Webster's New World Medical Dictionary

deficiency, iron
An inadequate amount of iron,
the most common known form of nutritional disor-
der in the world. Iron is necessary to make hemo-
globin, the molecule in red blood cells that
transports oxygen. Iron deficiency results in anemia.
The prevalence of iron deficiency is highest among
young children and women of childbearing age
(particularly pregnant women). In pregnant women,
iron deficiency increases the risk for preterm deliv-
ery and delivery of babies with low birth weight. In
children, iron deficiency causes developmental
delays, behavioral disturbances, failure to thrive, and
increased infections. The treatment of iron defi-
ciency anemia includes using iron supplements and
iron-containing foods in the diet. Food sources of
iron include meat, poultry, eggs, vegetables, and
cereals (especially those fortified with iron).
However, iron supplements should not be given to
children unless a physician recommends them.
deficiency, lactase
Lack of the enzyme lactase in
the small intestine. Lactase is needed to digest lac-
tose, a sugar found in milk and most other dairy
products and also used as an ingredient in other
foods. Although most people are born with the abil-
ity to make adequate amounts of lactase, the pro-
duction of lactase normally decreases with age, and
there are significant differences in lactase produc-
tion among ethnic groups. People of African or Asian
descent commonly have difficulty digesting products
that contain lactose. The most common symptoms of
lactase deficiency are diarrhea, bloating, and gas.
Treatment usually involves avoiding lactose in the
diet or taking over-the-counter lactase supplements
before eating foods that contain lactose.
deficiency, LCHAD
Deficiency of the enzyme
long-chain-3-hydroxyacyl-CoA dehydrogenease
(LCHAD), an abnormality of fatty acid metabolism.
Acute fatty liver of pregnancy (AFLP) has been found
to be associated in some cases with LCHAD defi-
ciency. In such cases, both parents have LCHAD
activity at half of normal levels, but the fetus has
none. The metabolic disease in the baby’s liver
apparently causes the fatty liver disease in the
mother. In women who have had AFLP, the risk of
AFLP increases with each pregnancy. See also 
acute
fatty liver of pregnancy.