Calcium deficiency, called hypocalcemia, can
occur because of inadequate calcium intake, excess
calcium excretion by the kidney (usually caused by
kidney damage), the inability to adequately absorb
calcium, or because of interactions between calcium
and some prescription drugs.
People at highest risk of
calcium deficiency are teenagers, women past the age
of menopause, individuals who are lactose intolerant,
vegans, and people with kidney (renal) damage.
Calcium deficiency rarely shows up in blood tests
because calcium is withdrawn from the bones to maintain
blood levels of calcium.
The bones then become
less dense, weaker, and more likely to break. This condition
is called osteoporosis and it is most noticeable in
the elderly who have a high rate of broken bones resulting
from falls.
Osteoporosis is a part of aging, but
eating a healthy diet high in calcium, getting adequate
vitamin D, and doing weight-bearing exercises regularly
can delay its onset. Severe calcium deficiency, is
usually caused by a medical condition rather than inadequate
calcium intake.
It causes symptoms such as
muscle cramps, tingling in the fingers, lethargy, convulsions,
heart rhythm abnormalities, and death. These
symptoms can also be caused by many other diseases.
Calcium excess
Calcium excess is called hypercalcemia. It usually
results from poor kidney function (renal failure) or
from a malignant cancer tumor. It can also be caused
by very large supplemental doses of vitamin D. Very
rarely is hypercalcemia caused by too much calcium
from food or dietary supplements. High levels of calcium
interfere with the absorption of other minerals
such as iron, zinc, magnesium, and phosphorous. People
with hypercalcemia usually have multiple medical
problems and are under the supervision of a physician.
Precautions
People of all ages, races, and gender need to be
alert to getting enough calcium in their diet. Building
strong, dense bones begins in childhood and adolescence,
even though the results cannot be seen until old
age. People mentioned above as being at especially
high risk of low dietary calcium intake should investigate
taking a calcium supplement.
Interactions
Absorption of calcium is affected by several
conditions.
-Age. Infants absorb as much as 60% of the calcium
in their digestive system. This decreases to 15–20% in
adulthood, and even less in old age.
-Pregnancy. Pregnancy increases the efficiency of calcium
absorption in the intestine to meet the demands
of fetal development.
-Amount of calcium consumed. The more calcium consumed
at one time, the less efficient absorption becomes. Calcium from supplements should be spaced
out during the day for maximum absorption.
-Vitamin D. The presence of vitamin D improves calcium
absorption. Vitamin D deficiency can worsen
calcium deficiency.
-Plant products. Phytic found in beans and oxalic acid
found in spinach and leafy greens decrease the amount
of calcium absorbed from those foods, but does not
affect the absorption of calcium from other foods
present at the same time in the intestine. Fiber such
as wheat bran also reduced calcium absorption.
Prescription medications can also affect or be
affected by the absorption of calcium. These include:
-digoxin
-fluroquinolones
-levothyroxine
-tetracycline antibiotics
-anticonvulsants
-thiazide-type diuretics
-glucacorticoids
-mineral oil
-stimulant laxatives
-antacids
People taking these drugs should check with their
healthcare provider or pharmacist about potential adjustments
in their medications or calcium intake.
Complications
No complications are expected when healthy people
take calcium in amounts equal to the AI level and
less than the UL level. Some people experience gas,
nausea, and abdominal discomfort from calcium supplements.
Taking the supplement with meals, taking
smaller doses spread out over the day, or changing the
type of supplement usually solves this problem. Complications
of excess calcium and calcium deficiency are
discussed above.
Parental concerns
Building strong bones starts in childhood, and
parents should be aware of how much calcium their
child needs compared to how much he or she is getting.
As children get older they tend to replace milk in their
diet with juice, bottled water, and especially carbonated
soft drinks. This leads to large calcium deficiencies
during adolescence. Parents should monitor their
child’s diet and encourage calcium supplements if they
cannot induce their adolescents to eat more dairy
products and other calcium-rich food.
