How can you have a truly healthy heart?


Is it possible to simply change your lifestyle and diet in order to gain a heart that has no clogged up arteries right into old age?

The BBC reports on the results of a new study that confirm that the answer is yes,  …

The healthiest hearts in the world have been found in the Tsimane people in the forests of Bolivia, say researchers.

Barely any Tsimane had signs of clogged up arteries – even well into old age – a study in the Lancet showed.

“It’s an incredible population” with radically different diets and ways of living, said the researchers.

… but …

They admit the rest of the world cannot revert to a hunter-gathering and early farming existence, but said there were lessons for all of us.

The BBC article then moves on to tell you who the Tsimane are, where they are, and what their lifestyle actually is. They address questions such as “What is their diet?”, and “How fit are they?”.

Let’s step aside from the article and mull over the study itself.

The Study in the Lancet

If interested in having a healthy heart, then this is a fascinating paper.

Coronary atherosclerosis in indigenous South American Tsimane: a cross-sectional cohort study

Normally you need to trawl through peer reviewed papers to get the precise details, but in this case their (free) summary covers it very well. I do have access to the full paper, but sadly that is not so easy because they want a rather large payment for that. Anyway, here is that summary …

Background

Conventional coronary artery disease risk factors might potentially explain at least 90% of the attributable risk of coronary artery disease. To better understand the association between the pre-industrial lifestyle and low prevalence of coronary artery disease risk factors, we examined the Tsimane, a Bolivian population living a subsistence lifestyle of hunting, gathering, fishing, and farming with few cardiovascular risk factors, but high infectious inflammatory burden.

Note the observation (highlighted) that their lifestyle that leads to a healthy heart comes with a price. I can’t help but wonder if there is a relationship there. Anyway … moving on …

Methods

We did a cross-sectional cohort study including all individuals who self-identified as Tsimane and who were aged 40 years or older. Coronary atherosclerosis was assessed by coronary artery calcium (CAC) scoring done with non-contrast CT in Tsimane adults. We assessed the difference between the Tsimane and 6814 participants from the Multi-Ethnic Study of Atherosclerosis (MESA). CAC scores higher than 100 were considered representative of significant atherosclerotic disease. Tsimane blood lipid and inflammatory biomarkers were obtained at the time of scanning, and in some patients, longitudinally.

Findings

Between July 2, 2014, and Sept 10, 2015, 705 individuals, who had data available for analysis, were included in this study. 596 (85%) of 705 Tsimane had no CAC, 89 (13%) had CAC scores of 1–100, and 20 (3%) had CAC scores higher than 100. For individuals older than age 75 years, 31 (65%) Tsimane presented with a CAC score of 0, and only four (8%) had CAC scores of 100 or more, a five-fold lower prevalence than industrialised populations (p≤0·0001 for all age categories of MESA). Mean LDL and HDL cholesterol concentrations were 2·35 mmol/L (91 mg/dL) and 1·0 mmol/L (39·5 mg/dL), respectively; obesity, hypertension, high blood sugar, and regular cigarette smoking were rare. High-sensitivity C-reactive protein was elevated beyond the clinical cutoff of 3·0 mg/dL in 360 (51%) Tsimane participants.

Interpretation

Despite a high infectious inflammatory burden, the Tsimane, a forager-horticulturalist population of the Bolivian Amazon with few coronary artery disease risk factors, have the lowest reported levels of coronary artery disease of any population recorded to date. These findings suggest that coronary atherosclerosis can be avoided in most people by achieving a lifetime with very low LDL, low blood pressure, low glucose, normal body-mass index, no smoking, and plenty of physical activity. The relative contributions of each are still to be determined.

They really are distinctly different

This chart from the study says it all. On the left you have MESA (Multi-Ethnic Study of Atherosclerosis) and on the right for comparison you have the Tsimane. This is specifically a measurement of coronary artery calcium (CAC).

You can see clear distinct differences …

One immediate thought is that perhaps it is genetics.

Actually no, it is already known that genetics plays only a minor part in the causation of coronary artery disease.

Yusuf S, Hawken S, Ôunpuu S, et al. Effect of potentially modifiable risk factors associated with myocardial infarction in 52 countries (the INTERHEART study): case-control study. Lancet 2004; 364: 937–52.

It really is just lifestyle.

But what does this mean for us?

It appears to tell us that a lifetime with very low LDL cholesterol, a subsistence diet of wild game,  fish, and high-fibre carbohydrates that are very low in saturated fat, combined with physical activity throughout much of the day sets a new target in the prevention of heart disease.

In other words, coronary atherosclerosis can be avoided in most people by achieving a lifetime with a similar diet, normal BMI, no smoking, and plenty of physical activity.

The rather obvious is that this is not something we can actually achieve. The degree of physical activity is way beyond what we would ever consider too be exercise or simply just active (even the over 60s). This perhaps suggests that part of the price we pay for the way we now live in an urbanised modern industrial society is the impact it has upon the health of our hearts.

Adopting some of what they do to some degree will yield you a health benefit, namely through diet, exercise and not smoking. What is not yet known is if there is a specific point at which no additional benefit is achieved. For example if you achieved half of their lifestyle activity and diet, would you only derive half of the benefit, or all if it?

Bottom line: adopt a better diet (forever, and not just for a few weeks), become more active, do not smoke, and you will not regret it.

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