What is a nutritional deficiency?
A ‘nutritional deficiency’ is defined as severely reduced levels of one or more nutrients, resulting in the body being unable to function normally and potentially increasing the risk of certain health conditions.1 Micronutrient deficiencies lead to clinically evident symptoms.2
This is not quite the same as a nutritional inadequacy, which is a suboptimal intake of one or more nutrients but doesn’t yet cause disease or a health condition.
Micronutrient intake is essential for maintaining health and preventing illness at every stage in life. Although they are only required in trace amounts, they play critical roles in many biochemical processes such as gene transcription (turning genes on and off), enzymatic reactions, and protection against oxidative stress.3
For example, methylfolate, vitamin B12, and vitamin B6 are required for the methylation cycle, in which they assist with homocysteine metabolism and the repair of DNA. Zinc and selenium are essential for protecting against oxidative stress.
Worldwide, the most common deficiencies include vitamin A, folate, iodine, iron, and zinc.4
Deficiencies in these nutrients can lead to cognitive impairment, poor growth, perinatal complications, degenerative diseases associated with aging, and higher risk of several diseases.