What is Gluten?  
Gluten is a protein contained in the grains wheat, barley, rye and oats. It is a unique protein based on its structure that lends a doughy/elastic consistency to flours derived from these grains. This is why over the centuries; gluten-containing grains have come to be used so extensively in breads and other baked goods. 

What is wheat-free diet?  
A wheat-free diet involves cutting out all products made from wheat and wheat flour, such as bread. It is not as gluten-free diet. On a wheat free diet you just have to cut out wheat products alone, but on a gluten-free diet you must cut out all wheat, oats, barley and rye, because all of these foods contain gluten. 

What is lactose free diet?  
Lactose is the simple sugar found in milk and milk products. It can also be found in a variety of other foods and even as a filter in some pills and capsules. The enzyme lactase, present in the lining of the small intestine, splits lactose into two simple sugars. These simple sugars can then be absorbed by the body and used as nourishment.