Download The Vitamins

The Vitamins
Introduction
 Vitamins
were discovered at the beginning
of the twentieth century.
 Vitamin: An essential, noncaloric, organic
nutrient needed in tiny amounts in the diet.
A
vitamin can cure a deficiency of that
vitamin
Classifying Vitamins
 Fat




A
D
E
K
Soluble Vitamins
Water Soluble Vitamins
 Vitamin
C
 B Vitamins:






Thiamin
-- Biotin
Riboflavin
-- Pantothenic acid
Niacin
B6
Folate (folic acid)
B12
Water Soluble Vitamins
 Digestion,


Absorption, and Transport
No chemical digestion needed
Absorbed in the SI into the capillaries
• Vitamin B12 must bind with a protein called the
intrinsic factor (IF) in the stomach for absorption to
occur in the SI

No carriers required for transport in the blood
Water Soluble Vitamins
 Storage


and excretion
Travel freely in the blood
Cells take up water soluble vitamins as
needed
• Limited storage beyond tissue saturation

Excess excreted in the urine
Water Soluble Vitamins
 Deficiency
is more common than toxicity
for the water soluble vitamins

Any toxicity is likely to be due to overuse of
vitamin supplements, not food intake
Water Soluble Vitamins
 Other



interesting information:
Many are destroyed by light, heat, or
exposure to oxygen
Best to cook whole in a minimum amount of
water
Frozen vegetables are often higher in vitamin
content than grocery store “fresh” veggies
•
The Fat-Soluble Vitamins

A, D, E, K






Found in fats and oils of foods
Require bile for absorption
Stored in liver and fatty tissues until needed
Not needed in the diet daily
Can reach toxic levels if too much is consumed
Deficiencies can occur when people eat diets
that are extraordinarily low in fat
Fat Soluble Vitamins
 Digestion,





Absorption, and Transport
Bile needed to emulsify fat soluble vitamins
Form chylomicrons (along with long chain
fatty acids and monoglycerides)
Chylomicrons are absorbed into the lacteals
Travel through lymph system  blood  liver
Many require protein carriers to be
transported in the blood
Fat Soluble Vitamins
 Other


interesting facts:
Found in the fatty parts of food
Removed with the fat when low-fat products
are made
• Many low-fat foods are supplemented with these
vitamins to make up for this


E.g. milk is vitamin A and D enriched
Other interesting vitamin cooking/storing facts – page 293
The Vitamins
 For




each vitamin we will consider:
Functions
Dietary needs and food sources
Deficiency
Toxicity
The B- Vitamins: An Introduction
 Thiamin,
riboflavin, niacin, pantothenic acid,
and biotin – participate in the release of
energy from the energy nutrients
 Folate and vitamin B12 help cells multiply
 Vitamin B6 helps the body use amino acids
to synthesize proteins
B Vitamin Deficiencies
In
a B vitamin deficiency, every cell is affected.

Symptoms include
•
•
•
•
•
•
•
Nausea
Severe exhaustion
Irritability
Depression
Forgetfulness
Loss of appetite and weight
Impairment of immune response
•
•
•
•
•
Abnormal heart action
Skin problems
Swollen red tongue
Teary, red eyes
Pain in muscles
Thiamin
History
Functions:
1.
Needed for energy metabolism
•
2.
E.g. -- required for conversion of pyruvate to
acetyl CoA
Needed for nerve and muscle function
Thiamin
Recommended Intake

1.1-1.2 mg/day
Food Sources




Found in small amounts in many foods
Easily destroyed by heat (cooking)
Lost in cooking water
Good sources include
• Pork products, soy, legumes, vegetables, whole
grains, watermelon…. Page 311
Thiamin Deficiency
Prolonged deficiency leads to beriberi


Results in damage to nervous system and
muscles (to include the heart)
Thiamin Deficiency

Symptoms Beriberi:
1. Dry form- muscle wasting, poor coordination
Muscle weakness
2. Legs heavy, hard to walk, calf pain
3. Apathy, confusion, memory loss
4. Anorexia and weight loss
5. Wet form has additional symptoms of:
–
edema, irregular heart beat, enlarged heart
Thiamin Deficiency
Thiamin Deficiency
 Populations

at risk:
Alcoholics
• Often obtain the majority of their calories from
alcohol
• Alcohol inhibits thiamin absorption and hastens its
excretion


Cultures that eat primarily refined grains (e.g.
white rice) and little else
Thiamin deficient moms  infant deaths from
deficiency
 In
alcoholics thiamin deficiency results in
Wernicke-Korsakoff syndrome.


Even if someone who drinks alcohol heavily follows a wellbalanced diet, most of the thiamine is not absorbed.
Symtpoms
• Mental confusion
• Staggering
• Rapid eye movements or paralysis of the eye
muscles

The City of New York
 DEPARTMENT OF HEALTH AND MENTAL HYGIENE

Michael R. Bloomberg
Thomas R. Frieden, m.d., m.p.h.

Mayor Commissioner

_______________________________________________________________

nyc.gov/health






2003 Health Alert # 39:
A cluster of infantile thiamine (vitamin B1) deficiency (beri-beri) has
been reported in Israel among infants fed a vitamin B1-deficient
kosher soy-based formula distributed by Remedia. It is possible
that this product may be imported into New York City and there
may be children in the Orthodox Jewish community who have
consumed it.
The New York City Department of Health and Mental Hygiene
(NYCDOHMH) asks that providers report immediately any suspect
case of thiamine deficiency among infants who have been fed this
product to:
The New York City Poison Control Center at:
1-212-764-7667 (212-POISONS) or 1-800-222-1222.
Please distribute to Pediatric staff in the Departments of
Cardiology, Critical Care, Emergency Medicine, Family Medicine,
General Pediatrics, Outpatient Pediatrics, Neonatology, Neurology,
and Infectious Disease
Thiamin
 Toxicity


None known
Excess thiamin is excreted and not stored
Riboflavin
Functions:
1.
Needed for the metabolism of
carbohydrates, fats, and proteins
•
•
2.
Places a role in Kreb’s cycle
Part of FAD
This text includes an antioxidant function as
well….most do not consider riboflavin an
anti-oxidant
Riboflavin
Recommended Intake:

1.1 – 1.3 mg/day
Food Sources:


Destroyed by ultraviolet light (sun light)
Good sources include (page 313)
•
•
•
•
•
Whole grain breads and cereals, oatmeal
Liver
Milk and milk products
Clams and squid!
Mushrooms
Riboflavin
Deficiency Symptoms
1.
2.
3.
4.
5.
6.
Eyes are inflamed and sensitive to light
Cheliosis (cracks at the corners of the mouth)
Sore throat
Inflammation of the tongue and mouth –
painful
Inflamed skin, with lesions covered with
greasy scales
Anemia
page 312
Riboflavin
Populations at Risk for Deficiency


alcoholics
any one with a marginal diet
• Poor, elderly, eating disorders, drug addicts…
Toxicity


None reported
Excess excreted
Niacin
Functions
1.
Plays an essential role in energy metabolism
•
•
Part of NAD
Needed by every cell of the body
Niacin
Recommended Intake:


14 – 16 mg/day of niacin or of NE
NE = Niacin Equivalents
• Niacin can be made from the essential amino acid
tryptophan
• It takes 60 mg of tryptophan to make 1 mg of
niacin
• Therefore, 1 NE is 60 mg of tryptophan
Niacin
Food Sources (page 315):

Sources of complete protein
• Dairy, meats, poultry, fish,…



Peanut butter
Tomato paste
Mushrooms
Niacin Deficiency
Niacin deficiency disease is called pellagra
Symptoms, 4 D’s:
1.
2.
3.
4.
Dermatitis especially with sun exposure
Diarrhea, vomiting
Dementia
Death
Other symptoms:
1. Inflamed, swollen, red, smooth tongue
2. Loss of appetite
3. Page 314
Niacin
 Pellagra




symptoms: 4 “D’s”
Diarrhea
Dermatitis
Dementia
Death
Niacin
 Pellegra


- Other interesting information
Originally believed to be caused by infection
Common up to early 1900’s in US and Europe
• Many in mental hospitals in south had niacin
deficiency, not mental illness


Incidence declined in US after WW II when mandatory
enrichment of grains began
Still common in Africa and Asia
• Poor bioavailability form corn unless it’s soaked in
lime juice
Niacin
Toxicity


Tolerable Upper Intake Level (UL) = 35
mg/day
High doses of niacin are commonly used to
treat high cholesterol
• 1500 -3000 mg/day recommended for treating high
cholesterol
Niacin
Toxicity Symptoms
1.
2.
3.
4.
5.
Niacin flush
Excessive sweating
Tingling
GI distress
Frequent need to urinate
•
6.
7.
May mask prostrate cancer symptoms in men
Blurred vision, headaches
Liver damage
Folic Acid = Folate
Functions:
1.
Needed for DNA synthesis
•
•
2.
Need to make all new cells
E.g. Need to make new RBC
Reduces incidence of neural tube defects
•
Defects occur in first weeks of pregnancy
Folate
3.
4.
Plays a role in protein synthesis
Breaks down the amino acid homocysteine
– High levels of homocysteine increases risk of
blood clot formation
5.
May reduce risk some cancers
– Pancreatic cancer in men who smoke
– Breast cancer in women who drink
Folate
 Absorption


and Activation
Folate in foods must be acted upon by an
intestinal enzyme for it to be absorbed and
transported to cells
Folate in cells needs to be activated by
vitamin B12
• Process also activates the B12
Folate
 Recommended
intake: 400 mcg/day
 Factors impacting needs




Pregnancy -600 mcg/day
Aspirin, antacids, smoking, oral
contraceptives reduce absorption
Some cancer drugs reduce absorption
GI tract damage reduces absorption
• Occurs with alcoholism, anorexia
• Poor absorption, leads to even more damage to GI
tract
Folate
 Food



Sources
Cooking destroys up to 50% of folate
Oxygen destroys folate
Good sources include (page 323):
•
•
•
•
•
•
Green leafy vegetables
Asparagus
Legumes
Fortified cereals and Seeds
Liver
Orange juice (ok, but not great source)
Folate
Folate Deficiency (page 321)
 Impairs cell division and protein
synthesis
 Symptoms:
1. Megaloblastic anemia

Fewer red blood cells (RBC) made

RBC larger than normal

RBC do not carry oxygen as well
Folate Deficiency
2.
Confusion, irritability, weakness, fatigue
•
3.
4.
5.
6.
Related to the anemia
GI tract deterioration
Elevated homocysteine levels
Smooth red tongue
Increased risk neural tube defects
Folate
 Toxicity


No known symptoms
May mask a vitamin B12 deficiency
• B12 deficiency is VERY serious
Vitamin B12
 Dorothy

Crowfoot Hodgkin
Awarded the Nobel prize in chemistry for
deducing the structure of vitamin B12
• Took her eight years

Headline in the London paper announcing this
read
“Nobel Prize for British Wife”
Vitamin B12
Functions:

Needed to activate folate
• Therefore, needed for DNA and new cell (RBC)
synthesis

Helps maintain myelin sheath around nerve
cells
Vitamin B12
Recommended intake:

2.4 microgams per day
Food Sources*:

ONLY found naturally in animal products
• Meat, poultry, fish, eggs, dairy, liver….

Fortified grains
*Easily destroyed by microwave cooking
Vitamin B12
Deficiency:

Pernicious anemia (VERY SERIOUS)
•
•
•
•
Megaloblastic anemia
Nerve damage  creeping paralysis
Smooth sore tongue
Fatigue
Vitamin B12
Vitamin B12
 Pernicious
anemia frequently goes
undiagnosed
 Pernicious anemia can be masked by high
intakes of folate

Generally as supplements
B-12 and Folate
 Presence
of immature red blood cells symptom of folate or vitamin B12
deficiency
 Extra folate corrects this blood condition

B12 deficiency continues
B12’s other functions then become
compromised
 Vitamin
Vitamin B12
 Gastric
by-pass patients and vegans are
at elevated risk

Takes several years to develop
 Toxicity:

None reported
B6
Functions:


Need for protein and fatty acid metabolism
Need for amino acid metabolism
• E.g. For converting tryptophan to other niacin
• need to make serotonin form tryptophan


Helps make RBC
Other functions under study
B6
Recommended Intake:


1.3 mg/day
UL: 100 mg/day
Food sources (page 318): destroyed by heat





Meat, fish, poultry
Legumes
Seeds and nuts
Liver
Non-citrus fruits
B6
Deficiency: (rare)




Anemia  Weakness and fatigue
Depression, confusion
Abnormal brain waves, convulsions
Greasy dermatitis
B6
Increased risk of deficiency:

Alcoholics
• Alcohol contributes to increased B6 breakdown
and excretion
Oral contraceptives may increase risk of B6
deficiency
Drug INH inactivates B6

INH used to treat tuberculosis
B6
Toxicity: Serious


Stored in muscle cells, toxicity seen with
supplements
Symptoms:
• Irreversible nerve damage  numbness in hands
and feet  Difficult to walk
• Convulsions
• Insomnia, restlessness
B6
 B6



does not help with:
Carpal tunnel syndrome
PMS
Supplementation above the UL is NOT
recommended
Biotin
Functions:



Need for energy metabolism
Need to make glycogen
Plays a role in fatty acid and amino acid
synthesis
Biotin
Recommended Intake:

30 micrograms/day (AI)
Food Sources*:


Widespread in foods: liver, egg yolk,
legumes, fish, mushrooms, whole grains…
Some produced by GI tract bacteria
*easily destroyed by processing
Biotin
Deficiency:

RARE
•
•
•
•
•
Skin rash
Hair loss
Depression
Hallucinations
Numbness in legs/arms
Biotin
 Deficiency
can be induced by eating
LARGE quantities of raw egg whites


2 dozen daily for ~2 months!
Prevents biotin absorption
 Toxicity:
none reported
Pantothenic Acid
Functions:

Need for energy metabolism
• Part of acetyl CoA

Plays a role in the synthesis of many
substances:
•
•
•
•
Lipids
Hormones
Neurotransmitters
Hemoglobin
Pantothenic Acid
Recommended intake:

5 mg/day (AI)
Food Sources:

Widespread in foods
Pantothenic Acid
Deficiency: Rare





Fatigue
GI distress
Insomnia, depression
Apathy, irritable
Increased sensitivity to insulin
 Toxicity:
none known
Vitamin C
Functions:

Collagen synthesis
• Part of scar tissue
• Strengthens blood vessels
• Provides matrix for bone growth



Antioxidant
Need for healthy immune system
Need for thyroxine production
Vitamin C
Functions:

Need for thyroxine production
• Regulates body temperature and metabolic rate


Enhances iron absorption
Need to make hemoglobin
Vitamin C
Recommended intake:



Men: 90 mg/day
Women: 75 mg/day
Smokers: an extra 35 mg/day
• More free radicals that need to be “neutralized”

UL: 2000 mg/day
Vitamin C
Food sources* (page 329):



Citrus fruits
Strawberries, melon
Vegetables
• Tomatoes, dark green leafy vegetables, potatoes,
broccoli…
*Heat and oxygen sensitive
Vitamin C
Deficiency:  Scurvy








Poor wound healing
- Increased infection
Weakness
Bleeding gums
Loose teeth
Broken blood vessels
Loss of appetite
Joint pain and fragile bones
Anemia
Deficiency Symptoms
Vitamin C
Populations at increased risk:





Alcoholics
Elderly
Babies and toddlers fed only milk/cereals
Smokers
After illness or stress
• Fever and stress deplete vitamin C stores
Vitamin C
Toxicity Symptoms:






Diarrhea
Cramps, nausea
Headaches, insomnia
May interfere with lab tests and meds
Increased risk kidney stones
Over-absorption of iron
Fat Soluble Vitamins
A
D
E
K
Vitamin A
Chemical nature:

Active forms of vitamin A
• Retinol
• Retinoic acid
• Retinal

Precursor form
• Beta-carotene
• Converted to active vitamin A as needed
 Vitamin
A plays a role in
• Gene expression
• Vision
• Maintenance of body linings and skin

Need to build healthy epithelial and mucous tissue
• Immune defenses
• Growth of bones and of the body
• Normal development of cells

Plays a role in cell differentiation
• Reproduction
Vitamin A - Functions
 Vitamin


A plays two roles in eye sight:
Process of light perception at the retina
Maintenance of a healthy cornea
Beta-Carotene
Functions beta-carotene;


Can be converted to active vitamin A as
needed
Antioxidant
Vitamin A
Recommended intake:


700-900 RAE micrograms/day
RAE = retinol activity equivalents
• Older unit is IU = International Units

UL 3000 RAE
• UL refers to active vitamin A only, not betacarotene
Vitamin A
Food Sources pre-formed Vitamin A:

All animal sources
•
•
•
•
•
In fatty portion of the food
Dairy products
Eggs
Meat, liver
Fortified skim milk and margarine
• Page 296
Beta-Carotene
Food Sources beta-carotene:


All plant sources
Yellow/orange/red fruits and vegetables
• Carrots, apricots, cantaloupe, mangos, pumpkin,
sweet potato, winter squash, peppers……

Dark green leafy vegetables
• Spinach, kale, broccoli, beet greens (but not the
beet!)
Vitamin A
Deficiency Symptoms – eye sight related


Night blindness
Blindness
• Leading cause of blindness worldwide
• ~ ½ million children go blind each year due to a
vitamin A deficiency
Eyesight
Vitamin A
Deficiency:


Keratinization  dry, cracked skin
Reduced secretions
• GI tract
• Bladder
• Lungs

Above symptoms increase risk of infection
Skin And Body Linings
 The
skin in vitamin A deficiency
Vitamin A
Deficiency:





Anemia
Slow bone growth
Painful joints
Cracked, cracked teeth
Delayed sexual maturity
Vitamin A
Toxicity:

Teratogenic
• “monster producing”


GI distress, weight loss
Bone issues
• Joint pain
• Stunted bone growth and more
Vitamin A
Toxicity:






Headaches, pressure inside skull
Blurred vision
Fatigue, muscle weakness
Skin rashes
Dry, cracked, bleeding lips
Dry, brittle hair
Vitamin A
 Vitamin
A toxicity can be fatal
 Symptoms go away quickly if diet changes
 Toxicity is never from beta-carotene
sources

Beta-carotene toxicity…..
Vitamin D
Chemical nature:


Vitamin D is a sterol
Body can make from cholesterol – see page
299
• Requires sunlight exposure, action of skin, liver,
and kidney
Vitamin D
Functions:

Bone mineralization
• Works with other nutrients



Vitamins A, C. K
Several minerals
Regulates calcium and phosphorus levels
• Stimulates Ca and P absorption in SI
• Regulates movement of Ca and P in/out of bones
• Stimulates kidneys to retain Ca and P

All of the above are related to bone mineralization
Vitamin D
Other Functions:

Acts as a hormone
• Not fully understood
• Many target organs:
 Brain and CNS
 Muscle
 Reproductive cells…
Vitamin D
Recommended intake:

Depends upon sun exposure and skin color
5-10 micrograms/day (AI)

UL: 50 mcg/day

Vitamin D
Food sources* (page 301):





Fortified milk and margarine
Butter
Egg yolks
Liver
Fatty fish and fish oils
*natural sources are all animal sources
Vitamin D
Deficiency:

Bone abnormalities
• Kids  rickets
• Adults  osteomalcia
Vitamin D
Populations at risk for deficiency:







Inner-city kids
Dark skinned
Live in a northern climate
Limited sun exposure
Elderly
Kidney or liver disease
Vegans
Vitamin D
Toxicity:

Very toxic
• Can be lethal
• Milk story

Toxicity is never from sun exposure
Vitamin D Toxicity
 Symptoms:

Calcium deposits in soft tissue
• Muscles, lungs, heart





Kidney stones
Calcium deposits on walls of arteries
Joint pain
Frequent urination
GI distress
Vitamin E
Chemical nature:


A type of tocopherol
4 forms
• Alpha, beta, gamma, delta
• Alpha-tocopherol is the most active form
• Other forms have very limited bioactivity
Vitamin E
Functions:

Antioxidant
• Component of animal cell membranes
• Protects unsaturated fatty acids in cell membranes

Other roles are not clearly defined, but likely
exist
Vitamin E
Recommended intake:



15 mg/day
Need more if eat more polyunsaturated fats
most students did not meet their vitamin E
requirement on the day analyzed
Vitamin E
Food sources* (page 303):







Vegetable oils
Nuts and seeds
Whole grains
Green leafy vegetables
Liver
Wheat germ
Egg yolks
*easily destroyed by heat and oxygen
Vitamin E
Deficiency:


Rare as most vitamin E is recycled
See in premature babies
• Transferred from mom to baby in last weeks of
pregnancy

Cystic fibrosis patients
• Due to poor fat absorption
Vitamin E
 Symptoms

deficiency:
Hemolytic anemia
• RBC break open

Neurological problems with prolonged
deficiency
• Loss of coordination
• Vision and speech problems
• Does not prevent/cure MD
Vitamin E
Vitamin E may help with:

Leg cramps
• Intermittent claudication

Fibrocystic breasts disease
• “lumpy” breasts
Vitamin E
Toxicity: Rare

Supplements recommended by many, but not
above the UL = 1000 mg
• 200 mg supplement probably enough

May interfere with blood clotting
• Stop taking supplements prior to surgery

Other symptoms: nausea, fatigue, blurred
vision
VITAMIN K
Functions:


Need for synthesis of blood clotting proteins
Plays a role in regulation of calcium levels
Vitamin K
Recommended intake:

90-120 mcg/day
Sources:




Made by GI tract bacteria
Dark green leafy vegetables, cabbage family
Liver
Milk
Vitamin K
Deficiency: rare

Symptoms:
• Bleeding, hemorrhaging
• Bone weakness

Populations at risk
• Babies
• After long-term antibiotic treatment
• CF
Vitamin K
Toxicity: rare

Occurs with supplement overuse
• Take with caution, even if prescribed

Symptoms:
•
•
•
•
RBC break open
Jaundice
Brain damage
Interferes with anti-clotting meds