Please review my grammar and writing skills in the below passage - Recently, scientists have discovered that vitamin D initiates insulin secretion. In fact, high vitamin D levels can reduce the chances of developing cancer by 67%. People have been discussing its existing bioavailability and usefulness in the body every now and then. However, too many questions surrounding vitamin D nutrition remain unanswered. Accounting the efficacy of vitamin D sources with respect to its functionality in the body would help absolve these concerns.
Vitamin D is available externally through natural and synthetic sources. Dietary sources such as sea fish, milk and its derivatives, and eggs make it readily available, but they account for only 10% of the necessary intake. Synthetic sources comprise supplementary tablets and syrups, fortified foods such as packaged fruit juice, milk products, and fortified margarine. In fact, all dairy products and mushrooms contain it as an additive. Upto 50% of it is lost from vitamin D foods when they’re overcooked.
Internally, vitamin D is produced when exposed to sunlight. Photolysis of 7-dehydrocholesterol produces cholecalciferol and UVB radiation increases its production. This accounts for 80-90% of its presence in the body. Breastfed milk is another rich source of vitamin D and enhances its production capabilities in the growing years. Taking vitamin D pills is a common advice to pregnant women, especially for this reason.