Phytonutrients Flashcards
What are phytonutrients
chemical compounds produced by plants which are beneficial to human health and help prevent diseases. There are over 25,000
Organic compounds are a by-product of glycolysis or photosynthesis. The compounds can be divided into primary and secondary metabolites. What are they
Primary metabolites:
compounds necessary for the plant’s survival, eg carbs, proteins, lipids, enzymes, chlorophyll
Secondary metabolites:
synthesised by plant in reaction to its environment - adaptive response. For survival and to protect from predators.
Why is it not advisable to isolate phytonutrients in food
There are synergistic interactions between the phytonutrients of the whole plant. Beta-carotene for example was found to worsen lung cancer when isolated.
What are teh roles of secondary metabolites in plants
protect against herbivores, pathogens
Protect against physical stressors eg UV light
Signals for communication and attract pollinators
What are the roles of secondary metabolites in the human body
Antioxidant (eg quercetin)
Regulate the cell cycle
Increase detoxification of carcinogenic and other toxic compounds
Reduce DNA damage (eg lycopene in toms)
Mimic or interact with hormones (eg lignans in flaxseeds can support low oestrogen levels.)
Why do organic plants have higher levels of phytonutrients
What is a chemotype
they have to protect themselves in their environment
Chemotype is a variation / chemically distinct entity of a plant with differences in the composition of the secondary metabolites
What factors influence the difference in phytonutrients between plants
chemotype of plant
Soil and water condition
Fungi and mycorrhizae
Insect friends and foes
climate
seasonal cycles
variability of plant part
bacteria, virus, pathogens
humans and animals around them
Name phytochemicals that can be toxic to humans and what class of phytochemicals are they from
ALKALOID
Morphine - from opium poppy
Digoxin - found in foxglove
It’s all about dosage
List less harmful examples of potentially toxic phytonutrients
Caffeine - alkaloid
Solanine and Chaconine - alkaloids from the nightshade family
Phytates - found in legumes, beans and may prevent absorption of some minerals (zn, Fe, Ca). But only if consumed in large amounts
Name foods where flavonoids are found (purple, blue, black)
Blueberries, blackberries, red cabbage, black olives
Name foods where chlorophyll is found (green)
Kale, spinach, broccoli, watercress, cucumber, avo
Name foods where lycopene are found (red, pink)
tomatoes, watermelon, guava
Name foods where carotenoids are found (orange)
carrot squash, orange, melon, peppers, turmeric
Name foods where sulphur are found (White)
garlic, onions, leeks, ginger, mushrooms, parsnips
What are the benefits of blue, purple, black foods - flavonoids
antioxidant. heart health, circulation, vision
What are the benefits of green foods - chlorophyll
liver detoxification, binds with toxins preventing reabsorption into the body
What are the benefits of red foods
reduces inflammation, high in vit C and supports the prostate
What are the benefits of orange, yellow food
improves immune system, vision and joint health
What are the benefits of white, brown foods
heart, circulation, liver detox
What is the largest family of phytonutrients and what is the most common phytonutrient within it
Phenols and polyphenols
Flavonoids
What are phytonutrients found within phenols
Flavonoids - quercitin, catechins, anthocyanins, isoflavins
phenolic acids - gallic acid (grapes), caffeic acid (thyme, sage)
Salicylic acid
Lignana
Stilbenes
Flavonoids belong to the polyphenol family and contain six subgroups, What are they
FlavOnols (kale, spinach, quercitin in red onions/apples)
Flavones (parsley, celery)
Isoflavones
Flavanones
Anthycuanins
FlavAnols or catechins
Name three classes of phytonutrients
Terpenes - carotoineds
Phytosterols (lipids) - Omega 3, 6, 9, Tocopherols
Sulphur compounds - I3C, sulforophane and DIM, Allicin
What are catechins and epicatechins
flavonoids with strong antioxidant properties
Name four food sources of catechins and epicatechins
Tea - green, black, oolong
Cocoa
Black grapes, berries, apples, pears, plums
Vinegar
List four functions of catechins and epicatechins
anti inflammatory - strong antioxidant, inhibits COX-1 and LOX-5, reduces histamine response
Neurological health - inhibits momoamine oxidase
CV health - antioxidant, lowers BP and LDL, increases NO, reduces insulin resistance
Joint health - green tea polyphenols lessen joint degeneration
List therapeutic uses of catechins and epicatechins
RH and OA, asthma, eczema, hayfever, IBD, Parkinsons, depression
What is the therapeutic dose range of quercetin and why should it be consumed regularly
150-1500mg/day
It has a fast excretion rate so needs to be consumed regularly
Name food sources of quercitin
apples, onions (red), grapes, capers, asparagus, tomatoes, kale, brassicas, berries
List functions of quercitin
CV health - antioxidant protecting vascular endothelium, inhibits LDL oxidation. Lowers BP. Support athletic performance by increasing circulation
Anit cancer - anti tumour functions, induces apoptosis. Inhibits BV growth
Immune system - anti infammatory as inhibits COX and LOX and downregualtes NF-kB
Xanthine oxidase - inhibits it, it converts purines to uric acid
List therapeutic uses of quercitin
Hayfever, histamine reactions, aasthma, hives, IBD, RA, OA, Gout, CVD, hypertension
How is quercetin best taken for absorption
It’s hydrophobic so best with fats or apple pectin.
It occurs in most food as a glycone (attached to a sugar molecule), so must be split from the sugar to become active.
Naringin - how is it metabolised in the body
by gut bacteria
List food sources of naringin
citrus (esp grapefuit)
Cooked tomato paste
WHy is grapefruit contraindicated with numerous medications
It inhibits intestinal CYP3A4 (the pathway used for many pharma drugs) resulting in less metabolism and higher circulating levels of drugs
List functions of Naringin
CV - protects vascular endothelium, antioxidant and LDL lowering
Anti cancer - reduces antiongenesis
Diabetes - reduces diabetic retinopathy and neruopathy
List therapeutic uses of naringin
atherosclerosis
hyperlipidaemia
cancer prevention
slows progression of diabetes and complications
Name food sources of isoflavonoids
soy, lentils, peas, chickpeas, peanuts
alfalfa sprouts
red clover
brussel sprouts
Why is the fermentation or digestion of soy products important
The isoflavones are present as glycosides (bound to sugar molecule) and fermenting releases the sugar molecule, leaving the aglycone
Why is gut bacteria important for the digestion of isoflavones/soy
colonic bacteria can convert the soy isoflavone daidzein to equol, which has greater oestrogenic activity
What can you do to increase equol production
eat isoflavones from a young age
regularly consume seaweed, green tea.
What is the main therapeutic use of isoflavonoids
they have weak oestrogenic activity.
Bind to oestrogen receptors, mimicking the effects of oestrogen in some tissue and antagonising (blocking) effects in other tissue
Reduces menopausal symptoms - SAGE tea provides regular delivery of flavonoids
Reduce risk of hormone related cancers
List other therapeutic uses of isoflavonoids
Hormonal/Oestrogen support
CV health - antioxidant and LDL lowering
Reduce arterial stiffness
Osteoporosis - can increase bone mineral density
What type of soy must NOT be recommended
All GMO sources
Soy protein isolate (SPI) is highly process, unfermented and poss. GMO
MINIMALLY PROCESSED SOY - STIMULATES GENES THAT SUPPRESS CANCER.
HIGHLY PROCESSED PROMOTE TUMOUR GROWTH
Name food sources of Lignans
Flaxseeds
sesame seeds
beans
pulses
cruciferous veg
Why is intestinal bacteria important for lignan metabolism
intestinal bacteria metabolise lignans to the phytoestrogen compounds enterodiol and enterolactone
What are the functions of lignans
Oestrogen modulation - binds to oestrogen receptors exerting an oestrogenic effect that is milder than endogenous oestrogens. Can increase or antagnoise oestrogen activity.
MENOPAUSE SUPPORT
CYCLE IRREGULARITIES
Anti cancer - anti cancer properties, especially hormonally driven breast and prostate.
Mechanisms:
- modulation of oestrogen metabolism
- strong antioxidant
- reduces 5a-reductase activity, reducing DHT
25g/day (providing 50mg lignans)
What are the safety precautions of lignans
may lower blood glucose levels and might have additive effects when used with anti diabetic drugs
Proanthocyanidins - list food sources
Grapes (skin and seeds)
cranberries, blueberries, elderberry
Cocoa
Apples, cinnamon, cashews
List 4 functions of proanthocyanidins
CV health - antioxidant properties prevent LDL oxidation
Enhance NO production
Improes circulation
Immune modulation - stabilise mast cells.
Stabilise lymphocyte and macrophage activity
Neurological health - neuroprotective against alzheimers and parkinsons
Anti cancer - inhibit cell proliferation and induce apoptosis
What are the possible therapeutic uses of proanthocyanidins
atherosclerosis
hypertension
diabetic retinopathy and neuropathy
Anti allergic
immune response
Alzheimers and parkinsons
What proanthocyanidin food is recommended for specific health conditions
grape seed
pine bark extracts
A plant rich diet is considered to provide enough for general health
Name food sources of anthycyanins
acai, blueberry, blackcurrent, cherry, red grape
blue, red, purple pigments
List 3 functions of anthocyanins
CV health - antioxidant scavenging ROS. Anti inflammatory; inhibits NF-kB. Protects against endothelial damage and reduces LDL oxidation
T2DM - improves insulin secretion and increases sensitivity, upregulates GLUT4
Eye health - protect occular tissue from oxidative stress. Improves night vision.
Neurological health - crosses the BBB to exert neuroprotective effects
Supports cognitive performance
List therapeutic uses of anthocyanins
neurodegenerative conditions - eg alzheimers, Parkinsons, MND
Protects against age related memory loss.
Hypertension
Atherosclerosis
T2DM
What are the dosage recommendations for anthocyanins when taken as a whole food and supplement
1/3 cup of blueberries daily for reduced risk of CVD, T2DM, neurological decline.
25-50mg daily for visual health
What are the possible interactions with anthocyanins
may increase bioavailability of certain drugs including anti cancer agents, antibiotics and B-blockers.
High supplemental dose could increase risk of bleeding with anticoagulant drugs
Resveratrol - list the food sources
Red grapes
Blueberries, raspberries, cranberries,
Peanuts
pistachios
cocoa
List three functions of resveratrol
Antioxidant - prevent LDL oxidation; support fertility; anti cancer
Insulin sensitivity - esp in obese
oestrogen modulation - phytoestrogen. Can inhibit aromatase
List therapeutic uses of resveratrol
CV health,
anti ageing
T2DM (dose 150mg day)
Oestrogen dominance
What is the recommended dose of resveratrol
10mg - 1g/day
what plant is most resveratrol supplementation sourced from
Japanese knotwood
What are the interactions with resveratrol
High intake could increase risk of bleeding with anticoagulants
Inhibits CYP450 - Supplementation could increase bioavailability and toxicity of drugs (statins, immune suppressants etc)
Name the two significant classes of phytosterols
sterols
stanols - only compromise 10% of dietary phytosterols
List food sources of phytosterols
unrefined veg oils, nuts, seeds, whole grains, legumes
Three highest are:
Wheat germ
Sesame oil
Pistachios
List 4 therapeutic uses of phytosterols
- promotes healthy serum cholesterol. Lowers LDL by displacing dietary cholesterol from micelles decreasing absorption; impeding transport from entercytes into circulation; increasing intestinal clearance of cholesterol
- Anit cancer - inhibit cell proliferation, induce cell cycle arrest and apoptosis; reduce angiogenesis
- Benign prostate hyperplasia - inhibits 5-a- reductase and aromatase
- allergy/asthma - supports immune modulation by increasing T-helper cell activity
What is the main interaction of phytosterols
additive effects with cholesterol lowering meds - statins
Isothiocyanates (ITCs) - what are they
biologically active breakdown products of glucosinolates (from sulphur rich compounds)
Name food sources of isothiocyanates
cruciferous veg
horseradish
mustard
What is the enzyme needed to hydrolise clucosinolates to form ITCs (isothiocyanates) and how is it released and what inactivates it
Myrosinase
Released by chopping/slicing/chewing
Inactivated by heat - though gut bacteria can hydrolise glucosinolates to a certain extent
Name the top three food sources of glucosinolates
brussels sprouts
garden cress
mustard greens
List the three key functions of glucosinolates/isothiocyanates
Antioxidant/anti inflammatory - increase tissue glutathione levels. Inhibits pro inflammatory signalling molecules
Liver detox - potent inducer of phase II and down regulates phase I
Anti cancer - protect DNA from carcinogenic damage
Inhibit angiogenesis
Enhance glutathione S-transferase (phase II enzymes for detoxification of carcinogens)
What quantity of cruciferous veg is recommended per week to reduce cancer risk
at least five servings (80g per serving) of cruciferous veg
What is a safety consideration of glucosinolates
some degrade to goitrogens (decrease uptake of iodine in thyroid). If low thyroid function limit brassicas to 1-2 serves/day and ensure good intake of iodine
Indole-3-carbinol - what is is derived from
the breakdown of glucobrassicin - a glucosinolate found in cruciferous veg
Why are isothiocyanates/glucosinates said to be protective against cancer - what conditions promote cancer development
Chronic inflammation and increased oxidation, with poor detoxification pathways are key factors for cancer development
In the acidic environment of the stomach, what indole products does I3C form, and which is more active - I3C or its metabolite
3,3’-diindolylemthane (DIM)
I3C and DIM have the same physiological effects
Name the food source that is most abundant in I3C
Broccoli sprouts - 20-50 times more I3C than normal broccoli
Name three functions of I3C
- Oestrogen modulation - selectively binds to oestrogen receptors acting as an oestrogen antagonist.
Influences phase I CYP enzymes to increase conversion of oestradiol to protective form of oestrogen
Inhibits aromatase, reducing conversion of testosterone to oestrogen
50g broccoli sprouts day
- Cervical intraepithelial neoplasia (CIN). Modulates risk factors for CIN (and cervical cancer) such as elevated oestrogen and inflammation.
Reduces activity of NF-kB, reducing cytokines
- Breast and prostate cancer
regulates oestrogen and androgen levels
Induces cell cycle arrest, activates tumour suppressor genes, reduces angiogenesis
Name therapeutic uses of I3C
oestrogen sensitive cancers
cervical dysplasia
CIN
Breast and prostate cancer
what is the general therapeutic dose of I3C
200-800mg/day
1 head of cabbage = 1200mg
List 4 ways of supporting oestrogen clearance
optimise fibre intake to bind to and excrete oestrogen via the bowel
Optimise gut microbiome to prevent to prevent de-conjugation of excreted oestrogens
Support methylation with folate, B6, B12 foods
Avoid dairy and oestrogen mimicking agents et BOA, dioxins (pestacides). Smoking, alcohol, caffeine which burden the liver.
Name the most common carotenoids in the western diet
a-carotene
b-carotene
b-cryptoxanthin
lutein
zeaxanthin
lycopene
What class of phytonutrients do carotenoids belong to
terpene
Name food sources of carotenoids
yellow, orange and red fuit and veg.
Green veg
What is the primary function of lutein and zeaxanthin and name therapeutic uses
Eye health
age related macular degeneration
cataracts
diabetic retinopathy
uveitis
What are the mechanisms by which lutein and zeaxanthin protects the eye
they collect in the macula of the eye and absorb up to 90% of blue light
Protects retinal cells from oxidative stress
Inhibits NF-kB signlling - reducing inflammation associated with eye disorders.
What dosage of lutein and zeaxanthin have been shown to protect against age related macular degeneration, and how does this relate to cooked spinach or kale
Lutein - 10mg day
Zeaxanthin - 2mg day
1 cup cooked spinach or kale contains between 3-20 mg of the two carotenoids.
Name two ways of increasing the bioavailability of carotenoids
consume with small portion of fat
Lightly steam
Name food sources of lycopene
tomatoes
Guava
Pink grapefruit
watermelon
papaya
Name three therapeutic uses of lycopene
- Anti cancer - antioxidant, prevents oxidative damage to DNA. Inhibits cancer cell growth. Decreases inflammation (which mediates tumour growth) by:
- reducing COX-2, Interleukin-1 and 6 and TNF-a
- Inhibits NF-kB - Prostate health - Lycopene accumulates in the prostate and can inhibit progression of BPH and decrease PSA. Induce apoptosis.
- Cardiovascular health - prevents oxidation of LDLs, reduces plaque formation.
What health benefit is intake of tomato juice linked with
improvements in endothelial dysfunction
What is the recommended dosage of lycopene
8-22mg/day
What preparation methods can aid the absorption of lycopene
juicing
cooking
mixing with oils and fats.
What is the difference between primary and secondary plant metabolites
Primary : compounds in all plants necessary for survival
- carbohydrates
- proteins
- lipids
- enzymes
- chlorophyll
Secondary: synthesised by plant in reaction to its environment. Stressors. Protect against physical/environmental stressors. Eg flavonoids, quercitin
