Food Chemis y: Molecula Sciences 4 (2022) 100060
A ailable online 3 Decembe 2021
2666-5662/© 2021 The Au ho s. Published by Else ie L d. This is an open access a icle unde he CC BY-NC-ND license
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Die a y a y acid me abolism: New insigh s in o he simila i ies o lipid
me abolism in humans and hams e s
Alai z Be iozabalgoi ia, Juan Ca los Ruiz de Go doa, Gus a o Amo es, Mailo Vi o
*
Lac ike Resea ch G oup, Depa men o Biochemis y and Molecula Biology, Uni e si y o he Basque Coun y UPV/EHU, Paseo de la Uni e sidad 7, 01006 Vi o ia-
Gas eiz, Spain
ARTICLE INFO
Keywo ds:
Fa y acids
Fa y acids/me abolism
Plasma
E y h ocy es
Animal models
Hams e s
Oli e oil
Dai y a
ABSTRACT
Hams e s ha e been long accep ed as animal models o s udy he lipid me abolism in humans. Howe e , e y ew
scien i ic wo ks desc ibed in de ail he a y acid (FA) composi ion o plasma and e y h ocy es in hams e s in
ela ion o hei die a y in ake, and none wo k was ound compa ing hem wi h ha desc ibed in humans.
The e o e, a s udy was ca ied ou o compa e he e ec o inges ing oli e oil o dai y a , as pa o an equil-
ib a ed die in heal hy subjec s, on plasma and e y h ocy es FA composi ion. Mo e han 40 FA we e de ec ed in
samples o bo h species. I was demons a ed ha plasma o al FA (TFA) concen a ion and FA p o iles a e simila
in humans and hams e s. In bo h species linoleic, oleic and palmi ic acids a e he main FA and accoun ed o he
70% o TFA. Di e ences ound be ween species can be explained by di e ences in he die a y in ake and di -
e ences in he p opo ion o iglyce ides, choles e yl es e s and phospholipid ac ions in plasma o bo h spe-
cies. Changes in die a y FA in ake causes simila changes in FA concen a ion in he plasma o bo h species and
can be explained by he same me abolic p ocesses. The e y h ocy e FA p o ile di e s mo e be ween he wo
species. Mo eo e , unlike humans, he FA p o ile o hams e e y h ocy es is mo e sensi i e o changes in die a y
FA han ha o plasma.
1. In oduc ion
The majo p opo ion o plasma a y acids (FA) is es e i ied in
a ious lipid classes ( iglyce ides, TG; phospholipids, PL; choles e yl
es e s, CE), which a e componen s o lipop o eins, whe eas small
amoun s a e no es e i ied (NEFA) and a e bound o albumin. Ne e -
heless, FA composi ion o di e en blood lipid ac ions is in e ela ed
(Hodson, Skea , & Fielding, 2008). The e o e, plasma o al FA (TFA)
pool ep esen s a mix u e o all lipid ac ions ha con ain FA and also
e lec s he FA p o ile o issues (McCloy, Ryan, Pencha z, Ross, &
Cunnane, 2004).
The FA composi ion o plasma and issues a e he esul o a ious
p ocesses, e.g. die a y in ake, in es inal abso p ion, me abolism and
s o age and exchanges among compa men s.
When he die a y a is diges ed, FA a e inco po a ed in o
chylomic ons in o m o TG in he en e ocy e and en e he sys emic
ci cula ion. A e wa ds, hey a e inco po a ed in o endogenous lipids o
en e me abolic pa hways, which a e speci ic o each FA (Hodson,
McQuaid, Ka pe, F ayn, & Fielding, 2008). Thus, he ela ionship be-
ween inges ed FA and hei p esence in plasma lipid ac ions is a iable
and has been ex ensi ely s udied. In he e iew o Hodson e al. (2008)
he au ho s conclude ha , in gene al, posi i e co ela ions ha e ound
o polyunsa u a ed FA (PUFA) in ei he , o al plasma and plasma
ac ions. Howe e , o sa u a ed FA (SFA) and monounsa u a ed FA
(MUFA) he esul s a e mo e a iable and depend on he FA. Fo
example, he co ela ion ound be ween he in ake o my is ic acid
(14:0), 14:1, 15:0 and 17:1 and he FA composi ion o blood lipids is, in
gene al, s ong. Howe e , o o he SFA and MUFA, he epo ed co -
ela ions a e mo e a iable and, gene ally, weake (Hodson e al., 2008).
On he o he hand, i has been demons a ed ha he FA composi ion
Abb e ia ions: ALA, Alpha-linolenic acid; ARA, A achidonic acid; BCFA, Me hyl-b anched chain a y acids; CE, Choles e yl es e s; CLA, Conjuga ed linoleic acids;
c-MUFA, cis-Monounsa u a ed a y acids; DHA, Docosahexaenoic acid; D6D, Del a-6 desa u ase; EPA, Eicosapen aenoic acid; FAME, Fa y acid me hyl es e s; LA,
Linoleic acid; LCPUFA, Long chain polyunsa u a ed a y acids; LCSFA, Long chain sa u a ed a y acids; MCSFA, Medium-chain sa u a ed a y acids; OA, Oleic acid;
PUFA, Polyunsa u a ed a y acids; PL, Phospholipds; RA, Rumenic acid; SCD-1, S ea oyl-CoA desa u ase-1; SFA, Sa u a ed a y acids; TC, To al Choles e ol; TFA,
To al a y acids; TG, T iglyce ides; -MUFA, ans-Monounsa u a ed a y acids; VA, Vaccenic acid.
* Co esponding au ho .
E-mail add ess: [email p o ec ed] (M. Vi o).
Con en s lis s a ailable a ScienceDi ec
Food Chemis y: Molecula Sciences
jou nal homepage: www.sciencedi ec .com/jou nal/ ood-chemis y-molecula -sciences
h ps://doi.o g/10.1016/j. ochms.2021.100060
Recei ed 16 Sep embe 2021; Recei ed in e ised o m 25 No embe 2021; Accep ed 27 No embe 2021
Food Chemis y: Molecula Sciences 4 (2022) 100060
2
o e y h ocy es, which e lec s mainly he composi ion o hei mem-
b ane PL, is sensible o changes in FA composi ion o he die . Fo
example, Fuh man e al. (2006) showed ha e y h ocy es memb ane FA
con en is a alid bioma ke o die a y le els o linoleic acid (18:2n-6,
LA), oleic acid (cis9-18:1, OA) and PUFA. Be iozabalgoi ia e al. (2021)
ound a signi ican co ela ion be ween dai y a inges ion and he
concen a ion o FA as my is ic acid, 17:0 o accenic acid ( ans11-18:1,
VA) in e y h ocy es.
In he scien i ic li e a u e, special a en ion has been paid o he e -
ec o dai y a inges ion on plasma lipids because o i s ela i ely high
con en o sa u a ed a and he con lic ing heal h e ec s desc ibed in
he li e a u e (Tho ning e al., 2017). Howe e , dai y a has been also
ex ensi ely s udied because o i s unique FA composi ion. Mo e han 400
di e en FA ha e been iden i ied in bo ine dai y a . Some o hem a e
syn hesized de no o by umen bac e ia. Fo example, ans-FA, p ima ily
VA and umenic acid (cis9, ans11-18:2, RA) a e p oduc s o C18 PUFA
biohyd ogena ion in he umen (La e oux, Glasse , Gille , Joly, &
Do eau, 2011). Bac e ia in he gu o uminan animals also p oduce
me hyl-b anched chain FA (iso and an eiso FA, BCFA) by deamina ion
and elonga ion o b anched amino acids (Val, Leu and Ile) (Vlaeminck,
Fie ez, Cab i a, Fonseca, & Dewhu s , 2006). All hese FA can each he
mamma y gland whe e hey a e inco po a ed in o dai y lipids. Because
hei main die a y sou ce a e dai y p oduc s, hey ha e been p oposed as
bioma ke s o dai y a in ake (Be iozabalgoi ia e al., 2021). Besides,
hese FA ha e been ela ed o bene icial heal h e ec s. Fo example, RA
has been ela ed o educed isk o cance , a he oscle osis and obesi y
(Bu dge e al., 2005) and BCFA ha e been shown o ha e an i-cance
ac i i y (Vlaeminck e al., 2006).
On he o he hand, oli e oil is he main a in he Medi e anean die ,
i s composi ion o FA is well de ined and i s a ou able e ec s on human
heal h ha e been widely demons a ed.
Animal models a e impo an o unde s and he physiological and
me abolic mechanisms o pa hological s a es in which lipid me abolism
is in ol ed. Mos o lipid me abolism compa isons be ween species a e
p ima ily ocused on plasma lipop o ein p o iles and majo lipid com-
ponen s such as o al choles e ol (TC) and TG (Kaabia e al., 2018; Yin
e al., 2012). In hese s udies, hams e s we e shown o be he animal
model wi h a lipid me abolism mos simila o ha o humans.
Golden Sy ian hams e s (Mesoc ice us au a us) began o be used in
he 1980s o s udy die -induced a he oscle osis and ca dio ascula dis-
ease in humans. Al hough no ye widely used oday, hey a e a sui able
model o esea ch in o diseases o his ype, as hey end o su e om
hype choles e olemia and a he oscle osis ea ly lesions wi h an a he o-
genic die (Nis o , Bulla, Filip, & Radu, 1987). Mo eo e , hams e s and
human lipid p o iles a e compa able and bo h sha e CE ans e ase
p o ein (CETP). This p o ein acili a es he anspo o CE and TG be-
ween lipop o eins (Kaabia e al., 2018). Howe e , e y ew scien i ic
wo ks desc ibed in de ail he FA composi ion o plasma and e y h ocy es
in hams e s, and none wo k was ound compa ing hem wi h ha
desc ibed in humans.
The FA composi ion o dai y p oduc s and oli e oil is e y di e en .
Ye , bo h a e habi ual componen s o he human die . Thus, he com-
pa ison o hei e ec on plasma and e y h ocy es FA, when hey a e
inges ed as pa o an equilib a ed die in heal hy subjec s, is in e es ing
in o de o unde s and he me abolic a e o di e en kind o FA, and o
analyse whe he , in his aspec o lipid me abolism hams e s pe o m in
simila way han humans.
2. Ma e ials and me hods
2.1. Hams e s, die s and expe imen al design
Expe imen s wi h hams e s we e ca ied ou in acco dance wi h he
ins i u ion’s guide o he ca e and use o labo a o y animals (app o al
documen e e ence CEBA/209/2011/VIRTO LECUONA).
Fou -week-old male Golden Sy ian Hams e (Mesoc ice us Au a us)
RjHan:AURA (Jan ie Eu ope, F ance) (n =16) we e housed in
con olled oom empe a u e and humidi y and unde a 12:12 h a i i-
cial ligh /da k cycle (ligh on a 21:00) wi h ee access o wa e and
ood. A e a week adap a ion pe iod, he hams e s we e andomly
dis ibu ed in wo expe imen al g oups o eigh animals each, wo ani-
mals in each cage.
Each g oup ollowed an expe imen al die o 14 weeks. Basal mix
die s we e p epa ed by Ha lan (Teklad Cus om Resea ch Die , Ha lan
Labo a o ies, Madison, WI, USA) and we e supplemen ed wi h oli e oil
(OO7 die ) o milk a (MF7 die ) o ob ain a inal concen a ion o 7% o
a by weigh . Comme cial oli e oil was pu chased om local ma ke
(Vi gin Oli e Oil, La Espa˜
nola, Acesu , Spain). Milk c eam was ob ained
by cen i uga ion (2000 g a 4 ◦C o 30 min) o aw sheep milk pu -
chased om a local sheephe de . Sheep milk was used because o i s
highe con en o a and FA as VA and RA compa ing wi h cow milk.
Gene al composi ion o die s and FA composi ion o used a s a e shown
in Table 1 and Supplemen a y Table 1, espec i ely.
Faeces we e collec ed o 3 consecu i e days immedia ely p io o he
end o he s udy and s o ed a −80 ◦C un il analysed. Hams e s we e eed
dep i ed o 12 h and anes he ized wi h iso lu ane (100% w/w, Es e e,
Ba celona) be o e sac i ice. Blood samples we e collec ed by ca diac
punc u e using capilla y ubes, wi h EDTA as an icoagulan . Plasma and
e y h ocy es we e sepa a ed by cen i uga ion a 800 g du ing 30 min.
A e sepa a ion, samples we e kep ozen a −80 ◦C un il analysed.
2.2. Human s udy
Samples o plasma and e y h ocy es we e ob ained om he in e -
en ion s udy p e iously desc ibed (Be iozabalgoi ia e al., 2021).
B ie ly, pa icipan s in he s udy we e asked o ollow hei habi ual die
bu wi h no dai y p oduc s du ing 18 days (no dai y die , NDD). A he
end o he 18 days, and o ano he 18 days, subjec s we e asked o
con inue wi h hei habi ual die adding a leas 375 g o ull a dai y
p oduc s and eco ding he amoun o dai y p oduc s inges ed e e y day
(dai y ich die , DRD). The in e en ion s udy was conduc ed acco ding
o he guidelines o he Decla a ion o Helsinki, and app o ed by he
E hics Commi ee o he Uni e si y o he Basque Coun y (p o ocol code
CEISH/199/2013/ VIRTO LEKUONA). All pa icipan s signed he
In o med Consen documen p io o he s a o he s udy.
Blood samples we e collec ed a e o e nigh as ing a he end o
each pe iod, in 5 mL acuum ubes imp egna ed wi h EDTA. Plasma and
e y h ocy es we e sepa a ed by cen i uga ion a 800 g du ing 30 min.
A e sepa a ion, samples we e kep ozen a −80 ◦C un il analysed.
2.3. Fa ex ac ion and FA analysis
A modi ied Folch me hod was used o ex ac a om c eam, oli e
oil and aeces. B ie ly, 1 g o sample was dispe sed in 40 mL chlo o o m:
me hanol: wa e (2:1:1). In he case o aeces, samples we e g ound in a
mo a and homogenized wi h he sol en mix u e in a po e homoge-
nize . The chlo o o m phase was sepa a ed by cen i uga ion (2200 g,
15 min, 4 ◦C) and washed wice wi h 25 mL o deionised wa e . The
Table 1
Gene al composi ion o die s.
OO7
1
MF7
2
P o ein (g/kg) 180.8 180.6
Ca bohyd a es (g/kg) 511.5 511.7
Fa (g/kg) 70.0 70.4
Fibe (g/kg) 64.6 64.6
Ene gy (kcal/g) 3.4 3.4
P o ein (% kcal) 21.3 21.2
Ca bohyd a es (% kcal) 60.2 60.1
Fa (% kcal) 18.5 18.6
Choles e ol (mg/kg) 157 155
1
Die con aining 7% (w/w) o oli e oil.
2
Die con aining 7% (w/w) o milk a .
A. Be iozabalgoi ia e al.
Food Chemis y: Molecula Sciences 4 (2022) 100060
3
chlo o o m was emo ed unde acuum and he ex ac ed a was
weighed. Ex ac ed a was hen dissol ed in oluene and glyce ides
we e anses e i ied o he co esponding FA me hyl es e s (FAME) by a
solu ion o sodium me hoxide in me hanol as desc ibed by Collomb and
Bühle (2000).
Fa ex ac ion om plasma and e y h ocy es, bo h om humans and
hams e s, and TFA me hyla ion we e accomplished in one-s ep,
ollowing a modi ied me hod o Bondia-Pons (Bondia-Pons, Mol ´
o-
Puigma í, Cas ello e, & L´
opez-Saba e , 2007). FAME we e p epa ed
om 200 µL o plasma by sequen ially adding 2.5 mL o 0.5 M sodium
me hoxide in me hanol ollowed by 2.5 mL o 14% bo on i luo ide in
me hanol. Resul ing FAME we e ex ac ed adding 1.0 mL n-hexane and
collec ed in a ial wi h anhyd ous sodium sulpha e. Fo e y h ocy es,
a e adding sodium me hoxide, he cell suspension was sonica ed o 3
min in 10 s cycles.
FAME sepa a ion was achie ed by gas ch oma og aphy on a 100 m
CpSil88 capilla y column (Va ian Inc.). The ch oma og aph (Agilen
7890A Ch oma og aph, Agilen Technologies) was equipped wi h a FID
de ec o . FAME we e sepa a ed as desc ibed by Collomb and Bühle
(2000) and iden i ied by compa ing he e en ion imes o he ob ained
peaks wi h hose o au hen ic s anda ds. In e nal s anda d me hod was
used o quan i y he amoun o each compound, wi h undecanoic (11:0),
idecanoic (13:0) and nonadecanoic (19:0) acids as in e nal s anda ds.
The absolu e concen a ion o FA was exp essed in µmol/L and, om
his, he mola pe cen age was calcula ed.
S ea oyl-CoA desa u ase 1 (SCD-1) ac i i y was es ima ed using
indices based on he p oduc o p ecu so FA a ios 16:1n-7/16:0 o
18:1n-9/18:0 in plasma and e y h ocy es a (Vessby, Gus a sson,
Tengblad, & Be glund, 2013).
2.4. Plasma choles e ol, TG, and glucose measu emen s
Plasma biochemical pa ame e s we e analysed by colo ime ic
enzyma ic assays, using comme cial ki s: as ing glucose, TG and TC by
Biosys ems ki s (Biosys ems, Ba celona, Spain) and Wako ki o ee
choles e ol (Wako Chemicals, Richmond, VA). CE we e calcula ed by
sub ac ing ee choles e ol om TC.
2.5. S a is ical analysis
Da a we e exp essed as mean ±SEM. S uden s T es was used o
compa e means o wo g oups, a e checking o homogenei y o
a iance using Le ene’s es . S a is ical signi icance was decla ed a P <
0.05. All analyses we e done using he IBM-SPSS s a is ical so wa e o
Windows, e sion 25 (IBM, Chicago, Ill, USA).
3. Resul s
3.1. Hams e s
The pe o mance o hams e s ed expe imen al die based on oli e oil
(OO7) o milk a (MF7) was simila and no s a is ical di e ence was
ound in ood and ene gy in ake, weigh gain and eed e iciency
(Table 2). To al plasma choles e ol and CE we e sligh ly, bu signi i-
can ly, highe in OO7 hams e s.
3.2. FA in ood and hams e aeces
The p o ile o FA o bo h ype o ood is e y di e en (Fig. 1A,
Supplemen a y Table 1). Main FA g oup in oli e oil co esponds o cis
MUFA (c-MUFA) (77 mol%), while milk a con ains SFA in he highes
p opo ion (30% o medium chain SFA, MCSFA and 40% o long chain
SFA (LCSFA)).
The concen a ion o a in aeces was simila in bo h animal g oups
(Table 2). FA composi ion o ood and aeces we e compa ed in o de o
de e mine he abso p ion e iciency o di e en ype o FA. Main FA
g oups in aeces a e shown in Fig. 1B. De ailed FA composi ion is shown
in Supplemen a y Table 1.
The FA p o ile o he s ool was mo e simila o each o he han ha o
ood (Fig. 1B). The mola concen a ion o c-MUFA was much lowe in
aeces han in ood in bo h g oup o animals, which indica ed ha hey
we e p e e en ially abso bed. LCSFA in aeces we e in simila p opo ion
as in ood. On he con a y, PUFAn-6 and PUFAn-3 we e de ec ed in
aeces o bo h animal g oups in highe p opo ion han in hei espec-
i e oods. Some FA we e ound in aeces bu no in ood. Fo ins ance,
MCSFA, BCFA, ans-MUFA ( -MUFA) and conjuga ed linoleic acids
(CLA) we e de ec ed in aeces o hams e s ed oli e oil, almos in he
same concen a ion han in hose ed milk a , al hough hei concen-
a ion in he ood was e y low.
Wo h men ioning indi idual FA a e LA, which concen a ion was
much highe in aeces (26.90% and 14.29% in hams e s o OO7 and MF7
g oup, espec i ely) han in ood (6.07% and 1.88% in oli e oil and milk
a , espec i ely). Docosahexaenoic acid (22:6n-3, DHA) was no
de ec ed in any o he oods, bu i did appea in aeces in a signi ican
p opo ion (3.87% and 8.19%, o OO7 and MF7, espec i ely). The
p opo ion o VA, which is e y low in oli e oil (0.00136%), was highe
in aeces o OO7 (5.72%) g oup han in he MF7 g oup (2.85%).
3.3. FA in plasma o hams e s
The concen a ion o TFA in he plasma o hams e s, calcula ed as he
sum o he concen a ion o indi idual FA, we e 8711 ±1180 µmol/L
and 6059 ±999.4 µmol/L o hams e s o he OO7 and MF7 g oups,
espec i ely. The e was no signi ican di e ence (P >0.05) be ween
bo h animal g oups (Table 2).
The FA p o ile o plasma TFA was e y simila in bo h g oups o
animals, ega dless he ype o inges ed a . As i can be obse ed in
Table 3, PUFAn-6 we e he main FA g oup (40 mol%), while he sum o
LCSFA and c-MUFA we e in simila p opo ion (26–28%). Only he
concen a ion o he sum o MCSFA was signi ican ly highe in hams e s
ed milk a han in hose ed oli e oil.
In bo h g oups o animals he FA p esen in he highes concen a ion
was LA (25.7 and 28.8 mol% in OO7 and MF7 g oups, espec i ely),
ollowing by OA (24.1 and 21.8 mol%) and palmi ic acid (18.8 and 19.8
mol%). No s a is ical signi ican di e ence was ound be ween animal
g oups in he concen a ion o he main indi idual FA. The only ex-
cep ions we e s ea ic (18:0), cis- accenic (cis11-18:1) and a achidonic
acids (20:4n-6, ARA) whose concen a ion we e sligh ly bu signi ican ly
highe (Table 3) in OO7 g oup, and palmi oleic acid (cis9-16:1) ha was
in highe pe cen age in MF7 g oup. In ela ion o mino indi idual FA
Table 2
Gene al physical and plasma biochemical pa ame e s o hams e s.
Hams e s
OO7
1
MF7
2
SEM P
Gene al pe o mance
Ini ial weigh (g) 87.52 90.74 1.960 0.429
Final weigh (g) 117.5 121.0 3.705 0.656
Weigh gain (g) 32.48 33.36 2.639 0.876
Food in ake (g/d) 7.489 7.446 0.1590 0.897
Ene gy in ake (kcal/d) 25.46 25.32 0.5407 0.897
Fa in aeces % 1.665 1.463 0.09002 0.353
Plasma biochemis y
TC (mmol/L) 3.764 3.457 0.07418 0.005
CE (mmol/L) 3.017 2.659 0.1043 0.008
TG (mmol/L) 0.4700 0.5733 0.03371 0.133
TFA (mmol/L) 8.711 6.059 0.8862 0.136
FA in CE (%) 39.94 44.43 3.588 0.237
FA in TG (%) 16.65 29.37 3.720 0.008
Glucose (mmol/L) 8.515 8.209 0.1392 0.323
1
Hams e s ed he die con aining 7% (w/w) o oli e oil.
2
Hams e s ed he
die con aining 7% (w/w) o milk a . CE: Choles e yl es e s; FA: Fa y acids; TC:
To al Choles e ol; TFA: To al FA; TG: T iglyce ides.
A. Be iozabalgoi ia e al.
Food Chemis y: Molecula Sciences 4 (2022) 100060
4
(p esen in concen a ions < han 1%, Table 3), signi ican di e ences
we e ound in he pe cen age o 14 FA. Some o hese di e ences can be
a ibu ed o hei highe concen a ion in he die a (e.g., 12:0,
iso16:0, ans-palmi oleic, VA o eicosapen aenoic acid (20:5n-3, EPA)
acids in milk a , o γ-linolenic acid (18:3n-6) in oli e oil, Supplemen a y
Table 1).
Mo eo e , he p opo ion o some BCFA, ans-FA and CLA, whose
p opo ions we e below 0.1% in he inges ed a , especially in oli e oil,
and a e no syn he ized by mammals, we e ound in plasma in signi i-
can p opo ions.
3.4. FA in e y h ocy es o hams e s
The FA composi ion o e y h ocy es in hams e s ed di e en a s,
classi ied in FA g oups is shown in Fig. 2A. De ailed FA composi ion is
epo ed in Supplemen a y Table 2. When analysed by g oups, FA p o-
ile was e y simila in bo h animal g oups. The main FA g oups we e
PUFAn-6 (53.54% and 53.16% o OO7 and MF7 hams e s, espec i ely)
and LCSFA (19.67% and 19.57%). The e was no signi ican di e ence in
hese FA g oups be ween animals. c-MUFA p opo ion (19.84% and
17.41%, espec i ely) was sligh ly, bu signi ican ly, highe in hams e s
o OO7 g oup.
Howe e , signi ican di e ences we e ound in mino FA (in g oups
and indi idually). Mo eo e , e y h ocy e FA composi ion in hams e s
seems o be mo e sensible o change in ood a han plasma FA, because
o he 40 FA de ec ed in e y h ocy es, he p opo ion o 30 changed
depending on he a in he die . The sum o MCSFA, BCFA, -MUFA and
CLA we e signi ican ly highe in e y h ocy es o hams e s o MF7 g oup.
Among indi idual FA, wen y-one FA we e in highe p opo ion in MF7
g oup han in OO7. These included all MCSFA, mos BCFA,
α
-linolenic
acid (18:3n-3, ALA), EPA and mos CLA (Supplemen a y Table 2). All
hese FA we e also in highe p opo ion in milk a han in oli e oil
(Supplemen a y Table 1). FA whose pe cen age was highe in OO7
hams e s e y h ocy es included OA, cis- accenic acid and ARA, which
a e also in highe p opo ion in oli e oil. DHA was in he same p o-
po ion in bo h g oups.
3.5. Humans
Die s and baseline cha ac e is ics o pa icipan s in he human s udy
we e published p e iously (Be iozabalgoi ia e al., 2021). No di e ence
we e ound in biochemical pa ame e s in pa icipan s a e ollowing
bo h die s (Table 4).
3.6. FA in human plasma
FA concen a ion in plasma samples o pa icipan s in he human
in e en ion s udy a e ollowing NDD and DRD die s was 9778 ±1643
and 10849 ±1871 µmol/L, espec i ely. No signi ican di e ence was
ound be ween die s (Table 4). Resul s o main FA g oups and da a o
indi idual FA a e shown in Table 3. Main FA g oup we e PUFAn-6
(44–42 mol%), ollowing by LCSFA (28–26 mol%) and c-MUFA
(a ound 22 mol%) in all pa icipan s. Wi h espec o FA g oups, small
bu signi ican di e ences we e ound in he concen a ion o he sum o
MCSFA, LCSFA and CLA when he die o he pa icipan s changed om
NDD o DRD (Table 3).
A
B
0
10
20
30
40
50
60
70
80
90
100
MCSFA LCSFA BCFA cMUFA MUFA n6PUFA n3PUFA CLA
mol %
0
10
20
30
40
50
60
70
80
90
100
MCSFA LCSFA BCFA cMUFA MUFA n6PUFA n3PUFA CLA
mol %
Fig. 1. FA composi ion (mol%, mean alues +SD) o
die s (A) and aeces o hams e s (B). FA a e g ouped in
ca ego ies: Medium-chain sa u a ed FA (MCSFA);
long chain sa u a ed FA (LCSFA); me hyl-b anched FA
(BCFA); cis-monounsa u a ed FA (cMUFA); ans-
monounsa u a ed FA ( MUFA); n-6 polyunsa u a ed
FA (n6PUFA); n-3 polyunsa u a ed FA (n3PUFA);
conjuga ed linoleic acids (CLA). In panel A black ba s
co espond o 7% (w) oli e oil die (OO7) and whi e
ba s co espond o 7% (w) milk a die (MF7). In
panel B, FA o aeces samples om hams e s ed OO7
(black ba s) o MF7 (whi e ba s). As e isks show sig-
ni ican di e ences: *, P <0.05; **, P <0.01; ***, P
<0.001.
A. Be iozabalgoi ia e al.
Food Chemis y: Molecula Sciences 4 (2022) 100060
5
Table 3
Fa y acid (FA) concen a ion means (mol%) in plasma samples.
FA Hams e s Human
OO7
1
MF7
2
SEM P NDD
3
DRD
4
SEM P
MCSFA
10:0 0.3017 0.4085 0.03329 0.075 0.2805 0.3112 0.009159 0.094
12:0 0.1209 0.2565 0.03963 0.012 1.095 1.077 0.03796 0.818
14:0 0.2844 0.5941 0.1124 0.204 0.9390 1.420 0.05673 0.000
15:0 0.08550 0.08821 0.002072 0.624 0.3386 0.3261 0.01020 0.549
Sum 0.7925 1.348 0.1674 0.043 2.653 3.135 0.08764 0.004
LCSFA
16:0 18.85 19.81 0.5355 0.484 19.07 20.61 0.2836 0.005
17:0 0.3678 0.4226 0.01784 0.113 0.1921 0.2269 0.005486 0.001
18:0 7.234 6.126 0.3256 0.018 6.262 6.226 0.1013 0.859
20:0 0.03933 0.06024 0.00604 0.000 0.05709 0.04835 0.002053 0.031
21:0 0.02730 0.02100 0.00194 0.070 0.02311 0.02501 0.001402 0.506
22:0 0.4373 0.1610 0.08443 0.055 0.1423 0.1573 0.01673 0.660
24:0 0.01141 0.00952 0.00176 0.674 0.4135 0.4695 0.05877 0.640
26:0 0.04700 0.1490 0.02946 0.000 0.1690 0.1734 0.003800 0.337
Sum LCSFA 27.02 26.76 0.4260 0.826 26.33 27.94 0.2798 0.003
Sum SFA 27.81 28.11 0.4599 0.831 28.99 31.07 0.3323 0.001
BCFA
iso14:0 0.01201 0.01512 0.00090 0.013 0.01704 0.01571 0.000698 0.350
an eiso14:0 0.01571 0.01794 0.00215 0.703 0.1133 0.1070 0.03115 0.922
iso15:0 0.05683 0.001271 0.01308 0.028 0.02060 0.04315 0.003469 0.001
an eiso15:0 0.01622 0.02881 0.00525 0.307 0.08240 0.02070 0.001397 0.000
iso16:0 0.04899 0.07687 0.00853 0.019 0.04034 0.06334 0.002415 0.000
an eiso16:0 0.006033 nd 0.00176 0.013 0.00555 0.00441 0.000317 0.074
iso17:0 0.3780 0.5019 0.05403 0.338 0.06532 0.1237 0.006279 0.000
an eiso17:0 0.4279 0.1081 0.09302 0.007 0.3430 0.2821 0.008854 0.000
Sum 0.9728 0.7868 0.08062 0.334 0.6134 0.6602 0.03974 0.454
c-MUFA
cis9-14:1 0.3318 0.5072 0.05359 0.055 0.1646 0.2647 0.009999 0.000
cis9-16:1 1.494 2.331 0.2456 0.016 1.229 1.247 0.07653 0.908
cis10-17:1 0.1365 0.3470 0.06081 0.001 0.1084 0.09964 0.002826 0.122
cis6-18:1 nd 0.09561 0.02812 0.00966 0.03752 0.002774 0.000
cis9-18:1 24.08 21.77 0.9600 0.304 17.83 17.52 0.5337 0.774
cis11-18:1 2.071 1.546 0.1570 0.036 1.481 1.212 0.03397 0.000
cis11-20:1 0.1408 0.06092 0.02300 0.099 0.1081 0.09413 0.004018 0.081
cis13-22:1 0.04174 0.03773 0.00338 0.313 0.9235 1.110 0.04286 0.027
Sum 28.30 26.70 0.7361 0.372 21.85 21.59 0.5719 0.817
-MUFA
ans10-15:1 0.01122 nd 0.00324 0.01549 0.01597 0.000482 0.629
ans9-16:1 0.02592 0.2181 0.05680 0.023 0.01874 0.02064 0.001302 0.472
ans9-18:1 0.07440 0.05905 0.01086 0.593 0.2074 0.1654 0.09567 0.026
ans11-18:1 0.05533 0.1346 0.02444 0.063 0.03410 0.06887 0.003756 0.000
Sum 0.1667 0.4118 0.07691 0.080 0.2757 0.2709 0.01148 0.835
PUFA
18:2n-6 25.71 28.77 1.043 0.153 33.40 32.36 0.7815 0.515
18:3n-6 0.9268 0.3476 0.1694 0013 1.248 1.271 0.07613 0.882
18:3n-3 0.07681 0.1386 0.02109 0.155 0.3365 0.3916 0.02232 0.222
20:4–6 13.16 11.52 0.4806 0.015 9.280 8.595 0.2651 0.200
20:5n-3 0.06990 0.1988 0.03725 0.001 0.3046 0.2878 0.01051 0.432
22:6n-3 2.615 2.456 0.1258 0.635 3.390 3.123 0.1284 0.304
PUFAn-6 39.79 40.63 0.6307 0.615 43.93 42.23 0.6856 0.221
PUFAn-3 2.762 2.793 0.1270 0.929 4.031 3.803 0.1311 0.390
Sum PUFA 42.55 43.50 0.1336 0.593 47.96 46.03 0.6583 0.146
n-6/n-3 14.42 14.70 0.6633 0.880 11.40 11.60 0.4390 0.827
CLA
cis9, ans11CLA 0.05111 0.3090 0.09702 0.233 0.04986 0.1199 0.007336 0.000
ans10,cis12CLA 0.03555 0.02911 0.00297 0.380 0.06715 0.05770 0.005337 0.383
cis9,cis11CLA 0.08300 0.1205 0.01225 0.115 0.09198 0.09397 0.003910 0.803
ans9, ans11CLA 0.03021 0.03172 0.00454 0.902 0.02939 0.03992 0.02553 0.037
Sum 0.1998 0.4902 0.1119 0.251 0.2384 0.3115 0.01171 0.001
SCD-1 indices
16:1/16:0 0.07960 0.1177 0.01142 0.038 0.0627 0.0602 0.00308 0.693
18:1/18:0 3.334 3.555 0.1456 0.561 2.903 2.850 0.1090 0.811
cis9, 11CLA/
11-18:1 0.9175 2.174 0.4896 0.259 1.523 1.784 0.07801 0.095
1
Hams e s ed he die con aining 7% (w/w) o oli e oil.
2
Hams e s ed he die con aining 7% (w/w) o milk a .
3
Humans a e non-dia y die .
4
Humans a e dai y
ich die . BCFA: me hyl-b anched chain FA; CLA: conjuga ed linoleic acid; c-MUFA: cis-monounsa u a ed FA; LCSFA: long chain sa u a ed FA; MCSFA: medium chain
sa u a ed FA; nd: no de ec ed; SFA: sa u a ed FA; SCD-1: S ea oyl-CoA-1 desa u ase; -MUFA: ans-monounsa u a ed FA.
A. Be iozabalgoi ia e al.
Food Chemis y: Molecula Sciences 4 (2022) 100060
6
In plasma o humans ollowing he wo die s, FA p esen in he
highes concen a ion was LA (33.4 and 32.4 mol% in NDD and DRD,
espec i ely), ollowing by palmi ic acid (19.9 and 20.6 mol%) and OA
(17.8 and 17.5 mol%). Among FA p esen in pe cen ages highe han 1
mol%, my is ic and palmi ic acids we e in signi ican ly highe p o-
po ions a e DRD and cis- accenic acid a e NDD, in ag eemen wi h
he highe p opo ions in hei espec i e die s. Mos di e ences we e
ound in mino FA. Thus, ou mino FA we e in highe p opo ions in
plasma o pa icipan s a e NDD and en FA in plasma o pa icipan s on
DRD. In he la e case, he inc ease can be a ibu ed o hei p esence in
dai y p oduc s (e.g., iso15:0, iso16:0, iso17:0, 17:0, VA and RA)
3.7. FA in human e y h ocy es
The FA composi ion o e y h ocy es in human samples, classi ied in
FA g oups is showed in Fig. 2B. Mola pe cen ages o indi idual FA a e
collec ed in Supplemen a y Table 2. No s a is ical di e ences we e
ound in main FA g oups in human a e bo h die s. PUFAn-6 cons i u ed
he main FA g oup (37 mol%.), ollowing by LCSFA (31 mol%) and c-
MUFA (16 mol%).
On he o he hand, he sum o -MUFA and CLA and he pe cen age o
en indi idual FA changed when he die o pa icipan s changed om
NDD o DRD. Nine o hem we e highe in e y h ocy e samples a e DRD
and we e signi ican ly co ela ed wi h hei inc ease in plasma and hei
p esence in dai y a (e.g., my is ic acid, iso17:0, 17:0, VA and RA).
3.8. Compa a i e analysis
FA composi ion in hams e s’ die was con olled and known. How-
e e , in he human in e en ion s udy pa icipan s we e asked o ollow
hei habi ual Medi e anean die , a oiding any dai y p oduc du ing
A
B
0
10
20
30
40
50
60
70
80
90
100
MCSFA LCSFA BCFA cMUFA MUFA n6PUFA n3PUFA CLA
mol %
**
***
***
***
***
0
10
20
30
40
50
60
70
80
90
100
MCSFA LCSFA BCFA cMUFA MUFA n6PUFA n3PUFA CLA
mol %
**
*
*
Fig. 2. FA composi ion (mol%, mean alues +SD) o
e y h ocy es samples o hams e s (A) and humans (B).
FA a e g ouped in ca ego ies: Medium-chain sa u a ed
FA (MCSFA); long chain sa u a ed FA (LCSFA);
me hyl-b anched FA (BCFA); cis-monounsa u a ed FA
(cMUFA); ans-monounsa u a ed FA ( MUFA); n-6
polyunsa u a ed FA (n6PUFA); n-3 polyunsa u a ed
FA (n3PUFA); conjuga ed linoleic acids (CLA). In
panel A, black ba s co espond o e y h ocy e samples
o hams e s ed a die wi h oli e oil7% (w) (OO7) and
whi e ba s co espond o hams e s ed 7% (w) milk a
die (MF7). In panel B, black ba s co espond o
e y h ocy e samples om pa icipan s in he in e -
en ion s udy a e ollowing a die wi hou dai y
p oduc s, and whi e ba s co espond o e y h ocy e
samples a e ollowing a die ich in dai y p oduc s.
As e isks show signi ican di e ences: * P <0.05; **
P <0.01; ***; P <0.001.
Table 4
Plasma biochemical pa ame e s o human s udy.
NDD1 DRD2 SEM P
TC (mmol/L) 6.136 6.857 0.1517 0.097
CE (mmol/L) 5.030 5.620 0.1248 0.098
TG (mmol/L) 0.5462 0.5821 0.03555 0.905
TFA (mmol/L) 9.778 10.85 0.3916 0.177
FA in CE (%) 52.12 52.39 1.226 0.373
FA in TG (%) 16.75 15.82 0.7698 0.437
Glucose (mmol/L) 5.028 5.631 0.1290 0.110
Humans a e non-dia y die .
2
Humans a e dai y ich die . CE: Choles e yl
es e s; FA: Fa y acids. TC: To al Choles e ol; TFA: To al FA; TG: T iglyce ides.
A. Be iozabalgoi ia e al.
Food Chemis y: Molecula Sciences 4 (2022) 100060
7
NDD pe iod, o including a con olled amoun o dai y p oduc s in DRD.
This means ha , in bo h pe iods, he pa icipan s in he human s udy
inges ed simila amoun s o oli e oil (25.2 ±5.45 g/d) and o he sou ces
o FA, as ege ables, nu s, mea and ish. In spi e o his, he di e ences
ound be ween he wo species, ollowing any die , in ela ion o he
main g oups o FA in plasma we e small. In bo h species, main FA g oups
we e PUFAn-6 and LCSFA, which we e in simila p opo ions in bo h
species. c-MUFA p opo ion was sligh ly highe in hams e s han in
human, e en in animals ed milk a , whe eas PUFAn-3 and MCSFA we e
in highe p opo ions in humans.
NDD in humans can be conside ed equi alen o he OO7 die in
hams e s, since oli e oil is he main sou ce o a in he Medi e anean
die . Compa ing da a o indi idual FA in plasma o hese wo g oups, LA,
OA and palmi ic acid we e he FA in he highes p opo ions in bo h,
al hough LA was ound in a highe pe cen age in humans han in
hams e s, and he opposi e occu ed wi h OA, which is highe in ham-
s e s. Di e ences we e ound be ween humans and hams e s in he
pe cen age o o he n-6 and n-3PUFA. All, excep ARA, we e in highe
p opo ion in humans han in hams e s (Table 3). These di e ences we e
due, mos p obably, o he p esence o oods ha a e he main sou ce o
hese FA in he human die , as ege ables, nu s and ish. Mos o he FA
a e in simila p opo ions.
Wi h ega d o he e y h ocy e FA p o ile, i seems o be mo e
cha ac e is ic o each species, wi h di e ences in pe cen ages o majo
and mino FA be ween he wo species, al hough in bo h PUFAn-6
cons i u ed he main FA g oup. Howe e , i s p opo ion in hams e s
was conside ably highe han in humans, con a y o LCSFA whose
pe cen age was much lowe in hams e s (Fig. 2).
The e ec o dai y a inges ion on plasma and e y h ocy es FA was
di e en in hams e s compa ed o humans. In humans, he e ec was
simila in plasma TFA and e y h ocy es FA, since in bo h ype o samples
a signi ican inc ease in he p opo ion o almos he same indi idual FA
was de ec ed. Howe e , in plasma TFA o hams e s ha we e ed milk a
nine FA we e in highe p opo ion han in he o OO7 g oup, bu o hose
nine, only wo (iso16:0 and pe oselinic acid (cis6-18:1)) coincided wi h
hose ha inc ease in humans a e he DRD die . In addi ion, he e ec
o milk a consump ion was mo e no iceable in hams e s e y h ocy es
han in humans, because he pe cen age o wen y-one FA was highe in
MF7 g oup han in OO7, including all FA whose p opo ion we e highe
in human plasma and e y h ocy es a e DRD.
On he o he hand, cis- accenic acid and an eisohep adecanoic acid
(an eiso17:0) seem o be ela ed wi h oli e oil in ake, as hei p opo ion
we e highe in plasma and e y h ocy es o hams e o OO7 g oup han
MF7 and in plasma o humans a e NDD.
4. Discussion
FA ound in as ing plasma a e he complex esul s o a ious phys-
iological p ocesses ela ed o lipid me abolism and e lec he nu i ional
and heal h s a e o he o ganism. Al hough hams e s ha e been long
used as animal model o he analysis o lipid me abolism in humans,
e y ew a icles ha e analyzed in dep h hei plasma FA composi ion.
Mo eo e , only one a icle (Yin e al., 2012) was ound in which au ho s
analyse he dis ibu ion o FA g oups among plasma lipid ac ions in
a ious animal models in compa ison o dyslipidemic humans. This
wo k showed ha non-human p ima es and no mally ed hams e s a e
he bes animal model in his ega d. No simila compa ison has been
ound o heal hy subjec s.
One p ocess ha can in luence he plasma FA p o ile is he in es inal
abso p ion o die a y a . Faecal exc e ion has been used as a measu e o
he p opo ion o FA abso bed. Howe e , he scien i ic li e a u e
desc ibing he FA p o ile in aeces is sca ce, ei he in expe imen al an-
imals (Sugano & Imaizumi, 1995; Yokoyama e al., 2011) o in humans
(e.g., McKimmie, Eas e , & Weinbe g, 2013; Ney inck e al., 2021). FA
exc e ed by hams e s depends pa ially on he FA con en o inges ed
ood. In hams e s, Sugano and Imaizumi (1995) showed ha he aecal
exc e ion o FA in hams e s ed a die ich in sa u a ed FA ended o
inc ease p opo iona ely wi h he chain leng h o he FA, bu he ab-
so p ion was highe han 90% o all. Yokoyama e al. (2011) demon-
s a ed a p e e en ial exc e ion o SFA o e unsa u a ed FA in hams e s
ed die s wi h di e en p opo ions o bo h ype o FA. Resul s o he
p esen s udy a e in ag eemen wi h hose indings, as LCSFA appea s o
be abso bed p opo ionally o he amoun ound in ood. To he con-
a y, c-MUFA a e p e e en ially abso bed. Resul s in human s udies
(Ney inck e al., 2021) showed simila esul s han in hams e s, wi h
p opo ion o he main FA in aeces simila o ha ound in he p esen
s udy.
Howe e , i should be aken in o accoun ha aecal a may include
a om ood, as well as a ac ion o he sec e ed bile lipids, mainly
leci hin, bac e ial lipids and lipids exc e ed by in es inal cells (Mu &
Høy, 2004). The e o e, FA p esen in aeces a e he esul o a complex
p ocess ha only can gi e an o e all ision on FA abso p ion e iciency.
Thus, he p esence in aeces o signi ican amoun s o BCFA, ans-FA
and CLA, e en in hams e s ed oli e oil, indica es an impo an con i-
bu ion o FA o mic obial o igin in hams e s. Hams e s possess a com-
pa men alized s omach, which consis s o a o es omach and a
glandula s omach (Ma ounek, M ´
azek, Volek, Skˇ
i ano ´
a, & Kille ,
2016). The o es omach o e y h ocy es and he umen o uminan s a e
e y simila , he mic obio a is e y abundan in i and can be he
esponsible o he p oduc ion o he a o emen ioned FA. Mo eo e , he
highe p opo ion o C18 PUFA in oli e oil han in milk a can explain
he highe pe cen age o VA in aeces o hams e s o OO7 g oup, since
hese FA a e he subs a es o he mic obial biohyd ogena ion p ocess
(La e oux e al., 2011).
Some au ho s (D ua e al., 2015) ha e demons a ed he p oduc-
ion o ans-FA and CLA in he gu o animals o he han uminan s (as
a s and abbi s). Ney inck e al. (2021) also ound ans-FA and CLA in
human aeces in p opo ions simila o ha ound in hams e s in he
p esen s udy and demons a ed hei ela ionship wi h he p esence o
speci ic gu bac e ia.
In he same way, he BCFA simila p o ile in he aeces o bo h g oup
o animals suppo he mic obial o igin o mos BCFA p esen in ham-
s e s’ aeces, since he BCFA p o ile in he gu seems o be mo e de e -
mined by he FA syn hase ac i i y o he mic oo ganisms han by he
p ecu so a ailabili y, a shown o uminan s ((Vlaeminck e al., 2006).
Mo eo e , he highe p opo ion o some o hese FA in aeces o MF7
g oup also shows he pa ial con ibu ion o ood in ake.
As commen ed be o e, aecal a may include a ac ion o bile and
bac e ial lipids and lipids exc e ed by in es inal cells (Mu & Høy, 2004).
These may be he sou ce o he high p opo ion o PUFA ound in
hams e aeces compa ed o hei p esence in ood.
Few scien i ic wo ks desc ibed a de ailed FA composi ion o plasma
(Ishida e al., 2013; Sihag & Jones, 2018) o e y h ocy es lipids (Ban-
da a, Lopes, Ma ins, Fe ei a, Al aia, Rolo, Co eia, Pin o, Ramos-
Bueno, Ba is a, P a es, & Guil-Gue e o, 2016; Mo ise e al., 2004) o
hams e s. Besides, die s composi ion (in a cha ac e is ics and pe -
cen ages) a ies widely among s udies, which makes any compa ison
e y di icul . Mo eo e , he numbe o indi idual FA de e mined in all
cases was smalle han in he p esen s udy. Sihag and Jones (2018)
analysed he plasma TFA o hams e s ed, among o he s, oli e oil (10%
weigh ). In his s udy, he main FA we e ound in pe cen ages simila o
ou s, wi h some impo an excep ions. In Sihag’s wo k c-MUFA a e he
main FA g oup and PUFA a e in pe cen ages simila o SFA. PUFAn-3 a e
in amoun s simila o ou s. Ishida e al. (2013) analysed only 13 FA in
plasma o hams e s ed high a die (21%) wi hou o wi h some PUFA
added. In hams e s ed he con ol die he FA a e in simila pe cen ages
ound in he p esen wo k.
Simila ly, FA p o ile in e y h ocy es o hams e s desc ibed in he
li e a u e a ies among wo ks and depending on he die (Banda a
e al., 2016; Mo ise e al., 2004). In gene al, in he published wo ks SFA
a e in a highe p opo ion han in ou s, con a y o PUFAn-6, whose
concen a ion is much highe in ou wo k.
A. Be iozabalgoi ia e al.
Food Chemis y: Molecula Sciences 4 (2022) 100060
8
In human s udies, he e iew o Hodson e al. (2008) shows ha he
p o ile o plasma FA o heal hy people, wi h an equilib a ed die , is
simila o ha desc ibed in he p esen s udy when FA g oups and main
indi idual FA a e compa ed. Howe e , he same e iew (Hodson e al.,
2008) also epo s, in gene al, a highe p opo ion o SFA and lowe o
PUFAn-6 o human e y h ocy es, al hough in some cases (Fuh man
e al., 2006) he composi ion esembles mo e he esul s o he p esen
s udy. E y h ocy es cons an ly exchange FA in hei memb ane PL wi h
hose o plasma PL al hough hei hal -li e is 28 days (Fuh man e al.,
2006). Di e ences in die a y PUFA in ake could explain his a iabili y
in da a because die a y PUFA inco po a e in o plasma PL as e and in
highe p opo ions han MUFA o SFA (Hodson e al., 2008).
The FA p o ile o plasma and e y h ocy es di e s g ea ly om he
p o ile o die a y a . This may be because in as ing plasma he main
lipop o eins ( e y low-densi y lipop o eins, VLDL) a e p oduced in he
li e , in which die FA a e dilu ed by endogenous li e FA. The inco -
po a ion o FA in o he componen s o VLDL in he li e mus be a deeply
egula ed p ocess, di ec ed by he speci ici y o enzymes implica ed in
he p ocess. This p ocess seems o be simila in hams e s and humans,
since plasma TFA concen a ion (µmol/L) and FA p o ile in hams e s and
humans ollowing an equilib a ed die di e only sligh ly be ween he
wo species and is only pa ially in luenced by he FA p o ile o he
inges ed a .
The concen a ion o OA, palmi ic and s ea ic acids a e e y di e en
be ween die s. Howe e , hei concen a ion in plasma TFA di e s e y
li le, bo h in humans and in hams e s. OA and o he non-essen ial FA as
palmi ic and s ea ic acids a e inco po a ed mainly in TG (McCloy e al.,
2004; Yin e al., 2012). Aa sland and Wol e (1998) epo ed ha OA was
he p edominan sou ce o VLDL-TG syn hesis in he li e compa ed o
o he FA. Simila ly, Hodson e al. (2008) epo ed a signi ican highe
amoun o die a y OA compa ed o palmi ic acid in VLDL-TG ac ion.
They explained ha i is due o he speci ici y o he mic osomal i-
glyce ide ans e p o ein (MTP) in hepa ocy es a ou ing MUFA
inco po a ion du ing VLDL-TG syn hesis. The same p o ein is in ol ed
in VLDL syn hesis and sec e ion in hams e s (Gao, He, Ding, & Liu,
2010).
The o igin o OA in li e can be die a y o “de no o” syn he ized. The
subs a es o he enzyme esponsible o he desa u a ion o FA in li e ,
SCD-1, can be “de no o” syn hesized o die a y SFA (Rhee, Kayani,
Ciszek, & B enna, 1997). SCD-1 ac i i y indices in plasma and e y h-
ocy es a e shown in Table 3 and Supplemen a y Table 2. In gene al,
desa u ase indices o s ea ic acid a e highe han o palmi ic acid and
in hams e s highe ha in humans, as also obse ed by Rhee e al.
(1997). In any case, OA and palmi oleic acid ound in plasma and
e y h ocy es ei he may come om ood o be o med by he ac ion o
SCD-1 in he li e . As he e is no di e ence in palmi oleic acid among
hams e s’ die s, he p opo ion o palmi oleic acid ela ed o palmi ic
acid may e lec be e he changes in SCD-1 ac i i y. In hams e s, his
index is highe in animals ed wi h milk a . A s udy wi h humans
(Vessby e al., 2013), compa ing he e ec s o a die based on bu e a
wi h a die con aining MUFA a , keeping all o he die a y componen s
cons an , showed a highe SCD-1 ac i i y index, calcula ed by he a io
palmi oleic o palmi ic acids in CE, on a die ich in bu e a han on a
die con aining MUFA. The eason may be he ac ha SFA a e s ong
ac i a o s o SCD-1, as a de ence mechanism agains he nega i e e ec s
o SFA in cells, as specula ed by Mau oisin and Mounie (2011). Mille
and N ambi (1996) highligh ed he impo ance o main aining he a io
o OA o s ea ic acid cons an o main ain he memb ane luidi y. Small
changes in his a io can a ec he abili y o he cell o espond o
ex e nal s imuli. Because o ha , i is a high- egula ed a io in humans,
and seems o be also in hams e s, as 18:1n-9/18 index is simila in
humans and hams e s and i does no change wi h die . The p oduc ion
o OA om s ea ic acid, in o de o main ain his a io, may be he
eason why he concen a ion o s ea ic acid was lowe in he plasma o
hams e s ed milk a , al hough i s concen a ion was highe in he ood.
In he li e FA a e inco po a ed mainly in TG, bu also in PL and CE,
and eleased o he ci cula ion in VLDL. FA in TG a e mo e p one o be
inco po a ed in o o gans and issues o be oxidized o s o ed, while FA in
PL and CE can s ay longe in plasma lipop o eins (McCloy e al., 2004).
As can be seen in Table 2, FA in CE accoun s o a ound he 40% o TFA
o plasma o hams e s, while FA in TG a e he 17 and 29% o TFA (in
OO7 and MF7 g oups, espec i ely). Kaabia e al. (2018) compa ed
plasma lipid concen a ion in humans wi h hams e s, among o he an-
imal models. They also ound ha in hams e s CE we e in highe con-
cen a ion han TG and ha he concen a ion o CE was 10% highe in
humans han in hams e s, as in he p esen wo k.
Yin e al. (2012) analysed he p opo ion o FA in di e en lipid
ac ions, aking in o accoun hei condi ion o non-essen ial, o
essen ial, di ided in n-6 and n-3 amilies in dyslipidemic humans and
se e al animal models. They ound g ea simila i ies o his espec be-
ween humans and no mal- ed hams e s. They ound ha PUFAn-6 a e
he main FA in CE (64% o TFA), while PUFAn-3 we e in PL (5%), TG
(3%) and CE (2%). O he au ho s also demons a ed ha PUFA a e
p e e en ially inco po a ed in CE and PL in humans (Hodson e al., 2008;
McCloy e al., 2004). G ea e acyla ion in o plasma (and issue) PL and
CE could explain he g ea e whole-body e en ion o LA and o he PUFA
(McCloy e al., 2004) and hei highe concen a ion in plasma and
e y h ocy es in compa ison wi h hei con en in ood. In he same way,
as CE a e in highe concen a ion in humans han in hams e s, his di -
e ence can explain he highe concen a ion o PUFA ound in human
plasma han in hams e s. This also can explain he p esence o LA (and
o he PUFA) in aeces in ela i e high concen a ion, coming om
en e ocy es me abolism o om bile leci hin, as commen ed be o e.
In any case, he con en o PUFA in plasma and e y h ocy es seems o
be highly egula ed. PUFA con en and n-6/n-3 a ios di e ed g ea ly
be ween hams e s’ die s, bu no di e ence was obse ed in o al PUFA
p opo ion in plasma and e y h ocy es. Banda a e al. (2016), eeding
hams e s wi h di e en combina ion o a wi h a ious n-6/n-3 a ios,
also obse ed ha , al hough o al n-3 and n-6 PUFA in e y h ocy es
a ied depending on he die , o al PUFA p opo ion did no change. The
main PUFAn-6 is LA and he main PUFAn-3 is ALA in bo h kind o di-
e a y a , bu hei p opo ions a e e y di e en (Supplemen a y
Table 1). Bo h n-6 and n-3 FA a e known o compe e o common en-
zymes in he syn hesis o longe and mo e unsa u a ed FA (long-chain
PUFA, LCPUFA). LA and ALA a e bo h subs a es o mic osomal del a-6
desa u ase (D6D). Howe e , his enzyme has a wo- o h ee- old highe
a ini y o ALA (Wien, Raja am, Oda, & Saba ´
e, 2010). The main
p oduc o LA me abolism is ARA and he main p oduc s o ALA me a-
bolism a e EPA and DHA. EPA concen a ion in plasma and e y h ocy es
o hams e s ed milk a was highe han in oli e oil ed hams e s,
consis en wi h a highe concen a ion o ALA in he milk a . To he
con a y, ARA p opo ion in bo h, plasma and e y h ocy es was highe
in animals ed oli e oil, as he p opo ion o LA is h ee imes highe in
he oil. Mo ise e al. (2004) also ound ha EPA augmen ed in e y h-
ocy es o hams e s when die a y supply o ALA inc eased, while DHA
s ayed cons an , as in he p esen s udy. They explained ha he e is a
complex balance be ween n-6 and n-3 PUFA as he esul o wo
simul aneous mechanisms. On he one hand, he compe i ion be ween
ALA and LA o D6D causes ha as he ALA/LA a io inc eases, less LA
becomes ARA. And, on he o he hand, he inc eased a ailabili y o n-3
LCPUFA can lead o a dec ease in n-6 LCPUFA in o de o espec he
physicochemical p ope ies (e.g., luidi y and cu a u e) o memb anes
and lipop o ein pa icles. Mo eo e , Wien e al. (2010) men ioned ha
he limi ing s ep in he me abolism o PUFAn-3 amily is he memb ane
sa u a ion wi h DHA. This a gumen can explain why in hams e s di -
e ences we e ound in indi idual n-6 and n-3 FA (especially in e y h-
ocy es) bu DHA pe cen s ayed cons an . In humans, he e a e also no
di e ences in he concen a ion o DHA in each compa men .
VA and RA a e in much highe concen a ion in dai y a han in oli e
oil, whe e hey a e ound only in ace amoun s (Supplemen a y
Table 1). Howe e , hei concen a ion in plasma and e y h ocy es o
hams e s and humans a e in simila le els, al hough di e ences we e
A. Be iozabalgoi ia e al.
Food Chemis y: Molecula Sciences 4 (2022) 100060
9
ound be ween g oups. They we e also de ec ed in simila concen a ion
in aeces o all hams e s, as commen ed be o e. In human s udies, i has
been p obed ha he consump ion o ela i e high amoun s o dai y a
p oduced a signi ican inc ease in he concen a ion o VA and RA in
plasma and e y h ocy es (Be iozabalgoi ia e al., 2021). RA:VA a io is
app oxima ely 1:2 in he milk a and 1:50 and 1:16 in aeces o OO7 and
MF7 g oups, espec i ely (Supplemen a y Table 1). Howe e , in plasma
and e y h ocy es o bo h species RA is in highe concen a ion han VA
in almos all cases. This can be due o he endogenous desa u a ion o VA
o RA by SCD-1 ac i i y, as demons a ed by Tu peinen e al. (2002) in
humans and by Lock, Ho ne, Bauman, and Sal e (2005) in hams e s.
Mo eo e , Tu peinen e al. (2002) ound g ea in e -indi idual di e -
ences, anging om non- esponde s o con e sion a es highe han
30%. This a iabili y can be seen also in hams e s, whose mean alues
o VA and RA pe cen ages a e much highe in he plasma o MF7 g oup
han in OO7 g oup, bu he e is no signi ican di e ence be ween hem
because o he high s anda d de ia ion alue. In hams e s’ e y h ocy es,
as he a iabili y is lowe , he di e ences a e signi ican . In addi ion, i
has been demons a ed ha , when consumed in he die , RA is inco -
po a ed in all lipid ac ions, bu p e e en ially in CE, while VA is p e -
e en ially inco po a ed in TG and canno be ound in CE (Bu dge e al.,
2005). This ac can also accoun o he highe concen a ion o RA han
VA in plasma, as CE a e in highe p opo ion in plasma han TG, as
commen ed be o e. In summa y, i can be concluded ha VA and RA in
plasma can ha e h ee sou ces: ood, gu mic obial me abolism and
endogenous p oduc ion o RA om VA by SCD-1 ac i i y. Fu he mo e,
when he dai y a is he ood sou ce o hese FA, i s in luence can be
ampli ied because he high con en in SFA o his a inc eases SCD-1
ac i i y. San o a, Palmquis , and Roeh ig (2000) in es iga ed he desa-
u a ion o VA in a s and epo ed ha VA aken wi h ood can inc ease
he RA concen a ion use ul o he body by 6–10 imes. This can be he
eason o he con adic o y heal h e ec s o CLA when i is aken as
supplemen in compa ison wi h en iched oods (La sen, Toub o, &
As up, 2003).
In he same way, BCFA a e in highe concen a ion in milk a han in
oli e oil, bu appea ed in plasma o hams e s and humans in simila
pe cen ages. These ype o FA ha e been s udied in he scien i ic li e -
a u e in ela ion o hei p esence in ood, especially in dai y p oduc s
and ood o uminan o igin (Vlaeminck e al., 2006) and ha e been
de ec ed in human speci ic issues as skin o b ain (Mika e al., 2016).
Few wo ks de ec ed hei p esence in human plasma (Lin e al., 2020)
and, o he bes o ou knowledge, besides ou p e ious wo k (Be io-
zabalgoi ia e al., 2021), only one (Mika e al., 2016) de e mined hei
concen a ion. The da a ob ained by hese au ho s a e in he same le el
o ou s, and coincide in he ac ha an eisohep adecanoic acid is he
BCFA ha is p esen in he highes pe cen . No da a o animal models
ha e been ound. In ou p e ious wo k, we demons a ed ha in human
plasma and e y h ocy es iso16:0 and iso17:0 can be used as bioma ke s
o dai y in ake, as hei concen a ion inc eases p opo ionally wi h he
in ake o dai y a . In hams e s, despi e being also p oduced in he in-
es inal ac , hei p esence in plasma and e y h ocy es is as low as in
humans, and he e ec o milk a in ake on iso16:0 and iso17:0 con-
cen a ion is mo e clea ly obse ed in e y h ocy es han in plasma, as i
was commen ed o VA and RA. Mo ise e al. (2004) also ound ha in
hams e s changes in esponse o modi ica ion in die FA composi ion
we e mo e clea ly seen in e y h ocy es han in plasma lipids.
Pe oselinic acid was also p oposed as dai y in ake bioma ke o
humans (Be iozabalgoi ia e al., 2021), al hough i was no ela ed
be o e o he in ake o hese p oduc s. The esul s o he p esen s udy in
hams e s con i m he eliabili y o his FA as a bioma ke since i was
only de ec ed in samples ( aeces, plasma and e y h ocy es) o milk a
ed hams e s.
5. Conclusions
In conclusion, i was demons a ed ha plasma TFA concen a ion
and FA g oup p o iles a e simila in humans and hams e s. Di e ences
we e ound be ween bo h species in he pe cen age o some indi idual
FA. These di e ences can be explained by di e ences in he die a y
in ake and di e ences in he p opo ion o TG, CE and PL ac ions in
plasma o bo h species. Changes in die a y FA in ake causes simila
changes in FA concen a ion in he plasma o bo h species and can be
explained by he same me abolic p ocesses.
The e y h ocy e FA p o ile di e s mo e be ween he wo species,
p obably due o he cha ac e is ic PL composi ion o he e y h ocy e
memb anes in each species. Fu he mo e, he FA p o ile o hams e
e y h ocy es is mo e sensi i e o changes in die a y FA han plasma,
because he p opo ion o a highe numbe o FA changed signi ican ly
in esponse o he change in die a y a . One eason o his could be he
g ea e a iabili y in he da a ob ained in plasma samples, which, in
u n, could be due o he mo e complex composi ion o plasma lipids.
Decla a ion o Compe ing In e es
The au ho s decla e ha hey ha e no known compe ing inancial
in e es s o pe sonal ela ionships ha could ha e appea ed o in luence
he wo k epo ed in his pape .
Appendix A. Supplemen a y da a
Supplemen a y da a o his a icle can be ound online a h ps://doi.
o g/10.1016/j. ochms.2021.100060.
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