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Critical Reviews in Food Science and Nutrition
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Coenzyme Q10 Contents in Foods and Fortification Strategies
Igor Pravst a; Katja Žmitek b; Janko Žmitek b
a Nutrition Institute, Ljubljana, Slovenia b VIST-Higher School of Applied Sciences, Ljubljana, Slovenia
Online publication date: 17 March 2010
To cite this Article Pravst, Igor, Žmitek, Katja and Žmitek, Janko(2010) 'Coenzyme Q10 Contents in Foods and
Fortification Strategies', Critical Reviews in Food Science and Nutrition, 50: 4, 269 — 280
To link to this Article: DOI: 10.1080/10408390902773037
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Critical Reviews in Food Science and Nutrition
, 50:269–280 (2010)
Copyright C
Taylor and Francis Group, LLC
ISSN: 1040-8398
DOI: 10.1080/10408390902773037
Coenzyme Q10 Contents in Foods
and Fortification Strategies
IGOR PRAVST,1KATJA ˇ
ZMITEK,2and JANKO ˇ
ZMITEK2
1Nutrition Institute, Ljubljana, Slovenia
2VIST–Higher School of Applied Sciences, Ljubljana, Slovenia
Coenzyme Q10 (CoQ10)is an effective natural antioxidant with a fundamental role in cellular bioenergetics and numerous
known health benefits. Reports of its natural occurrence in various food items are comprehensively reviewed and critically
evaluated. Meat, fish, nuts, and some oils are the richest nutritional sources of CoQ10 , while much lower levels can be found
in most dairy products, vegetables, fruits, and cereals. Large variations of CoQ10 content in some foods and food products
of different geographical origin have been found. The average dietary intake of CoQ10 is only 3–6 mg, with about half of
it being in the reduced form. The intake can be significantly increased by the fortification of food products but, due to its
lipophilicity, until recently this goal was not easily achievable particularly with low-fat, water-based products. Forms of
CoQ10 with increased water-solubility or dispersibility have been developed for this purpose, allowing the fortification of
aqueous products, and exhibiting improved bioavailability; progress in this area is described briefly. Three main fortification
strategies are presented and illustrated with examples, namely the addition of CoQ10 to food during processing, the addition
of this compound to the environment in which primary food products are being formed (i.e. animal feed), or with the genetic
modification of plants (i.e. cereal crops).
Keywords CoQ10, ubiquinone, ubiquinol, Q10vital, fortification, functional food, antioxidants
INTRODUCTION
Coenzyme Q are natural lipophylic compounds present in
each and every living cell; due to its ubiquitous occurrence in
nature they are also called Ubiquinones (Lenaz, 1985; Lenaz
et al., 1990; Kagan and Quinn, 2001; Haas et al., 2007). The
predominant form in humans and most animals is Coenzyme
Q10, containing 10 isoprenoid units attached to substituted ben-
zoquinone moiety. It was first isolated from beef heart mito-
chondria in 1957 during an investigation of the mitochondria
electron-transport system (Crane et al., 1957; review Crane,
2007). In the following years the fundamental role of CoQ10 in
the mitochondrial respiratory chain and in oxidative phospho-
rylation was determined and Peter D. Mitchell was awarded the
Nobel Prize in Chemistry in 1978 for his contribution to the un-
derstanding of the role of CoQ10 for biological energy transfers
at the cellular level (Crane, 2007). Today it is well established
that CoQ10 is an essential component of the mitochondrial en-
ergy metabolism, responsible for energy conversion from carbo-
hydrates and fatty acids into adenosine triphosphate (ATP), an
Address correspondence to Igor Pravst, Ph.D., Nutrition Institute, Vodnikova
Cesta 126, SI-1000 Ljubljana, Slovenia. Tel. +386 (0) 5 9068 870,fax +386(0)
1 2831 701. E-mail: igor.pravst@ijs.si
energy source involved in a multitude of physiologic functions
in organisms, including muscle contraction (Crane, 2001). In
the body it exists in either an oxidized (ubiquinone) or reduced
form (ubiquinol and hydroquinone). Mainly in its reduced form,
CoQ10 is also known as a very effective antioxidant (Bentinger
et al., 2007; Mellors and Tappel, 1966), protecting against lipid
peroxidation, DNA, and protein oxidation and capable of func-
tioning synergistically with other antioxidants (Challem, 2005).
Recent studies show that it also cannot be discounted as a pos-
sible antioxidant when in an oxidized form (Petillo and Hultin,
2008).
Coenzyme Q10 is chiefly found in the most active organs like
the heart, kidney, and liver, where an even greater decline can
be observed with increasing age (Fig. 1) (Kal´
en et al., 1989).
Only up to 10% of total CoQ10 is located in cytosol and about
50% in mitochondria, making it very accessible to free radicals
that mainly form during the oxidative phosphorylation process
(Sastry et al., 1961). In the body it is mostly present in a re-
duced form (ubiquinol), except in the lungs and brain where
the oxidized form is predominant (Aberg et al., 1992). Continu-
ous conversion between ubiquinone and ubiquinol (reduction–
oxidation) takes place in vivo. Ubiquinone is also reduced dur-
ing or following absorption in the intestine and over 95% of
CoQ10 in circulation exists in the ubiquinol form (Bhagavan
269
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270 I. PRAVST ET AL.
40
50
60
70
80
90
100
110
120
0 1020304050607080
Age (years)
Heart Liver Kidney
CoQ10 content (mg /kg)
Figure 1 Age-related changes in CoQ10 content in human organs; data
source: K´
alen et al. 1989.
and Chopra, 2006) and therefore its function is not affected by
the form in which it is consumed. In this review, the term Coen-
zyme Q10 (CoQ10) is used for both the oxidized and reduced
forms, and ubiquinone or ubiquinol only when distinguishing
between the two forms is relevant.
The important role of CoQ10 has been reported in various
clinical aspects (Kagan and Quinn, 2001). The beneficial effect
in cardiovascular (Belardinelli et al., 2006; Pepe et al., 2007;
Rosenfeldt et al., 2007; Singh et al., 2007), neurodegenerative
and mitochondrial conditions (Galpern and Cudkowicz, 2007;
Shults et al., 2002; Shults, 2003), diabetes (Chew and Watts,
2004), periodontal disease (Matthews-Brzozowska et al., 2007),
male infertility (Balercia et al., 2004), and some other diseases
is suggested in a number of case reports—preclinical and clin-
ical studies (Dhanasekaran and Ren, 2005; Littarru and Tiano,
2005; Littarru and Tiano, 2010). A helpful effect in the treat-
ment of cancer patients was reported either due to its antioxidant
or bioenergetic activity (Lockwood et al., 1994), while an im-
provement in the tolerability of cancer treatment with CoQ10
supplements is also under investigation (Roffe et al., 2004). It
is also reported that CoQ10 also reduces the formation of oxida-
tive stress in the human skin, which is mainly connected with
increasing age (Blatt et al., 1999). The human body biosynthe-
sizes CoQ10, but its endogen tissue levels drop progressively
with increasing age (Ely and Krone, 2000; Kal´
en et al., 1989).
CoQ10 deficiency was also observed in various medical con-
ditions (Quinzii et al., 2007)—in persons with inappropriate
nutrition and in smokers (Elsayed and Bendich, 2001). The in-
tracellular biosynthesis of CoQ10 begins from tyrosine through
a cascade of eight aromatic precursors, which indispensably
require eight vitamins, namely—tetrahydrobiopterin, vitamins
B6, C, B2, B12, folic acid, niacin, and pantothenic acid (Folk-
ers, 1996). Mevalonate is one of the precursors of CoQ10, which
is also included in the biosynthesis of cholesterol. It has been
shown that the endogenous synthesis of CoQ10 is inhibited by
cholesterol-lowering drugs (statins), which inhibit mevalonate
biosynthesis, and supplementation has therefore been suggested
for some of their users (Bliznakov, 2002; Littarru and Langsjoen,
2007).
While extensive research is in progress to confirm the role of
CoQ10 in these and other clinical aspects, clinical results of its
beneficial effects on human health were sufficiently supported
to approve CoQ10 as a drug first in Japan and later also in some
other countries. Further, CoQ10 is now widely used as a food
supplement throughout the world. We have to mention the ex-
cellent safety record of this compound as shown in many clinical
trials (Hathcock and Shao, 2006). Very high and chronic expo-
sures have also been studied. No abnormal changes in clinical
parameters or serious adverse events were observed in a study
in which healthy human adults chronically consumed 900 mg
of CoQ10 daily (Kikkawa et al., 2007). In animal studies, the
lethal single-dose administration has been determined to be over
5 g/kg in rats (Hidaka et al., 2007). All available data from pre-
clinical and clinical studies show that the supplementation of
CoQ10 is very safe.
The total amount of CoQ10 in an adult human body is approx-
imately 2 grams, whereas 0.5 grams must be replaced daily by
endogenous synthesis and nourishment (food) (Bliznakov and
Wilkins, 1998; Kal´
en et al., 1989). The average turnover rate in
the body is therefore around 4 days (Ernster and Dallner, 1995)
and the importance of exogenous sources increases with the im-
pairment of endogenous synthesis. The suggested daily intake
of CoQ10 from exogenous sources varies from 30–100 mg for
healthy people to 60–1200 mg when used as an adjunctive ther-
apy in some medical conditions (Bonakdar and Guarneri, 2005;
Challem, 2005; Jones et al., 2002).
This article aims to review the natural occurrence of CoQ10
in dietary sources as these data have been scattered across many
papers in different languages. Further the possibilities of forti-
fying both processed and primary food products are discussed
and presented with some examples.
FOOD SOURCES
Beside endogenous synthesis, CoQ10 is also supplied to the
organism by various foods. However, despite the scientific com-
munity’s great interest in this compound (currently over 6,000
hits in the ISI Web of Science
R), quite a limited number of stud-
ies have been performed to determine the contents of CoQ10 in
dietary components. The first reports on this issue were pub-
lished in 1959 by Lester and Crane, and Folkers et al., leading
researchers of this compound (Lester and Crane, 1959; Page
et al., 1959), but the sensitivity and selectivity of the analytical
methods at that time did not allow reliable analyses, especially
for products with low concentrations. These and other early stud-
ies of the natural distribution of Coenzyme Q were reviewed in
1985 (Ramasarma, 1985). Subsequent developments in analyt-
ical chemistry, particularly in high-pressure liquid chromatog-
raphy (HPLC), have enabled a more reliable determination of
CoQ10 concentrations in various foods (Mattila and Kumpu-
lainen, 2001). The results of CoQ10 contents in various food
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COENZYME Q10 271
Tab l e 1 Overview of CoQ10 contents in various foods
CoQ10 cont. Notes
Foods [mg/kg]aand Ref. Class
Meats and their processed foods
Reindeer (not spec.) 157.9 hA
Beef
- heart 113.3 hA
- liver 39.2–50.5 [39.2],h[50.5];◦(3.8)dB
- shoulder 40.1 ◦B
- sirloin 30.6 nB
- thigh 30.3 ◦B
- tenderloin 26.5 nB
- beef (not spec.) 16.1–36.5 [16.1],g[31.0],e,f [36.5]hB
Pork
- heart 118.1–282 [118.1],n[203 (151–282)],f
[127],h(64.0)g
A
- liver 22.7–54.0 [22.7],h[54.0],n(2.7)dB
- shoulder 45.0 ◦B
- sirloin 14.0 nB
- thigh 13.8 ◦B
- pork (not spec.) 24.3–41.1 [20],h[24.3–41.1]eB
- lard 10.0 eB
Chicken
- heart 92.3–192 [92.3],j[123.2],n[192],◦
(10.8)d
A
- liver 116.2–132.2 [116.2],n[132.2],j(5.6)dA
- thigh 24.2–25.0 [24.2],j[25.0]◦B
- breast/chest 7.8–17.1 [7.8],j[16.6],n[17.1]◦B
- wing 11.0 jB
- chicken (not spec.) 14–21 [14],h[17],f[21]eB
Egg
Chicken egg 0.7–3.7 [1.9 (1.0–2.9)],f[1.2],h
[3.7],e[0.7]◦
D
- yolk 5.2 jC
Dairy products
Butter 7.1 eC
Cheese [1.4],◦[2.1]eD
- Emmental 1.3 h
-Edam 1.2 h
Cow milk D
- fresh, 3.6% fat 1.9 i
-3.5%fat 1.3 i
- 1.5–1.6% fat 0.7–1.2 [0.1],h[0.7–1.2]i
- UHT, 3.5% fat 1.7 i
- UHT, 1.6% fat 1.2 i
- UHT, 0.5% fat 0.5 i
Yogurt [0.3],◦[1.2],f[2.4]hD
- 3.2% fat 0.7–1.1 i
- 1.5–1.6% fat 0.7–1.4 i
- 0% fat up to 0.1 i
Yogurt from goat and sheep milk E
-6.0%fat 0.3 i
Sour milk E
- 3.2% fat 0.5–0.9 i
-1.6%fat 0.5 i
-0.1%fat / c,i
Kefir E
-3.5%fat 0.9 i
-1.6%fat 0.7 i
Cream E
- 35% fat 0.9 i
- 20–22% fat 0.5–0.9 i
Curd E
- 35% fat 0.7 i
- 13% fat, pressed 0.7 i
CoQ10 cont. Notes
Foods [mg/kg]aand Ref. Class
Fishes and shellfish
Horse mackerel (3.6–130)b[3.6],l[20.7],e[130]◦B
Sardine (5.1–64.3)b[5.1],l[11.9],◦[64.3]eB
Herring B
- heart 120.0–148.4 k
- flesh 14.9–27.0 [14.9–23.9],k[27.0]f
Yellowtail 12.8–20.7 [12.8],◦[20.7]eB
- young 33.4 ◦
Baltic herring 10.6–15.9 [14.0],g[15.9]hB
Mackerel [43.3]eB
- heart 105.5–109.8 k
- red flesh 67.5–67.7 k
- white flesh 10.6–15.5 [10.6],◦[12.3–15.5],k(4.3)l
Pollack 14.4 hB
Eel 7.4–11.1 [7.4],n[11.1]eB
Rainbow trout 8.5–11 [8.5],h[11]fB
Common mussel 9.5 lB
Cuttlefish 4.7–8.2 [4.7],◦[8.2]lC
Salmon 4.3–7.6 [4.3],f[5.7],◦[7.6],nC
Grooved carpet shell 6.6 lC
Albacore 6.2 lC
Flat fish 1.8–5.5 [1.8],◦[5.5]eD
Scallop 5.0 ◦C
Pike 5.4 lC
Tuna 4.9 [4.9]◦C
- canned 14.9–15.9 [14.9],◦[15.9]hB
Striped sea bream 4.9 lC
Octopus 3.4 ◦C
Curled picarel 4.6 lC
Oyster 3.4–4.3 [3.4],◦[4.3]lD
Squid 3.8 nD
Cod 3.7 ◦D
Bogue 3.7 lD
Octopus 3.5 lD
Annular sea bream 3.4 lD
Common pandora 3.1 lD
European hake 2.9 lD
Shrimp 1.7–2.8 [1.7],◦[2.8]lD
Bondex murex 2.6 lD
Red mullet 2.6 lD
Striped mullet 2.4 lD
Redbandfish 2.4 lD
Striated buccinum 2.3 lD
Brill 1.9 lD
Loligo 0.4 lE
Tub gurnad 0.4 lE
Great weever 0.3 lE
Comber / c.l E
Piper gurnad / c.l E
Sea bass / c.l E
Streaked gurnad / c.l E
Oils
Soybean oil
- Italian studies 221–279 [221],p[279]mA
- Japan studies 53.8–92.3 [53.8],◦[92.3]eA
- refined (Ital.) 199 pA
Corn oil
- Italian studies 113–139 [113],p[139]mA
- Japan study 13.0 eB
- refined (Ital.) 106 pA
Olive oil
- Italian study 109 pA
(Continued on next page)
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272 I. PRAVST ET AL.
Tab l e 1 Overview of CoQ10 contents in various foods (Continued)
CoQ10 cont. Notes
Foods [mg/kg]aand Ref. Class
- Japan study 4.1 eD
- extra virgin (Ital.) 114–160 [114],m[160]pA
Rapeseed oil 63.5–73.4 [63.5],h[73.4]eA
Peanut oil 77 mA
Sesame oil 32.0 eB
Cottonseed oil 17.3 eB
Sunflower oil
- Italian studies 10–15 [10],p[15]mB
- Japan study 4.2 eC
-refined 15 pB
Safflower oil 4.0 eD
Rice bran oil / c,e E
Coconut oil / c,e E
Nuts and seeds B
Peanuts (roasted) 26.7 eB
Sesame seeds (roast.) 17.6–23.0 [17.6],◦[23.0]eB
Pistachio nuts (roast.) 20.1 eB
Walnuts (raw) 19.0 eB
Hazelnuts (roasted) 16.7 eB
Almond 5.0–13.8 [5.0],◦[13.8]eBC
Chestnuts (raw) 6.3 eC
Cereals
Corn
- whole grain / c,e E
-corngerm 7.0 dC
Wheat
- whole grain / c,e E
- wheat germ 3.5–6.8 [3.5],e[6.8]dCD
Rice
- whole wheat / c,e,f E
-ricebran 4.9 eD
Japan. barnyard millet
(whole grain)
1.4 eE
Buckwheat (whole gr.) 1.1 eE
Job’s tears (whole gr.) 0.6 eE
Barley (whole gr.) / c,e
Oats (whole gr.) / c,e
Pulses, vegetables, mushrooms, and their proceeded foods
Parsley (7.5–26.4)b[7.5],◦[26.4],nB
Soybean
- whole, dry 6.8–19.0 [6.8],◦[19.0]eB
- green (raw) 18.7 eB
- boiled 12.1 eB
- natto (fermented) 5.6–10.0 [5.6],◦[10.0]eC
- sprout 1.1 ◦D
-tofu 2.9 ◦D
-soydrink(milk) upto2.5 [<0.1],i[2.5]◦E
- soy yogurt <0.1 iE
Perilla (leaves) (2.1–10.2)b[2.1],◦[10.2]eCD
Spinach (0.4–10.2)b[0.4],◦[4.9],d[10.2]eCD
CoQ10 cont. Notes
Foods [mg/kg]aand Ref. Class
Broccoli 5.9–8.6 [6.6 (5.9–7.7)],f[7.0],◦
[8.6]e
C
Rape (flower cluster) 6.7–7.4 [6.7],◦[7.4]eC
Cauliflower (1.4–6.6)b[1.4],e[2.7],h[4.9],f[6.6]◦DE
Chinese cabbage 2.1–4.5 [2.1],e[2.7],n[4.5]◦D
Sorrel 3.6 dD
Sweet potato 3.0–3.6 [3.0],◦[3.6]eD
Garlic 2.7–3.5 [2.7],e[3.5],◦D
Sweet pepper 3.3 eD
Japanese radish
-leaves 3.3 eD
- root 0.7–1.0 [0.7],◦[1.0]eF
Cabbage 1.0–3.1 [1.0],d[1.6],e[3.1]◦D
Pea 2.3–2.7 [2.3],◦[2.7]hD
Asparagus 2.2 ◦D
Carrot up to 2.2 [<0.2],f[1.7],h[2.2]eD
Eggplant 1.0–2.2 [1.0],◦[2.1],e[2.2]nD
Mustard spinach 2.0 ◦D
Bean 1.8 hD
Japanese taro 1.8 ◦D
Welsh onion 1.1 ◦DF
Potato 0.5–1.1 [0.5],d,f,h [1.0],e[1.1]◦D
Lotus root 1.0 ◦DF
Onion 0.7–1.0 [0.7],◦[1.0]eF
Brussels sprout 0.9 dF
Tomato up to 0.9 [/],c,o [0.2],f[0.9]hF
Cucumber up to 0.1 [/],c,f,h [0.1]◦F
Basella / c,e F
Button mushroom / c,o F
Editable burdock / c,e F
Garland chrysanthemum / c,e F
Lettuce / c,e F
Okra / ◦F
Pumpkin / c,e,o F
Fruits, berries and their proceeded foods
Avocado 9.5 ◦B
Blackcurrant 3.4 hD
Strawberry 1.4 hD
Orange 1.0–2.2 [1.0],◦[1.4],h[2.2]fD
- juice 0.3 hE
Grapefruit 1.3 ◦D
Apple 1.1–1.3 [1.1],f[1.2],◦[1.3]hD
Lingonberry 0.9 hE
Clementine 0.9 hE
Banana 0.8 ◦E
Persimmon 0.8 ◦E
Kiwi 0.5 fE
Strawberry 0.5 ◦E
aIf more than one reference is available, the CoQ10 content interval is stated. Data that differentiate significantly from the majority of reliable studies are not
stated in the CoQ10 content column, but are included in the Notes and References column in parentheses.
bFood items with a large CoQ10 content interval (min. 8 mg/kg and three times difference between higher and lower reliable CoQ10 content) are stated in round
brackets and need to be re-evaluated.
cBelow the detection limit.
d(Kraszner-Berndorfer and Kov´
ats, 1972); determination of the oxidized form.
e(Kamei et al., 1986); determination of the oxidized form.
f(Weber et al., 1997); determination of the oxidized form
g(Mattila et al., 2000); determination of the oxidized form with an electrochemical detector.
h(Mattila and Kumpulainen, 2001); determination of the oxidized form.
i(Straˇ
ziˇ
sar et al., 2005); determination of the oxidized form.
j(Proˇ
sek et al., 2007); determination of the oxidized form.
k(Souchet and Laplante, 2007); determination of the oxidized form.
l(Passi et al., 2002); total CoQ10 after determination of the oxidized and reduced form.
m(Cabrini et al., 2001); total CoQ10 after determination of the oxidized and reduced form; recalculated to mg/kg with an approximation of oil density: 0.92 g/cm3.
n(Kettawan et al., 2007); total CoQ10 after determination of the oxidized and reduced form.
◦(Kubo et al., 2008); total CoQ10 after determination of the oxidized and reduced form.
p(Pregnolato et al., 1994); total CoQ10 after determination of the oxidized and reduced form; recalculated to mg/kg with an approximation of oil density: 0.92
g/cm3).
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COENZYME Q10 273
Tab l e 2 Classes of CoQ10 levels in food sources
Class Approx. CoQ10 content Description
Aover 50 mg/kg very rich CoQ10 source
B10–50 mg/kg rich CoQ10 source
C5–10 mg/kg modest CoQ10 source
D1–5 mg/kg poor CoQ10 source
Ebelow 1 mg/kg very poor CoQ10 source
products as determined in studies since 1985 are overviewed
comprehensively in Table 1, together with some interesting
earlier reports after 1970. The reviewed results should be em-
ployed carefully as significant variations of reported CoQ10
content in similar products are reported in some cases. Pos-
sible reasons for these differences lie in variations seen around
the world, different types of analyzed tissues, or their treatment
along with different sample species. All analytical procedures
include a phase in which CoQ10 has to be extracted from a food
matrix to a non-polar solvent; in practice, this process cannot be
completely quantitative. Further, a certain difference between
analyses can also be generated due to differences in analyti-
cal methods; a difference of about 15% was noted when the
same samples were analyzed with LC and LC/MS determina-
tion (Straˇ
ziˇ
sar et al., 2005). It should also be mentioned that the
uncertainty of the analytical results has been neglected in many
studies, even though up to ±50% uncertainty is reported in sam-
ples with a low CoQ10 content (Straˇ
ziˇ
sar et al., 2005). Due to the
mentioned variations in CoQ10 content, we have assigned food
items into 5 classes (A, B, C, D, E) depending on their CoQ10
level; products that are the richest in CoQ10 (over approx. 50
mg/kg) are assigned to class A, while class E represents its very
poor sources (below approx. 1 mg/kg) (Table 2).
Kraszner-Berndorfer and Kov´
ats studied the levels of
CoQ10 of several food items by column chromatography and
determined some other bioquinones, such as vitamin K1–
phylloquinone, vitamin K2–menaquinone, plastoquinone, and
tocopheryl quinine (Kraszner-Berndorfer and Kov´
ats, 1972).
While their reports of CoQ10 levels in vegetables are mostly in
line with later reports (Table 1), the results for meats and oil
appears to be too low (i.e. 1.0 and 3.8 mg/kg for sunflower oil
and beef liver, respectively, 4 to 13-times lower than in subse-
quent reports). The first extensive study of Coenzyme Q levels in
food products was published in Japan in 1986; CoQ10 and CoQ9
were determined in over 70 samples using the HPLC technique
(Kamei et al., 1986). The intake of CoQ10 in the average Danish
diet was then investigated on the basis of analytical results for
selected 25 food items; CoQ9and α-tocopherol were also deter-
mined and the effect of cooking studied (Weber et al., 1997). No
detectable destruction of CoQ10 was observed by boiling, while
14–32% destruction occurred by frying. A Finnish research
group analyzed some food samples during their comparison
of different detectors in determinations of CoQ10 (Mattila et al.,
2000). The same group further determined CoQ10 and CoQ9lev-
els in 35 selected food items and studied dietary intake in Finns
(Mattila and Kumpulainen, 2001). CoQ10 contents were studied
in detail as regards many Slovenian and other European dairy
products such as milk, yogurt, sour milk, probiotics, cream, and
curd (over 50 samples) as well as soy products (Straˇ
ziˇ
sar et al.,
2005). The same group also performed an interesting investi-
gation of different poultry tissues, revealing CoQ10 variations
in different tissues of the same animal species (Proˇ
sek et al.,
2007). Seasonal variations of CoQ10 content in different tissues
of pelagic fish like mackerel and herring were recently studied in
Canada (Souchet and Laplante, 2007; Laplante et al., 2009). Due
to the rapid oxidation of ubiquinol to ubiquinone during sam-
ple preparation and extraction, CoQ10 content has usually been
measured by a determination of the ubiquinone content. How-
ever, the separate determination of ubiquinone and ubiquinol
in food products is also possible and the results of those stud-
ies are included in Table 1 as total CoQ10 content. Two Italian
research groups determined the contents of the reduced and oxi-
dized forms of CoQ9and CoQ10 in samples of edible oils (olive,
peanut, soybean, corn, and sunflower oil) (Cabrini et al., 2001;
Pregnolato et al., 1994). Another Italian group further studied
the Coenzyme Q content in the muscle tissue of 30 different ma-
rine species of fish and shellfish, together with levels of vitamin
E and various fatty acids; they determined that the ubiquinol ver-
sus the ubiquinone ratio is relatively high in fresh species, there-
fore this parameter was suggested as being useful as an index
of fish freshness (Passi et al., 2002). Thirteen food items were
recently analyzed in Japan during an assessment of the qual-
ity of CoQ10-containing dietary supplements (Kettawan et al.,
2007). The dietary intake of ubiquinone and ubiquinol was re-
cently established for the Japanese population; analyses of 70
food items showed that the intake of ubiquinol accounts for 46%
of the total CoQ10 intake (Kubo et al., 2008).
As expected, meats and fishes are the richest source of di-
etary CoQ10 due to their relatively high levels of fats and mito-
chondria (Mattila and Kumpulainen, 2001). The compound is
non-equally distributed among different tissues of the same an-
imal source depending on its function, e.g. heart, liver, muscle,
etc. (Kal´
en et al., 1989). For this reason, the origin of analyzed
tissue is stated in Table 1 where such information is available.
The highest tissue level of CoQ10 was determined in reindeer
meet (158 mg/kg), beef, pork, and chicken heart and chicken
liver (class A: over 50 mg/kg). Contents in most other beef and
pork tissues (except liver) are lower (14–45 mg/kg), while lard
only contains 10 mg CoQ10/kg. Substantial differences in CoQ10
content within different tissues of chickens were also confirmed
by several authors; while liver and heart are rich in CoQ10, much
lower levels were determined in the thighs, breasts, and wings
(below 25 mg/kg). Nevertheless, together meats represent the
most important source of dietary CoQ10 [64% in Danes (Weber
et al., 1997), 55% in Finns (Mattila and Kumpulainen, 2001)
and 44% in Japanese (Kubo et al., 2008)].
The CoQ10 concentration in chicken eggs was also deter-
mined, yet substantial differences can be observed between dif-
ferent studies (1–4 mg/kg); only egg yolk can be regarded as a
modest CoQ10 source (5 mg/kg). Dairy products are also much
poorer in CoQ10, when compared to animal tissues. Modest
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274 I. PRAVST ET AL.
content was found in butter (7 mg/kg). A connection was found
between the technological processing of food, its fat content
and concentration of CoQ10 (Straˇ
ziˇ
sar et al., 2005)—namely,
less processed products and foods with a higher amount of fat
usually have greater amounts of CoQ10,e.g. full-fat fresh milk
(3.6% fat: 1.9 mg/kg) contains more CoQ10 than UHT milk
with reduced milk fat content (1.2 and 0.5 mg/kg for 1.6%
and 0.5%, respectively). Similarly, fermented products such as
yogurts (3.2% fat: 0.7–1.1 mg/kg), sour milk (3.2% fat: 0.5–
0.9 mg/kg), and kefirs (3.5% fat: 0.7–0.9 mg/kg) only contain
approximately 2/3 of the CoQ10 in milk with the same con-
tent of milk fat (3.5% fat: 1.3–1.9 mg/kg), while the content
is even lower in products with reduced milk fat; yogurts with
declared 0% of milk fat only contain negligible concentrations
of CoQ10. Interestingly, a lower content was found in yogurt
from goat and sheep milk (0.3 mg/kg) despite their much higher
fat content (6%). Similarly, very low levels are present in cream
(0.9 mg/kg) despite its high fat content (35%).
Within fish, substantial differences in reported CoQ10 con-
tent were observed in some cases, particularly in horse mackerel
(3.6–130 mg/kg) and sardine (5.1–64.3 mg/kg). Mackerel and
herring were recently studied in detail; the highest CoQ10 con-
centration was found in the heart (over 100 mg/kg) (Souchet and
Laplante, 2007). In mackerel, a 5-times higher concentration of
CoQ10 in red flesh as compared with white flesh was explained
mainly by the higher abundance of mitochondria in red flesh
and since red flesh is generally used for continuous swimming
activities and obtains its energy from oxidative phosphorylation,
whereas white flesh is mostly active during vigorous movements
and mainly acquires its energy from anaerobic glycolysis; slight
seasonal variations in CoQ10 levels were also determined in
white flesh (Souchet and Laplante, 2007). Lower contents of
CoQ10 were observed in bottom fish, for example flat fish and
eels (2–6 and 7–11 mg/kg) and interestingly also in salmon (4–8
mg/kg), despite its significant fat content. On average, a higher
CoQ10 content was found in the Crustacea subphylum than in
the Teleostei infraclass (Passi et al., 2002). The consumption
of fish and shellfish is very different throughout the world and
their importance for the dietary intake of CoQ10 is estimated
to range from 9% in Northern European countries (Mattila and
Kumpulainen, 2001; Weber et al., 1997) to 22% in Japan (Kubo
et al., 2008).
Looking at products of non-animal origin, the highest CoQ10
levels have been observed within oils. The composition of oils
is of course closely connected to the composition of the source
plants—CoQ10 is dominant in oils from plants belonging to
the Brassicaceae and Fabaceae family, while CoQ9prevails in
grasses (Poaceae) and plants belonging to Asteraceae (Kamei et
al., 1986). Two independent Italian research groups determined
much higher levels of CoQ10 in soybean, corn, and olive oil
(199–279, 106–139, and 109–160 mg/kg, respectively) (Cabrini
et al., 2001; Pregnolato et al., 1994) than two groups in Japan
(54–92, 13, and 4 mg/kg, respectively) (Kamei et al., 1986;
Kubo et al., 2008). It is known that the content of some com-
ponents in natural oils differs significantly with regard to the
region in which the source plants were grown, but no such
studies have yet been performed for CoQ10. The different con-
centrations observed in the mentioned oils may indicate that
the level of Coenzyme Q in oils is also strongly connected
with the geographical and climatic origin of plants, yet further
investigations are needed to confirm this hypothesis. Such an in-
vestigation would also be very useful for evaluating the quality
of oils. Moving on to other oil samples, rapeseed oil is also very
rich in CoQ10 (63–73 mg/kg). About half of that level can be
found in sesame oil (32 mg/kg) and about a quarter in cottonseed
and sunflower oil (17 and 4–15 mg/kg, respectively). It should
be noted that some of these oils, particularly corn oil (186–405
mg/kg), are very rich in CoQ9(Cabrini et al., 2001; Kamei et
al., 1986). The content of CoQ10 in rice bran and coconut oil
were below the detection limit.
Various nuts and seeds are also quite rich in CoQ10 with
peanuts, sesame seeds, and pistachio nuts being the richest rep-
resentatives (over 20 mg/kg). While walnuts and hazelnuts are
also relatively rich in CoQ10 (17–19 mg/kg), less than half of
that content can be found in chestnuts. Two quite different re-
sults are reported for almonds, namely 14 mg/kg (roasted sweet
almond) and 5 mg/kg.
In most cereals CoQ9is dominant (4–23 mg/kg) and the con-
tents of CoQ10were below or near the detection limit (Kamei et
al., 1986). Interestingly, while rice bran and wheat germ con-
tain high levels of Coenzyme Q when compared to brown rice or
whole grain wheat, it was suggested that these compounds local-
ize upon germs (Kamei et al., 1986). Similarly to corn oil, a high
CoQ9level was found in whole grain corn (23 mg/kg) while its
CoQ10 content was below the detection limit. Some CoQ10 can
be found in whole-grain Japanese barnyard millet, buckwheat,
and Job’s tears (1.4, 1.1 and 0.6 mg/kg, respectively), while its
content in barley and oats was not detected.
Soybeans are relatively rich in CoQ10 (8–19 mg/kg), while
much less CoQ10 can be found in their processed products such
as in tofu, soy milk and yogurts. Within vegetables, high CoQ10
was also recently found in parsley (26 mg/kg), but this value has
to be reevaluated as a much lower level was previously reported
(8 mg/kg). Something similar applies to perilla and spinach as
very large CoQ10 content intervals are available in the literature
(2.1–10.2 and 0.4–10.2 mg/kg, respectively). Broccoli, rape,
and cauliflower are modest sources of CoQ10, while concentra-
tions below 5 mg/kg were found in other analyzed samples. No
CoQ10 has been found in plants of Asteraceae,Cucurbitaceae,
and Basellaceae family, while concentrations of CoQ9are 1–5
mg/kg (Kamei et al., 1986).
Most fruits and berries represent a poor to very poor source of
CoQ10, with the exception of avocado where the relatively high
CoQ10 content (9.5 mg/kg) is probably connected with its high
fat content. Blackcurrant is another exception with a modest
CoQ10 level (3.4 mg/kg), while concentrations in other samples
were determined to be below 1.4 mg/kg.
The CoQ10 content in people’s diets in the developed world
was determined to be 3–6 mg per day, primarily derived from
meat, whereas cereals, fruit, and vegetables only make up a
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COENZYME Q10 275
minor contribution (Kubo et al., 2008; Mattila and Kumpu-
lainen, 2001; Weber et al., 1997). Such CoQ10 intake is not
sufficient to either compensate age-related CoQ10 decline or
the lack of it due to other reasons. A greater CoQ10 intake can
be achieved with the consumption of substantially increased
amounts of CoQ10-rich food products, but even when looking at
just the few richest CoQ10 sources (class A), over 0.5 kg of these
products would need to be consumed daily for an intake of 30
mg CoQ10. Additional intake of exogenous CoQ10 is therefore
beneficial and can be consumed either in the form of food sup-
plements or, more naturally, with functional food fortified with
CoQ10, or both.
COENZYME Q10 AND FUNCTIONAL FOODS
The functional foods concept started in Japan in the early
1980s with the launch of three large-scale government-funded
research programs on “systematic analyses and development of
functional foods,” “analyses of physiological regulation of the
functional food,” and “analyses of functional foods and molec-
ular design.” In 1991 a category of foods with potential benefits
in a nutritional effort to reduce the escalating cost of health care
was established (Foods for Specified Health Use – FOSHU)
(Ashwell, 2002). In the United States, evidence-based health
or disease prevention claims have been allowed since 1990
when the Nutrition Labeling and Education Act was adopted;
claims have to be approved by the Food and Drug Administra-
tion (FDA) (Arvanitoyannis and Houwelingen-Koukaliaroglou,
2005). In the European Union, the harmonized Health and Nu-
trition Claims Regulation was accepted in 2006 and will reach
its full affect the European market in 2011 (EC Regulation no.
1924/2006) when all nutritional and health claims will require
specific authorization by the European Commission through
the Comitology procedure, following scientific assessment and
verification of a claim by the European Food Safety Authority
(EFSA).
The definition of functional foods is an ongoing issue and
many variations have been suggested by different organizations
(Arvanitoyannis and Houwelingen-Koukaliaroglou, 2005). A
consensus on the functional foods concept was reached in the
European Union in 1999 when a working definition was es-
tablished whereby a food can be regarded as functional if it is
satisfactorily demonstrated to beneficially affect one or more
target functions in the body beyond adequate nutritional effects
in a way that is relevant to either an improved state of health and
well-being or a reduction of disease risk. Functional foods must
remain foods and demonstrate their effects when consumed in
daily amounts that can be normally expected (Ashwell, 2002).
Examples of such functional foods are products fortified with a
sufficient amount of an active component to provide evidence-
based health benefits for consumers. Regardless of the vari-
ous definitions, the main purpose of functional food should be
clear—to improve health and well-being. Current legislation
concerning this matter is progressing very slowly and the reg-
ulations often allow manufacturers to imply that a food item
promotes health without providing proper scientific evidence or
ban claims that food prevents disease, even when it does (Katan
and De Roos, 2004). The basic problem is that marketing such
“healthy” foods to otherwise healthy people is very success-
ful and therefore this area should be sufficiently regulated and
carefully watched by the scientific community. Special attention
should be paid to the adequate scientific background of health
claims which as part of product labeling present important in-
formation to consumers (Hooker and Teratanavat, 2008).
On the basis of the reported health benefits of the supplemen-
tation of CoQ10 to human nutrition, quite some time ago scien-
tists started thinking about fortifying foods with Coenzyme Q10
(Borekova et al., 2008). In addition to the relatively high price
of CoQ10 two main problems are closely connected with this
issue: (a) the diverse legislation and regulation of health claims
within different countries; and (b) fortification technology.
At least three classes of health claims are in proceedings at
the European Food Safety Authority (EFSA) on the proposal
of the European Federation of Associations of Health Prod-
uct Manufacturers (EHPM); energy metabolism, heart health,
and antioxidant properties are currently being addressed. In the
United States, CoQ10 is regulated as a food component, mean-
ing that the approval of products that contain this compound
is not required by the FDA unless specific health claims are
made; to our knowledge, no food health claims have been ac-
cepted or declined. In respect of extensive scientific work and
the determined important role of CoQ10 in various clinical as-
pects we believe that further human efficacy studies will allow
the world-wide approval of CoQ10 health claims, but any pre-
diction of what will or might be claimed about related contents
could at this stage be very speculative. Nevertheless, the impor-
tant role of CoQ10 in cellular bioenergetics and its antioxidant
properties are beyond question and its use in neurodegenerative
disorders is clinically recommended (i.e. for slowing down the
functional decline in patients with Parkinson’s disease), while its
value in other conditions is under further clinical investigation
(Bonakdar and Guarneri, 2005). We should also add that health
claims are not always the main marketing tool for sales growth.
The perception of customers to the beneficial effects of CoQ10
is in many countries already at such a high level that the “for-
tified with Coenzyme Q10” statement can convince customers
to purchase fortified products. This sometimes allows the man-
ufacturer to mislead customers with the addition of very low
quantities of CoQ10 (i.e. 1 mg/L) to their products. Even though
there are no regulations to prevent these marketing tools in most
countries, such manipulative techniques should be persistently
rejected, at least by the scientific community.
Until recently, the fortification of most food products with
CoQ10 was not easily achievable due to the compound’s molec-
ular structure and physical properties. In pure form, CoQ10 is a
crystalline powder. Its lipophilicity and high molecular weight
(Mr=863) makes it insoluble in water, which represents the
main limitation on the fortification of foods, particularly those
with a low fat content. In most food products very small increase
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276 I. PRAVST ET AL.
in the CoQ10 level can be achieved with the use of a crystalline
compound, which is reflected in the negligible effect of such
foods on human health when consumed in normally expected
daily amounts and such products therefore cannot be consid-
ered to be functional food. New forms of CoQ10 have been
developed to solve this problem and will be discussed in the
following chapter. In addition to insolubility in water, the solu-
bility of CoQ10 in lipids is also limited and CoQ10 is thus very
poorly absorbed (Bhagavan and Chopra, 2007). The absorption
can be improved by food intake (Ochiai et al., 2007), by di-
viding the daily dose into smaller dosages throughout the day
(Singh et al., 2005) and by increasing the solubility of CoQ10 in
water (Bhagavan and Chopra, 2007; ˇ
Zmitek et al., 2008a). The
stability of CoQ10 presents a problem at increased temperatures
or when products are stored in light (UV irradiation) (Mat-
suda and Masahara, 1983; Milivojeviˇ
c Fir et al., 2009). Despite
the antioxidant properties of CoQ10, ubiquinone or ubiquinol
cannot be used alone to preserve food; it has been determined
that ubiquinol reacts with peroxidizing lipid forming the corre-
sponding semiquinone radical, yet it is rapidly transformed into
ubiquinone in the air (Lambelet et al., 1992).
ENHANCING THE WATER-SOLUBILITY OF COQ10
The increased water-solubility of otherwise insoluble com-
pounds not only allows the fortification of aqueous-based prod-
ucts but also contributes to their improved absorption, which
is a common pharmaceutical strategy (Liu, 2008). A number
of different approaches have been developed to achieve this
goal with CoQ10, although many of them have been developed
mainly for cosmetic or pharmaceutical use. An example of such
an approach are the liposomal or micellar aggregates of CoQ10
derivatives that have been formed in aqueous media for use in
cosmetics (dermal application) (Zappia and De Rosa, 1989).
Further, nanomicelles have been successfully formed with con-
jugated polyethylene glycol and proposed as a drug carrier sys-
tem (Scheme 1: A) (Borowy-Borowski et al., 2004) and aqueous
pharmaceutical solutions of CoQ10 for injectable preparations
have been prepared with the use of a hydrogenated lecithin
containing at least 85% of phospholipid components (Ohashi
et al., 1984). Polisorbates have also been used as solubilizing
agents and suggested for medical use for perfusion solutions
(Masterson, 1998). Pharmaceutical formulations have also been
prepared by the solubilization of CoQ10 with polyethoxylated
40 hydrogenated castor oil as a non-ionic surfactant (Seghizzi
et al., 1993) or with decaglyceryl stearate (Shibusawa et al.,
2000); 3–30% of emulsifier and high pressure homogeniza-
tion was needed in the latter case. The aqueous dispersion of
solid CoQ10 has also been developed and non-ionic liquid poly-
mer tyloxapol has been used for its stabilization (Westesen and
Siekmann, 2001). Technological solutions achieved without ad-
ditives are most desired by the food industry which would like to
avoid unnecessarily expanding product ingredient lists, particu-
larly with compounds that are new and unknown to customers,
even though the safety of such compounds is sometimes not in
question. If additives have to be used, recognized and widely
used compounds such as starch or its derivatives are very conve-
nient. Starch-based hydrophilic coatings have been successfully
used for stable solutions or dispersions of CoQ10 in water. In one
such attempt, small CoQ10 beadlets were finely dispersed into a
water-soluble fish gelatine matrix and coated with starch-based
granules (Scheme 1: B) (Chen et al., 2004). While these beadlets
include a number of CoQ10 molecules, a further breakthrough
was achieved by the use of cyclodextrins (CD) (Moldenhauer
and Cully, 2003; Proˇ
sek et al., 2005). Among the latter, β-
cyclodextrin (β-CD) has been found to be very convenient as
this starch derivative is already commonly used in the food in-
dustry and as a drug carrier system (Uekama et al., 1998) due to
its proven safety, round-the-world approval, and easy accessi-
bility. An inclusion complex can be formed in which a molecule
of CoQ10 is associated with one β-CD (CDQ10, Scheme 1: C)
(Proˇ
sek et al., 2005). The stability, solubility in diverse aqueous
media, and easy handling with such a form of CoQ10 in addition
to the unchanged organoleptic properties of fortified foods has
led to a breakthrough in CoQ10-fortification and the number of
Scheme 1 Schematic models of various novel forms of CoQ10: (A) nanomicelles, (B) CoQ10 beadlets finely dispersed in a water-soluble fish gelatine matrix
and coated with starch-based granules (Chen et al. 2004), (C) CDQ10 - inclusion complex of CoQ10 in β-cyclodextrin (Proˇ
sek et al. 2005).
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COENZYME Q10 277
fortified products is rising rapidly. In the last few years, many
products such as dairy (milk, yogurt, kefir, etc.), fruit nectars
and juices, syrups, and other beverages, honey, tea etc. have
been launched in different markets around the world. These
novel forms of CoQ10 have also allowed the development of
new pharmaceutical formulations like syrups and effervescent
tablets. It should also be mentioned that the better in vivo absorp-
tion of some forms of CoQ10 with increased water-solubility has
been determined, resulting in improved bioavailability (Bhaga-
van and Chopra, 2007; Proˇ
sek et al., 2008; ˇ
Zmitek et al., 2008a;
ˇ
Zmitek et al., 2008b).
FORTIFICATION STRATEGIES
The novel forms of CoQ10 allow the fortification of diverse
food products. Fortification can be theoretically achieved by
three main strategies: (1) the addition of CoQ10 to food during
processing; or (2) with the addition of this compound to the
environment in which primary food products are formed (animal
feed etc.), or (3) with the genetic modification of plants. All three
strategies are presented below with some examples.
Fortification of Processed Foods
The fortification of many essential processed foods can be
achieved today with the use of the novel CoQ10 forms. For
example, milk and dairy products were determined to be very
suitable for this purpose (Straˇ
ziˇ
sar et al., 2005). The concen-
tration of CoQ10 in them is low (below 2.5 mg/kg), while their
consumption by the average population is quite high. Further,
it was shown that their CoQ10 content can be increased sig-
nificantly by using appropriate forms of CoQ10 with enhanced
solubility in aqueous media, without affecting the product sta-
bility or organoleptic properties (Proˇ
sek et al., 2005). Processed
cow milk is such an example (Table 3). While unfortified milk
(3.5% fat, Ljubljanske mlekarne dairy, Slovenia) contains 1.7
mg CoQ10/kg, a relatively small increase can be achieved by
saturation with a crystalline compound (3.2 mg/kg). On the
contrary, even as high as a 5000-times increase in the initial
CoQ10 concentration can be accomplished (8500 mg/kg) by us-
ing the water-soluble CDQ10 form (Proˇ
sek et al., 2005). Such a
high concentration is, of course, not of practical importance for
the food industry but reflects the impact of the development of
Tab l e 3 Concentrations of CoQ10 in milk before and after the addition of
various forms of CoQ10 (Proˇ
sek et al. 2005)
Milk sample mg CoQ10/kg
Regular, 3.5% fat (no CoQ10 added) 1.7
Saturated with crystalline CoQ10,3.5%fat 3.2
Saturated with CDQ10, 3.5% fat 8500
Example of fortified milk in stores, 1.6% fat* 50
*UHT milk “Alpsko mleko Q10,” produced by Ljubljanske mlekarne dairy
(Slovenia)
new forms of CoQ10. This approach has already been success-
fully implemented and used by several dairies in the production
of fortified milk; usual concentrations of CoQ10 in such prod-
ucts are around 50 mg/kg, about 30 times more than the natural
content in milk.
The fortification of yogurts and other dairy products, fruit
juices, nectars, and several other beverages was also achieved
simply by the addition of the water-soluble form of CoQ10 to
the product upon stirring. In an analogous manner, CoQ10 in
an appropriate form with increased solubility in aqueous media
can be added to semi-solid products such as liver pˆ
at´
e, honey,
marmalade, jam etc. (Proˇ
sek et al., 2005), but sufficient homog-
enization should be assured as to which liquid or semi-liquid
forms of CoQ10 are the most convenient.
While the fortification of many products seems very simple,
great care has to be taken with the composition and homogeneity
of the final product. Products have to contain the declared CoQ10
content throughout the time period in which they should be
used. Stability studies are therefore necessary, particularly for
types of products for which stability with the used CoQ10 form
has not yet been confirmed, or where interactions with other
components and materials such as primary packaging materials
could occur. Very recently a stability study of Coenzyme Q10 in
various fortified foods was published (Pravst et al., 2009).
Fortification of Unprocessed Foods
The addition of CoQ10 to foods during processing is, how-
ever, not usable for the enrichment of primary foods, i.e. meat.
While the fortification of animal feed with CoQ10 is reported to
have beneficial health effects for animals (Geng et al., 2004), up
until recently this method has not been used for the fortification
of meat. This fortification strategy is presented in the following
example.
Poultry is quite convenient for fortification with CoQ10.
Within the meats it has the lowest CoQ10 level, a relatively low
fats and cholesterol level, and in many countries its consumption
is at a high level and growing quicker than with beef and pork.
The fortification of poultry was recently successfully achieved
with broiler chickens (Proˇ
sek et al., 2007). Twenty days prior
to slaughter, chickens were fed with CoQ10-fortified feed (test
group) with about 5 mg of a water-soluble formulation of CoQ10
(CDQ10) per kg of body weight daily. Concentrations of CoQ10
in the animal tissues significantly increased in comparison to the
reference group given non-fortified feed (Fig. 2). An almost dou-
bled increase was observed in breast meat (7.8 and 13.6 mg/kg
for the reference and test groups, respectively), while a smaller
increase is typical of tissues with naturally higher concentra-
tions of CoQ10. At the same time, a higher CoQ10 ratio towards
cholesterol was observed in the test group, especially in breast
meat (0.022 and 0.044 for the reference and test groups, respec-
tively). The content of CoQ10 in meat has been further increased
by gradually increasing the amount of CoQ10 in the feed.
Chicken eggs can also be fortified if hens are fed with
CoQ10-fortified feed; a 67% increase in CoQ10 content in yolk
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278 I. PRAVST ET AL.
0%
10%
20%
30%
40%
50%
60%
70%
80%
Blood
Breast
Thighs
Wings
Hearts
Liver
0
20
40
60
80
100
120
140
160
CoQ10 increase CoQ10 conc. (test gr.)
CoQ10 increase in test group
CoQ10 conc. in test group (mg/kg)
Figure 2 Comparison of the average CoQ10 increase in chickens fed with
CoQ10-fortified feed (CDQ10 ) for 20 days (test group) in comparison to the
reference group given non-fortified feed, and the average content of CoQ10 in
the test group; data source: Proˇ
sek et al. 2007.
(8.7 mg/kg) has been achieved after three weeks of feeding hens
with about 7 mg of water-soluble CoQ10 (CDQ10)(Pro
ˇ
sek et al.,
2007). Even a higher CoQ10 content in egg yolk was recently
achieved (22 mg/kg) with a much higher addition of CoQ10 to
the feed of laying hens (800 mg CoQ10 per day of 28 days)
(Kamisoyama et al., 2010).
Another option for the enrichment of foods with CoQ10 is
development plants with increased Coenzyme Q10 content by
genetic modification. This strategy is most interesting when used
on crops. Very recently CoQ10 -enriched rice was successfully
produced with CoQ10 levels as high as 35 mg/kg (Takahashi
et al., 2009; Takahashi et al., 2010).
CONCLUSIONS
Coenzyme Q10 is a natural substance present in all human
cells. It plays a fundamental role in cellular bioenergetics and
is an effective antioxidant. Beside endogenous synthesis, food
is also a source of CoQ10. Meat, fish, nuts, and certain oils
are the richest nutritional sources, while much lower levels can
be found in most dairy products, vegetables, fruits, and cere-
als. Large variations of CoQ10 content in some food products
of different geographical origin have been found, especially
within oils. The average dietary intake of CoQ10 is only 3–
6 mg, about half of it being in reduced form. Numerous health
benefits of CoQ10 supplementation have been reported which,
in addition to the growing demand for CoQ10 as a food sup-
plement, has also been reflected in the growing demand for its
use in functional foods. The latter have been becoming more
popular and widely used since forms of CoQ10 with enhanced
water-solubility have been developed which enable the fortifi-
cation of low-fat aqueous-based products and exhibit improved
bioavailability. Three main strategies have been used for fortifi-
cation purposes. Processed food can be fortified by the addition
of the compound during food processing; dairy products have
been determined to be especially suitable for this purpose. For
example, Coenzyme Q10 content in milk can now be increased
significantly over its natural level without negative effects on
product stability and taste. Similarly, the fortification of other
dairy products along with fruit juices, nectars, and several other
beverages has been also performed. Analogously, CoQ10 can
also be added to semi-solid products such as pˆ
at´
e, honey, mar-
malade, etc. However, this strategy is not usable for the enrich-
ment of primary foods, i.e. meat. The content of CoQ10 in animal
tissues can be improved by the use of fortified feed, as shown
with poultry. The biggest increase in CoQ10 content has been
observed in tissues in which the concentrations of CoQ10 are
naturally low. Using the same approach, an increase in CoQ10
content has also been reported for egg yolk. Another option for
the enrichment of foods is the genetic modification of plants to
increase their Coenzyme Q10 content. This strategy was recently
successfully used on rice.
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