CARDIOVASCULAR JOURNAL OF AFRICA • Vol 22, No 6, November/December 2011
326
AFRICA
described by Christie
21
was slightly modified to suit our analyti-
cal requirements: 100 mg of sample was dissolved in 20 ml
chloroform/methanol (2:1); 200
μ
l of this solution was then
dried under a stream of nitrogen and 2 ml of a fresh solution
of 5% sulphuric acid in methanol was added in glass-stoppered
tubes and incubated in a water bath at 70°C for two hours. After
cooling, 1 ml of distilled water and 2 ml of hexane were added to
the sample and vortexed for one minute. The hexane phase was
allowed to separate and was then transferred to a glass tube to be
evaporated under a stream of nitrogen at 40°C.
The residue was then re-dissolved in 50
μ
l carbon disul-
phide (CS
2
) and 1
μ
l was injected into the gas chromatograph.
Heptadecanoic acid was used as an internal standard. Butylated
hydroxy toluene was added as an antioxidant to all samples.
The EPA and DHA content of the samples were quantified and
expressed as a percentage of EPA and DHA of total fatty acid
content.
One of the objectives of this research was to compare the
EPA and DHA contents, as claimed by manufacturers on the
supplement label, with the actual measured contents. An accept-
able range between 90 and 110% of the manufacturers’ claimed
content for EPA and DHA was proposed. Therefore, supplements
containing
≤
89% of the claimed EPA and/or DHA content were
perceived as substandard supplements, while those containing
more than 110% were considered to be excessive. The coeffi-
cient of variance (CV) for the analysis of EPA and DHA was 2%.
Results
Comparison with the manufacturers’ labelling information (Fig
1) showed that 56% (
n
=
25) and 51% (
n
=
23) of the supple-
ments failed to meet the lowest range of 89% for EPA and DHA
concentrations, respectively. Only 31% (
n
=
14) of the EPA and
36% (
n
=
16) of the DHA contents of supplements were within
the acceptable range of 90 to 110%. Thirteen per cent (
n
=
6)
of the preparations held more EPA than stated, while a similar
number (13%;
n
=
6) of supplements had a higher DHA content
than indicated.
Number of capsules and price to reach
recommendations
Currently there are no South African daily dietary intake recom-
mendations for n-3 fatty acids. However, manufacturers of
n-3 fatty acid supplements suggest a daily dosage of capsules
on their labels, with no indication of the basis on which these
recommendations were made. For the purpose of this publica-
tion, the International Society for the Study of Fatty Acids and
Lipids (ISSFAL)
14
recommendation of 500 mg EPA
+
DHA per
day for the prevention of cardiovascular disease was applied as
guideline. Fig. 2 provides a summary of the number of capsules
needed to reach ISSFAL’s
12
recommendations while Fig. 3 high-
lights the cost (ZAR) to achieve a daily intake of 500 mg EPA
+
DHA/day.
Forty-two per cent (
n
=
19) of supplements were able to
supply 500 mg EPA
+
DHA/day with the administration of two
capsules per day, while only 7% (
n
=
3) of supplements could
provide the recommended intake by consumption of one capsule
per day. In 20% (
n
=
9) of the supplements, more than five
capsules per day had to be ingested daily to meet the ISSFAL
14
recommendation.
The majority (38%;
n
=
17) of the supplements varied
between R2.01 and R5.00 per day to meet the ISSFAL
14
recom-
mendation of 500 mg EPA
+
DHA/day. This represents an
amount of R60.30 to R150.00 per month. Less than a third (31%;
n
=
14) of the supplements were priced between R1.01 and R2.00
per day (R30.30 to R60.00 per month). Some supplements (4%;
n
=
1) even cost up to R30.00 to R40.00 per day to supply a
500-mg EPA
+
DHA dosage.
Fig. 1. Percentage of claimed EPA and/or DHA content.
*Acceptable range
=
90–110%.
45
40
35
30
25
20
15
10
5
0
Supplements (
n
=
45)
56% 51%
<
89% 90–99% 100–109%
>
110%
Percentage (%)
24% 20%
7%
16% 13% 13%
% claimed EPA % claimed DHA
Fig. 2. Summary of the number of capsules needed to
meet ISSFAL
14
(500 mg EPA
+
DHA per day) recommenda-
tion.
3/day
18%
4/day
13%
1/day
7%
2/day
42%
>
5/day
20%
(
n
=
45)
Fig. 3. Price (R) to achieve daily intake of 500 mg EPA
+
DHA.
45
40
35
30
25
20
15
10
5
0
Supplements (
n
=
45)
<
R1.00 R1.01–
R2.00
R2.01–
R5.00
R5.01–
R10.00
R10.01–
R15.00
R30.00–
R40.00
Price (R)
31%
38%
4%
18%
4%
5%
