Thursday, September 7, 2017

Medical Dietetics, Science or Fashion?

Food containing magnesium
The advices given by medical dieticians about healthy food oscillate continuously as time goes by. They rather look like the alternatives of fashion, than the discoveries of science. Here are a few examples:
         In the fifties and sixties it was fashionable to disparage the consumption of olive oil and recommend the use of seed oils, supposed to be healthier. Heart patients were advised to consume various seed oils, while olive oil was not even mentioned. Sometimes it was asserted that the consumption of olive oil increases cholesterol in blood. This policy caused significant damage to Spain, one of the main olive oil exporters, as stated in a newspaper article published in 1968:
The economic problems of the olive grove are motivated, to a great extent, by the change in the taste of the consumers, who sometime ago were forced to use different seed oils, and now, when we are trying to bring them back to a higher consumption of olive oil, they don’t want to do it in the proportion advisable for this market of the Spanish fruit, as it is rather more expensive.
In the 1980s the situation had changed completely, as indicated by this article, published in 1983, where a page sponsored by the Ministry of Agriculture, Fisheries and Food promotes the consumption of olive oil, because it contains no cholesterol, among other advantages. Three pages later in the same newspaper issue, olive oil is praised with these words:
Olive oil is the most easily digestible fat for the body. It also has an enormous nutritional value and caloric power (943 calories per 100 grams of pure oil). Let us glorify, consume and integrate in our organism this outstanding luxury of Spanish cuisine.
White fish (Atlantic cod)

  •         Around the same time (the 1950s and 60s) doctors were very clear: white fish (hake, sole, monkfish, cod) were much better than blue fish (tuna, bonito, salmon, swordfish), which was unadvisable in almost all cases:
And we will also say that the meat of some fish is lean, while in others it is greasy. The first usually correspond to the so-called white fish, the others to the so-called blue... The essential thing is that white lean fish is easily digested and highly recommended for delicate people, while greasy fish is more difficult to digest.
Today things have changed completely. Blue fish, as part of the Mediterranean cuisine, so good for our health, should be eaten three times a week, as it contains omega-3, the fashion fat.
         Eggs have long been said to contain cholesterol and to have negative effects on circulatory diseases. It was usually advised not to eat more than one egg a week, and some companies even tried to produce eggs without cholesterol. By 2008, however, the usual recommendation had been increased to three or four eggs per week. In 2013, a meta-analysis (a large-scale review of scientific publications) concluded that one egg per day does not cause harmful effects in coronary heart disease.
         In the case of palm oil, the evolution has been the opposite. First it was very good for health, now it is declared dangerous. On the other hand, coconut oil, formerly reviled because it raised the level of cholesterol, has now become excellent.
         Let us finish by remembering the scandal raised two years ago by the media when the World Health Organization  (WHO) declared red meats carcinogenic.
All this is complicated because doctors are continually reducing the normal levels of cholesterol, and we can detect the first attempts to do the same with blood pressure and blood sugar. Nasty-minded people could conclude that their objective is pushing us all into abnormal levels, so that every human being is forced to consume continuously many different kinds of pills, thus fattening the revenue account of pharmaceutical companies. But then, the meaning of the word normal would have to be redefined.

Manuel Alfonseca

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