There is no question that dietary habits can affect your health and risk for disease via a number of mechanisms. What you may not know that diet can also affect the way in which our DNA – our genetic material – is expressed. Our genes provide all the information to produce the proteins and other molecules necessary to create our cells and tissues. However, the manner in which our DNA expresses its instructions to build these molecules in highly regulated by factors outside the genes referred to as “epigenetic factors” which are highly influenced by diet and environmental factors.
A number of dietary factors have been shown to exert effects on DNA expression in ways that can prevent serious diseases like cancer and heart disease from developing. The research in this field is in the early stages and it is extremely exciting.
The Mediterranean Diet:
The traditional Mediterranean diet reflects food patterns typical of some Mediterranean regions in the early 1960s, such as Crete, parts of the rest of Greece, and southern Italy. The traditional Mediterranean diet has shown tremendous benefit in preventing and even reversing heart disease and cancer as well as diabetes. It has the following characteristics:
* Olive oil is the principal source of fat.
* An abundance of plant food (fruit, vegetables, breads, pasta, potatoes, beans, nuts, and seeds).
* Foods are minimally processed, and there is a focus on seasonally fresh and locally grown foods.
* Fresh fruit is the typical daily dessert, sweets containing concentrated sugars or honey being consumed a few times per week at the most.
* Dairy products (principally cheese and yogurt) are consumed daily in low to moderate amounts.
* Fish is consumed on a regular basis.
* Poultry and eggs are consumed in moderate amounts (1-4 times weekly) or not at all.
* Red meat is consumed in low amounts.
* Wine is consumed in low to moderate amounts, normally with meals.
One of the key components of the Mediterranean diet is olive oil which consists not only of the monounsaturated fatty acid oleic acid; but also contains several antioxidant agents that may also account for some of its health benefits. Olive oil is particularly valued for its protection against heart disease.
Because the Mediterranean diet has shown such tremendous protection against cancer and heart disease, researchers felt that it might be affecting genetic expression. To test this hypothesis, men and women with the metabolic syndrome characterized by abdominal obesity were allocated to an 8-week dietary program consisting of either 19% of calories as saturated fat (SFA); 20% of calories of mono-unsaturated fat from refined olive oil; or a Mediterranean diet providing 21% of calories as mono-unsaturated fat from extra virgin olive oil. Dividing the subjects into these three groups helped to answer the question “Is it the mono-unsaturated fat (MUFA) in the Mediterranean diet or some other factor that might be affecting gene expression.” Several parameters were examined that involved the production of inflammatory compounds that play a key role in the development of atherosclerosis (hardening of the arteries).
What the results indicated was that consumption of olive oil, compared with the SFA in the typical American diet, decreased the expression of the genes that produce a number of inflammatory mediators. These results are quite significant as it shows that some of the underlying beneficial effects of olive oil and the Mediterranean diet against cancer and heart disease maybe the result of direct effects on the expression of our DNA.
van Dijk SJ, Feskens EJ, Bos MB, et al. Consumption of a high monounsaturated fat diet reduces oxidative phosphorylation gene expression in peripheral blood mononuclear cells of abdominally overweight men and women. J Nutr. 2012 Jul;142(7):1219-25.