Here are 4 easy tips to follow that will minimise these effects:
1- Grill on an area without a direct flame as the temperatures are highest directly above the flame.
2- Be sure not overcook or burn your food as this helps prevent the formation of toxic compounds.
3-Marinade with mixtures that contain antioxidant-rich ingredients such as lemons and onions, rosemary and black pepper.
4-Use an oil to coat your food and make sure its an oil that has a high smoking point such as safflower oil or Coconut oil. Olive oil is never a good idea as it has a very low smoking point and will go rancid when used for high temperature cooking.
Remember that the principles of nutrient loss from grilled or charcoaled food is very similar to the principles of all cooking. The shorter the time of exposure to heat and the lower the heat, the less the nutrient loss.