Magnesium is found in a wide variety of foods, such as: 1  green leafy vegetables – such as spinach. 2  nuts. 3  brown rice. 4  bread (especially wholegrain). 5  fish.6  meat. 7  dairy foods.oron is a trace element, which means the body only needs very small amounts of it. Boron is thought to help the body make use of glucose, fats, oestrogen and other minerals, such as calcium, copper and magnesium, in the food we eat.