IMPORTANCE OF CALCIUM
Dr. Betty J. Larson, LRD, FADA
Concordia College
Moorhead, MN 56562
Osteoporosis
Prevention
Blood Pressure
Control
(Calmodulin)
Impact of
Calcium
Muscle
Contraction
Bone
Calcification
Blood Clotting
(thromboplastin)
Nerve Impulse transmission
Tooth
Formation
Calcium and Hypertension
 When
animals are deprived of calcium
blood pressure increases.
 Increasing calcium in animals lowers blood
pressure or lessens the development of high
blood pressure.
 Hypertension is more prevalent in
populations with a low calcium intake.
Calcium and Hypertension
Osteoporotic women have a 2-3 fold increase in
hypertension.
 Increasing calcium decreases blood pressure.
 McCarron (1999) demonstrated that men with
higher blood pressure levels also had lower bone
mineral density and bone mineral content.
 DASH diet demonstrated that a low fat diet rich in
dairy, fruits and vegetables could significantly
reduce blood pressure.

Journal of the American
College of Nutrition (1999).
18(5):373S-412S.
 Calcium
in the Prevention of Kidney Stones
 Dairy Foods Prevent Colon Cancer
 Vitamin D and Calcium Prevent Breast
Cancer
 Calcium Control of Blood Pressure
 Implications for Osteoporosis
 Implications for weight management
PMS
 Daily
consumption of 1,200 mg of calcium
may decrease some adverse side effects of
PMS including psychological symptoms,
food craving, and water retention
Dairy’s Role in Weight
Management
 Calcium
may play an important role in the
regulation of energy metabolism and may
result in a reduction of body fat and an
acceleration of weight and fat loss during
caloric restriction. Dairy sources of calcium
may have a substantially greater effect than
supplemental or fortified sources.
 Increasing
dietary calcium or dairy intake may
reduce future weight gain.
 Nutrients found in dairy, including calcium, may
contribute to the reduction of body weight, body
fat and insulin resistance syndrome.
 Increasing calcium intakes to recommended levels
may reduce the incidence of overweight and
obesity by 60-80% in a population.
 Low daily calcium intake was associated with
greater body fat and body weight, particularly in
women.
Benefit of Dairy Foods
Dairy foods provide
calcium, vitamin A,
thiamin, riboflavin,
B12 , magnesium, and
phosphorus.
 Milk provides vit D
 CLA

Calcium Sources
Calcium content is highest in dairy products
 One 8-ounce glass of skim milk contains about
300 mg which supplies about 1/3 of the RD for an
adult
 Equivalent dairy foods are 1.5 oz of cheese, 1 c
yogurt, 1.75 c of ice cream
 Other good sources include fish with small bones
such as sardines, canned salmon, dark green leafy
vegetables (broccoli, kale, turnip greens), tofu,
legumes, nuts, fortified OJ or fortified cereals
 DV for calcium is 1,000 mg

Dietary Calcium Intake of
Females in mg – 75% of F do
not consume the AI for calcium
1400
1200
1000
800
Intake
Ideal
600
400
200
0
age age age 15- 18- 25- 35- 45- 551-2 3-5 12- 17 24 34 44 54 64
14
Factors that Enhance Calcium
Absorption
 Acid
 Normal
GI Motility
 Calcium-Phosphorus Ratio
 Vitamin D
 Need for Calcium
 Lactose
 PTH
Factors that Hinder Calcium
Absorption
 Inadequate Vitamin
D Intake
 Alkaline Conditions
 Impaired GI Motility
 Imbalance in Calcium:Phosphorus Ratio
 Excess Intake of Iron, Zinc, or Magnesium
 Phytic or Oxalic Acid
Calcium and Sodium
 Excess
sodium can increase calcium
excretion
 For every 500 mg increase in urinary
sodium excretion there is about a 10 mg
increase in urinary calcium loss.
Calcium, Protein, and
Exercise
 Excessive
protein intake may lead to
calcium excretion. About 1 mg of calcium
is lost for every gram of protein consumed.
 Intense exercise may increase urinary loss
of calcium
Coffee, alcohol and calcium
 High
intakes of coffee and alcohol may
increase calcium loss from the body
 Up to five cups of coffee and moderate
alcohol consumption appear to have little
effect on calcium balance
If Blood Calcium is Too Low
It will be a signal to Parathyroid
Gland to secrete Parathormone
Viamin D raises
calcium absorption
in the gut
PTH & Vitamin D
promote kidney
reabsoprtion of
calcium
PTH & D
stimulate
calcium release
from bone
Bioavailability
 Calcium
absorption from broccoli, cabbage and
kale is good, but the calcium content per
serving is much less than that for milk
Osteoporosis
 Porous
Bones
 Back Pain
 Spontaneous Fracture
 Loss of Height
 Dowager’s Hump
Dowager’s Hump
Osteoporosis Prevention
 Adequate
Calcium Intake
 Increased Exercise
 Adequate Vitamin D Intake
 Avoid Excessive Protein Intake, Alcohol,
Fiber and Cigarettes
 Resources for health professionals on
calcium www.nationaldairycouncil.org
Calcium Content of Food
Broccoli: 36 mg per
1/2 cup
 Sardines: 324 mg per 3
oz
 Milk: 316 mg per cup
 Pork & Beans: 77 mg
per 1/2 cup
 Cheddar Cheese: 305
mg per 1 1/2 oz
 Almonds: 80 mg per 2
Tbs

Calcium Supplements
Consumers Union notes that most people absorb
calcium from different preparations equally well
and recommends pills that deliver calcium at the
lowest price.
 Over age 50 may do better with chewable
calcium-carbonate
 Check label for calcium content per tablet – range
from 50-600 mg.
 Best choice a tablet with about 200 mg with
snacks or small meals – gastric acidity and slower
transit time in the gut may enhance absorption

Calcium Toxicity
NEVER FROM FOODS
 Excess Vitamin D with Calcium Supplements
 Symptoms include abnormal heart contractions,
constipation, development of kidney stones
 May interfere with absorption of key minerals
notably iron and zinc
 Supplements without food may contribute to
oxalate stones in the kidney

Osteoporosis in Sports
Concern about disturbed calcium metabolism in
young ahtletes in endurance or weight control
sports.
 Female Athlete Triad – disordered eating,
amenorrhea, osteoporosis
 Restrictive diets and excessive exercise may affect
hormone status including the hypothalamus and
pituitary glands resulting in reduced levels of
estrogen.

Athletic Amenorrhea
Amenorrheic athletes were found to have
significantly less bone mineral content in the spine
and other bones, including the femur.
 Increased dietary calcium may be useful in
maintaining bone but limited research.
 Four glasses of skim milk provide 1200 mg of
calcium.
 Other nutrients such as protein, magnesium, zinc,
copper, iron, fluoride and vitamins A, C, D, and K
are also required for bone metabolism.

How can you get your peers to
consume adequate calcium?
 2001
jingle to “Here comes Santa Claus”
Here comes calcium, here comes calcium
right down mineral lane. Bones growing
stronger, blood clotting faster don’t deny
your calcium need. Calcium everyone, not
just anyone, oh what a wonderful thing.
Broccoli, Sardines, Milk and Pork & Beans,
drink your calcium today.
Phosphorus
 Phosphorus
is part of ATP for energy processes
 Bones and Teeth
 Acid-Base balance
 Lipids contain phosphorus as part of their
structure in phospholipids
 Phospholipids are major components of cell
membranes
 Important for muscle contraction in ATP and PCr
 Glucose also needs to be phosphorylated in order
to enter glycolysis to produce energy
Phosphorous is found in
 Animal
 Meat,
Protein
seafood
 Eggs
 Milk
 Cheese
 Processed
foods such as soda pop
 Nuts, dried beans and peas, grain products
Phytate
 Phosphorus
is part of phytate that might
diminish absorption of minerals like
calcium, iron, zinc and copper by forming
insoluble phosphate salts in the intestine.
 Recommended calcium phosphorus ratio is
2:1 calcium to phosphorus or 1:1.
 Too much phosphorus might impair calcium
abosrption
Intake
Deficiency of phosphorus is very rare – recovering
alcoholics or with excess antacids
 PhosFuel –phosphorus to enhance exercise
performance but in the past 50 years most
research has discredited use of phosphorus
supplementation on athletic performance and they
may create imbalance with calcium. It may have a
limited impact on perceived exertion.

Magnesium
Involved in over 300 enzyme systems
 A major role is to act as a catalyst in the reaction
that adds the last phosphate to ATP
 Acts together with calcium in muscle contraction
and blood clotting; while calcium promotes the
process, magnesium inhibits the process.
 Helps prevent dental decay by holding calcium, in
the tooth.
 Helps prevent bone fragility
 PART OF AN ENZYME NECESSARY FOR
GLUCOSE METABOLISM IN THE MUSCLE
AND FOR GLUCONEOGENESIS.

Magnesium Requirement
Almost 3 of every 4 Americans do not meet need
 Found in chocolate, nuts, seafood, green leafy
vegetables, black beans, and whole grain products.
 ½ cup of shrimp or cooked spinach contains about
20% of the RDA
 A glass of skim milk has 10% of the RDA
 Hard water may contain up to 20 mg of
magnesium/liter
 Some bottled waters may have over 100 mg/liter
 UL is 350 mg FROM SUPPMENTS – not an issue
with food as absorption varies from food 25-60%

Magnesium Deficiency
Can develop with prolonged diarrhea, use of
diuretics or excess alcohol
 Symptoms include apathy, muscle weakness,
muscle twitching and tremor, muscle cramps
(particularly in the feet) and cardiac arrhythmias
 Lack of Mg may contribute to increased blood
pressure
 No data available on the benefit of magnesium
supplements for athletic performance.
 Excess Mg may cause nausea, vomiting, diarrhea
