Nutrients are the nourishing substances in food that are essential for the growth, development and maintenance of body functions. Essential meaning that if a nutrient is not present, aspects of function and therefore human health decline. When nutrient intake does not regularly meet the nutrient needs dictated by the cell activity, the metabolic processes slow down or even stop.

- Perspectives in Nutrition, Wardlow and Insel

In this context the amount and type of nutrients depends on the cell activity. In short the more activity the more nutrients are required. According to Teresa A. Marshall and Connie C. Mobley an improper diet and to much or less activity can cause chronic deases.

Below are 2 points for their book1:

  • Dietary excesses and inadequate physical activity increase risk of obesity and chronic diseases including cardiovascular disease, diabetes, and some cancers

  • Protein energy malnutrition, nutritional anemia, nonalcoholic liver disease, and osteoporosis are associated with nutrient deficiencies that increase risk of oral diseases and conditions

There are more researches available that link nutrient deficiency to chronic desease:

Upon addition of magnesium ions in vitro, the expression of inflammatory mediators such as tumour necrosis factor α (TNFα) and nuclear factor κβ (NFκβ) is down regulated. Dysregulation of these and other inflammatory mediators has been linked to several inflammatory disorders, including asthma, arthritis, atherosclerosis and neuroinflammation. 2
we discuss the impact of elevated free serum copper on accompanying Alzheimer's disease, knowing that copper plays a crucial role in the formation of amyloid plaques and tau aggregation.3
Copper binding proteins play important roles in the establishment and maintenance of metal-ion homeostasis, in deficiency disorders with neurological symptoms (Menkes disease, Wilson disease) and in neurodegenerative diseases (Alzheimer’s disease).4

I would appreciate more research into optimum nutrient levels in the body along with a way to detect deficiencies or excesses.