Vitamins and minerals collaborate with each other to carry out functions in the body. If someone is deficient in a nutrient, it can affect the functioning of other nutrients. Vitamin D, calcium, and magnesium have a very intricate relationship. Most people are aware of the calcium-magnesium relationship, but they are also co-nutrients of vitamin D. While the majority of individuals get enough calcium, at least half of us do not get enough magnesium. Magnesium is one of the most import co-nutrients for vitamin D metabolism and utilization. This means if you are deficient in magnesium, you are not properly metabolizing vitamin D and research shows a relationship between magnesium deficiency, chronic inflammation, CRP levels, and the development of cancers such as breast and colorectal. Another factor is calcium and achieving the right calcium to magnesium ratio. Research suggest the ideal ratio is 2 to 1, however, most people fall a bit higher. Knowing and understanding your levels of these three nutrients is extremely important.