Flashcards in 18 phytosterols Deck (29):
Phytosterols are structually similar to?
What are phytosterols
plant derived sterols
- similar to cholesterol
- not synthesized by humans
Phytosterols can be subdivided into?
- double bond at position 5
- reduced double bond
- less in food
- product of intestinal degradation of sterols
tending to promote the formation of fatty plaques in arteries
- Phytosterols and Cholesterol
Difference between phytosterols and cholesterol
- 1-15% absorbed (helps its function)
- blood levels 200times less
Highest food sources of phytosterols
- processing influences content
- hydrogenation DOESNT influence content
Cholesterol lowering effects of phytosterols apparent in what amount?
low gram amounts
Phytosterols 3 areas of focus on health
1. CVD**(most attention)
3. Immune Health
Phytosterols and CVD
lowers blood lipids (2gram sterol/stanols per day)
- total and LDL
- no effect HDL cholesterol of TG
*note - no direct link to heart disease yet
Phytosterols mechanism for reducing total and LDL-cholesterol?
- compete with cholesterol for limited space on mixed micelles in the intestine
- more hydrophobic - therefore greater affinity
- decreases cholesterol absorption 30-50%
- dietary and endogenous chol.
Types of cholesterol phytosterols compete with?
dietary chol. (20%)
endogenous chol. (80%)
- biliary chol, secreted in bile
where does unabsorbed cholesterol go?
Does form of phytosterols influence efficacy?
plant sterol/stanol esters
Study on CVD; phytosterols vs drugs
American Journal of Cardiology 2002
- cervistatin and sterol-ester margarine together
- possible synergistic effect
- result additive effect
sterols added further benefit to drug (lower cholesterol in different ways)
why phytosterols hard to incorporate in foods?
how to overcome this?
low fat solubility
- esterfied with fatty acid to increase solubility
* esterfied gram amounts higher than sterol itself (overestimated)
USA recommendation of phytosterols for CHD
2 servings of foods
Typical foods phytosterols are incorpertated in?
- margarine, salad dressing, yoghurt, cream cheese
-Benecol Softgels (supplement)
-Take Control (supplement)
Why are phytosterol functional foods NOT in canada?
- caused many problems when labelling regulations were limited
Phytosterols and cancer
- inhibited cancer cell growth in vitro
-improved symptoms associated with benign prostate hyperplasia in humans
-inhibit colon cell proliferation
-inhibit proliferation of cancer cells (in vitro)
Potential mechanisms of action of phytosterols on cancer
- bound enzymes
effects on neutral and acidic sterols in the colon
What is a glucoside
a glycoside derived from glucose
- a molecule which sugar is bound to another functional group
What phytosterols are shown to be immune modulators?
and its glucoside (BSSG)
Phytosterols relation to immunity
BSS and BSSG
- increase proliferation of lymphocytes
- recovery tuberculosis
- improvement HIV
- rheumatoid arthritis
Phytosterol safety issues?
Decreased absorption of fat soluble nutrients (acute)
- consumed with phytosterols
Fat soluble nutrients affected / not affected when consumed with phytosterols
decreased plasma carotenoids
- beta carotenoids 25%
- alpha carotenoids 10%
Vitamin A, D, E and K NOT affected
-carotenoids carried by LDL but Vit A is not
>1 serving of veggies will maintain satisfactory levels
- error in phytosterol metabolism
- intestinal inability to distinguish between phytosterol and cholesterol
- no sterol excretion in bile
-Extremely high conc. of phytosterols
VERY RARE (40 worldwide)
rate limiting step in bile acid synthesis
- inhibited by sitosterol during phytosterolemia
Max free phytosterol amount allowed in food per serving?
1g per serving
- effects believed to plateau >3g