Arguments over salt and health have broken out on both sides of the Atlantic, with dissenting opinions among individual experts and even professional societies. What’s going on?
New IOM report
The latest round of the salt controversy was triggered by the Institute of Medicine (IOM) in the United States, a very conservative and scientific organisation. Their latest report had two key messages, the first confirming the positive association between high sodium intakes, high blood pressure and the risk for heart disease. No drama there. The contentious finding was that there was not a strong scientific case for shifting from moderate to low salt intake.
Just to get your bearings, a high sodium intake is considered to be about 5000 mg/day – the average intake in China. Intakes in many western countries are moderate by comparison, about 3300-3700 mg/day. However, the upper limit of sodium intake recommended in Australia’s Nutrient Reference Values is only 2300mg/day, the same figure recommended in the Dietary Guidelines for Americans. Just last week the European Society of Hypertension and the European Society of Cardiology published new guidelines for the management of hypertension, recommending sodium intakes in the range of approximately 2000-2300 mg/day. The American Heart Association goes even further, recommending just 1500 mg/day.
Paleo diets are the flavour of the month. Their premise is that our hunter-gatherer genes are out of kilter with our modern agriculture-driven diet and this disconnect is making us all sick. Adopting the diet of our ancestors is considered to be the pathway to health. Sounds plausible enough, yet critics say it’s based on false assumptions.
What are paleo diets?
Although paleo diets come in several guises they are all based on a similar theme. Throughout most of our time on planet Earth humans were hunter-gatherers eating game meats and wild plant foods and this shaped our genetic make-up. The development of agriculture during the last 10,000 years radically changed the human diet yet, as human evolution is slow, we have essentially retained our ancient genes. The mismatch between new diet and old genes is the root cause of high rates of obesity and other chronic diseases in the modern era.
The proposed solution is to eat like a caveman. Modern day paleo diets rely on meat, fish and seafood as staple foods. Fresh fruits and vegetables, nuts and seeds, eggs and healthful oils are all recommended. Sugar and many processed foods are restricted, though paleo diets also restrict grains, legumes, potatoes and dairy foods, which are fixtures in many healthy eating guides. The argument goes that these foods were all recently introduced into the human diet and are deleterious to health.
That’s the theory but critics of paleo diets are now coming out in force.