 Abstract | Epidemiological studies have consistently demonstrated positive association of infant neurodevelopment with maternal fish consumption, mostly attributed to the abundance of long chain n-3 polyunsaturated fatty acids (LCn3PUFA) in fish. However, fish consumption by Australian women is overall less than optimal. Secondary analysis of nationally conducted surveys (1995 National Nutrition Survey and the Australian Longitudinal Study on Women's Health in 2003 and 2009) demonstrated that less than half of Australian women of child-bearing age would consume fish at least twice a week as recommended by the Australian Dietary Guidelines. Of concern was the even lower fish intake in women who were pregnant or had recently given birth when compared with other women in the ALSWH surveys. This observation suggests that women may consume less fish whilst pregnant for fear of potential contaminants that might be present in fish.
A dietary modelling exercise based on the food consumption pattern from the Australian Dietary Guidelines confirms that one would need to consume three serves of oily or high LCn3PUFA fish per week to meet the suggested dietary target of 430 mg of LCn3PUFA for women as recommended by the National Health and Medical Research Council.
In order to ascertain the levels of LCn3PUFA and other nutrients present in Australian fish/fish products, several commonly consumed fish/fish products selected for use in the ensuing randomised trial were analysed following standardised procedure. Mercury contents of these fish study foods were also tested and found to be relatively low (range: 1.1 µg-7.0 µg/100 g).
To assess the acceptability of a diet that included more fish and its effects on biological parameters, a single-blinded randomised controlled eight-week trial was conducted in healthy women aged 18-50 years who normally consumed no more than one oily fish meal per week. The higher fish diet included four serves per week of a variety of fresh and convenience fish products (including canned and frozen, oily and non-oily) and were provided to the participants. The control group was asked to maintain their usual lower fish/higher meat diet and participants were provided with four serves of beef, chicken or deli-meat per week. After eight weeks, significant increases in mean eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and methyl mercury levels were observed in the intervention group when compared to the control group. Although blood mercury level did rise with increased fish intake, it was still at a level accepted as safe. The median acceptability score for both diets was the same suggesting no difference in diet acceptance.
A cost-effectiveness study conducted post-trial demonstrated that including fish in a diet is an economical means to obtain LCn3PUFA. To obtain equal amount of DHA, it would have cost sixty times more if consuming the meat study food compared to the fish study food.
In conclusion, it has been demonstrated that consuming a variety of fish and fish products several times a week is an acceptable and cost-effective means of improving LCn3PUFA status without causing detrimental increases in mercury levels, provided low-mercury containing fish are consumed. Women of child-bearing age are advised to consume high-LCn3PUFA but low-mercury containing fish as part of a healthy diet.
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