Nutrition Science and Everyday Application - beta v 0.1

526 ALICE CALLAHAN, PHD, HEATHER LEONARD, MED, RDN, AND TAMBERLY POWELL, MS, RDN
Deficiency and Toxicity
The B vitamins important for energy metabolism are naturally present in numerous foods,
and many other foods are enriched with them; therefore, B vitamin deficiencies are rare.
Similarly, most of the minerals involved in energy metabolism and listed above are trace
minerals that are not frequently deficient in the diet. However, when a deficiency of one
of these vitamins or minerals does occur, symptoms can be seen throughout the body
because of their relationship to energy metabolism, which happens in all cells of the body.
A lack of these vitamins and minerals typically impairs blood health and the conversion
of macronutrients into usable energy (i.e., ATP). Deficiency can also lead to an increase
in susceptibility to infections, tiredness, lack of energy, and a decrease in concentration. 1
Groups most at risk for a deficiency in any of these micronutrients are people on calorielimited
diets, people with imbalanced or insufficient nutrition, people with eating disorders,
and people experiencing extensive levels of physical or emotional stress. 1
Because of their water-solubility, toxicities of most of these nutrients are also uncommon,
as excess intake is often excreted from the body. That doesn’t mean taking high doses comes
without risks. Large quantities, particularly through supplements, can lead to adverse side
effects or cause interactions with medications. For example, too much niacin can cause
flushing of the skin or dangerous drops in blood pressure, and a high intake of B 6 can lead
to neuropathy. When taking vitamin or mineral supplements, always pay attention to the
recommended dietary allowance and avoid exceeding the tolerable upper intake level (UL).
FOLATE
Folate, or vitamin B 9 , is a required coenzyme for the synthesis of several amino acids and for
making RNA and DNA. Therefore, rapidly dividing cells are most affected by folate deficiency.
Red blood cells, white blood cells, and platelets are continuously being synthesized in the
bone marrow from dividing stem cells. When folate is deficient, cells cannot divide normally.
A consequence of folate deficiency is macrocytic anemia. Macrocytic means “big cell,” and
anemia refers to fewer red blood cells or red blood cells containing less hemoglobin.
Macrocytic anemia is characterized by larger and fewer red blood cells that are less efficient
at carrying oxygen to cells. It is caused by red blood cells being unable to produce DNA and
RNA fast enough—cells grow but do not divide, making them large in size.