In this study, we evaluated the performance of a modified SFFQ by comparing the daily
nutrient intake obtained from the FFQs with those derived from the three days 24 h FR.
As there is no approved nutritional database available in Saudi Arabia, we used a
nutritional analysis software program that was developed in the UK. This was chosen
for several reasons; firstly, it provides comprehensive information on the nutrient High LOA = 161.1 Low LOA = -180.3 Average Di ff e re n c e 0 100 200 300 400 -400 -200 0 200 400 High LOA = 6.94 Low LOA = - 5.79
121
content of approximately 5000 foods, including levels of fat, sodium, fibre, and
carbohydrates, vitamins and minerals. Secondly, it includes foods used by many
immigrants, such as South Asian and Arabs (for example Tabulla, Hummus, Falafel,
Kebbab, Samosa, biryiani rice). Thirdly, a high level of agreement has been confirmed
between the British and American food composition table (Kushi 1994; Garcia et al.
2003). Finally, it is well established and many studies have been published using the
same nutrition analysis program to assess dietary intake (Hill et al. 2004; Magee et al.
2005; Broadfield et al. 2007; Harrington et al. 2008).
Our results showed firstly, that the SFFQ generally has a higher energy and
nutrient estimate compared to the 24 h FR. The mean EI/BMR ratios indicated that the
24 h FR was under-reporting habitual energy intake compared to the SFFQ. For the EI
to be representative of habitual or average dietary intake, it must be greater than 1.35 ×
BMR. The 1.35 indicates the lowest physical activity level for any healthy individuals
and values less than 1.35 cannot represent habitual intake (Goldberg et al. 1991;
Goldberg and Black 1998). For women between 30 - 60 years of age with light,
moderate and heavy levels of physical activity, the EI/BMR ratio is estimated to be 1.4,
1.65 and 1.95, respectively (Goldberg and Black 1998). As our study participants were
moderately active, an EI/BMR ratio of 1.65 estimated by an SFFQ seems more
appropriate than a 24 h FR.
The recommended dietary allowance of energy intake for Saudi adult women
with BMI 22.1 has been estimated to be 2100 kcal per day (Khan and Al-Kanhal 1998).
Based on this estimate, the total energy intake for our sample with a mean BMI of 24.2
should be approximately 2299 kcal. This also supports that our modified SFFQ could
reflect the right food consumption pattern among the Saudi population compared to 24 h
121
probably reflects the current trend in Saudi Arabia where there is an increasing fat
intake and a decreasing carbohydrate intake since the 1960s (Stephen et al. 1995). In
addition, this is also supported by the recent national nutrition survey of the
representative population of Saudi Arabia which showed that the percentage of energy
from carbohydrates decreased from 75% to 43% and from fat increased from 10% to
42% between the years 1971 and 1992. Protein intake increased from 49 g to 114 g/day,
while fat intake increased from 34 g to 144 g/day during the same period (Al-
Othaimeen et al. 2004). All of the above points support that our modified SFFQ with a
pre-specified standard portion size gives a good dietary intake estimation particularly
for energy and macronutrients intake and its’ results correspond to the national estimates.
The lower estimation of the FFQ and 24 h FR could be due to inaccurate self-
reported portion size a deliberate underestimation of the actual dietary intake by the
participants. Because the degree of under-reporting increases with intake, individuals
tend to report intakes that are closer to perceived norms than to actual intake (Schoeller
1990). As previously reviewed (Macdiarmid and Blundell 1998), the under-reporting is
higher among women than men. This has been linked to the increased prevalence of
weight consciousness and thus dietary restraint in this group (Hill and Davies 2001).
This could be true as our study participants were well-educated women. On the other
hand, it could also be due to the limitation of the 24 h FR as only three days of 24 h FR
were used in our study. It has been shown that the correlations for most nutrients
increase with an increasing number of recalls (Block and Hartman 1989).
Secondly, the correlations between the two Food Frequency Questionnaires
were overall more similar to each other than between the frequency questionnaires and
122
Noethlings et al. 2003), where the same questionnaires, asking about portion size (FFQ)
or applying standard portion sizes (SFFQ) showed a good correlation.
Thirdly, despite the fact that the FFQ was not different from the 24 h FR in the
median energy, macro- and some of the micronutrients intake, they generally had a
weaker correlation compared to other methods. In addition, the FFQ tends to have a
limited agreement with the 24 h FR for many nutrients except vitamin C and
cholesterol, for which there was very good agreement with 1.7% and 3.2% bias, and
LOA (-180.3, 161.1) and LOA (-208.5, 210.4) respectively. Interestingly, the SFFQ vs.
24 h FR had a good correlation in terms of total fat, saturated fat, monounsaturated fat,
and cholesterol, as well as vitamin C and D intake, compared to the FFQ vs. 24 h FR.
More importantly, energy-adjusted correlation tends to be better between the SFFQ vs.
24 h FR compared to the FFQ vs. 24 h FR, particularly for retinol, vitamin B12, copper,
fibre, vitamin C, and folate. Vitamin E has 0% bias between the SFFQ vs. 24 h FR. This
supports the use of our SFFQ when a particular nutrient intake is to be tested.
Finally, our pilot study has several limitations; first it uses < 50 years old women
only. Thus the overall impression in dietary estimate is biased towards this younger
female group. Secondly, eating patterns may differ from men to women, even though a
prior study suggested that major eating patterns apply to both men and women (Slattery
et al. 1998). Another limitation is the small sample size, which may have affected our
results by having a wider confidence interval. However, this is a pilot study and the
SFFQ needs to be replicated and validated on a large group of people from different
parts of Saudi Arabia
In conclusion, the SFFQ that has been used in this study gave useful estimates of
energy and some nutrient intakes and appears to be a valid tool in comparison to a 24 h
123
comparing the dietary intake versus actual levels in the blood to give accurate validity,
particularly for the relevant micronutrients, in order to understand the diet-disease
124