For many years scientists have been trying to understand the secret of the Mediterranean diet, which is linked to prolonged lifespan. This diet is low on processed food and high on vegetables and olive oil.
Recently, it has been suggested that such diet helps to fight elevated blood pressure and the risk of hypertension-assisted heart disease. Now we have a good biochemical mechanism supporting this theory.
Green vegetables are full of nitrites, which can react with olive oil’s unsaturated fatty acids to produce nitro-fatty acids. These compounds are claimed to be protective for our blood vessels by lowering blood pressure.
The latest study headlined by King’s college Prof. Eaton has shown that nitro-fatty acids, derived from components of the Mediterranean diet, inhibit an enzyme in the blood called epoxide hydrolase or EH, that processes vasoactive compounds called EETs (or epoxyeicosatrienoic acids). EH inhibition by known drugs results in elevation of EETs in the blood plasma and subsequent vasodilation (the widening of blood vessels), which is helpful if you want to fight hypertension.
Eaton’s team have engineered transgenic mice that had their EH mutated into a form insensitive to inhibition by nitro-fatty acids. So, while normal mice maintained on the Mediterranean diet didn’t develop hypertension and cardiac hypertrophy, the mutant mice did, since their EH enzyme was not sensitive to nitro-fatty acids.
If it works as good in humans, this may explain why regular consumption of Greek salad and related dishes may lower the risk of heart disease.
Nitrites are also high in salami, pastrami, ham, bacon, red meats, but in these foods they are considered to be harmful and increase risk of cancer, why? It’s because of how you cook it. Under high temperatures (frying, roasting), nitrites react with amines to form carcinogenic compounds. So, what’s good in one form, can be harmful in another.
It appears not just food intake but many other factors, like infections and stress can lead to heart problems. A recent study used artificial arteries to show that bacterial bio-films that often form inside certain areas of human blood vessels, especially on lipid plaques, break up in response to stress hormones. This breakage can release the underlying plaque into the bloodstream, where it can block the vessel and cause ischemia (lack of blood flow) and hemorrhage – in the brain or heart – and therefore, stroke or myocardial infarction.
A newest article suggested another mechanism how stress may trigger heart disease. Under chronic variable stress a surplus noradrenaline is released by sympathetic nerve fibers in bone marrow where it causes blood cell progenitors called hematopoietic cells to proliferate more and give rise to larger quantities of inflammatory cells, monocytes and neutrophils. The result is accumulation of these cells in blood vessel walls and formation of plaques, a disease process called atherosclerosis.
No wonder that heart disease is a major killer in the developed world where we often have stressful work environments coupled with the processed food diet. And we have all heard about more relaxed attitude to work in the South Europe and their famous fresh food and great wine.
I never stop wondering how, despite our already extensive knowledge of metabolism, we keep discovering new things that cause diseases or protect us from them. And sometimes, we find that not an expensive medication but a simple lifestyle choice can significantly improve our health and longevity.