Nutrition Module 5- Vitamins and antioxidants

What is a vitamin? How do vitamins differ from minerals?

Vitamins- essential micronutrients. Needed in small doses, very organic, and do not provide calories.

Minerals- inorganic chemical elements, have NO carbon

Fat soluble vs Water soluble vitamins

Remember fat-soluble (Fat DRAKE minus the R:

A, D, E, K. Stored in body and adipose (fat) tissue

Don’t need it every day. Resistant to heat. Higher risk of toxicity because of accumulation in the body.

Water-soluble vitamins

Vitamin C and all B vitamins

Not stored much in the body

Excess is excreted in urine

Consume it more regularly

VERY sensitive to heat.

How Solubility Affects Vitamins

Solubility affects:

Heat sensitivity

• Water-soluble vitamins are generally more sensitive to heat and cooking

Storage

• Fat-soluble vitamins are stored in liver and fat tissue

Secretion

• Water-soluble vitamins are easily excreted in urine

• Fat-soluble vitamins are retained longer

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4. What are antioxidants?

Antioxidants are chemicals that protect cells from damage caused by free radicals.

They stabilize harmful molecules by donating electrons.

5. What are free radicals?

• Free radicals are atoms or molecules with unpaired electrons.

• They are produced during cellular respiration and metabolic reactions.

• Because they are unstable, they steal electrons from other molecules, damaging cells.

How do antioxidants protect cells?

Antioxidants:

• Donate electrons to free radicals

• This stabilizes the free radicals

• Prevents them from damaging lipids, proteins, and DNA

Example:
Vitamin E stabilizes cell membrane phospholipids by donating electrons.

Vitamins with Antioxidant Properties

The main antioxidant vitamins are:

• Vitamin A

• Vitamin C

• Vitamin E

Functions and Food Sources of Vitamins A

Vitamin A

Type: Fat-soluble

Functions

(VIGIL)

• Vision (pigments required for sight)

• Immune function

• Cell growth and development

• Skin and epithelial tissue health

• Antioxidant activity (especially beta-carotene)

• Carrots

• Sweet potatoes

• Spinach

• Kale

• Liver

• Dairy products

Functions and Food Sources of Vitamins C

Type: Water-soluble

Functions

• Antioxidant in the blood

• Collagen synthesis (skin, cartilage, tendons)

• Wound healing

• Enhances iron absorption

• Regenerates oxidized vitamin E

Food sources

• Citrus fruits

• Strawberries

• Bell peppers

• Broccoli

• Tomatoes

Functions and Food Sources of Vitamins E

Type: Fat-soluble

Functions

• Protects cell membranes

• Antioxidant for lipids

• Protects phospholipids

• Supports immune function

Food sources

• Vegetable oils

• Nuts

• Seeds

• Spinach

• Whole grains

Deficiencies and Toxicity of A

Vitamin A

Deficiency

• Night blindness

• Poor immune function

• Dry eyes and skin

Toxicity

• Liver damage

• Headaches

• Birth defects (during pregnancy)

Deficiencies and Toxicity of C

Deficiency

• Scurvy

• Weak connective tissue

• Bleeding gums

• Poor wound healing

Toxicity

• Rare, but large doses may cause

• Kidney stones

• Gastrointestinal distress

Deficiencies and Toxicity of E

Deficiency

• Rare

• Nerve damage

• Muscle weakness

• Impaired immune function

Toxicity

• Excess supplementation may cause bleeding problems

Non-Vitamin Antioxidants

Examples include minerals that help antioxidant systems:

• Selenium

• Copper

• Zinc

These minerals assist antioxidant enzymes that protect cells from oxidative damage. (Small amounts are needed for important health goals.)

Selenium helps

thyroid function, DNA synthesis.

Goes well with protein.

Copper helps

enzymes function, iron metabolism, synthesis of connective tissues.

Zinc helps

enzyme cofactor (especially in cellular respiration), fetal child development, and growth.

Food sources: shellfish, meat, fish, etc.