Malnutrition, which refers to a deficiency, excess, or imbalance of nutrients in the body, can lead to various diseases and health conditions. Here are some examples of diseases that can be caused by malnutrition:

1. Protein-Energy Malnutrition (PEM): PEM occurs when there is a deficiency of both protein and energy (calories) in the diet. It is commonly seen in undernourished children in developing countries and can manifest in two forms:
   a. Kwashiorkor: This condition results from inadequate protein intake despite sufficient energy intake. Symptoms include edema (swelling), skin lesions, impaired growth, and muscle wasting.
   b. Marasmus: Marasmus is characterized by overall calorie deficiency, causing severe wasting of muscle and fat tissues. It leads to extreme weight loss, weakness, and stunted growth.
2. Micronutrient Deficiencies: Inadequate intake of essential vitamins and minerals can result in specific deficiency-related diseases:
   a. Vitamin A Deficiency: It can cause night blindness, increased susceptibility to infections, and in severe cases, lead to xerophthalmia, a condition that can cause irreversible blindness.
   b. Iron Deficiency Anemia: Insufficient iron intake can lead to a decrease in hemoglobin levels, causing fatigue, weakness, pale skin, and impaired cognitive function.
   c. Iodine Deficiency Disorders: Lack of iodine can result in goiter (enlargement of the thyroid gland), hypothyroidism, and mental impairments.
   d. Vitamin D Deficiency: Inadequate vitamin D intake can lead to rickets in children, causing weak and deformed bones. In adults, it can cause osteomalacia, resulting in bone pain and fractures.
3. Scurvy: Scurvy occurs due to a deficiency of vitamin C (ascorbic acid). It can lead to weakness, fatigue, bleeding gums, joint pain, and impaired wound healing.
4. Pellagra: Pellagra results from a deficiency of niacin (vitamin B3) and can arise from a diet mainly dependent on maize (corn). Symptoms include dermatitis, diarrhea, dementia, and in severe cases, death.
5. Beriberi: Beriberi is caused by a deficiency of thiamine (vitamin B1). It can lead to weakness, nerve damage, cardiovascular problems, and impaired muscle coordination.
6. Osteoporosis: Prolonged inadequate intake of calcium and vitamin D can lead to weak and brittle bones, increasing the risk of fractures.

These are just a few examples, and there are other diseases and health conditions associated with specific nutrient deficiencies or imbalances. Proper nutrition and a balanced diet are essential for maintaining overall health and preventing these diseases.