No fruits are naturally rich in vitamin D; however, many brands of orange juice are fortified with it. Milk, soy products and breakfast cereals are also often fortified with vitamin D.
Few foods contain naturally high levels of vitamin D. The exceptions include tuna, salmon, beef liver and egg yolks. Many cheeses are also good sources of this vitamin. The greatest source of vitamin D is sunlight, which causes the body to produce it when the sunlight hits the skin.
Vitamin D is an essential nutrient that fights inflammation, bolsters the immune system and promotes calcium absorption. Insufficient levels of vitamin D contribute to health problems, such as osteoporosis, rickets and brittle bone disease. Dietary calcium deficiency also increases the risk of these conditions. Fortunately, many foods are naturally rich in calcium. Foods with high levels of calcium include broccoli, citrus fruits, kale, spinach and soybeans. Milk, salmon and rainbow trout are also excellent sources.
Although vitamin D is crucial for health, excessive levels of it are harmful. The consequences of vitamin D toxicity include abnormal heart rhythms, vascular rigidity, kidney problems and uncontrolled weight loss. Some individuals also develop anorexia. The primary cause of vitamin D toxicity is over-consumption of nutritional supplements.