Nutrition Mt 2 Trace Minerals

Front 1

Where do we find iron in the body?

Back 1

most of the iron in the body is a component of either hemoglobin (oxygen carrying protein of RBCs) or myoglobin (oxygen holding protein of muscles)

Front 2

Additional roles of iron

Back 2

*important roles in immune and brain function
-helps many enzymes use oxygen
-needed to make: new cells, amino acids, hormones, neurotransmitters

Front 3

DRI recommendations:

Back 3

DRI:
men = 8 mg
women = 18 mg
women over 51 = 8 mg
pregnant women = 27mg

UL = 40 mg for children, 45 mg for adults

Front 4

Why do vegetarians need a higher intake of iron? what is the recommendation?

Back 4

Because iron from plant sources is less efficiently absorbed than that from animal sources, the RDA for iron from a completely vegetarian diet should be adjusted

-14 mg/day for adult men and postmenopausal women
-33 mg/day for premenopausal women

Front 5

Two forms of iron in food:

Back 5

Ferrous Iron (heme): More readily absorbed and is present only in animal sources. 


Ferric Iron (non-heme): From plants, not as easily absorbed. Increase absorption with Ascorbic acid (vitamin C). Converts the ferrous form in the food to ferric form.

Front 6

How is iron absorption maximized?
How is iron absorption inhibited?

Back 6

It is maximized by:
1. MFP (meat, fish, poultry) factor
2. Vitamin C
3. Presence of iron deficiency

Inhibited by:
1. fibers, phytates (whole grains cereals, nuts)
2. Tanins (tea, coffee, nuts)
3. Calcium and phosphorus (milk)
4. Food additive (EDTA)

Front 7

Iron Absorption:

Back 7

*only about 10-15% of iron is absorbed

The absorption reflects the amount of transport proteins produced in the intestine to absorb the iron...

This increases with diminished blood supply of iron and with need (eg. pregnancy)

Decreases absorption when iron is abundant (As body iron supply increases, and an optimal level is reached, the genes slow their production of these proteins)

Front 8

How do we lose iron on a day to day basis?

How do we recycle iron?

Back 8

Lost by:
1. nail clippings
2. hair cuttings
3. shed skin cells
4. feces, urine
5. menstrual blood

Recycled by:
when RBCs die, the liver and spleen break them down and recycle their iron.

Front 9

How have we reduced iron deficiency in toddlers, adolescent girls, and women of child-bearing age?

Back 9

it has improved due to:
-increased breast feeding which promotes iron absorption
-greater use of iron-fortified infant formula
-increased use of iron-fortified cereals

Front 10

what is the most common nutrient deficiency worldwide?

Back 10

iron deficiency.. it affect 1.2 billion people (almost half of preschool children and pregnant women suffer iron deficiency)

Front 11

Symptoms of iron deficiency:

Back 11

1. anemia
2. weakness
3. increased infection
4. decreased concentration
5. impaired intelligence
6. increased heart rate

Front 12

Causes of iron deficiency:

Back 12

1. overconsumption of foods rich in sugar and fat and poor in other nutrients
2. Within the digestive tract, ulcers, sores, and inflammation can cause sufficient blood loss to cause anemia
3. In developing countries: parasitic infections of the digestive tract cause people to lose blood daily

Front 13

Iron deficiency anemia:

Back 13

Anemia refers to depletion of iron stores resulting in low blood hemoglobin

Cells contain too little hemoglobin and thus deliver too little oxygen → limits cell’s energy metabolism → tiredness, apathy, a tendency to feel cold

blood cells will be pale and small

Front 14

can a person be iron deficient without being anemic?

Back 14

Yes, Even slightly lowered iron levels cause fatigue and can impair physical work capacity and productivity

Front 15

How can a person get iron-deficient anemia but still have an adequate dietary intake if iron?

Back 15

Most often this is due to blood loss (80% of iron is in blood)

Front 16

Benefits and risks of iron supplements:

Back 16

benefits: it can reverse iron-deficient anemia

risks: can create oxidative reaction in the digestive tract that may damage its linings

Front 17

Toxicity of iron:

Back 17

Iron supplements are a leading cause of fatal accidental poisonings among U.S. children under 6 years old

Once absorbed it is difficult to excrete

Iron supplements should only be taken when recommended by a physician

Excess Fe Could Have a Potential Role in Increasing the Risk of Developing Alzheimer’s Disease, Cancer and Heart Disease

Front 18

How does our body protect is from iron overload (hemochromatosis)? (2 ways)

Back 18

1. Intestinal cells trap some of the iron and hold it within their boundaries; when these cells are shed the excess iron they collected is lost from the body

2. When iron stores fill up, less iron is absorbed

Front 19

Hereditary iron overload:

Back 19

In hereditary iron overload, the intestine continues to absorb iron at a high rate despite the excess iron building up in the body tissues

Early symptoms are general and vague: fatigue, mental depression, abdominal pains

Later, tissue damage occurs, with liver failure, abnormal heart beats, diabetes

Infections are likely because bacteria thrive on iron-rich blood

Front 20

Iron requirement for athletes and "sports anemia"

Back 20

The average requirement for iron may be 30 – 70 % higher for those who engage in regular intense exercise

"Sports Anemia" = Transient decrease in serum iron and hemoglobin at the initiation of training due to hemodilution subsequent to an increase in plasma volume (cannot be resolved by increasing intake)

Front 21

4 reasons why athletes can have inadequate iron intake:

Back 21

1. inadequate energy intake (major one)
2. increased iron loss in the sweat, urine, feces, menstrual blood
3. microscopic bleeding from the gastrointestinal tract or increased fragility of red blood cells
4. intravascular hemolysis, foot-strike hemolysis,

Front 22

Role of Zinc:

Back 22

*ON EXAM JUST NEED TO KNOW ZINC HAS MANY FUNCTIONS.. WON'T ASK FOR WHAT THEY ARE
1. works with proteins in every body organ
2. helps enzymes to:
-make part of the cells genetic material
-make heme in hemoglobin
-assist the pancreas with its digestive functions
-Help metabolize carbohydrate, protein, and fat
-Liberate vitamin A from storage in the liver
3. Regulation of gene expression in protein synthesis
4. Affects behavior and learning
5. Assists in immune function
6. Wound healing
7. Reproduction
8. Growth and development in children
9. Keeps sense of taste and smell sharp
10. Produces the active form of vitamin A in visual pigments
11. protective role in oxidative damage?

Front 23

Zinc Recommendations:

Back 23

DRI:
men: 11 mg/day
women: 8 mg/day

Vegetarians are advised to eat a varied diet that includes whole-grain breads well leavened with yeast (leavening helps make the zinc available for absorption)

Front 24

Major food sources of zinc:

Back 24

Major:
1. Meats
2. Shellfish
3. Poultry

Less readily absorbed plant sources:
1. some legumes
2. whole grains

Front 25

Why were there problems in the Middle East with too little zinc?

Back 25

Adolescent boys were not growing in the Middle East:
1. Native diets were low in animal protein and high in whole grains and beans
2. Thus, diets were high in fiber and phytates (which bind zinc and iron)
3. The breads were not leavened (In leavened bread, yeast breaks down phytates as the bread rises)

Front 26

Zinc deficiency symptoms:

Back 26

1. Profoundly alters digestive function
2. Diarrhea (which leads to even further malnutrition)
3. Infections of the intestinal tract worsen malnutrition
4. drastically impairs the immune response
5. Adverse effects on growth

Front 27

How come zinc deficiency symptoms are accompanied by vitamin deficiency symptoms?

Back 27

Normal vitamin metabolism depends on zinc

Front 28

Zinc and thyroid function:

Back 28

zinc deficiency disturbs thyroid function: slowing body's energy metabolism (causing reduced appetite and wound healing)

Front 29

People at risk for zinc deficiencies:

Back 29

1. pregenant woman
2. young children
3. elderly
4. poor

Front 30

Problem with too much zinc:

Back 30

In high enough doses, supplements can cause serious illness or death

Excess Intake Causes Copper and Iron Deficiency and Oxidative Stress

Over time, regular doses a few milligrams above the recommended intake can block copper absorption and lower the body’s copper content (leads to degeneration of heart muscle)

May reduce blood concentrations of HDLs

Front 31

Role of Iodine and RDA:

Back 31

Component of thyroxine (Manufactured by the thyroid gland that is responsible for the regulation of basal metabolic rate)

RDA = 150 ug/day

Front 32

Sources of Iodine:

Back 32

1. seafood
2. iodized table salt (sea salt has little iodide b/c it flies off in the salt-drying process)
3. Milk
4. Bakery products (Baking industry use of iodine-containing dough conditioners)
5. Plants and animals (Amount food varies with the soil in which plants are grown or on which animals graze)

Front 33

Iodine Deficiency (and symptoms):

Back 33

Enlarged Thyroid Gland (Goiter)
Effects 200 million people worldwide

Symptoms: Sluggishness, Weight Gain, Severe Birth Defects, Impaired Intelligence in Children (cretinism)

Front 34

Cretinism:

Back 34

Extreme irreversible mental and physical retardation from iodine deficiency

Can be averted if the woman’s deficiency can be detected and treated within the first six months of pregnancy

(Iodine deficiency is one of the most treatable and preventable causes of mental retardation)

Front 35

Iodine Toxicity:

Back 35

Also forms a goiter..

Like chlorine and fluorine, deadly poison in large amounts

Front 36

Iodine and radioactivity:

Back 36

Radioactive iodine (131I) may be released into the environment as a result of nuclear reactor accidents. This increases the risk of thyroid cancer..

Potassium iodide administered in large doses (50-100 mg for adults) within 48 hours before or 8 hours after radiation exposure reduce thyroid uptake of radioactive iodine and decrease the risk of radiation-induced thyroid cancer

Front 37

Role of Selenium

Back 37

1. Protects vulnerable body chemicals against oxidative destruction
-Assists a group of enzymes that, with vitamin E, work to prevent the formation of free radicals and prevent oxidative harm to cells and tissues

2. Plays roles in activating thyroid hormone

3. Detoxifies Toxic Metals (Lead, Mercury) and Other Toxins

Front 38

Selenium and Cancer:

Back 38

Low blood selenium correlates with the development of some forms of cancer.

Men with adequate selenium in their blood have a lower incidence of prostate cancer than men whose blood measures are low

however: supplements may slightly increase the risk of a form of skin cancer

Front 39

Good sources of selenium/ RDA for selenium:

Back 39

Fish, organ meats and grains are excellent sources of selenium

RDA: 55 ug/day

Front 40

Deficiency and Excess Selenium:

Back 40

Deficiency: possible heart disease?

Excess: Causes Hair Loss and Brittle Nails

Front 41

Role of fluoride:

Back 41

It is not essential but...

Help to form decay-resistant crystals (fluorapatite)

Suppresses bacterial metabolism and reduces the amount of acid they produce

Promotes remineralization of early lesions in the enamel in erupted teeth

Front 42

Recommendations for fluoride:

Back 42

3 mg/day females >18years
4 mg/day males > 18 years

Front 43

Where do we find fluoride:

Back 43

mostly in our water

Fish and Teas Are a Significant Source

Front 44

Excessive intake of fluoride leads to..

Back 44

fluorosis (Permanent White or Brown Discoloration of Teeth)

Front 45

Fluoride Deficiency

Back 45

Where fluoride is missing, the incidence of dental decay is very high