Nature's Answer Vitamin D-3 delivers 4,000 IU per serving. Vitamin D-3 is vital for many body processes, including the promotion of strong bones by assisting in calcium metabolism. Vitamin D also influences a host of key biological functions vital to health and well-being. Vitamin D is called the "Sunshine Vitamin" because it's produced naturally by the body after exposure to sunlight. Nature's Answer Vitamin D-3 drops in extra virgin olive oil are free of salt, wheat, corn, yeast, sugar, milk, preservatives and fish.