Calcium
What food source is the nutrient found in?
Dairy products are the best source for calcium.
Dark green leafy vegetables and fish with edible bones, such as salmon,
are also good sources. Many breakfast cereals and orange juice brands have
added calcium.
Some foods can interfere with the absorption calcium. Foods
that may do this include:
vegetables, such as spinach
some grains
caffeine
High protein intake can also interfere with the body's
uptake of calcium.
Sources of calcium include:
milk, skim = 300 milligrams (mg) per cup
yogurt = 345 to 450 mg per cup
mozzarella cheese = 200 mg per ounce
tofu = 130 mg per half cup
calcium-fortified orange juice = 225 mg per 3/4 cup
mustard greens = 50 mg per half cup
broccoli = 45 mg per half cup
canned fish, 3 ounces of salmon (with bones) = 195 mg, 3
ounces of sardines (with bones) = 370 mg
How does the nutrient affect the body?
The most well known function of calcium is to preserve
bone density. This process is aided by other key vitamins and
minerals including magnesium and vitamin D. Without enough calcium,
bones may lose density. This condition is called osteoporosis.
More than 25 million Americans, mostly women, suffer from it. This disease
puts people at greater risk for hip and other bone fractures. Bones
act as a reservoir for calcium. If there is not enough calcium circulating
in the blood to meet the body's needs for the mineral, it will be pulled
from the bones.
Typically, people keep building up calcium in the bones
through their late 20's and early 30's. After age 30 to 35, bones begin
to naturally lose minerals such as calcium that give them strength.
After age 50, calcium loss from bone becomes even more common,
especially among women. The hormone estrogen helps keep
calcium in bones. After menopause,
a woman's body stops producing estrogen. This increases the loss of calcium from
bone . Hormone replacement therapy
and weight-bearing exercise such as walking and weight lifting can help
maintain bone density in post-menopausal women.
If people get enough calcium in their youth, they can
build a healthy reservoir to draw from in later years. Later in life, a person needs
to consume enough calcium so that it is not robbed from the bones. Vitamin D
also helps the body to absorb calcium into the bones.
Bone health is not the only function of calcium in the body.
Calcium is also needed for vital nerve and muscle transmission including
the healthy function of the heart. Several recent studies have shown how
calcium can help lessen both the physical and emotional symptoms of
pre-menstrual syndrome,
which is also known as PMS. The mechanism behind this effect is not yet
known. It may be because of calcium's close link with certain hormones.
The dose used in these studies was 1200 mg a day.
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