Over 40% of adults are vitamin D deficient. Checking the levels of vitamin D in your blood to see if your levels are too low is essential for good health. Low Vitamin D can cause symptoms such as low mood, fatigue and frequent illness.

Vitamin D is a vital nutrient that plays an essential role in maintaining the immune system, bone strength, mood and energy levels. Vitamin D is found in some foods, but our main source is sunlight. During the winter months the sun’s rays may be weaker and vitamin D deficiency may be more common.

Iron and good thyroid function also play a role in energy levels: 2San recommends these tests alongside the Vitamin D test.