Transcript 7. Major minerals

Focus on Minerals
Sodium and Potassium
Calcium and Vitamin D
Iron
Minerals: Key Concepts
About 20 are essential
Minerals are single atoms that cannot be
created or destroyed by any ordinary means
These single atoms usually carry a charge, which
makes them reactive
Minerals are components of body structures and
play key roles in the regulation of body processes
Minerals: Key Concepts
Macrominerals needed in
relatively large amounts
7 macrominerals
Sodium
RDA 2,300 milligrams
Calcium
RDA 1,000 mg for adults
under 50
Microminerals needed
in smaller amounts
9 microminerals
Iron
RDA for women
postmenopause 8 mg
Iodine
RDA 150 mcg
Mineral Charges
Charge allows minerals to combine with minerals of
opposite charge to form stable compounds
These become part of bones, teeth, cartilage, and other
tissues
In body fluids, charged minerals are a source of electrical
power to stimulate muscles to contract and nerves to
react
Charge of minerals is related to many other functions
helps maintain an adequate amount of water in the body
assists in neutralizing body fluids when too acidic or basic
minerals are components of proteins and enzymes
Charge Problems
Minerals may combine with other substances in food
and form highly stable compounds not easily
absorbed
Much of the calcium in spinach is
bound to oxalic acid
Zinc in whole-grain products is poorly absorbed
because it is bound tightly to phytate
Absorption of iron decreases by about 50% if tea or
cola is consumed
Iron binds with tannic acid in tea and colas
Hypertension
aka High Blood Pressure
How Sodium and Potassium
Affect blood pressure
Table salt is sodium
chloride, NaCl.
It is 40% sodium by
weight; one teaspoon
of salt contains about
2300 milligrams of
sodium
Sodium
Recommendation is to limit
sodium chloride to one
teaspoon a day from all
sources– and even less for
African Americans.
Sodium in the Body
Sodium and potassium work together in the
body to maintain normal water balance
Both chemically attract water, to maintain an
optimal level of water in and out of cells
Water balance and cell functions are by a
balance of sodium and potassium
Body’s adaptive mechanisms provide a buffer
against upsets in water balance due to high
sodium intake– up to a point.
Blood Pressure
Systolic blood pressure is highest
at heartbeat and diastolic is when
heart is relaxing between pulses
Normal blood pressure is less
than 120/80 mm of mercury
Prehypertension is 120/80-139/89
Hypertension is 140/90 mmHg
and higher
Several measurements are
needed
Hypertension
High blood pressure
is a leading cause of
cardiovascular
disease.
It accounts for twothirds of all strokes
and half of heart
disease.
US Rates of Hypertension
Causes of Hypertension
10% of all cases of hypertension can be
directly linked to a cause
90% with no identifiable cause: essential
hypertension
Risk factors for hypertension have been
identified
Dietary factors are the most important
Hypertension-Promoting Diet & Lifestyle
(if you wanted to develop high blood pressure)
Eat mostly processed foods high in sodium
Eat more calories than you can use
Drink alcohol beverages in excess
Eat few dairy products or sources of calcium
Eat few vegetables, fruits; avoid potassiumrich foods
Enjoy plenty of foods high in saturated fat
Avoid exercise
Ethnic Group
Epidemiological Studies
In countries with
low sodium intakes,
rate of hypertension
is low
In countries with
moderate sodium
intakes, rate of
hypertension is
moderate…
Causes of Hypertension
Not everyone is equally susceptible to highsalt diets
People often develop salt-sensitivity before
they develop hypertension.
But over 50% of people with hypertension
and 26% of people with normal blood
pressure are salt sensitive
Salt Sensitivity
Most of our
population will
develop high blood
pressure as they age
But when people
reduce salt intake,
they are likely to
maintain normal blood
pressure longer
CUTTING DOWN ON SODIUM!
1. Never pick up the salt shaker.
2. Never eat potato chips, corn chips, salted nuts, or FRENCH
FRIES!
3. Stay away from salty meats: ham, bologna, bacon,
livermush, sausage, vienna sausage, FATBACK, pork skins,
and other salty meats.
4. What meats can you eat?
Okay: fried chicken (don’t eat the skin), hamburger, beef
and fresh pork (remember—small servings, the size of a
deck of cards)
Best: turkey, chicken, fish baked or grilled or fried in oil,
not shortening. Canned tuna or salmon is good, too.
Eat fewer frozen or canned entrees or meals, and more food
fixed at home. Buy low sodium soups and vegetables with “No
Added Salt.”
Major Sources of Sodium in
US Diet
Processed foods
Fresh foods
Salt added at the table
Salt added during cooking
in the home
77%
12%
10%
3%
10 Foods responsible for over
40 % of people’s sodium intake
Breads and rolls
Luncheon meat such
as deli ham or
turkey
Pizza & cheese
Poultry
Soups
Pasta dishes with
cheese, cream or meat
sauces with salt added
Meat dishes such as
meat loaf
Snack foods like potato
chips, pretzels and
popcorn.
100 calories instant grits 500 mg
old fashioned grits
0 mg
Fig. 23-16, p. 22
Balance Sodium and Potassium
High potassium intake helps relax blood
vessels and excrete the sodium, so
decreases blood pressure.
We need more potassium than sodium
each day!
Americans average about 3,300 mg of
sodium per day
But only about 2,900 mg of potassium
High Potassium Foods Reduce
Blood Pressure (RDA 4700 mg)
TO Avoid Hypertension
Follow the DASH
diet
Even better at
reducing blood
pressure than a
low salt diet!
Simplified DASH Diet
1. Have 1 small
glass of fruit juice
and 3 more
servings of fruit
every day—
fresh, frozen or
canned.
Simplified DASH Diet
2. Eat 4 servings of
vegetables every day.
French fries don't
count!
Sweet potatoes,
broccoli, greens,
carrots, tomatoes,
tossed salad…
Simplified DASH Diet, cont.
3. Have 2 servings of
nonfat or low-fat
dairy products daily,
including yogurt.
Count soy beverage
or other high-calcium
beverages here, too.
Simplified DASH Diet, cont.
4. Limit red meat and saturated fats
Simplified DASH Diet, cont.
5. Limit sweets.
Make fruits your main
sweets and snacks.
Simplified DASH Diet, cont.
6. Use a salt substitute like "no-salt" lightly
at the table (not in cooking—it gets bitter)
NO!
Enjoy Foods Naturally Low in Sodium
Learn to use spices, peppers, onions,
garlic, and lemon juice for flavor
A low sodium diet and the DASH diet
are two separate ways to reduce
your risk of hypertension—
Or to treat it!
How Is Hypertension Treated?
Lifestyle and diet changes, and medications
Weight loss, smoking cessation, regular
exercise
DASH diet (Dietary Approaches to Treating
Hypertension)
Low sodium diet
Low alcohol consumption
Learn One of
These!
Fig. 23-17, p. 22
Blood Pressure Medications
Prescribed when diet & lifestyle changes don't
bring pressure down to normal.
Still need to follow diet and lifestyle changes
Side effects of various anti-hypertensive
medications may include:
excess urination, low blood potassium,
weakness, fatigue, depression, confusion,
erectile dysfunction, headache, edema
However, some people have no side effects
from medication.
IN THE UNITED STATES
Half the people who have hypertension
don’t know it
Half of those who know it, aren’t
getting treatment
Half of those getting treatment, aren’t
treated adequately to control BP
Many unnecessary strokes, heart
attacks, and early deaths
Farm Stand:
Good source of
Low Sodium,
High Potassium,
And Low Cost
Foods
CALCIUM AND VITAMIN D
Calcium
Calcium in the diet is absorbed with the help
of Vitamin D either in the blood or in food
99% of the 3 lbs of calcium in the body is
located in bones and teeth
1% is found in blood and other body fluids,
where it has many important roles
Calcium’s noted function is in bone
formation and osteoporosis prevention
Bones
206 bones in our body are slightly flexible living
tissues infiltrated by blood vessels, nerves, and
cells
Solid parts are networks of protein fibers
embedded with mineral crystals
Calcium is abundant in bone, along with
magnesium and other minerals
Teeth are like bone plus covering called enamel
Enamel protects teeth from acids and wear
Bone Formation
Bones develop and mineralize
throughout the first 3 decades of life
Every day, cells called osteoclasts break
bone down
Cells called osteoblasts repair damage
by forming new, healthy bone.
Called “remodeling”
Inadequate calcium Bangladesh
Treating Rickets
Building Strong Bones
Adequate calcium and vitamin D
Regular exercise, especially weight-bearing
and muscle strengthening exercise.
Adequate vitamin K, found in green, leafy
vegetables
What’s the RDA–and how to get it
Calcium
1,000 mg/day for
those age 19 to 50
1,200 mg/day for
women over 50
and men over 70
Vitamin D
Sunshine
Fortified foods
a multivitamin that
supplies 800 to
2,000 IU of vitamin
D per day
Sources of Calcium
Dairy
Milk
Fortified w/ Ca and
Vit D
Yogurt
Cheese
Cream,
icecream
Non Dairy
Soy beverages
Fortified w/ Ca and
Vit D
Tofu
Fish with bones
i.e. sardines
Dark greens
Legumes
Remodeling Bones
During remodeling, old protein matrix is
replaced and remineralized
Total bone replacement every 10 years
Up to about age 30, osteoblasts build more
bone than is lost
Peak bone density reached by age 30
Bone Remodeling
After that, bone mineral content no longer
increases
The higher the peak bone mass, the less
likely it is that osteoporosis will develop
After age 50, blood levels of estrogen and
testosterone decrease
Bones demineralize as osteoclasts
“outperform” osteoblasts
Insufficient calcium is one cause of …
Osteoporosis
Over 20 million
adults in the United
States have
osteoporosis
About half of all
women and about
one third of men will
have an osteoporotic
fracture during their
lives
Osteoporosis
1.5 million suffer
broken bones each
year due to the
disease
300,000 hip
fractures/year with a
20% death rate
within one year
Many permanent
disabilities
Causes of Osteoporosis
Related to genetics, race, sex, diet,
exercise, childbearing
Develops later in
Men
African Americans
Women who have had several children
Typically, by the time a woman is 70 her
bones are 30 to 40% less dense
Early Osteoporosis
Who’s at most risk?
Asians and Caucasians
Women, especially
childless
Small-boned, thin
people
Smokers
Sedentary people
And, of course, those
with poor diet
Build and Maintain Bones
Vitamin D increases calcium absorption and
the deposition of calcium into bone
Few foods naturally have Vitamin D
Supplements, fortified foods, or sunshine
can provide Vitamin D
In much of the world, exposing hands and
face to sunshine for 15 to 30 minutes
produces a day’s supply of vitamin D
Build and Maintain Bones
After age 50, preserving bone density
requires adequate calcium and vitamin D
Regular exercise, especially weight-bearing
and muscle strengthening exercise.
Adequate vitamin K (source: dark greens)
RDA for women is 90 mcg
Data from Nurses’ Health Study suggests that
over 110 mcg is better for bone health
Prevent Osteoporosis
Avoid excessive preformed vitamin A
Retinol
May increase number of osteoclasts
Caffeine may increase calcium loss in urine
Phosphoric acid (in cola) may increase
calcium loss also
High protein diet may increase calcium loss
Osteoporosis Treatment
Calcium supplements or intakes to 10001500 milligrams per day
Vitamin D supplements (1000 IU or more)
Other medications (phosphomax, etc)
Weight-bearing exercise (walking, tennis)
stimulates bone growth and decreases
progression of osteoporosis
Where do You get your Calcium?
To meet recommended
level of intake choose 2
or 3 foods rich in
calcium every day
Calcium absorption
decreases with age
and Vitamin D
inadequacy
Too Much Calcium
You can consume too much calcium
Supplement doses exceeding 2.5
grams (2500 mg) per day produce
drowsiness, constipation, and cause
calcium to deposit in tissues
New Vitamin D Research
Bone and Muscle
Strength
Heart Disease
Cancer
Immune Function
Multiple Sclerosis
Type 1 Diabetes
Flu and Colds
Risk of Premature
Death
Read more at
www.hsph.harvard.
edu/nutritionsource/
vitamin-d/
IRON BASICS
Charge Problems
Minerals may combine with other substances in food
and form highly stable compounds not easily
absorbed
Much of the calcium in spinach is bound to oxalic acid
Zinc in whole-grain products is poorly absorbed
because it is bound tightly to phytate
Absorption of iron decreases by
about 50% if tea or cola is consumed
Iron binds with tannic acid in tea
and colas
Iron
Most iron is found in hemoglobin
Hundreds of hemoglobin molecules
are in each red blood cell
Blood cells are made in bone marrow
Small amounts of iron are present in
myoglobin in other cells
Iron in Hemoglobin
Iron readily combines with oxygen
Iron in hemoglobin attaches to oxygen in the
lungs
Hemoglobin releases oxygen from iron to cells
Free iron picks up carbon dioxide from cells
Blood returns to lungs, carbon dioxide is released
Free iron combines with oxygen
The cycle continues
Hemoglobin Structure
Four polypeptide
strands
Each has a
Heme ring, in red,
which contains the
iron.
Oxygen is bound
and then released
by the iron
Iron in Myoglobin
Iron in myoglobin traps oxygen, stores
it, and releases it as needed for energy
for muscle activity
Myoglobin boosts oxygen available to
muscles
These functions require supply of iron
that is sufficient
Iron Deficiency
1/3 of people in world are iron deficient
Iron deficiency affects mostly children and
women with high need and low
consumption
In Developing Countries
Half of pregnant woman are estimated to
be anemic.
Anemia contributes to 20% of all maternal
deaths.
About 40% of preschool children are
estimated to be anemic.
Iron Deficiency
Develops in people
who have lost blood,
including women
with heavy menses
(slow bleeding to
death)
Can develop with
chronic use of
antacids, which can
impair iron
absorption
Consequences
People with iron deficiency
are weak and tired
have short attention span
have poor appetite
are susceptible to infection
become irritable easily
Iron-deficiency anemia
Develops with additional symptoms
People with iron-deficiency anemia
look pale
are easily exhausted
have rapid heart rates
Iron-deficiency anemia in infants and young
children is related to lasting retardation in
mental development
Getting Enough Iron
Sources of iron:
heme in meat, iron in plant foods
Iron in fortified foods and supplements
Foods cooked in iron and steel pans
Enough iron is 8 milligrams for men and
postmenopausal women
18 milligrams per day for women under 50
Women have to consume about 2500 calories
per day of good foods to obtain 15 milligrams
of iron
Treating Deficiency
Supplements
Ferrous sulfate (Feosol,
Slow Fe)
Ferrous gluconate
(Fergon)
Ferrous fumarate
(Femiron, Feostat)
Preventing Deficiency
maybe with a lucky fish
Read about the
www.luckyironfish.com/
Getting Enough Iron
Most iron in plants and eggs tightly bound
A three-ounce hamburger and a cup of asparagus
both contain three milligrams of iron
20 times more iron is absorbed from hamburger than
from the asparagus
Transferrin in intestinal mucosa regulates iron
absorption increased by low levels of iron stores;
when iron stores high, less iron absorbed
Such regulation of iron absorption provides some
protection against iron deficiency and overdose
Cross-section of Digestive Tract
Overdosing on Iron
Excess iron absorbed into the body cannot be
easily excreted
Iron is deposited in the liver, pancreas, and
heart
Iron excess results in liver disease, diabetes,
and heart failure
People at risk of iron toxicity:
Heavy drinkers (increased absorption of iron)
Very high iron intake or one time overdose
Genetic disorder
Hereditary Hemochromatosis
Most common genetic disease in whites
Nonspecific early symptoms:
Fatigue
Weight loss
Abdominal pain
Weakness
Joint Pain
As Iron Accumulates:
Arthritis
Diabetes
Grey or bronze tone to skin
Cirrhosis of the liver Liver cancer
Heart failure
Frequency & Treatment
North & western European ancestry:
0.5% homozygous, 10% carriers
Mexican Americans .03% homozygous
African Americans .06%
Occurrence of symptoms
Earlier for men than women
Detection & Prevention
Treatment: Phlebotomy
Overdosing on Iron Supplements
Can cause rapid tissue damage, seizures,
coma & heart failure
Victims often young children
Lethal dose of iron for a two-year-old child
is about three grams, amount in 25 120
mgm pills
40 children’s multivitamins with iron could
seriously injure a child
Iron Overdoses, 1990's
In 1991, 10 children died from iron
overdoses.
Government required warning labels and
childproof bottles
1998 2500 children under 6 overdosed on
iron, 730 required treatment, 0 deaths
Between 1999-2002, only one child death
Childproof containers and careful parents
protect children