Download Metabolism of the Unsaturated and Saturated Fats

180.
M E TABOL I S H O F T H E U N S A TURA T E D A N D S A TURA T E D F A TS
F. A . KUMMEROW
No chemical d i s t i n c t i o n exists between p l a s t i c f a t s (shortening)
and vegetable o i l s (salad o i l s ) ; both contain glycerol connected t o or
" e s t e r i f i e d " w i t h three moles of f a t t y acid (Table 1). The s a t u r a t e d f a t t y
acids i n t h e comrnon e d i b l e f a t s vary from C4 t o C22 i n chain length and
-7.9 t o 79.9% i n melting p o i n t . The unsaturated f a t t y acids i n edible
t o C20 i n chain length and -1 t o -49OC i n melting point
fats vary from C
(Markley '60). '$fe high melting p o i n t s of t h e saturated and t h e l o w m e l t ing p o i n t s of t h e unsaturated f a t t y acids are important t o t h e physical
c h a r a c t e r i s t i c s of f a t s and o i l s .
If t h e glycerol i s e s t e r i f i e d with more than t w o unsaturated
f a t t y acids, i . e . , o l e i c or l i n o l e i c acid, t h e r e s u l t i n g t r i g l y c e r i d e i s a
l i q u i d or an ''oil" at room temperature. If, on t h e o t h e r hand, glycerol
i s e s t e r i f i e d with only long chain s a t u r a t e d f a t t y acids o r only one mole
of o l e i c and t w o moles of palmitic o r s t e a r i c acid, t h e r e s u l t i n g t r i g l y c e r i d e s i s a s o l i d or "fat" at room temperature (Table,2). A study of i s o l a t e d
t r i g l y c e r i d e s has shown t h a t t h e s u b s t i t u t i o n of one mle of o l e i c f o r
s t e a r i c acid i n an d -position i n t r i s t e a r i n f o r example lowers t h e melting
point from 73 t o 38OC and t h e same s u b s t i t u t i o n i n t r i p a l m i t i n from 66 t o
35OC (Bailey '50). When one considers t h a t t h e body temperature of a
human being i s 37.ZoC, t h e &
s u b s t i t u t i o n of l i n o l e i c o r o l e i c acid
f o r one mole of s t e a r i c o r palmitic acid m a y change t h e physical character
of t h e depot f a t and i t s a b i l i t y t o a c t as EL "cushioning agent" t o vital
organs. These depot f a t s m a y become s o f t and o i l y .
N a t u r a l f a t s and o i l s have been found t o contain mixtures of
t r i g l y c e r i d e s which are uniquely c h a r a c t e r i s t i c of a s p e c i f i c f a t (Hilditch
'56). As indicated by t h e melting p o i n t s of i s o l a t e d t r i g l y c e r i d e s , t h e
physical p r o p e r t i e s of t h e mixture of t r i g l y c e r i d e s are governed by t h e
physical p r o p e r t i e s of t h e p a r t i c u l a r f a t t y acid which i s e s t e r i f i e d with
t h e glycerol (Table 3). I n ''soft" f a t s such as corn or cottonseed o i l ,
which c o n t a b t h e unsaturated o l e i c and l i n o l e i c acids as t h e predominant
f a t t y acids, "the o i l s " are composed of a high proportion of d i and t r i
unsaturated glycerides. I n "hard" fats such as coconut o i l , b u t t e r f a t and
beef tallow, which contain t h e saturated, myristic, palmitic and s t e a r i c
acids as t h e predominant f a t t y acids, "the f a t s " are composed of a high
proportion of d i and t r i saturated glycerides. Although coconut o i l i s a
vegetable o i l , it i s c l a s s i f i e d as a f a t as it contains 84% tri s a t u r a t e d
glycerides and i s a s o l i d at room temperature. Human adipose t i s s u e f a t
and human milk f a t are semi s o l i d f a t s with a high proportion of mono and
d i saturated glycerides.
181.
The glycerides of human adipose t i s s u e contain approximately 4%
myristic, 25% palmitic, 7% s t e a r i c , 6% palmitoleic, 46$ o l e i c and 2% of
f a t t y acids which are shorter than 14 o r longer than 18 carbon atoms i n
chain length (Cramer and Brown '43). These f a t t y acids may be c l a s s i f i e d
t h e "non e s s e n t i a l f a t t y acids" as they can a l l be synthesized i n t h e body
f r o m non f a t precursors. They are also found i n corn o i l , beef tallow and
l a r d but i n d i f f e r e n t percentage composition i n each case. I n addition t h e
adipose t i s s u e f a t i s composed of approximately 9% l i n o l e i c and 1%
arachidonic acid which contain two and four double bonds respectively.
These two f a t t y acids have been c l a s s i f i e d t h e " e s s e n t i a l f a t t y acids" as
l i n o l e i c acid cannot be synthesized by a n i m a l t i s s u e and serves as an
e s s e n t i a l precursor f o r t h e synthesis of arachidonic acid.
The a b i l i t y of unsaturated f a t t y acids t o form "geometric
isomers", plays an important r o l e i n t h e degree of hardness of a "hydrogenated" f a t such as margarine (Table 4) and probably of human depot fats.
Geometric isomers are important t o t h e p l a s t i c i t y of fats because t h e
t r a n s isomers of o l e i c and l i n o l e i c acid, which are produced during t h e
commercial hydrogenation of an edible o i l have melting points of 52OC and
29OC respectively and therefore tend t o "harden" margarine. The natural
c i s isomers of o l e i c and l i n o l e i c acid have melting points of 14OC and
m C respectively and therefore tend t o "soften" margarine at room temperature o r 21OC. This property of o l e i c and l i n o l e i c acids t o e x i s t i n either
a s o l i d o r a l i q u i d state at room temperature i s important t o t h e product i o n of margarines of high l i n o l e i c acid content f o r two reasons. One,
even though t h e trans isomers of o l e i c and l i n o l e i c acids influence t h e
p l a s t i c i t y of margarine, these t r a n s isomers have t h e same degree of unsaturation o r iodine number as t h e n a t u r a l cis isomers and therefore both
contribute t o t h e calculated tfpolyunsaturates" and both thus increase t h e
polyunsaturated t o saturated o r P/S r a t i o of t h e f a t . Two, t h e deliberate
production of t h e high melting t r a n s o l e i c and l i n o l e i c acid during commercial hydrogenation allows t h e margarine mnaufacturer t o add a higher
percentage of t h e low melting l i n o l e i c acid t o a margarine f a t without
s a c r i f i c i n g t h e degree of desirable hardness. Thus mdern margarines,
whether m a d e from corn o i l , cottonseed o i l , o r soybean o i l , all contain two
t o t h r e e t i m e s more l i n o l e i c acid then a few years ago, but they also cont a i n more t r a n s o l e i c acid.
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W e purchased four t y p i c a l brands of both high and low priced
margarine at a l o c a l supermarket and subjected them t o f a t t y acid and
i n f r a r e d analysis (Table 5 ) . The r e s u l t s (Kummerow '64) indicated t h a t a l l
of them contained more l i n o l e i c acid than t h e margarines which were available a f e w years ago (Bailey '51). F u r t h e m r e , t h e cost of these margarines
was independent of t h e i r l i n o l e i c acid content; t h e lowest priced margarine
contained 15%more l i n o l e i c acid than the medium priced brand and only 54
less l i n o l e i c acid than the highest priced brand. The large arnount of
"trans" f a t t y acid i n all of t h e margarines indicated t h a t both t r a n s o l e i c
and trans, t r a n s l i n o l e i c acid may have been produced during t h e hydrogenation of soybean o i l , which forms the base stock of most margarines.
The t r a n s f a t t y acids present i n human t i s s u e apparently arise
s o l e l y from dietary fat, and as i n rats, they do not normally appear i n t h e
tissues unless a source of t r a n s f a t t y acids i s included i n t h e d i e t .
Samples of f a t from human placental, maternal., f e t a l , and baby t i s s u e were
182.
examined f o r t h e presence of t r a n s f a t t y acids. While t h e maternal t i s s u e
contained considerable amounts of trans f a t t y acids, these l i p i d s were not
found t o any measurable extent i n placental, f e t a l , or baby f a t (Johnston
'58)
a
The percentage of t r a n s f a t t y acids i n rat f a t decreased when
t r a n s f a t t y acids were removed from t h e d i e t (Johnston '58a). However,
they did not completely disappear from t h e tissue even at t h e end of two
months on a d i e t f r e e of trans f a t t y acid. After one month on t h e d i e t
f r e e of trans f a t t y acid, t h e carcass f a t of t h e rats which had received
10% of margarine stock had decreased from 18.6 t o 6.5% and after two months
t o 4.4% of t r a n s f a t t y acids. The carcass f a t of t h e animals which had received margarine stock and o l i v e o i l contained approximately 11% of t r a n s
f a t t y acids. After one month on a d i e t f r e e of t r a n s f a t t y acids, t h e carcass f a t decreased t o 4.9% and after two months t o 2.8% of trans f a t t y
acids. It seems evident t h a t t h e high t r a n s f a t t y acid content of margar i n e f a t could "harden" human depot f a t and counteract t h e "softening" i n fluence of l i n o l e i c acid. The iodine value of such depot f a t would
indicate a higher P/S r a t i o . However, t h e melting point and other physical
c h a r a c t e r i s t i c s of t h e depot f a t might not be changed s i g n i f i c a n t l y from a
depot f a t which contained s t e a r i c instead of trans o l e i c acid, t h a t i s
someone eating b u t t e r f a t instead of margarine.
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The palmitic and s t e a r i c acid which i s found i n t i s s u e f a t does
not have t o be consumed as a component of dietary f a t s . It has been shown
w i t h t h e aid of CI4 labeled acetic acid (two carbon atoms long i n chain
i n vivo so t h a t
length) t h a t f a t t y acids can be shortened o r elongated -t r i g l y c e r i d e s specific t o each species can be synthesized i n animal t i s s u e .
For example (Table 6), it has been shown t h a t s t e a r i c acid can be converted
t o palmitic acid through t h e collaboration of f i v e d i f f e r e n t enzymes and t h e
presence of t h e proper cofactors (Bloch '60). I n t h e o v e r a l l reaction
coenzyme A adds t o s t e a r i c acid and two carbon atoms are removed as acetyl
Co A. The r e s u l t i n g palmityl Co A can add i n vivo t o a dig1ycerj.de t o produce a t r i g l y c e r i d e which contains one mole of p d m i t i c instead of s t e a r i c
acid. When it i s not needed f o r t r i g l y c e r i d e synthesis, t h e palmityl Co A
can be degraded u n t i l a l l of it i s converted t o acetyl Co A.
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The acetyl Co A, i n t h e presence of bicarbonate, adenosine
triphosphate and b i o t i n enzyme, can be carboxylated t o form malonyl Co A
(Table 7). The malonyl Co A i n t h e presence of reduced triphosphopyridine
nucleotide (TFNH) and with t h e elimination of water can be converted back
t o palmitic acid (Lynen '61). I n the process of synthesis, both palmitic
and s t e a r i c acid can be dehydrogenated t o palmitoleic o r o l e i c acid respect i v e l y . Thus with t h e a i d of a dietary source of e s s e n t i a l f a t t y acids,
animal t i s s u e can produce f a t t y acids of proper chain length and t h e degree
of unsaturation which i s best suited f o r i t s needs. However, t h e excessive
consumption of d i e t a r y sources of e s s e n t i a l f a t t y acids such as corn o i l
w i l l contribute t o t h e "metabolic pool" of acetyl Co A as e f f e c t i v e l y as an
excessive consumption of animal fats. F u r t h e m r e , when t i s s u e s are flooded
with large arrounts of a highly unsaturated fat, they appear t o accumulate
i n t i s s u e s i n abnormal amounts (Chu and Kummerow '50). (Table 8 ) .
Under normal conditions carbohydrates furnish t h e major r a w
material f o r t h e synthesis of f a t t y acids. Pyruvic acid (Table 9 ) by means
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of oxidative decarboxylation forms acetyl Co A. Metabolic pathways are
a l s o available f o r t h e synthesis of f a t t y acids from amino acids. The
glucogenic amino acids are convertible t o pyruvic acid; t h e ketogenic amino
acids form acetate o r acetoacetate both of which are lipogenic. I n a l l
cases acetyl Co A i s t h e immediate s t a r t i n g material f o r t h e formation of
f a t t y acids.
The "metabolic pool" of acetyl Co A does not e x i s t as such but i s
i n a continuous state of flux. If t h e d i e t a r y intake of metabolites i s j u s t
s u f f i c i e n t o r i s m a d e d e f i c i e n t by t h e excessive use of muscles and acetyl
Co A i s used up i n t h e c i t r i c acid cycle t o produce heat and energy (I),
t h e conversion of acetyl Co A t o f a t t y acids (11) and cholesterol (111)
would be minimal. However, i f t h e t o t a l c a l o r i c intake i s i n excess of
energy and maintenance requirements, acetyl Co A i s converted t o f a t t y
acids and cholesterol. The major portion of t h e excess serum cholesterol
i s c o n v e r t e d t o b i l e acids i n t h e l i v e r and excreted. However, t h e excess
f a t t y acids are deposited as t r i g l y c e r i d e s and along with cholesterol,
phospholipids and other l i p i d s add t o t h e unwanted deposits of t i s s u e f a t s .
It i s therefore e s s e n t i a l t o balance t h e energy requirements against t o t a l
c a l o r i c need i n order t o prevent an accumulation of t i s s u e fats. The
adipose t i s s u e f a t and serum cholesterol l e v e l can be reduced by increasing
energy expenditures o r by decreasing c a l o r i c intake. However, t h e obesity
problem attests t o t h e f a c t t h a t it i s d i f f i c u l t t o carry out 812 orderly
metabolism of n u t r i e n t s i n an atmosphere of dietary abundance.
The highly unsaturated f a t t y acids have been divided i n t o t h r e e
families (Mead ' 6 0 ) , t h e o l e i c , l i n o l e i c , and linolenic acid families respectively (Table 10). Curing t h e i r metabolism these f a t t y acids are
elongated and desaturated t o a s e r i e s i n which t h e f i r s t double bond i s
located at t h e 9th, 6th or 3rd position from t h e methyl end of t h e f a t t y
acid chain. The elongated o l e i c family i s characterized by t h e CH3(CH2)3
ending; it e x i s t s t o an appreciable extent i n f a t - d e f i c i e n t animals. I n
such animals a considerable amount of a C20 t r i p l e unsaturated 5,8,11eicosatrienoic acid i s formed by elongation of o l e i c acid, by the addition
of acetyl Co A and by desaturation of t h e carbon chain. The l i n o l e i c derived family present i n d i e t a r y fats i s characterized by the CH3(CH2)4
terminal group of t h e "essential" l i n o l e i c acid and i t s elongated derivative, t h e C20 arachidonic acid. The linolenic family i s characterized by
t h e CH3CH2 end group and i s found i n t h e serum l i p i d s of animals fed
linolenic acid. Holman and Mohrhauer ('63) believe t h a t when linolenic
acid i s present i n t h e dietary f a t i t s conversion t o higher unsaturated
f a t t y acids takes precedence over t h e metabolism of l i n o l e a t e by a f a c t o r
near tenfold. Linoleate metabolism proceeds i n preference t o o l e a t e
metabolism and o l e a t e metabolism t o higher unsaturated acids can take place
only when l i n o l e a t e and linolenate are present i n low concentration.
Mead ('60) has traced t h e steps involved i n t h e conversion of
l i n o l e i c t o arachidonic acid. However, t o date, t h e degradation of
l i n o l e i c acid has not been f u l l y elucidated. It i s not known whether unsaturated fatty acids are f i r s t biohydrogenated and then degraded i n t o two
carbon u n i t s o r whether they are d e s d u r a t e d f u r t h e r before they are
metabolized. W e are presently following t h e metabolism of t r i t i u m labeled
l i n o l e i c acid, which has been prepared i n our laboratory, and hope t o
c l a r i f y t h i s point i n t h e near future.
184.
An i n t e r e s t i n g r e l a t i o n s h i p between t h e t h r e e families of unsatur a t e d f a t t y acids (Table 11) has been noted when they are incorporated i n t o
Vitamin E d e f i c i e n t d i e t s . A l l t h r e e f a m i l i e s of unsaturated f a t t y acids
cause exudative d i a t h e s i s i n chick and muscular dystrophy i n rats, rabbits,
sheep and c a t t l e . However, only t h e e s s e n t i a l f a t t y acids of t h e l i n o l e i c
acids s e r i e s cause chick encephalomalacia (Kummerow '64).
Since polyunsaturated f a t t y acids are incorporated i n t o t h e l i p i d s
which are involved i n t h e surface s t r u c t u r e of t h e c e l l w a l l , d i e t a r y f a c t o r s may e x e r t some influence on t h e i n t e g r i t y of t h e c e l l s . For example
(Walker '64) v a r i a t i o n of t h e d i e t a r y f a t and t h e omission of Vitamin E
f r o m t h e d i e t r e s u l t e d i n changes i n t h e s t a b i l i t y of erythrocytes. Vitamin
E deficiency r e s u l t e d i n t h e most s i g n i f i c a n t changes, whereas t h e nature of
t h e d i e t a r y f a t tended t o modify t h e degree of change. The c e l l s from
Vitamin E-supplemented rats showed l i t t l e o r no hemolysis; w i t h corn o i l
t h e degree of hemolysis was g r e a t e r than w i t h t h e more saturated l a r d . Replacement of c e l l u l a r oxygen with carbon monoxide i n h i b i t e d t h i s hemolytic
a c t i v i t y , which i s consequently believed t o be oxidative i n nature.
I n another s e r i e s of experinents, t h e importance of t h e e s s e n t i a l
f a t t y acids t o t h e s t r u c t u r a l i n t e g r i t y of t h e c e l l w a s studied (Walker
'64). A n increasing amount of d i e t a r y l i n o l e i c acid as supplied by coconut
o i l , b u t t e r f a t , c a s t o r o i l and corn o i l r e s u l t e d i n increased incorporation
of l i n o l e i c acid i n t o t h e c e l l w a l l of erythrocytes and a l s o t o increased
arachidonic acid incorporation (Table 1 2 ) . Where d i e t a r y l i n o l e a t e was res t r i c t e d , more palmitoleic and o l e i c acids were incorporated i n t o t h e
c e l l u l a r l i p i d s , and t h e eicosatrienoic acids c h a r a c t e r i s t i c of e s s e n t i a l
f a t t y acid deficiency w e r e also found i n increasing amounts, comprising
over 16% of t h e t o t a l f a t t y acids when hydrogenated coconut o i l was t h e
dietary fat.
The erythrocytes f r o m t h e s e animals were subjected t o hemolysis
by isotonic solutions of t h r e e non-electrolytes glycerol, t h i o u r e a and triethylene glycol. With each s o l u t e studied, t h e hemolysis r e s u l t i n g from
t h e permeation of t h e s o l u t e i n t o t h e c e l l was most rapid i n c e l l s from t h e
a n i m a l s fed coconut o i l . A s t h e d i e t a r y l i n o l e i c acid intake increased,
t h e r a t e of hemolysis decreased. It i s possible t h a t hemolysis r e f l e c t e d
s t r u c t u r a l changes a r i s i n g i n t h e erythrocyte membrane from t h e incorporat i o n of s p e c i f i c f a t t y acids.
I n a recent report, Vendenheuvel ( ' 6 3 ) advanced a model f o r biol o g i c a l organization at t h e molecular l e v e l . T h i s model involved a complex
r e s u l t i n g from the association of c h o l e s t e r o l with sphingomyelin or
glycerophosphatide and w a s applied s p e c i f i c a l l y t o t h e s t r u c t u r e of t h e
myelin sheath. It i s i n t e r e s t i n g , however, t o consider t h e p o s s i b i l i t y of
t h e r o l e of t h e e s s e n t i a l f a t t y acids i n t h e phospholipid of such complexes
(Fig. 1). I n a representation of l e c i t h i n constructed geometrically from
the parameters given by Vandenheuvel, t h e d -position of t h e glycerol moiety
i s esterified w i t h s t e a r i c acid (ABC) and t h e & - p o s i t i o n with arachidonic
(ABDE) or 5,8,11-eicosatrienoic acid (ABDF). I n a complex such as t h a t
proposed by Vandenheuvel, t h e curvature of t h e arachidonic acid chain would
r e s u l t i n g r e a t e r stearic hindrance t o t h e c h o l e s t e r o l than would mono- or
dienoic acids. However, t h e s u b s t i t u t i o n of t h e t r i e n o i c acid for t h e
arachidonic acid also r e s u l t s i n an increase i n t h e o v e r - a l l width of t h e
185.
l e c i t h i n moiety. This increase, Y, i s about 20% of t h e width, X, of t h e
arachidonyl-lecithin. It i s tempting t o speculate t h a t some of t h e properties of c e l l membranes may be governed by t h e type of f a t t y acid i n t h e
complex. For example, when t h e o l e i c o r linolenic series of polyunsatur a t e d f a t t y acids are incorporated i n t o t h e c e l l at t h e expense of
arachidonic acid, a change i n s t r u c t u r e of t h e molecules may occur and m a y
result i n a looser packing of t h e phospholipid complexes i n t h e membrane
thus a l t e r i n g i t s s t a b i l i t y and permeability.
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It i s i n t e r e s t i n g t o note t h a t t h e c18 cis-9, trans-12,
octadecadienoic acid, a possible component of hydrogenated soybean o i l , can
be elongated and desaturated t o t h e Czo, 5,8,11,14-eicosatetraenoic acid,
t h e C18 t r a n s f a t t y acid w i l l not prevent t h e symptoms of e s s e n t i a l f a t t y
acid deficiency. The Cz0 f a t t y acid i s a geometric isomer of arachidonic
acid with a t r a n s double bond i n t h e 14- position. The orthogonal project i o n of a phosphatide containing t h i s C 2 0 f a t t y acid would be very similar
t o t h a t of t h e phosphatide containing t h e non-essential eicosatrienoic
derived from o l e i c acid and m a y also alter the s t a b i l i t y and permeability
of erythrocytes. Thus a simple change i n t h e composition of t h e unsaturated
f a t t y acids i n t h e t i s s u e lipids may influence t h e i n t e g r i t y of c e l l
membranes.
SUMMARY
I n summary, d i e t a r y fats represent t h e most compact food energy
source available t o man. However, dietary f a t s should not be thought of
s o l e l y 88 providers of unwanted c a l o r i e s as f a t s are as v i t a l t o c e l l
s t r u c t u r e and biological function as protein. Tissue f a t can be synthesized from either carbohydrate o r protein, therefore, t h e t o t a l c a l o r i c
intake rather than any one dietary component i s c r u c i a l t o t h e amount of
deposition of l i p i d s i n t o t h e t i s s u e .
An optimum intake of e s s e n t i a l f a t t y acids may be important t o
t h e i n t e g r i t y of t h e c e l l w a l l of erythrocytes. However, u n t i l t h e e n t i r e
p i c t u r e of t h e r o l e of d i e t a r y f a t s i n optimum n u t r i t i o n i s c l a r i f i e d , it
would seem judicious t o consume a well-balanced d i e t of meat, milk, eggs,
vegetables, fruits, and s u f f i c i e n t c e r e a l s and bread t o provide f o r an adequate protein, vitamin, and c a l o r i c intake. The optimum t o t a l intake of
l i n o l e i c acid by man has not been established. The l e v e l of l i n o l e i c acid
i n t h e American d i e t a r y p a t t e r n could be increased through t h e a v a i l a b i l i t y
of less severely hydrogenated shortenings but t h e indiscriminate d i e t a r y
substitution of "soft" f o r "hard" fats seems undesirable.
REFERENCES
Bailey, A. E. 1950 Melting and S o l i d i f i c a t i o n of F a t s .
Publishers, New York, p . 166.
Bailey, A. E. 1951 I n d u s t r i a l O i l and Fat Products.
Publishers, New York, p . 759.
Interscience
Interscience
186.
Bloch, K.
1960 Lipid Metabolism.
John Wiley & Sons, New York, p. 41.
Chu, T. K. and F. A. Kummerow 1950 The Deposition of Linolenic Acid i n
Chickens Fed Linseed O i l . Poultry S c i . , 24: 846.
Cramer, D. L. and J. B. Brown 1943 The Component F a t t y Acids of Human
Depot F a t . J . Biol. Chem., 151: 427.
Hilditch, T. P. 1956 The Chemical Constitution of Natural F a t s .
Wiley & Sons, New York, p . 391.
John
Johnston, P. V., D. C. Johnson and F. A. Kummerow 1958a Deposition i n
Tissues and Fecal Excretion of Trans F a t t y Acids i n t h e R a t . J.
Nutrition, 65: 13.
-
Johnston, P. V., F. A. Kummerow and C. H. Walton 1958 Origin of Trans
F a t t y Acids i n Human Tissue. D o c . SOC. Exptl. Biol. Med., 99: 735.
-
Kummerow, F. A. 1964 The Possible Role of Vitamin E i n Unsaturated F a t t y
Acid Metabolism. Fed. Proc., i n p r e s s .
Kummerow, F. A. 1964 The Role of Polyunsaturated F a t t y Acids i n Nutrition.
Food Tech., i n p r e s s .
Lynen, F.
1961 Biosynthesis of Saturated F a t t y Acids.
Markley, K. S.
p . 34.
1960 F a t t y Acids.
Fed. Proc., g : 9 4 1 .
Interscience Publishers, New York,
Mead, J. F. 1960 Metabolism of t h e Polyunsaturated F a t t y Acids.
Clin. Nutrition, 8: 55.
-
Am. J.
Mohrhauer, H . and R. T. Holman 1963 The Effect of Dietary E s s e n t i a l
F a t t y Acids Upon Composition of Polyunsaturated F a t t y Acids i n Depot
Fat and Erythrocytes of t h e Rat. J . Lipid Res., 4:
- 346.
Vendenheuvel, F. A. 1963 Study of Biological Structure at t h e Molecular
Level with Stereomodel Projections. I. The Lipids i n t h e Myelin
40: 455.
Sheath of Nerve. J. Am. O i l Chem. SOC., Walker, B. and F. A. Kummerow 1964 Dietary Fat and t h e Structure and
Properties of R a t Erythrocytes. J . Nutrition, 82: 323.
Walker, B. and F. A. Kummerow 1964 Erythrocyte F a t t y Acids and Apparent
Permeability t o Non E l e c t r o l y t e s . h o c . SOC Exptl. Biol. Med.,
115: 1099.
-
.
187.
TABLE 1
Melting; Points of F a t t y Acids
Saturated
c4
Butyric
m.p .OC
-7.9
C14 m i s t i c
m.p .OC
54.4
c6
Caproic
-3.4
c16 Palmitic
62.9
cg
Caprylic
16.7
C18
Cl0
Capric
31.6
Cz0 Arachidic
75.3
C12
Lauric
44.2
C22 Behenic
79.9
Stearic
69.6
Uns a t u r a ted
'16 :1
Palmitoleic
-1
%8:1
Oleic
14
Linoleic
-12
Arach idonic
-49
%8:2
c20:4
TABm 2
-
---
The E f f e c t of Unsaturated F a t t y Acids on t h e
MeltiG -Triglyceride
---
Glyceride
M.P.
-
73%
P-P-P
66OC
s-s-0
38
P-0-P
35
s-0-s
43
P-0-0
19
s-0-0
23
M-0 -0
14
L-0-0
7
Glyceride
s-s-s
M.P.
-
O-Oleic; P-Palmitic; S-Stearic Acid; L-Linoleic; M-Myristic
188.
TABLE 3
Glyceride
-
-
-
Composition of Vegetable and A n i m a l F a t s
GS3
A-
GSzU
?b
GSU2
corn oil
1
15
45
38
Cottonseed o i l
0
13
44
43
Coconut o i l
84
12
4
0
Butterfat
35
36
29
0
Beef t a l l o w
15
46
37
2
Lard
2
26
55
17
Human (adipose)
5
26
43
24
Human (milk)
9
40
43
8
S
- Saturated f a t t y acid
U
2
- Unsaturated
f a t t y acid
TABLE 4
----
Melting Points of C i s and T r a n s Isomers
C------x
ll
Y
C
x-----c
11
Oleic
m.p. 14C
'
X
Y
C
Elaidic
m . p . 52OC
d
11
X
4
I1
C----c-----c
C + 4
II
ll
Y
C
Linoleic
m.p. -12'~
Linoelaidic
C
m.p.
29OC
Y
189.
TABLE 5
Comparative Composition
of
Margarines
F a t t y Acid
M39#
F39#
Palmitic
14.7
16.2
Stearic
7.3
T o t d sat.
A29k
9.4
11.7
9.3
5.1
13.0
22.3
25.7
14.8
25 .O
Oleic
41.7
43.4
73.3
47.5
Linoleic
35.4
30.2
10.8
25.8
T o t a l Unsat.
77.1
73.6
84.1
73.3
Total "Trans"
28.7
19.6
43.6
48.6
TABI;E 6
Conversion
of
S t e a r i c Acid to Metabolic Products
a3(CH2)16CmH
+
2HSCoA
( S t e a r i c Acid)
+
(Coenzyme A)
CH3(CH2) 14COOH
+
CH3COSCoA
(Palmityl CoA)
+
(Acetyl CoA)
1
BCH~COSCOA(Acetyl CoA)
190.
TABLE 7
-
The Synthesis of Palmitic Acid
CH3COSCoA
(Acetyl CoA)
+
HCO3
+HOOCCH2COSCoA
(Carbonate)
(Malonyl CoA)
CH~CHZCH~COSCOA
(Butyryl CoA)
1
J
CH; (CH2) 14COSCoA (Palmityl CoA)
&
TABLE 8
and Linolenic --i n Skin Fat
Acetone Soluble and Insoluble Oleic
Dietary
Lin. o i l
Soluble
Oleic
Insoluble
0%
23.3%
30.8%
6%
16.2%
1%
2570
Linolenic
Insoluble
Soluble
0.8%
0.3%
39.$
20.7%
0.9%
24.7%
47 .s$
22.276
1.1%
21-85
50 .l$
28.0%
1.2%
191.
TABLE 9
-
Relationship of Metabolites
Carbohydrate
4
Pyruvate
Protein
-C02
+&A
I
-
A
I
Citrate
'
Oxbo
acetate
u
coz+H20
+
-m2
+CoA
Acetyl
I
I
I1
-
A Long'chain
f a t t y acids
(CH~-CHZ)~COOH
-2H
Oleic acid
depos i t e d
i n tissue
4
amino
acids
I11
ste i o1s
1
bile
acids
excreted
(heat & energy)
TABLE 10
Metabolites of t h e Three Unsaturated F a t t y Acid Families
All
9
oleic
b-
eicosadienoic
20:2
b-.
machidonate
20:4
18:l
All
6
linoleake
18:2
All
3
linolenate
18:3
+-
e i cosapentaenoic
20:5
6,9,12,15
_____.)
b) - .
arachidonic acid
eico satrienoic
20:3
doc0 6 apentaenoic
22:s
doc0 Sapentaenoic
22:s
192.
TABLE 11
Pathology Caused b z V i t a m i n E, Deficiency
Pat ho logy
symptom
Case
Delayed by
diathesis
Edema
PUFA
Se
2.
Myopathy
rnscular
dystrophy
11
3.
Encephalomalacia
Spasm or
paralysis
EFA
1. Exudative
S amino
acids
Linolenic
series
TABLE 12
F a t t y Acid Composition of t h e Erythrocyte Lipids
-
Acid
Coconut 0i1
Castor o i l
corn O i l
16:O
22.4$
2s. 2%
24.2$
16:l
2.7
1.7
0.4
18:O
14.2
13.5
13.5
18:l
15.7
13.5
8.6
1a:2
2.2
5.3
11.5
20:3
15 .O
1.3
0.1
20: 3
1.o
1.1
0.5
15.4
26.3
31 .O
20:4
153.
PHOSPHATIDYL
CHOLINE
C
.
.e...
GLYCCEROL C
0
OXYGEN
-0-
OXYGEN
=O
@ OXYGIEN
.. .
. .... .....’
V
0
-0-
.
d
NITROGEN
F
ABC
m
A
- STEARIC ACID
ABDE
-
ARACHIDONIC ACID
ABOF
-
PHOSPHORUS
ECOSATRIENOIC ACID
Figure 1
DR. KASTEWC: Thank you, Dr. -row.
I thipk we w i l l withhold
questioning u n t i l a f t e r we have had an opportunity t o hear the next paper.
I take great pleasure i n introducing Dr. Hector DeLuca, who is a member of
the Department of Biochemistry here at the University of Wisconsin, a w e l l
known biochedst. I understand now t h a t he i s following the i n t e r e s t of Dr.
Steenbock, as might be surmised fromthe topic of h i s discussion t h i s afternoon. I take pleasure i n welcoming him t o t h i s group. D r . DeLuca,
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