This chapter examines the essential roles vitamins, minerals, and phytochemicals (phytonutrients) play in human health, nutrition, and disease.  The chapter highlights sodium and other minerals in hypertension, as well as the DASH diet, and examines the scientific evidence on vitamin C, zinc, and the common cold.  It reveals widespread vitamin D deficiency, which may contribute to a range of health conditions beyond bone fractures and osteoporosis.  The chapter explores phytochemicals—bioactive compounds found in plants—and discusses four major categories (polyphenols, carotenoids, phytoestrogens, and glucosinolates), emphasizing their antioxidant, anti-inflammatory, and immune-boosting effects that combat disease.  While a healthy, balanced diet meets micronutrient needs, vitamin and mineral deficiencies arise even in wealthy populations; supplements can fill nutrient gaps, although whole foods offer additional health advantages.  Finally, the chapter explains the complexity of nutrition science, advocating for a holistic dietary pattern approach over reductionist strategies that isolate single nutrients and individual foods.