Fatigue and vitamin or mineral deficiency

1- Iron
Anemia occurs when there aren't enough red blood cells to meet the body's need for oxygen, or when these cells don't carry enough of an important protein called hemoglobin. Fatigue is usually the first sign of anemia. A blood test to measure the number of red blood cells and amount of hemoglobin can tell if you have anemia. The first step in shoring up your body's iron supply is with iron-rich foods (such as red meat, eggs, rice, and beans) or, with your doctor's okay, over-the-counter supplements.

2- Vitamin B12
Your body needs sufficient vitamin B12 in order to produce healthy red blood cells. So a deficiency in this vitamin can also cause anemia. The main sources of B12 are meat and dairy products, so many people get enough through diet alone. However, it becomes harder for the body to absorb B12 as you get older, and some illnesses (for example, inflammatory bowel disease) can also impair absorption. Many vegetarians and vegans become deficient in B12 because they don't eat meat or dairy. When B12 deficiency is diet-related, oral supplements and dietary changes to increase B12 intake usually do the trick. Other causes of B12 deficiency are usually treated with regular injections of vitamin B12.

3- Vitamin D
A deficit of this vitamin can sap bone and muscle strength. This vitamin is unique in that your body can produce it when your skin is exposed to sunlight, but there also aren't many natural food sources of it. You can find it in some types of fish (such as tuna and salmon) and in fortified products such as milk, orange juice, and breakfast cereals. Supplements are another way to ensure you're getting enough vitamin D (note that the D3 form is easier to absorb than other forms of vitamin D).