Brown-shelled eggs are produced by hens with red feathers and red ear lobes. There is no difference in taste or nutrition between white and brown eggs. Brown eggs usually are more expensive because the red hens tend to be larger birds and require more feed. Sure, because they're basically egg with the cholesterol and fat removed from the yolk. Egg yolk is the major source of the egg's vitamins and minerals, but the yolk is also the part of the egg that has the most calories, fat and cholesterol.
Some egg substitutes are mostly egg whites.
The yolk is replaced with things like nonfat milk, tofu, vegetable oils, emulsifiers, stabilizers, antioxidants, gum, artificial color, minerals or vitamins. Of course, you can whip up something similar at home by separating your own eggs. But for most healthy people, the amount of cholesterol in the blood is not heavily affected by how much cholesterol they consume. High fat and saturated fat intake contribute more to the risk of heart disease than cholesterol. In the end, the AHA recommends no more than three to four eggs per week.