Antioxidants Dr Rania Abd El Hamid Hussein MBBSch

Antioxidants Dr Rania Abd El Hamid Hussein MBBSch Master’s degree in Internal Medicine Doctor in Nutrition and Public Health Assistant Professor of Nutrition Faculty of Applied Medical Sciences KAU dr Rania Hussein

What are antioxidants? These are a group of substances that protect cells from damage caused by free radicals, by interacting with free radicals , and stabilizing them. dr Rania Hussein

What is a free radical? • It is an atom that has at least one unpaired electron • Normally present in our body in small number • Free radicals are released by normal metabolism, as well as by pollution, smoking, radiation, and stress • Under normal circumstances, the body can keep them in check dr Rania Hussein

Antioxidant protection • Antioxidants, donate extra electrons to needed unpaired electrons in order to stop free radical damage potential. • Although free radical damage can’t be stopped all together, it can be minimized. dr Rania Hussein

There are 3 known free radicals: • The Superoxide • The Hydroxyl dr Rania Hussein

Oxidants’ effects Target Effect Results: 1. PUFA oxidation in the cell→ lipid membrane damage → cell damage → aging and degenerative process. 2. LDL-oxidation → atherosclerosis 3. Alteration in the way the cell codes the genetic material→ change in protein structure → DNA mutation → cancer dr Rania Hussein

Oxidative stress= ‘An imbalance between oxidants and antioxidants in favor of the oxidants, potentially leading to damage’ dr Rania Hussein

Net result of oxidative stress 1. 2. 3. 4. 5. Aging and degenerative changes Damage to human sperms Coronary artery disease Inhibition of the immune system Cancer dr Rania Hussein

What are the Benefits of antioxidants? �� Boost the Immune System. �� Prevent age-related degeneration, adult-onset diabetes, stroke �� Prevent coronary Artery Disease. �� Prevent Cancer. �� Promote growth and bone development, maintain healthy hair and nails. dr Rania Hussein

What is considered as antioxidant? dr Rania Hussein

1. Vitamins C, E 2. Certain enzymes: Superoxide dimutase (SOD), Catalase, and Glutathione peroxidase 3. Phytochemicals dr Rania Hussein

�� Vitamin E : Fat Soluble vitamin Present in: • oils (corn and soybean) • almonds , nuts, • broccoli Chief lipid“antioxidant” dr Rania Hussein

�� Vitamin C – Water Soluble In many fruits and vegetables. Common additive, often as a preservative dr Rania Hussein

�� Selenium - is NOT an antioxidant, but a cofactor to glutathione peroxidase enzyme It is a mineral present in: • Garlic, • seeds, nuts, whole grains, • eggs, • seafood, dr Rania Hussein

Phytochemicals Plant foods contain 1. Nutrients: • Protein • Fat • Carbohydrate • Micronutrients as vitamins and minerals 2. Non nutrient compounds as (phytochemicals) dr Rania Hussein

What are phytochemicals? • They are biologically active, naturally occurring chemical compounds in plant foods. • They act as natural defense mechanism for their host plants, and provide color, and flavor. dr Rania Hussein

Phytochemicals are present in fruits, vegetables, legumes, whole grains, nuts, herbs, spices. dr Rania Hussein

What are phytochemicals? Terpens: �� Beta-carotene �� Lycopene �� Limonoids Polyphenols → flavonoids �� Anthocyanins �� Isoflavones �� Catechins Thiols �� Indoles �� Allyl sulphide dr Rania Hussein

Terpens dr Rania Hussein

B - carotene (precursor of vitamin A) Beta Carotene is a water soluble precursor to Vitamin A, and is an antioxidant in itself; whereas Vitamin A has NO antioxidant activity. dr Rania Hussein

Beta-Carotene – Orange Colors: sweet potatoes, carrots, cantaloupe, squash, apricots, pumpkin, and mangos. dr Rania Hussein

�� Lycopene – Red Colors: tomatoes, watermelon, papaya, guava. �� Limonoids Citrus fruits dr Rania Hussein

Polyphenols dr Rania Hussein

• Phenols are sometimes referred to as “Super Antioxidants. ” • Shown to have: antiviral, antiallergic, anti inflammatory, anti thrombotic and anti carcinogenic effects. • Among phenols, over 4000 flavonoids have been found, fall in different groups: anthocyanins, isoflavones, catechins. dr Rania Hussein

Flavonoids 1–Anthocyanins: violet • Blue berries, cherries, grapes, red cabbages, apples • Onions 2–Catechins: • green tea, black tea dr Rania Hussein

Flavonoids 3– Isoflavones: In Soybeans They act as phytoestrogens: Bind to estrogen receptors Unlike estrogen, they act as: • Weak estrogen- like in some tissues → ↑bone density, ↓ serum cholesterol, ↓ post cancer prostate growth) • Anti-estrogen in other tissues → ↓risk of hormone dependant female cancer dr Rania Hussein

Thiols: Sulphur containing phytochemicals dr Rania Hussein

1. Indoles and isothiocyanates: Cruciferous vegetables: Broccoli, cabbage, watercress 2. Allyl sulphide: Onion, garlic, leaks Antioxidant role: Anticancer especially for lung and GI cancer dr Rania Hussein

Phytochemicals Most Commonly Studied Phytochemicals There also hundreds more phytochemicals existing and in need of discovery! dr Rania Hussein

Broccoli sprouts contain an abundance of the cancer-fighting indoles, vitamin E Tomatoes, with their abundant lycopene, may defend against cancer by protecting DNA from oxidative damage Rich in flavonoids – apples may Garlic, with its abundant allicin, dr Rania Hussein

Blueberries, a rich source of flavonoids, The limonene of citrus fruits may inhibit cancer growth Also High in Vitamin C Isoflavones of soybeans lower blood cholesterol and protect cardiac arteries. dr Rania Hussein Flavonoids found in grapes protects against cancer by inhibiting cell growth

Dietary Recommendations Consume a diet high in antioxidant-rich fruits and vegetables each and everyday. dr Rania Hussein

dr Rania Hussein

Functional foods These are foods that provide more benefits than basic nutritional benefits dr Rania Hussein

dr Rania Hussein

Potential Benefits of functional foods 1. Antioxidant: ↓ Cancer Risk, ↑ Heart Health, ↓ BP 2. ↓ Menopause Symptoms, and ↑ Bone Health 3. ↑ Gastro Intestinal Health dr Rania Hussein

References • Brown JE, Isaacs J, Wooldridge N, Krinke B, Murtaugh M. Nutrition through the lifecycle, 2007. 3 rd ed. Wadsworth publishing. • Mahan LK, Escott- Stamp S. krause’s food, and nutrition therapy 2008. 12 th ed. Saunders Elsevier. Canada. dr Rania Hussein