what happens to our health when our bodies are deprived of an essential nutrient?

Answer 1

In general, the body suffers some adverse response, and death can occur. For example, scurvy was a problem with sailors on long voyages, because their rations did not provide Vitamin C. So they became listless, had sores, their teeth fell out, and they eventually died (unless they landed somewhere are got nutritional food). The British solved this by having limes stocked away on voyages for consumption. From that came the term "Limey" for a British sailor.