The incidence of the western diseases, atherosclerosis, CHD and stroke is
progressively rising in black populations worldwide and in South Africa. Stroke is an
important cause of death in black populations in South Africa and may increases
even further if risk factor (coronary and some haemostatic risk factors) prevalence is
altered by change in lifestyle and diet, westernisation and migration to an urban
environment. Raised fibrinogen levels which are more prevalent in westernised
black men than white men, are accepted as an important risk factor for stroke and
CHD. It is believed that the possible protective effects of diet against the
development of atherosclerosis and thrombosis could be mediated, in part, through
haemostasis. A prudent low-fat, high-fibre diet may favourably influence
haemostasis. More specifically, oat bran (soluble fibre) has been shown to have
beneficial effects on some coronary risk factors and haemostasis. The physiological
effects of dietary fibre are strongly related to SCFAs, which are produced by colonic
fibre fermentation. According to available literature, SCFAs could possibly have a
beneficial effect on lipid profiles and haemostatic risk factors. Little information is,
however, available on the effect of a specific combination of SCFAs on fibrinogen
levels and other haemostatic factors in human subjects.
The main objective of the study was to examine the effect of a combination of
SCFAs, resembling oat bran (acetate:propionate:butyrate รข 65:19:16) on plasma
fibrinogen levels, some haemostatic risk factors and other related risk factors for
CHD and stroke in westernised black men.
The study was a randomised, placebo-controlled, double-blind clinical trial. 22
subjects falling within a pre-determined set of inclusion criteria, and with higher
normal fibrinogen levels were randomly selected into an experimental group (n = 11)
and placebo group (n = 10). Supplementation of 12 capsules daily was sustained for
five weeks. Total plasma fibrinogen, fibrin monomer concentration, fibrin network
properties, factor VII and factor VIII activity, serum lipids, glucose concentrations,
some metabolic indicators and fasting acetate concentrations were measured at
baseline and at the end of supplementation, in all subjects. The usual dietary intake of the subjects was obtained using a food frequency questionnaire and a 24-hour
recall.
According to the baseline results, the subject group was homogeneous with an
apparently healthy clinical and physical appearance. Although both subject groups
had a favourable coronary and haemostatic risk profile, total cholesterol levels as
well as factor VII and factor VIII activity were in the higher normal ranges.
Furthermore, the 24-hour recall indicated a tendency towards the adoption of an
atherogenic Westernised diet. Although SCFA supplementation had no effect on the
fibrinogen concentrations, a significant decrease was observed in the fibrin monomer
concentrations, network fibrin content, factor VII and factor VIII activity. A significant
increase was observed in the compaction of the fibrin networks, as well as a
tendency for the mass to length ratio of the fibrin fibres to increase. Furthermore, a
statistically significant although not clinically significant increase was indicated in
HDL cholesterol concentrations after SCFA supplementation.
It was evident from these findings that SCFA supplementation may have a direct
effect on haemostasis, especially the fibrin network characteristics, factor VII and
factor VIII activities, as well as fibrin monomer concentration. This observation
suggests that SCFA supplementation may have a strong protective effect against
atherosclerosis and thrombosis.
In conclusion, the hypothesis that soluble dietary fibre will influence fibrinogen
concentrations and other haemostatic risk factors through production of SCFAs, was
proven to be partially true. It was clear that, although fibrinogen concentration was
not influenced by SCFA supplementation, beneficial effects on the fibrin network
architecture and the positive cascade effect on haemostasis may be a direct effect of
SCFAs supplementation. The study further indicated that the known protective
effects of dietary fibre on CHD could partially be mediated through effects of SCFAs
on fibrin networks. It is recommended that the role of fibrin networks as a risk factor
for CHD and the effect of diet on haemostasis should be further investigated.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:ufs/oai:etd.uovs.ac.za:etd-12022009-105238 |
| Date | 02 December 2009 |
| Creators | de Wet, Martie |
| Contributors | Dr FJ Veldman, Prof A Dannhauser |
| Publisher | University of the Free State |
| Source Sets | South African National ETD Portal |
| Language | en-uk |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.uovs.ac.za//theses/available/etd-12022009-105238/restricted/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University Free State or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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