Do dietary deficiencies lead to a serious health problems?

Calling it a dietary deficiency already means that something necessary is missing from the diet.

The human body requires certain amounts and types of nutrients such as protein, fats, carbohydrates, vitamins and minerals to maintain body functions, immunity to disease, repair damage, and to grow. The body maintains reserves for periods when some nutrients are missing in the diet.

Sometimes one type of missing nutrient can be converted to another but with potential harmful side effects. An example is a very low carbohydrate diet. The body will try to convert some (hopefully excess) fats and proteins to carbohydrates for energy. This process however results in byproduct waste that is eliminated by and can damage the kidneys unless enough water is drunk and is available for the kidneys to ease the process.

Extended lack of required nutrients can result in lack of strength and energy, stunted growth, greater susceptibility to illness, body organs breaking down and failing and emotional instability. All these can be serious health problems that can result in death.