The effect of dietary vitamin A fortification on plasma fibrinogen levels of young females

Thesis

Epidemiological studies indicated that vitamin A status is associated with plasma fibrinogen levels. It has been shown that Africans have high plasma fibrinogen levels compared to Europeans, probably contributing to their high risk for stroke. In this study the hypothesis that increased intakes of vitamin A will lower plasma fibrinogen levels, has been examined. The study formed part of a clinical intervention trial under controlled conditions to examine the effects of vitamin A fortified sugar on plasma fibrinogen of African females aged \3-25 years. The methodology included questionnaires determining demographic profile, food consumption patterns and compliance to fortified sugar consumption. Measurements included anthropometric measurements and double baseline biochemical measurements on 95 subjects in the randomly selected sample population. The sample population was randomly divided into an experimental (n=46) group consuming fortified sugar (80 IU vitamin A per gram sugar), and a control group (11=49) consuming non-fortified sugar. Measurements were repeated after 4, 8 and 12 weeks of sugar consumption. Plasma fibrinogen levels were determined by the Dade Behring - Multifibren® U method. The method is a modification of the Clauss method. The baseline measurements of plasma fibrinogen showed that 5.1 % of respondents had a fibrinogen level of < 2.71 gil, 83.8% a fibrinogen level 2.72 - 3.30 gil and 11.1 % of respondents had a fibrinogen level> 3.30gll. Baseline measurements of serum vitamin A indicated that 12% of respondents had a level of<30 flgldl, 33.7 % a level of30-40flgldl, 38.6% a level of40-50flgldl and 15.7% of the respondents had a serum vitamin A level of>50flgldl. During the experimental period, the subjects consumed approximately 60g sugar per day, providing an additional 4800 IU or 1446 flg RE vitamin A per day to the experimental group. The results indicated that mean plasma fibrinogen levels of the experimental subjects were significantly lower than the baseline results (2.8t gIL) after 4 weeks (2.64 gIL) and 8 weeks (2 .65 giL). However, levels increased and returned to baseline levels at week 12 (2 .84 giL). The experimental subjects showed an increase in body weight at week 12, and it is speculated that this increase could have been responsible for the increase in plasma fibrinogen. In conclusion the study confirmed that by the intake of fortified sugar providing additional vitamin A in the diet of these African women, the plasma fibrinogen levels were significantly decreased at 4 and 8 weeks. It is further recommended that the influence of vitamin A on fibrinogen should be examined in subjects with raised fibrinogen and decreased vitamin A levels.