Evaluation of the impact of egg yolks enriched with bioactive fatty acids on human health

In recent years, there has been a considerable increase in metabolic disorders in the population, such as obesity, type 2 diabetes mellitus (T2DM) and cardio vascular diseases (CVD), which are associated to an unhealthy lifestyle and diet. As a result, there is a growing interest in improving the quality of foods and enriching it for human well-being and disease prevention. In particular, certain polyunsaturated fatty acids (PUFA) such as ω-3, as well as conjugated linoleic and linolenic acids have shown beneficial effects in the prevention of certain metabolic disorders. In this respect, eggs enriched with docosahexaenoic acid (DHA), α-linolenic acid (ALA), rumenic acid (RmA) and punicic acid (PunA) we were produced last year at the UCLouvain farm. The effects of these eggs (vs. control eggs) on human health were evaluated in a clinical study. One of the results of this study was a significant reduction of the waist circumference in the subjects who received the enriched eggs. The first step of this work was to incorporate the enriched and control egg yolks into two different crackers and to analyse these in terms of fatty acid profile and oxidation level. Both types of crackers were made of carrot, quinoa, apple, egg yolk, egg white and oil. The test crackers contained the enriched egg yolks as well as pomegranate seed oil and olive oil, while the control crackers contained the control egg yolks and sunflower oil. Both types of crackers showed an oxidative stability of at least 30 days. The fatty acid profile analyses showed that the test crackers were enriched in ω-3 PUFA (ALA and DHA), ω-5 (PunA) and ω-7 (RmA) compared to the control ones. The crackers were then put to test in a clinical trial conducted on 25 volunteers presenting a risk of developing metabolic disorders. These subjects were randomly assigned to eat a serving of the control or of the test crackers (on average 67.5 grams) every day for 70 days. Health and tolerance parameters were monitored during the study in order to assess, on the one hand, if the daily consumption of the enriched crackers was well tolerated by the consumers, and, on the other hand, if that intake had an influence on waist circumference and body fat accumulation. The results of the tolerance and health parameters determined that the crackers were well tolerated by the volunteers. However, no effects on waist circumference or body fat accumulation were observed. Substituting crackers instead of afternoon snacks showed an increase in feelings of satiety and fullness as well as a decrease in hunger and intention to eat in the future. In addition, the fatty acid composition of plasma and red blood cells was altered by the type of crackers consumed. The RmA and PunA contained in the test crackers were efficiently incorporated into plasma and the RmA into human red blood cells. Finally, both types of crackers provoked an overall increase in the PUFA content of the red blood cells at the expense of SFAs and MUFAs.