Dietary intakes and food sources of dietary fat among vegetarian and non-vegetarian female adolescents in New Zealand.

Abstract

Background: Adolescents are often exploring how they want to identify within society and this may be represented in the decisions they make surrounding food choices. One pattern of eating called vegetarianism appears to be increasing in popularity, often influenced by environmental concerns, animal welfare, or religious practices. The lower intake of saturated fatty acids [SAFA], and higher intake of unsaturated fatty acids [FA] that typically accompany the avoidance of meat, contribute to the cardioprotective FA profile found among vegetarians that follow traditional vegetarian diets. However, in an environment where processed foods are more readily available, it is not known whether ‘new age’ vegetarians are adopting vegetarian diets of the same nutrient profile. Female adolescents adhering to a vegetarian diet are an important, yet under-studied and vulnerable subset of the New Zealand population. It is therefore important to examine whether the food sources and dietary fat intakes among this group are healthful.

Objective: To describe and compare the dietary intakes and food sources of total fat, SAFA, cis-monounsaturated fatty acids [MUFA] and cis-polyunsaturated fatty acid [PUFA] among vegetarian and non-vegetarian female adolescents in New Zealand.

Design: This was a multi-centred, nationwide, cross-sectional survey called the Survey of Nutrition, Dietary Assessment and Lifestyles [SuNDiAL]. Two-hundred and eighty-two female adolescents aged 15 to 18 years old, who attended secondary schools throughout New Zealand were recruited as participants. Participants completed self-administered questionnaires to assess demographics and vegetarian status. Dietary assessment was conducted using two 24-hour diet recalls which were adjusted for usual intake using the multiple source method [MSM]. Energy and fat intakes were calculated from dietary data and these results were then compared to Australia and New Zealand nutrient reference values [NRV]. Food sources of fat were calculated and categorised based on Adult Nutrition Survey [ANS] 2008/09 food groups and then comparisons were made by self-defined vegetarian status.

Results: The population comprised 87.6% non-vegetarians, and 12.4% vegetarians. The mean intake of total fat and MUFA was similar between diet groups and in the combined study population provided 36.9% [CI: 36.2, 37.6] and 13.7% [CI: 13.4, 14.1] of total energy intake [TEI] respectively. TEI from SAFA was 2.4% [CI: 1.4, 3.4] higher and TEI from PUFA was 1.7% [CI: -2.3, -1.1] lower in the non-vegetarian diet group compared to the vegetarian diet group. Sixty-six percent of the combined study population exceeded the acceptable macronutrient distribution range [AMDR] for total fat [20-35% TEI], while 90.4% exceeded the AMDR for SAFA [<10% TEI]. A greater proportion of vegetarians were meeting these guidelines. The main food sources of total fat included: vegetables; nuts and seeds; and grains and pasta in the vegetarian group, compared to: poultry; potato, kumara and taro; and bread based dishes in non-vegetarian diet group.

Conclusion: Female adolescents in this study were consuming higher amounts of total fat and SAFA fat than is recommended. While total fat and MUFA intake among 15-18 year old females in New Zealand are similar between vegetarians and non-vegetarians, PUFA and SAFA intake differs and food sources of fat are variable. Favourable dietary fat profiles were found among the vegetarian participants, who consumed more energy from unsaturated FA, and less energy from SAFA. While these are promising findings that are in agreement with previous literature, larger studies are needed to confirm these results.