The next time you blame your genes for obesity, diabetes or, for that matter, anything you cannot find an answer to, think again.

Our DNA chemistry and composition has two parts. The first is the gene pool that contains the DNA patterning we are born with, which makes up our constitution in terms of who we are, our body structure, health, height, weight, skin colour and hair texture and a host of other traits. The second is gene expression. This is entirely dependent on our interaction with the external environment—what we do, what and how we eat, how often we eat. Our lifestyle, for instance, will shape our body weight; our nutrition and food choices will determine our overall health and the health of our hair, skin and nails; our physical activity and intake of sunlight for vitamin D and of calcium-rich foods will decide whether or not we attain our 100% height potential. Remember, nutrition and exercise drive healthy gene expression.

 In the case of most people, genes exist in pairs. In some people with genetic defects, however, say in those with Down Syndrome, genes may exist as a trisomy (three copies of a chromosome instead of two). Normally, one gene in a pair is dominant and the other, recessive. The dominant gene is expressed over the recessive gene. So, for instance, if you were to have a dominant gene that increases your chances of getting diabetes or polycystic ovary syndrome, and you eat too much junk or refined food and have a sedentary lifestyle, this dominant gene will most likely come to the fore.

But if you start eating sensibly and exercise every day, you could modify the expression of the dominant gene. In an article titled “Epigenetics: A New Bridge Between Nutrition And Health", published in 2010 in the Advances In Nutrition journal, the American Society for Nutrition mentioned that the “individual nutrients and bioactive food components or total diet can change DNA methylation and, subsequently, alter gene expression".

The food we consume plays a role in gene health. Vegetables like spinach and arugula, which have high levels of folate (an important vitamin that regenerates cells), omega 3-rich fish like mackerel and tuna, along with power-packed protein like chicken, eggs and paneer (cottage cheese), all contribute to the health of cell structures. If you have these foods regularly and exercise every day, you can prevent the weak and unhealthy genes from being expressed.

Here is a list of foods which contain nutrients that can help modify the expression of unhealthy genes.

u Include foods that are rich sources of the protein methionine. Some examples are sesame seeds, almonds, fish, peppers and spinach. Combining these foods with dal (lentils) and legumes can help improve the overall protein quality of the lentils, for they usually lack methionine. Consider adding a teaspoon of sesame seeds to your everyday dal for more methionine.

u Folic acid is important for cell regeneration and, therefore, gene expression. Leafy green vegetables like spinach, methi (fenugreek), dill leaves and sunflower seeds are rich sources. Take care to cook leafy greens for just a few minutes to preserve the folate content.

u Vitamin B12 is indispensable for improving gene health. Chicken, shellfish, milk and organ meat like liver are good sources of vitamin B12. If you have elevated cholesterol levels, check with your physician before consuming liver or shellfish.

u Vitamin B6 aids improved gene expression because it helps in the absorption of protein. It is available across a wide range of unrefined grains like millets, brown rice, quinoa and almonds, as well as coloured vegetables like purple cabbage and red and yellow bell peppers.

u Choline, a vital nutrient for energy metabolism, is found in non-vegetarian foods like egg yolk, chicken and turkey.

u Betaine, which plays an active role in improving healthy gene expression, is found in wholewheat, spinach, shellfish and beet sugar.

In addition to these foods, exercising daily and staying active leads to eustress, or positive stress (that motivates you to continue working), which in turn plays a significant role in managing your DNA.

Madhuri Ruia is a nutritionist and Pilates expert. She runs InteGym in Mumbai, which advocates workouts with healthy diets.