CARDIOVASCULAR JOURNAL OF AFRICA • Vol 22, No 6, November/December 2011
324
AFRICA
Analysis of omega-3 fatty acid content of South African
fish oil supplements
MARETHA OPPERMAN, DE WET MARAIS, AJ SPINNLER BENADE
Abstract
Introduction
: Substantial evidence describes the protec-
tive effects of marine-derived omega-3 (n-3) polyunsatu-
rated fatty acids (PUFA) on cardiovascular diseases as well
as many other conditions. Numerous fatty acid preparations
are marketed for supplementing the Western diet, which is
low in n-3 fats. Since these preparations may vary in their n-3
PUFA content, we tested 45 commercially available products
on the SouthAfrican market for their fatty acid composition.
Method
: Forty-five commercially available n-3 fatty acid
supplements were analysed using gas–liquid chromatogra-
phy to determine their fatty acid content.
Results
: More than half of the n-3 supplements available on
the South African market contained
≤
89% of the claimed
content of EPA and/or DHA as stated on the product labels.
To meet ISSFAL’s recommendation of 500 mg EPA
+
DHA/
day can cost consumers between R2 and R5 per person
per day (R60 to R150 p/p/month). Regarding rancidity,
the majority of capsules contained conjugated diene (CD)
levels higher than that of vegetable oil obtained from opened
containers (three months) used for domestic cooking purpos-
es, despite the addition of vitamin E as antioxidant.
Conclusion
: Since no formal regulatory structure for dietary
supplements currently exists in South Africa, consumers
depend on self-regulation within the nutraceutical industry
for assurance of product quality, consistency, potency and
purity. Our results indicate that more than half of the n-3
fatty acid supplements on the South African market do not
contain the claimed EPA and/or DHA contents as stated on
product labels, and they contained CD levels higher than that
in unused vegetable oils obtained from opened containers
used for domestic cooking purposes.
Keywords:
supplements, eicosapentaenoic acid (EPA), docosa-
hexaenoic acid (DHA), conjugated dienes (CD), fish oil
Submitted 19/3/10, accepted 31/8/10
Cardiovasc J Afr
2011;
22
: 324–329
DOI: 10.5830/CVJA-2010-080
During the past few years, evidence-based nutritional research
has confirmed the importance of omega-3 (n-3) fatty acids in
reducing the risk for cardiovascular disease (CVD). Recently,
there has been increasing understanding of the essentiality of
n-3 fatty acids in reducing cardiovascular disease (CVD).
1
N-3
fatty acids possess a wide range of biological effects, including
reducing inflammatory responses, lowering triglyceride levels,
reducing risk of arrhythmias, a small dose-dependent hypoten-
sive effect, anti-atherogenic effects and a reduction in platelet
aggregation, all of which contribute to protection against CVD.
2
The n-3 fatty acids of particular concern for the prevention
of CVD are eicosapentaenoic acid (EPA) and docosahexaenoic
acid (DHA). EPA and DHA are very-long-chain n-3 fatty acids.
The ability of the body to manufacture them from the precursors
is limited and to ensure adequate supply of these fatty acids,
their dietary source is of vital importance.
3
These fatty acids are
predominantly found in fish and fish oils.
4
Fatty fish such as
herring, mackerel, tuna, salmon and trout are rich dietary sources
of EPA and DHA.
1
Since solid and voluminous scientific backing for the health
benefits of n-3 fatty acids exists, a high level of public awareness
and acceptance of n-3 fatty acids is becoming more apparent.
Considering the fact that it is not always possible to consume
adequate amounts of n-3 fatty acids through the diet, the inter-
est in n-3 fatty acid supplements has soared. The position of the
American Dietetic Association
1
on nutritional supplements is
that supplements can help some individuals meet their nutrient
needs when their diet is inadequate due to different circumstanc-
es, including being in an ‘at-risk’ life-stage group for a nutrient
deficiency. Examples of such risk groups include the geriatric
population, pregnant women, individuals with compromised
nutritional status and those with a limited variety in food selec-
tion, which prevents achieving nutrient adequacy.
However, although research has shown beneficial effects with
increased intakes in n-3 fatty acids, excess intakes can be just as
harmful as a deficiency and therefore n-3 fatty acids should be
supplemented with caution. Detrimental effects of excess intake
of n-3 fatty acids in healthy populations include depression of the
immune function, bleeding and increased risk of haemorrhagic
stroke, as well as increased lipid peroxidation resulting in oxida-
tive damage to various tissues.
5
At this point in time there is not
sufficient supporting data to establish an upper limit (UL) or safe
intake of n-3 fatty acids, however, the FDA has ruled that intakes
of up to 3 g/d of marine n-3 fatty acids are generally recognised
as safe (GRAS) for inclusion in the diet.
6
Undesirable effects from consuming n-3 fatty acids have also
been identified in a few selected populations. It has been suggest-
ed that diabetics or individuals with impaired glucose tolerance
must use n-3 fatty acid supplements with caution since it might
have detrimental effects on glucose homeostasis. Increased
incidences of nosebleeds have also been reported in individuals
with hypercholesterolaemia with n-3 fatty acid supplementa-
tion. Furthermore, simultaneous intake of n-3 fatty acids with
medication such as aspirin and warfarin will excessively prolong
bleeding times in individuals using anti-coagulants.
5
Functional Food Research Unit, Department of Agriculture
and Food Science, Cape Peninsula University of
Technology, Cape Town, South Africa
MARETHA OPPERMAN, PhD,
AJ SPINNLER BENADE, DSc
The Nutritional Intervention Research Unit, Medical
Research Council of South Africa, Cape Town, South Africa
DE WET MARAIS, MSc
