time when the local diet included little animal produce - showed no disease. These patterns have also been found in civilian autopsies. It is hard to imagine a cause other than diet.
Diets where CVD is unknown: A landmark study of chronic diseases in rural China found large regions of the country where death from CVD was virtually unknown, and where diet is also overwhelmingly whole plant-based. Corroborating evidence has been found among tribal regions of Asia and Africa.
Population studies: These are more general studies of different diets over periods of years, measuring nutrition intake, other lifestyle factors, risk factors, disease and mortality. Results have often been inconclusive, but the whole plant theory has a persuasive argument to explain the lack of success: since so few people in these studies followed a true whole plant diet, everything else was noise. Only when animal produce is virtually absent and fat has fallen below about 15% of calorie intake (rarely found in the developed world) does blood cholesterol fall sufficiently to show up clearly in morbidity data.
Clinical trials: Population studies suffer from the inaccuracies and biases of self-reporting. This can only be solved by clinical trials - but the time constraints of such trials do not suit the long-term nature of chronic diseases. However, the short-term impact of different foods on arteries has been measured: animal produce has been shown to stiffen arteries for six hours following their ingestion. A causal connection to prolonged stiffening - an element of CVD - is clear.
Managed patient cohorts: CVD patients with advanced symptoms - among them President Bill Clinton - have, through management by individual doctors, experienced reversal of symptoms and even heart blockages over decades. Through rigorous adherence to whole plant diets, life expectancies have been extended. The hundreds of documented cases, overwhelmingly positive in outcome where the diet was adhered to (monitored by cholesterol and related measures), cannot be explained statistically in any way other than the chemical impact of the diet.
These categories of evidence amount to a persuasive case that the whole food, plant-based diet offers substantial protection against CVD. Moreover, the mechanism by which animal protein gives rise to CVD has been demonstrated in animals. Clinical trials have also linked animal protein with other chronic diseases, including some cancers. Could animal produce be the root cause of most fatal and disabling diseases in the developed world?
Mark O'Reilly FIA is senior adviser to Deloitte China and a retired partner of Deloitte Consulting LLP