Creation of snacks enriched with polyunsaturated fatty acids and benefits for metabolic parameters: a double-blind randomised controlled trial in overweight subjects

Background: There is a considerable increase in metabolic disorders in the world population, such as obesity, type 2 diabetes, cardiovascular disease and steatotic liver disease associated with metabolic dysfunction (SAMLD). There is growing interest in understanding dietary lipid metabolism and improving food quality for human well-being and disease prevention. In particular, certain polyunsaturated fatty acids (PUFAs) such as alpha-linolenic acid (ALA), docosahexaenoic acid (DHA), rumenic acid (RmA) and punicic acid (PunA) are known to have positive biological activities on human health and have attracted the interest of many scientists. The supply of healthy foods is also a priority. Aims. The aims are to study the feasibility of incorporating eggs naturally enriched with ALA, DHA, RmA and PunA into crackers, and to test their tolerance and their effects on metabolic parameters and body composition in humans fed with these test crackers compared with control crackers (Omegasnack study). Methodology: A double-blind randomized controlled trial was conducted on 25 overweight subjects with abdominal adiposity. Hens were fed with pomegranate oil and flax seeds to obtain eggs naturally enriched in ALA, DHA, RmA, PunA, which were used in the test crackers and hens were fed with olive oil to obtain eggs naturally enriched in oleic acid, which were used in control crackers. Human subjects were randomly assigned into two groups: a control group consuming control crackers and a test group receiving test crackers. Each group consumed a serving of the respective crackers (67.5 grams) as an afternoon snack every day for 70 days. Clinical, anthropometric and biological data were evaluated. Body composition was assessed by bioimpedance analysis and abdominal CT scan. Liver status was assessed by non-invasive scores and transient elastography. Results: Fatty acids of interest were efficiently incorporated into test crackers made with eggs from hens fed modified diets. The test crackers were significantly enriched with PUFAs n-3 such as DHA and conjugated fatty acids such as PunA and RmA, providing a daily intake of 141, 662 and 1119 mg, respectively (p<0.05 versus control crackers). The characteristics of the subjects were as follows with no difference between the two groups: mean age of 45.9 years, mean BMI of 28.1 kg/m², mean waist circumference of 99.1 cm, median hepatic elasticity of 4.6 kPa, mean controlled attenuation parameter of 258 dB/m. Insulin resistance was noted, with a mean HOMA-IR of 2.9. The mean triglyceride level was 105.3 mg/dL and the mean fatty liver index 48.5. The median visceral fat area was 114.3 cm². The median sekeletal muscle index was 48.6 cm²/m². The estimated compliance was 95% in both groups. Test and control crackers were well tolerated and increased satiety while reducing hunger and intention to eat in the future, but no impact on weight or waist circumference was noted. There was no change in circulating cholesterol or triglyceride levels. Liver transaminases and GGT remained stable during the study for both control and test group. Glucose metabolism and insulin resistance parameters were measured in the fasted state and did not appear to be strongly affected by either type of crackers. There was no difference in body composition (liver fat, adiposity, muscle surface or density) between the two groups. A significant transient decrease in HOMA-IR was detected with the test crackers during the study (HOMA-IR 2.77 ± 1.26 vs. baseline 3.15 ± 1.27, p< 0.05). The fatty acid composition of plasma and red blood cells was modified by the type of cracker consumed. In the test group, RmA and PunA significantly increased in plasma (12.9 ± 8.8 vs. 4.7 ± 2.6 mg/L and 4.4 ± 2.4 vs ND, p < 0.05) and RmA was efficiently incorporated into human red blood cells (0.33 ± 0.08 vs. 0.09 ± 0.03 weight % of total identified fatty acids, p<0.05). Conclusion: PUFAs can be successfully incorporated into snacks without adverse effects. The study demonstrates their potential long-term benefits by effectively incorporating them into plasma and red blood cells. These findings argue in favor of studying the inclusion of PUFAs in snack products to promote health through long-term trials in specific groups of patients