It is well proven that the Mediterranean diet is one of the healthiest in the world and can prevent cancer, cardiovascular disease, diabetes and other serious diseases. The most important parts of the Mediterranean diet are eating plenty of fruit and vegetables, vegetable fats such as olive oil and rapeseed oil, lots of fish and nuts and drinking moderate amounts of red wine. Red meat (such as beef, pork and lamb) should be avoided.
One of the explanations for why the Mediterranean diet is so beneficial is believed to be that it increases levels of the protein adiponectin in the blood. This protein is released from fat tissue. The protein increases the cells' sensitivity to insulin and counteracts atherosclerosis and inflammation, effects that in the long term reduce the risk of disease.
While the Mediterranean diet promotes adiponectin production in the body, smoking has the opposite effect. Smokers have lower levels of the protein on average, which may be a contributing factor to all of the negative health effects of smoking.
Researchers at King Saud University in Riyadh, Saudi Arabia, wanted to investigate whether a Mediterranean diet could reverse the suppressive effect of smoking on adiponectin. Plasma adiponectin levels were measured in four groups: 41 people who had never smoked and did not eat a Mediterranean diet, 45 people who had never smoked and ate a Mediterranean diet, and 61 smokers and 34 ex-smokers on the same diet.
Among non-smokers, the positive effect of the Mediterranean diet was clearly visible, those who ate it had higher levels of the beneficial protein. But among those who smoked, the diet did not help, their adiponectin levels were low despite the Mediterranean diet. Those who had quit smoking were better off than smokers and worse off than those who had never smoked.
The researchers' conclusion is that a healthy diet is not enough to reduce the health risks of smoking.
The study has been published by the Journal of Atherosclerosis and Thrombosis.
