1. Iron deficiency
Iron deficiency is very common, especially among young women, children, and vegetarians. It may cause anemia, fatigue, a weakened immune system, and impaired brain function.
2. Vitamin D deficiency
Vitamin D deficiency is very common. Symptoms include muscle weakness, bone loss, an increased risk of fractures, and — in children — soft bones. It is very difficult to get sufficient amounts from your diet alone.
3. Vitamin B12 deficiency
Vitamin B12 deficiency is very common, especially in vegetarians, vegans, and older adults. The most common symptoms include blood disorders, impaired brain function, and elevated homocysteine levels.
4. Calcium deficiency
Low calcium intake is very common, especially in women of all ages and older adults. The main symptom of calcium deficiency is an increased risk of osteoporosis later in life.