How would you feel if some 60 per cent of your diet was made up of fruit, vegetables and nuts? And if your daily exercise target was 16,000 to 17,000 steps? If I promised you it would guarantee your coronary arteries would remain in a pristine, unclogged condition until you were at least in your 60s, would you make these radical dietary and exercise changes?
I have just outlined the lifestyle of the 16,000 Tsimane people who hunt, fish and farm on the Maniqui River in the Amazon rainforest in the Bolivian lowlands; their way of life has similarities to human civilisation thousands of years ago. The extraordinary health enjoyed by the tribe was recently described in The Lancet by researchers from California and New Mexico. A long-term study of the isolated Tsimane people looked at their coronary artery calcium (CAC) scores and compared these scores with Americans of the same age. They found that at the age of 45, almost no Tsimane had CAC in their arteries while 25 per cent of Americans do. By the time they reach age 75, two-thirds of Tsimane are CAC-free compared with the overwhelming majority of Americans (80 per cent) having signs of blocked arteries.
This means the Tsimane people have the lowest reported levels of vascular ageing for any population, with hardening of the heart arteries being five times less common than in the US. "Our study shows that the Tsimane indigenous South Americans have the lowest prevalence of coronary atherosclerosis of any population yet studied," said senior anthropology author, Prof Hillard Kaplan of the University of New Mexico. "Their lifestyle suggests that a diet low in saturated fats and high in non-processed fibre-rich carbohydrates, along with wild game and fish, not smoking and being active throughout the day could help prevent hardening in the arteries of the heart. The loss of subsistence diets and lifestyles could be classed as a new risk factor for vascular ageing and we believe that components of this way of life could benefit contemporary sedentary populations."
To replicate this diet would mean 72 per cent of our calories would come from carbohydrates compared to about 50 per cent in the western world, while some 14 per cent would be from fat compared to a fat content of 34 per cent among US consumers.
Putting the Tsimane level of exercise in context, most of us struggle to achieve a recommended 10,000 steps a day. Even the over 60s in the Bolivian tribe have a step count over 15,000. And significantly they live in small, socially active communities, and are noted for their positive outlook.
One commentator suggested the study points to urbanisation and specialisation of the workforce as specific risk factors for an unhealthy heart. It also adds to a growing belief that a diet high in carbohydrates is actually good for our health.
Realistically, what are the prospects of us adopting this lifestyle in the West? Well from an exercise perspective it would mean walking to work, taking the stairs all of the time and working on computers set up on treadmill desks. And the dietary change would also be a challenge.
As it is just a quarter of us manage to eat the recommended five portions of fruit and vegetables a day. Recently a paper in the International Journal of Epidemiology suggested that upping our intake of fruit and veg to 10 portions a day would further reduce our risk of cancer and cardiovascular disease.
But to get most people to 10-a-day would mean the country would have to eat four times as much fruit and veg as it currently does. Fruit and vegetables are already expensive and increased demand might make them even more unaffordable for many people.
However impractical it may be, the Tsimane lifestyle reaffirms our understanding about how to best prevent heart disease.