natural trans fats

Question 1

Natural Trans Fats

Answer 1

Vaccenic acid
Conjugated linoleic acids
2-5% of milk and body fat of ruminants
Artificial – were up to 45% trans
Eg. Shortening ~ 30%, butter  4% trans

Question 2

Vaccenic acid

U of A – Wang et al 2008 J. Nutr. 138:2117

Answer 2

From latin “vacca”
18:1, trans-11, -7
(NB. Elaidic = -9, major trans fat in partially hydrogenated veg oils)

Main trans FA in milk fat
Converted to CLA by mammals
Delta-9-desaturase

U of A – Wang et al 2008 J. Nutr. 138:2117
Feeding to rats lead to decrease LDL, decrease TG
Formed in rumen of cows, goats, sheep, yaks
Biohydrogenation of PUFA
Grass-feeding increases
Yak cheese ~ 4 times that of cheddar from grain-fed cows

Question 3

Conjugated linoleic acids (cont.)

which kind of acid

from where

health benefits

Answer 3

Conjugated linoleic acid (CLA) is a mixture of positional and geometric isomers of linoleic acid
Lamb, beef and dairy products are major sources
anticarcinogenic, weight-reducing, increase insulin resistance, prevent cardiovascular diseases and improve bone health.

Question 4

Discovery

tobacco
what do studies show
Conjugated linoleic acids (cont.)

Answer 4

Discovery 1979
Beef extract protected skin from tobacco carcinogen (20% less tumors)
1987 – CLA identified as active agent
Several studies show  tumor growth
A few suggest  body fat

Question 5

But t10, c12  side effects

Answer 5

inrease C-reactive protein
decrease insulin sensitivity
increase and decrease in lipid peroxidation (conflicting findings)
Adverse effect on blood lipids
May affect essential FA distribution
Rats, chicks - decrease brain and heart DHA and AA

Question 6

Supplements

Answer 6

– may have high t10, c12
Prepared commercially from linoleic acid
Partial hydrogenation, or
Heating under alkaline conditions

Question 7

biohydrogenation is

Answer 7

the process of converting unsaturated fatty acids to more saturated end products by gut microbes.

Question 8

how many isomers of linoleic isomers

Answer 8

28

Question 9

how do mammals produce CLAs

Answer 9

Eg. Delta-9-desaturase

take trans isomers of oleic acids, such as vaccenic acids,

Question 10

which are the most abundant

Answer 10

C9, t11 and t10, c12 most abundant

2 molecules

Question 11

principal dietary form (85-90% of CLA in dairy products)-

Answer 11

C9, t11 CLA = bovinic acid, rumenic acid
= principal dietary form (85-90% of CLA in dairy products)- most common

all one molecule

Question 12

what may account for health benefits

Answer 12

Cis and trans  lower melting pont