BMS1064 - Selected non-nutrients Flashcards
(23 cards)
Why are diets rich in plant foods generally considered to be associated with long term health?
Avoiding certain substances in animal foods (e.g. SFAs, oxidised cholesterol, nitrites etc)
AND
Plants provide health promoting substances (e.g. MUFAs, SE, K, non-nutrients etc)
What is a non-nutrient?
A substance in food that may affect our health even though they are not nutrients.
e.g. fibre, choline (important for making phospholipids) and phytochemicals
Can non-nutrients be toxic?
Yes. most are potentially toxic (e.g. quercetin).
Some are acutely toxic but toxicity is generally a function of dose and at low doses some compounds may be advantageous to health (e.g. Strychnine)
What are some of the different non-nutrients?
Phenols
Polyphenols
Sulphur containing compounds
Alkaloids
What are Phenols? (draw)
What can they form?
Phenol = top image
Can be ionised and form radicals.
What is the basic structure of polyphenols? What are they also known as?
A compound containing more than one phenyl ring.
Also known as flavonoids, more specifically flavanols (found in green tea)
Why are polyphenols produced in plants?
In response to stress:
- pathogen defence - anti-fungal and anti-bacterial
- ultra-violet light protection, antioxidant
What are the different categories of polyphenols (flavonoid subgroups)?
Flavanols
Flavonols
Anthocyanidins (anthocyanins)
Isoflavones
In what foods are flavanols found?
note: flavanol is a subgroup of flavonoids, which are a subgroup of polyphenols.
Tea, apples, red wine
In what food is the flavOnols quercetin found?
Onions, green apples, broccoli, tea
In what foods are the flavones found?
Celery, red pepper, olives, lemons, kale
In what foods are Anthocyanidins found?
Raspberries, strawberries, red grapes, aubergine, red wine
In what foods are Isoflavones found?
Legumes, tofu, soy, split peas, milk
What are the daily intakes of flavanols? What about flavonols? Anthocyanidins? Isoflavones?
Up to 100mg/day - flavAnols
3-64mg/day - flavOnols
200mg/day - anthocyanidins
50mg/day in far eastern countries but as low as 1mg/day in UK - Isoflavones
How are polyphenols generally present in the diet?
What can these interact with in the duodenum?
What happens to non-interacting glycosides?
Attached to sugar (as glycosides)
Some interact with transporters in the duodenum where they are absorbed.
Non-interacting glycosides - pass to colon where bacterial glycosidases degrade them.
What are 2 different types of studies used to study polyphenols (and many other things)?
Longitudinal studies and Cross-sectional studies
How can polyphenols protect fro disease?
Some polyphenols supress radical-generating enzymes
Some scavenge free radicals (although polyphenols contribute little to the body’s overall antioxidant activity)
Bind metal ions (Fe3+, Cu2+, Zn2+ - inhibiting metal catalysed lipid peroxidation)
Can delay glucose uptake from gut (apple, coffee and onion)
Might encourage healthier gut microflora.
So many polyphenols occur in the diet that they probably have ______ effects in ______ different areas.
small
many
What are terpenes?
Large group of volatile unsaturated hydrocarbons found in the essential oils of plants.
e.g. carotenoids
Give an example of how terpenes can be beneficial to health?
Lutein and Zeazanthin -> prevent photo-oxidation (degeneration) in the eye
Give examples of Tetraterpenes
Stanols - reduce cholesterol absorbtion in gut
Caffestol and Kahweol - extracted by prolonged boiling of coffee. Can increase LDL cholesterol
What foods have sulfer containing compounds?
Onions, chives, garlic etc –> Alliaceae
produced enzymatically when tissue is damaged. responsible for hot taste and watering eyes.
Brassicas (cabbage, Brussel sprouts, brocolli etc) -> Glycosinolates
Also produced enzymatically when tissue is damaged. Some might protect against cancer of colon.
