Dier-en-Arts 2019; Nr 3: 50-51.
Anton C. Beynen
Diet and canine hypercholesterolemia*
*Based on article in Dutch (1)
A sample of dog blood serum with analysed cholesterol concentration > 7.5 mmol/l points to
hypercholesterolemia. The high value may result from intra-individual, spontaneous fluctuation of
cholesterol, hypothyroidism, obesity or consumption of a hypercholesterolemic diet. Moreover,
hyperresponsiveness to a cholesterol-raising diet (2) or primary hypercholesterolemia (3) can occur
Dogs are relatively resistant to atherosclerosis. On necropsy of 12,348 dogs, only 21 (0.17%) had
atheromatous plaques in their arterial vessel walls (4). Out of 8 animals with intimal cholesterol
deposits and known serum cholesterol, six had hypercholesterolemia. During the course of a PhD
research project, vascularized, lipid keratopathy was seen in 0.6% of the ophthalmic dog patients (5).
About half of the dogs with corneal lipidosis had no detectable abnormalities, while their serum
cholesterol ranged from 3.2 to 7.6 mmol/l.
As part of the treatment of lipid keratopathy, a low-fat diet is generally recommended (5-10). There
are 11 published case observations which, quite apart from their uncontrolled nature, do not
demonstrate convincingly that diet therapy ameliorates lipid keratopathy (5, 6, 11). Likewise, serum
cholesterol was not conceivably lowered. The degrees to which the habitual amount and
composition of dietary fat were changed by diet therapy, is not described.
Hypercholesterolemia in dogs seems undesirable, but there are no strong attestations that
cholesterol normalization mitigates or prevents certain disorders. In case of secondary
hypercholesterolemia, treatment of the disease is indicated. It is unknown whether primary
hypercholesterolemia responds to a cholesterol-lowering diet. Experiments show that cholesterol
drops after replacement of dietary saturated fatty acids by carbohydrates and/or polyunsaturated
fatty acids. In practice, substituting a dry food containing ≤ 8% total fat for a customary diet with
higher fat content will normally lower serum cholesterol.
Cholesterol only occurs in animal tissues and products. It is indispensable for the animal body. The
lipid is an essential part of cell membranes and is precursor of steroid hormones, bile acids and
vitamin D. The dog’s skin synthesizes insufficient vitamin D (12) so that dietary intake of the essential
is necessary. Lipoproteins in the blood furnish transportation of cholesterol between bodily tissues.
In dogs, HDLs (high-density lipoproteins) carry about 50% of total serum cholesterol (13).
The input of the body’s cholesterol balance comprises cholesterol absorption and synthesis. The
output, through bile and intestine into feces, is formed by cholesterol and bile acids, including their
bacterial modifications. Balance regulation is illustrated by the metabolic reactions to a cholesterol-
rich diet. In 1953, it was established in the dog that dietary cholesterol inhibits hepatic de-novo
cholesterol synthesis (14). Consumption of a high-cholesterol diet also increases the excretion of
cholesterol and derivatives (15, 16). Cholesterol-rich HDL particles and their liver receptors appear to
attend the supply cholesterol for excretion (17, 18).
Dietary cholesterol and fatty acids
In spite of cholesterol-balance control, high cholesterol intake causes an increase in serum
cholesterol. The dose-response relationship has been investigated fragmentarily in dogs (15, 19-21),
but compilation of the data (Note 1) shows that the addition of 0.44% cholesterol to dry food raises
a group-mean cholesterol level of 5.5 mmol/l to 7.5, the lower limit of hypercholesterolemia. By
comparison, a dry food containing 30% poultry meal, 5% whole egg powder and 2% fish oil has an
estimated cholesterol content of 0.12% in the dry matter (Note 2). A canned dog food was found to
contain 2.5 times as much (2).
According to a cross-over design with feeding periods of two weeks, dogs (n =12) ate diets
containing 60 energy% of a base mixture and 40 energy% coconut fat or sucrose (22). Compared
with coconut fat, sucrose lowered serum cholesterol by 33%. In a similar trial (23) replacement of
coconut fat by safflower oil induced a cholesterol lowering of 16% (n=16). Even though the subject
has not been studied extensively, it appears that serum cholesterol concentration in dogs reacts to
diet change in a species-spanning fashion: cholesterol is lowered by replacement of fats rich in
saturated fatty acids by either isoenergetic amounts of carbohydrates or oils rich in polyunsaturated
fatty acids (22-27).
In privately-kept, healthy dogs of six breeds, which received one of four commercial dry foods,
serum cholesterol was measured once in each animal (28). The extremes for the averages per food
brand were 4.1 and 6.4 mmol/l (n ≥50/food). About 30% of the dogs in the highest group had a
cholesterol value > 7.5 mmol/l. Possibly, those dogs had a fortuitous upward cholesterol fluctuation
or were hyperresponsive to the food concerned.
Racing huskies with minor infusions of other breeds were fed two commercial dog foods: a dry food
containing 9% fat and 0.08% cholesterol, followed by a canned food with 18% fat and 0.30%
cholesterol, the analysed lipid contents being expressed on the basis of dry matter (2). Six weeks
after the diet change, group-mean serum cholesterol (n=36) was increased from 3.8 to 5.7 mmol/l.
In addition, two separate distributions had formed, with means of 5.3 (n=29) and 7.7 (n=7) mmol/l,
while their starting means (3.7 and 4.0 mmol/l) were hardly different.
The authors combined the outcomes of the feeding trial with those of two comparable experiments,
thus identifying 14 hyperresponders out of a total of 56 dogs (2). Twelve of the 14 hyperresponders
descended from two unrelated bitches. The pattern of inheritance was consistent with an autosomal
A commercial or home-made diet rich in saturated fat and cholesterol may cause
hypercholesterolemia, especially in hyperresponders. Hypercholesterolemia also occurs in obesity,
hyperadrenocorticism, diabetes mellitus and hypothyroidism (29). Dogs with hypothyroidism
probably are extra sensitive to a cholesterol-raising diet (30). Offering excess of dry food induced
obesity and high serum cholesterol in Beagles, whereas providing the same food in restricted
amounts was neither fattening nor cholesterol elevating (31).
It has been suggested that subpopulations of Briards in the United Kingdom (32) and Shetland
Sheepdogs in Japan (33) have primary hypercholesterolemia. The investigated animals were healthy
according to clinical and laboratory examination. The triglyceride concentration in fasting blood
plasma was slightly elevated. Fifteen Briards and 64 Shetland Sheepdogs had mean serum
cholesterol concentrations of 8.0 and 8.6 mmol/l. About 50% of the serum samples contained > 7.5
mmol/l. The diet of the dogs is not described.
Lipid keratopathy refers to lipid deposition in one or both corneas. The lipidosis is accompanied by
preceding or following vascularisation. In a Boxer with lipid keratopathy a superficial keratectomy
was done (6). In the removed corneal tissue, the concentrations of cholesterol and cholesta-3,5-
diene were six times higher than in normal dogs (34). The Boxer dog had cholesterol and triglyceride
values of 7.0 and 0.7 mmol/l (6).
Lipid keratopathy generally does not go with hypercholesterolemia (5, 6, 11). After feeding an
unspecified, low-fat diet, serum cholesterol was decreased in 2 out of 6 patients and corneal
lipidosis was improved in 6 out of 11 patients (5, 6, 11, Note 3). Serum cholesterol in the above-
mentioned Boxer remained unchanged, but there was substantial clearing of the corneal fat deposits
(6). Three CEA-positive, rough Collie dogs, with lipid keratopathy and serum cholesterol levels of 6.7,
7.8 and 8.3 mmol/l, did not react convincingly to a low-fat dry food with added short-chain fructo-
Impact of dietary cholesterol (as sole variable) on serum total cholesterol in individual dogs
^ Added to dry food; np = no pre-experimental period during which the base diet was fed; + dogs
were fed 10 g cholesterol daily together with an estimated amount of 190 g of commercial dog
cakes; *mean value for 22 dogs fed a commercial dog chow. It is assumed that the basic, cholesterol-
free, experimental diet would have induced a similar cholesterol value. That diet contained 66%
sucrose, 10% corn oil, 20% casein and 4% salt mixture; # commercial dog cakes moistened with fresh
Linear regression calculation using the data for added dietary cholesterol (x, % of dry food) versus ∆
serum cholesterol (y, mmol/l) gave the equation: y = 1.38 + 1.40.x (n = 13; r = 0.84)
To assess the cholesterol concentration in a dry food containing 30% poultry meal, 5% whole egg
powder and 2% fish oil, the ingredients’ cholesterol contents were assumed to be 150, 1300 and 600
mg/100 g. The food would then hold 122 mg cholesterol/100 g.
Impact of a low-fat diet on serum total cholesterol and lipid keratopathy in dogs*
Description of the changes in serum total cholesterol and severity
of lipid keratopathy after switching to a low-fat diet
KE + 12 months LF; TC: ?; LK: “mild recrudescence”; “eyes had
changed little one year later”
KE + 9 months LF; TC: ?; LK: “opacities ... less dense” and “opacity
... incomplete removal ... almost completely disappeared”
12 months LF; TC = 5.2 mmol/l; LK: “corneal opacities were less
KE + 3 months LF; TC: ?; LK: “no recurrence of eye trouble”
KE + 18 months LF;
5.80 mmol/; LK: eyes “remained free of
opcacity” and “almost cleared spontaneously”
? months LF; TC: ?; LK: “cornea continued to clear”
KE + 9 months LF; TC: ?; LK: eyes “remained clear” and “partial
clearance of the deeper opacification”
KE + 16 months LF;
TC: “remained relatively unchanged”; LK:
“significant clearing of lipid deposits”
CEA; 24 months LF
FOS; TC = 8.02 mmol/l; no “worsening of
CEA; 24 months LF
FOS; TC = 7.37 mmol
/l; no “worsening of
CEA; 24 months LF
FOS; TC = 8.47 mmol/l; “lipid depositions in
the cornea had become more dense”
Number of dogs with improvement (B)/total
Ref = reference; Dog = identification in publication; BTC = baseline serum total cholesterol
concentration, mmol/l; KE = superficial keratectomy; LF = low-fat diet; CEA = Collie eye anomaly; FOS
= short-chain fructooligosaccharides, 1-3% of dietary dry matter; ∆TC = change in total cholesterol
after diet intervention; ∆LK = change in severity of lipid keratopathy; W = worse (increase), U =
unchanged; B = better (decrease)
*Mean baseline, fasting serum triglyceride concentration of the patients (5, 6, 11; n =11) was 0.51
mmol//l) with range of 0.18 to 0.84 mmol/l. Mean baseline serum total cholesterol was 6.80 mmol/l.
In 1964, it was reported that pet dogs had higher serum cholesterol than laboratory dogs (35). In
laboratory dogs (n = 156), mean and range were 3.44 and 1.45 - 6.73 mmol/l. For the pet dogs (n
=160), the values were 5.83 and 2.33 - 25.20 mmol/l. All dogs were apparently healthy. The pet dogs
were typically fed on a commercial dog food supplemented with various human foods. The
laboratory dogs primarily received commercial dry laboratory biscuits and white bread.
Mean serum cholesterol concentrations in healthy pet (n = 12) and working (n = 35) Border Collies
were found to be 5.15 and 3.32 mmol/l (36). Most of the pet dogs were on meat and biscuits,
whereas their working counterparts had a rather uniform diet, consisting mainly of complete, cereal-
based dog food. In a follow-up study, working and pet Border Collies were fed the same diet (37).
Serum total cholesterol of the pet dogs remained broadly unchanged, whereas that of the working
dogs rose, but to a level 15% lower than in the pet dogs. It appears that, apart from diet, serum
cholesterol in the pet and working dogs was also influenced by differences in lifestyle and/or
1. Beynen AC. Voeding en hypercholesterolemie bij de hond. Dier-en-Arts 2019; Nr. 3: 50-51.
2. Kronfeld DS, Johnson K, Dunlap H. Inherited predisposition of dogs to diet-induced
hypercholesterolemia. J Nutr 1979; 109: 1715-1719.
3. Xenoulis PG, Steiner JM. Canine hyperlipidaemia. J Small Anim Pract 2015; 56: 595-605.
4. Liu S-K, Tilley LP, Tappe JP, Fox PR. Clinical and pathologic findings in dogs with atherosclerosis: 21
cases (1970-1983). J Am Vet Med Assoc 1986; 189: 227-232.
5. Crispin S. Lipid keratopathy in the dog. PhD thesis, University of Edinburgh, 1984.
6. Linton LL, Moore CP, Collier LL. Bilateral lipid keratopathy in a Boxer dog: cholesterol analyses and
dietary management. Progr Vet Comp Ophthamol 1993; 3: 9-14.
7. Troiano C. What are the causes of lipid keratopathy in dogs? (September 26, 2017)
8. Corneal dystrophy. http://www.akorn.com/aec-corneal-dystrophy.php
9. Farricelli AJ. Cholesterol deposits in a dog’s eye. (November 14, 2016).
10. La Croix N. Corneal opacification – Corneal lipid deposition. (November 9, 2018).
11. Jeusette I, Grauwels M, Cuvelier C, Tonglet C, Istasse L, Diez M. Hypercholesterolaemia in a
family of rough collie dogs. J Small Anim Pract 2004; 45: 319-324.
12. How KL, Hazewinkel HAW, Mol JA. Dietary vitamin D dependence of cat and dog due to
inadequate cutaneous synthesis of vitamin D. Gen Comp Endocrinol 1984; 96: 12-18.
13. Mahley RW, Weisgraber KH. Canine lipoproteins and atherosclerosis. I. Isolation and
characterization of plasma lipoproteins from control dogs. Circ Res 1974; 35: 713-721.
14. Gould RG, Taylor CB, Hagerman JS, Warner I, Campbell DJ. Cholesterol metabolism. I. Effect of
dietary cholesterol on the synthesis of cholesterol in dog tissue in vitro. J Biol Chem 1953; 201: 519-
15. Pertsemlidis D, Kirchman EH, Ahrens Jr EH. Regulation of cholesterol metabolism in the dog. I.
Effects of complete bile diversion and of cholesterol feeding on absorption, synthesis, accumulation,
and excretion rates measured during life. J Clin Invest 1973; 52: 2353-2367.
16. Pertsemlidis D, Kirchman EH, Ahrens Jr EH. Regulation of cholesterol metabolism in the dog. II.
Effects of complete bile diversion and of cholesterol feeding on pool sizes of tissue cholesterol
measured at autopsy. J Clin Invest 1973; 52: 2368-2378.
17. Mahley RW, Weisgraber KH, Innerarity T. Canine lipoproteins and atherosclerosis. II.
Characterization of the plasma lipoproteins associated with atherogenic and nonatherogenic
hyperlipidemia. Circ Res 1974; 35: 722-733.
18. Mahley RW, Hui DY, Innerarity TL, Weisgraber KH. Two independent lipoprotein receptors on
hepatic membranes of dog, swine, and man. J Clin Invest 1981; 68: 1197-1206.
19. Steiner A, Kendall FE, Bevans M. Production of arteriosclerosis in dogs by cholesterol and
thiouracil feeding. Am Heart J 1949; 38: 34-42.
20. Shull KH, Mann GV, Andrus SB, Stare FJ. Response dogs to cholesterol feeding. Am J Physiol 1954;
21. Abell LL, Mosbach EH, Kendall FE. Cholesterol metabolism in the dog. J Biol Chem 1956; 220: 527-
22. Grande F, Prigge WF. Serum lipid changes produced in dogs by substituting coconut oil for either
sucrose or protein in the diet. J Nutr 1974; 104: 613-618.
23. Lindall AW, Grande F, Schultz A. The effect of dietary fats on the serum lipoproteins of normal
dogs. Proc Soc Exp Biol Med 1971: 136; 1032-1037.
24. Romsos DR, Belo PS, Bennink MR, Bergen WR, Leveille GA. Effects of dietary carbohydrate, fat
and protein on growth, body composition and blood metabolite levels in the dog. J Nutr 1976; 106:
25. Kronfeld DS, Hammel EP, Ramberg Jr CF, Dunlap Jr HL. Hematological and metabolic responses to
training in racing sled dogs fed diets containing medium, low, or zero carbohydrate. Am J Clin Nutr
1977; 30: 419-430.
26. Downs LG, Crispin SM, LeGrande-Defretin V, Pérez-Camargo G, McCappin T, Bolton CH. The
effect of dietary changes on plasma lipids and lipoproteins of six Labrador Retrievers. Res Vet Sci
1997; 63: 175-181.
27. Campbell KL, Czarnecki-Maulden GL, Schaeffer DJ. Effects of animal and soy fats and proteins in
the diet on fatty acid concentrations in the serum and skin of dogs. Am J Vet Res 1995; 56: 1465-
28. Pasquini A, Luchetti E, Cardini G. Plasma lipoprotein concentrations in the dog: the effects of
gender, age, breed and diet. J Anim Physiol Anim Nutr 2008; 92: 718-722.
29. Barrie J, Watson TDG, Stear MJ, Nash AS. Plasma cholesterol and lipoprotein concentrations in
the dog: The effects of age, breed, gender and endocrine disease. J Small Anim Pract 1993; 34: 507-
30. Grande F, Schultz A. Effect of coconut oil on serum lipids of normal and of thyroidectomized
dogs. Proc Soc Exp Biol Med 1966; 121: 1107-1110.
31. Jeusette I, Lhoest ET, Istasse LP, Diez MO. Influence of obesity on plasma lipid and lipoprotein
concentrations in dogs. Am J Vet Res 2005; 66: 81-86.
32. Watson P, Simpson KW, Bedford PGC. Hypercholesterolaemia in briards in the United Kingdom.
Res Vet Sci 1993; 54: 80-85.
33. Sato K, Agoh H, Kaneshige T, Hikasa Y, Kagota K. Hypercholesterolemia in Shetland sheepdogs. J
Vet Med Sci 2000; 62: 1297-1301.
34. Cenedella RJ, Linton LL, Moore CP. Cholesterylene, a newly recognized tissue lipid, found at high
levels in the cornea. Biochem Biophys Res Commun 1992; 186: 1647-1655.
35. Schiller I, Berglund NE, Terry JR, Reichlin R, Trueheart RE, Cox GE. Hypercholesterolemia in pet
dogs. Arch Pathol 1964; 77: 389-392.
36. Crispin SM, Bolton CH, Downs LG. Plasma lipid and lipoprotein profile of working and pet border
collies. Vet Rec 1992; 130: 185-186.
37. Downs LG, Crispin SM, LeGrande-Defretin V, Pérez-Camargo G, McCappin T, Bolton CH. The
influence of lifestyle and diet on the lipoprotein profile of Border Collies. Res Vet Sci 1997; 63: 35-42.