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aa NUTR 420 > carotenoids > Flashcards

carotenoids Flashcards

1
Q

Carotenoids

4 types

A

b-carotene, lycopene – hydrocarbon carotenoids in yellow and orange coloured fruits and vegetables
Lutein, zeaxanthin – oxygenated carotenoids in dark-green leafy vegetables
Pro-vitamin A - , , ,-carotenes, cryptoxanthin

Yellow to deep-red pigments
Accessory pigments in plant photosynthesis
Approx 600 different plant carotenoids
If non-oxygenated = carotenes
If oxygenated = xanthophyls
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2
Q

Sources:

B-carotene:

A

carrots, peaches, apricots, mango, papaya, sweet potatoes, spinach, collards, pumpkin, cantaloupe

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3
Q

A -carotene:

A

pumpkin, carrots

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4
Q

B -cryptoxanthin:

A

citrus fruits

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5
Q

Lutein/zeaxanthin

A

kale, collards, spinach, Swiss chard, mustard greens, red peppers, okra, romaine lettuce, corn

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6
Q

Lycopene:

A

tomato, watermelon, pink grapefruit, guava, red peppers

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7
Q

B-carotene most studied
Hydrophobic - absorbed with lipids
Levels in blood related to levels in diet
Carotenodermia (yellowing of skin) seen with increased consumption of carrots

A

Important singlet oxygen quenchers
Light &/or chemicals convert normal O2 to reactive singlet oxygen (1O2) – electron excited to higher energy
UV + O2  1O2
carotenoid + 1O2  O2 + carotenoid + heat

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8
Q

Carotenoids and Cardiovascular Disease

A

Carotenoids decrease LDL oxidation thus potentially decrease plaque formation
Role in decreased CVD risk?
no +ve evidence in intervention studies

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9
Q

Carotenoids & Cancer

A

Some models show beneficial effects with respect to carotenoids & cancer initiation, progression & proliferation
Cell culture, epidemiology, blood levels  risk
Possible protectors from DNA damage
Source of vitamin A – inhibits proliferation and induces differentiation
But, intervention trials mostly negative

Possible negative effect in smokers and asbestos workers:
Some studies suggest increased lung cancer with -carotene supplementation
J Natl Cancer Inst. 1996; 88:1550-9,1560-7
JAMA 2003; 290: 476-85
However only with high-dose -carotene supplementation (not physiological levels or dietary carotenoids)
Nutr Cancer. 2009;61(6):767-74

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10
Q

Lycopene and prostate cancer

A

Some +ve evidence:
decrease risk with high tomato/lycopene consumption
blood lycopene decrease risk
intervention studies (lycopene or tomatoes) -> decrease prostate cancer growth

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11
Q

Possible negative effect in smokers and asbestos workers:

A

Some studies suggest increased lung cancer with -carotene supplementation
J Natl Cancer Inst. 1996; 88:1550-9,1560-7
JAMA 2003; 290: 476-85
However only with high-dose -carotene supplementation (not physiological levels or dietary carotenoids)

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12
Q

Lycopene and prostate cancer

A

Some +ve evidence:
decrease risk with high tomato/lycopene consumption
blood lycopene decrease risk
intervention studies (lycopene or tomatoes) -> decrease prostate cancer growth

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13
Q

Carotenoids & Age Related Macular Degeneration (AMD)

A

Progressive retinal disease for which no cure or treatment available
20% of age > 65 years have clinical evidence
Lutein & zeaxanthin in macula lutea of retina (other carotenoids no)
Lutein & zeaxanthin may help prevent AMD by
Acting as optical filters to prevent photochemical damage
Acting as antioxidant
Supported by epidemiology and some intervention trials

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14
Q

Carotenoids & Skin Protection

A

UV-irradiation  photooxidative damage ( erythema (redding of skin- sunburn), skin aging, photodermatoses, skin cancer)
Carotenoids lost from skin on UV exposure (especially lycopene)
Several intervention studies show protection against UV-induced erythema
Carotenoid supplements
Tomato paste

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15
Q

BioPhotonic scanner – Pharmanex / NU SKIN

A
  • 2001 granted 20 year patent
    • based on resonance Raman spectrometry
      • used for macula carotenoids (102 higher than skin)
    • 475 nm excitation, 511 nm emission
    • measures total carotenoids in skin
    • carotenoid supplementation can increase score
    • validity between individuals?
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16
Q

Gac

A

70 times the lycopene of tomatoes per weight
10 times the -carotene of carrots or sweet potatoes

Gac is regarded as “Fruit from Heaven” not only for its widely known and prized health benefits, but because of the way it grows.
Chinese Lycium: Herb of LongevitySiberian Pineapple: The Skin’s SecretCili Fruit: “King of Vitamin C”

17
Q

Portable Reflection Spectroscopy Device (“Veggie Meter”)

for measurements of skin carotenoid levels/ nutrition status

A

white LED excitation; detection of diffusely reflected light; 20 sec. measurement of finger tip
skin contact lens gently squeezes blood from measured tissue volume
interfaced to laptop computer
algorithm for rapid determination of skin carotenoid levels
carotenoid levels obtainable in optical density units, which scale linearly with tissue concentration levels
automatic correction for skin chromophores (oxy-hemoglobin, de-oxy hemoglobin, melanin) and tissue scattering

Carotenoids are present in epidermis, including outer skin layer, stratum corneum

All carotenoids found in blood are also present in skin; highest concentrations: carotenes and lycopene

Challenge: optical methods need to work around potentially confounding chromophores and scatterers

18
Q

Terpenes

A

Terpene - Any of three classes of unsaturated hydrocarbons, based on the isoprene (formula C5H8) unit, that are present in plant resins and also form the main constituents of essential oils such as rose and jasmine oil.
from terpentin, an obsolete form of turpentine.

19
Q

Terpene examples

A 
Pyrethroids - insect toxins
Essential oils - insect repellents
    -menthol - peppermint
    -limonene - lemon oil
    -synthesized in glands (trichomes) in 	citrus 	peel
Carotenoids = tetraterpenes
Retinoids = diterpenes
20
Q

Terpenes

Cardenolides

A

Toxic
cardiac glycosides
- triterpene glycosides in plants such as milkweed and green hellebore
- bitter, very toxic to higher animals (sodium/potassium pump inhibitors- blood pressure)
- cattle problem, but not normally in human diet
- from Digitalis (foxglove) - heart drug digoxin

not aproblem for humans because we dont eat shrubs

21
Q

Saponins

A
  • both lipid and water soluble components
    • form emulsions, foam with water
    • triterpene or steroid glycoside
    • toxic to fish (remove natural slime)
    • toxic defense against fungi
    • bitter, but not highly toxic to mammals
22
Q

Limonoids

A

Monoterpene derivatives
In oranges, lemon, lime, grapefruit, cherries, mint, dill, caraway (flavor, aroma)
limonene, carvone
limonin, nomilin
Cancer chemopreventive effects
induce phase I and phase II enzymes
esp. ↑ glutathione-S-transferase and UDP-glucuronyl transferase
↑phase II outweighs ↑phase I and  ↑carcinogen removal
Some cancer therapeutic effects
Inhibit growth of cancer cells (↑differentiation)
Induce apoptosis
In phase I clinical trials in patients with breast cancer

aa NUTR 420 (10 decks)

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