Vitamin E and C: Functions, Sources, and Deficiencies in Human Nutrition

What are tocopherols?

Chemically related compounds with Vitamin E activity.

What is the active form of Vitamin E?

Alpha-tocopherol.

What type of antioxidant is Vitamin E?

Fat-soluble antioxidant.

What does Vitamin E prevent?

Free radical chain reactions.

How does Vitamin E protect PUFAs?

It prevents their oxidation.

What are PUFAs?

Polyunsaturated fatty acids that are easily damaged by oxygen.

What special effect does Vitamin E have in the lungs?

It has a protective effect.

How does Vitamin E defend against heart disease?

By protecting LDL from oxidation.

What is one of the roles of Vitamin E in relation to inflammation?

It reduces inflammation.

What other compounds does Vitamin E protect?

It protects other lipids and compounds, such as Vitamin A.

What is the recommended dietary allowance (RDA) for vitamin E in adults?

15 mg/day

What is the upper limit (UL) for vitamin E intake?

1000 mg/day

Name three food sources of vitamin E.

Vegetable oils, leafy greens, nuts

What happens to vitamin E when exposed to heat processing?

It is easily destroyed.

What is a common cause of vitamin E deficiency?

Fat malabsorption diseases (e.g., cystic fibrosis)

What happens to red blood cells in vitamin E deficiency?

Erythrocyte hemolysis occurs, causing red blood cells to break open.

Who is most commonly affected by erythrocyte hemolysis due to vitamin E deficiency?

Premature infants (born before maternal transfer of Vitamin E)

What condition can result from erythrocyte hemolysis in premature infants?

Hemolytic anemia, which is treated with Vitamin E.

What are the effects of prolonged vitamin E deficiency?

Neuromuscular dysfunction, loss of muscle coordination & reflexes, impaired vision & speech.

What is the toxicity level of the substance?

Rare (regulated by liver)

How does the substance impact Vitamin K function?

It increases bleeding risk.

What effect may the substance have on anticoagulant medications?

It may enhance their effects, leading to hemorrhages (stroke).

What is another name for Vitamin C?

Ascorbic Acid

What is one of the main functions of Vitamin C?

Antioxidant

How does Vitamin C neutralize free radicals?

Donates electrons

What unique property does Vitamin C have after donating electrons?

Reactivates itself → allows recycling

How does Vitamin C affect iron absorption?

Increases iron absorption by preventing oxidation

What role does Vitamin C play in collagen formation?

Cofactor in Collagen Formation

What does collagen support in the body?

Bones, teeth, tendons, scar tissue

What is another function of Vitamin C related to carnitine?

Cofactor in Carnitine Formation

What is the role of carnitine in the body?

Transports fatty acids across mitochondria for energy

How does Vitamin C assist in hormone production?

Helps produce thyroxine (thyroid hormone)

What does thyroxine regulate?

Metabolic rate

When do Vitamin C needs increase?

Under stress (e.g., infections, smoking)

What role does vitamin C play in the body?

Helps the body fight infections, burns, and toxic exposures.

Is vitamin C proven to prevent the common cold?

No, it is not proven to prevent colds.

How can vitamin C affect the symptoms of a cold?

It may shorten symptoms or reduce severity.

What effect does vitamin C have on histamine?

It can deactivate histamine, reducing nasal congestion.

What is the Recommended Dietary Allowance (RDA) of Vitamin C for men?

90 mg/day

What is the Recommended Dietary Allowance (RDA) of Vitamin C for women?

75 mg/day

What is the upper limit (UL) for Vitamin C intake?

2000 mg/day

Who has a higher need for Vitamin C?

Smokers

Food Sources for vitamin C

Citrus fruits, bell peppers, cabbage, dark green vegetables, berries, tomatoes

Deficiencies of Vitamin C: early signs

Early signs:

Scorbutic gums → bleeding gums

Pinpoint hemorrhages → small red dots under skin

Deficiencies of Vitamin C: severe

Severe Deficiency → Scurvy

- Poor wound healing Weakness, anemia, infections, - Hysteria & depression

- Can lead to sudden death from internal bleeding

What are the gastrointestinal effects of excess vitamin C?

GI distress and diarrhea due to excess Vitamin C drawing water into the intestines.

What is the maximum daily benefit of vitamin C?

No benefit beyond 200 mg/day.

How can excess vitamin C affect medical test results?

Excess excretion may affect medical test results, such as diabetes diagnosis.

What interaction does vitamin C have with blood-thinning medications?

Vitamin C interferes with blood-thinning medications.

What risk is associated with excess vitamin C in relation to iron?

May cause iron overload, as free iron acts like free radicals.

What is one function of Selenium?

Antioxidant

With which vitamin does Selenium work?

Vitamin E

What enzyme does Selenium assist that helps prevent free radical formation?

Glutathione peroxidase

What health benefit may Selenium provide regarding cancer?

May reduce risk of certain cancers

What hormone does Selenium activate that regulates metabolism?

Thyroid hormone

Recommendations for selenium

RDA: 55 μg/day (adults)

UL: 400 μg/day

food sources of selenium

Seafood, meat, whole grains, vegetables & fruit (depends on soil content)

selenium deficency

- Rare

- Linked to Keshan Disease (heart disease in selenium-deficient regions of China)

toxicity of selenium

Possible from supplements

symptoms of selenium toxicity

Hair loss, brittle nails, Garlic-like breath odor,

Nervous system abnormalities

Free Radicals and Disease

Unstable molecules with unpaired electrons → damage cells

source of free radicals

UV radiation, pollution, tobacco smoke

how to antioxidant neutralize free radicals

by donating electrons

what do enzymes defence system include

selenium & other minerals

What is a primary cause of cancer?

DNA damage

How may antioxidants help in cancer prevention?

By preventing cell damage

Is there stronger evidence for the cancer-fighting effects of antioxidant-rich foods or supplements?

Antioxidant-rich foods (fruits & vegetables)

What is the effect of Vitamin E-rich diets on heart disease?

They are associated with a lower risk of atherosclerosis and heart disease.

How does Vitamin E affect LDL cholesterol?

Vitamin E protects LDL from oxidation.

What caution should be taken regarding Vitamin E supplements?

High-dose Vitamin E supplements may be harmful.

What effect does Vitamin C have on arteries?

Vitamin C may reduce inflammation in arteries.

What is the current status of selenium research in relation to heart disease?

Selenium research is inconclusive.

What did a woman with breast cancer do before her treatment?

She went to a naturopathic doctor.

What vitamins were recommended to the woman with breast cancer?

Vitamins A, B, C, D, melatonin, and turmeric.

What was the doctor's concern about the vitamins?

The doctor thought they would interfere with treatment.

What did a new study suggest about taking vitamins during cancer treatment?

It supported stopping the vitamins.

What was the risk of cancer returning for women who took the vitamins?

40% higher.

Is there a correlation between vitamin intake and cancer return?

Yes, but correlation does not imply cause and effect.

How do antioxidants affect cancer cells?

They help repair cell damage, which can interfere with the destruction of cancer cells.

When should antioxidants be used in relation to cancer?

They should be used to prevent cancer, but not during cancer treatment.

What are vitamins?

Organic, essential nutrients required in small amounts

What do vitamins regulate in the body?

Body processes for growth and maintenance

Do vitamins yield energy?

No, they do not yield energy but help release energy from macronutrients

What are minerals?

Inorganic, essential nutrients

What role do minerals play in the body?

They are structural components and regulators of body processes.

Are minerals destroyed by processing?

No, they are not destroyed by processing but can be lost in cooking water.

Bioavailability of Nutrients

Amount absorbed & used by the body depends on: GI efficiency & transit time (Slower = more absorption), Nutritional status & prior intake

(The body self-regulates absorption based on how much it already has), Food preparation (raw vs. cooked, dry vs. moist heat), Dry what like frying (Moist heat using water), Source (natural, fortified, synthetic) Supplements? Natural? fortified? Interactions (e.g., vitamin C enhances iron absorption, phytates reduce mineral absorption)

What role do B vitamins play in energy metabolism?

B vitamins often act as coenzymes for energy metabolism.

Do vitamins yield energy?

No, vitamins don't yield energy, but they help metabolize energy.

Which trace minerals are important for energy metabolism?

Trace minerals like sulfur, chromium, manganese, and iodine play vital roles in energy metabolism.

What is the vitamin component of coenzyme TPP?

Thiamin (B1)

What is the role of Thiamin (B1) in metabolism?

Important in carbohydrate metabolism

What functions does Thiamin (B1) support?

Supports nerve and muscle function

RDA for thiamin

Men: 1.2 mg/day

Women: 1.1 mg/day

Source for Thiamin

Whole grains, pork, enriched grains

- small amounts in most foods

- Easily destroyed by heat specifically boiling

What is a common cause of Thiamin (B1) deficiency?

Malnutrition

How does alcohol abuse affect Thiamin (B1) deficiency?

It increases the risk of deficiency.

What syndrome is associated with Thiamin (B1) deficiency?

Wernicke-Korsakoff Syndrome

What are some symptoms of Wernicke-Korsakoff Syndrome?

Mental disorientation, memory loss, jerky eye movement, staggering gait

What is the prolonged effect of Thiamin (B1) deficiency?

Beriberi