Adequate calcium intake levels suggested for the United States of America are higher than those accepted internationally, and extend the increased needs of adolescents to young adults. Peak bone mass continues to increase until age of 24 years. Results of bone density measurements support the need for calcium intake beyond that required for calcium balance and retention for growth.
However, the situation in most Asian countries suggests that their populations may have sufficient calcium retention and bone mass despite lower levels of intake.
Calcium intake may need to be adjusted for dietary factors (e.g. observed animal protein, sodium intake, vitamin D intake) and for sun exposure, since both affect calcium retention.
Isaac Bashevis Singer
What do they know-all these scholars, all these philosophers, all the leaders of the world - about such as you? They have convinced themselves that man, the worst transgressor of all the species, is the crown of creation. All other creatures were created merely to provide him with food, pelts, to be tormented, exterminated.
Undernutrition is a form of malnutrition. (Malnutrition also includes overnutrition).
Undernutrition can result from:
- inadequate ingestion of nutrients,
- impaired metabolism,
- loss of nutrients due to diarrhea,
- increased nutritional requirements.
Undernutrition progresses in stages: it may develop slowly when it is due to anorexia or very rapidly. First, nutrient levels in blood and tissues change, followed by intracellular changes in biochemical functions and structure. Ultimately, symptoms and signs appear. Diagnosis is by history, physical examination, body composition analysis, and sometimes laboratory tests.
Undernutrition from micronutrient deficiencies, or "hidden hunger", affects over 2 billion people globally and can lead to reduced growth and cognitive development, birth defects, blindness, and overall poor health. Vitamin A deficiency, iron deficiency anaemia and iodine deficiency disorders are among the most common forms of micronutrient malnutrition.