Associations between food portion sizes, insulin resistance, VO2 max and metabolic syndrome in European adolescents: The HELENA study.

BACKGROUND AND AIMS: This study aims to examine the associations of food portion size (PS) with markers of insulin resistance (IR) and clustered of metabolic risk score in European adolescents. METHODS: A total of 495 adolescents (53.5% females) from the Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) study were included. The association between PS from food groups and homeostasis model assessment of insulin resistance (HOMA-IR) index, VO2 max, and metabolic risk score was assessed by multilinear regression analysis adjusting for several confounders. Analysis of covariance (ANCOVA) was used to determine the mean differences of food PS from food groups by HOMA-IR cutoff categories by using maternal education as a covariable. RESULTS: Larger PS from vegetables in both gender and milk, yoghurt, and milk beverages in males were associated with higher VO2 max, while larger PS from margarines and vegetable oils were associated with lower VO2 max (p < 0.05). Males who consumed larger PS from fish and fish products; meat substitutes, nuts, and pulses; cakes, pies, and biscuits; and sugar, honey, jams, and chocolate have a higher metabolic risk score (p < 0.05). Males with lower HOMA-IR cutoff values consumed larger PS from vegetables, milk, yoghurt, and milk beverages (p < 0.05). Females with lower HOMA-IR cutoff values consumed larger PS from breakfast cereals, while those with higher HOMA-IR cutoff values consumed larger PS from butter and animal fats (p = 0.018). CONCLUSION: The results show that larger PS from dairy products, cereals, and high energy dense foods are a significant determinant of IR and VO2 max, and larger PS from food with higher content of sugar were associated with higher metabolic risk score.

Modification of milk fatty acid composition by feeding forages and agro-industrial byproducts from dry areas to Awassi sheep.

The study tested the hypothesis that certain underused forages and agro-industrial byproducts available in dry areas may positively influence fatty acid (FA) composition and antioxidative properties of milk by their contents of residual oil or phenolic compounds or both. Sixty multiparous fat-tailed Awassi ewes were allocated to 6 groups in a completely randomized block design. During 50 d, the ewes were group-fed 2.5 kg of dry matter/d per ewe 1 of 6 isonitrogenous and isoenergetic diets (forage:concentrate, 0.3:0.7). The test feeds, comprising 30% of the diets, replaced either barley straw [lentil straw, olive leaves, and Atriplex (saltbush) leaves, rich in phenolic compounds or electrolytes] or conventional concentrate ingredients (olive cake and tomato pomace; ∼10% lipids) from the control diet. The diets containing olive cake and tomato pomace were rich in oleic acid (18:1 cis-9; 27% of total dietary FA) and linoleic acid (18:2 cis-9,cis-12; 37%), respectively. Profiles of FA were determined in individual milk samples drawn on d 0 and in wk 1, 3, 5 and 7. Data was analyzed by repeated measurement analysis. No consistent treatment effects on yield and gross nutrient composition of the milk were observed, although some differences occurred. Milk resulting from the Atriplex leaf diet expressed the highest antiradical activity, which was low with control and olive leaves. Feeding the tomato pomace and olive cake diets decreased the proportions of short- and medium-chain FA, whereas oleic acid clearly increased in proportion to total FA. Olive leaves most effectively increased rumenic acid (18:2 cis-9,trans-11) and α-linolenic acid (18:3 cis-9,cis-12,cis-15) in milk fat. This also resulted in the highest α-linolenic acid transfer rate from feed to milk and suggests that olive leaves affect ruminal biohydrogenation at several steps. Several alternative feeds exist with an added value, as they enhance FA with potential health benefits and the stability of the milk with higher antioxidative activity, even though responses to test feeds differed largely. It remains to be investigated whether combinations of these feeds would be complementary in these beneficial effects.