Urszula Pomietło

In recent decades, there has been increased in interest in the issue of heavy metal pollution in aquatic environments, which is directly linked to industrial development, the intensification of agriculture and ongoing urbanisation. Heavy metals such as mercury (Hg), lead (Pb), cadmium (Cd) and arsenic (As) belong to a group of particularly hazardous pollutants due to their persistence, lack of biodegradability and ability to accumulate in living organisms. Introduced into the aquatic environment from both natural and anthropogenic sources (e.g. industrial effluents, agricultural runoff), they can subsequently be taken up by aquatic organisms and incorporated into food chains. Study conducted in various regions of the world indicates, fish are an effective bioindicator of aquatic environmental pollution, and their analysis allows for the assessment of potential health risks to consumers. The objective of this study was evaluation of the effect of sprats or sardines addition to the experimental diets on accumulation of some heavy metals in selected organs of experimental rats.

Fish are an important part of well-balanced diet. According to current dietary recommendations, they should be consumed twice a week. Sardines, being small-boned fish, are most often consumed whole, but in the form of canned or smoked products. These fish can be consumed after heat treatment, such as baking. In form of baked products, they are a source of high-quality protein, fatty acids, including n-3 fatty acids, and minerals (e.g., calcium, magnesium, iron, copper, and iodine). The aim of this project was to evaluate the effect of baked and freeze-dried sardines added to experimental diets on selected biochemical parameters related to lipid metabolism, oxidative stress, inflammation, and the bioavailability of selected minerals in rats with induced oxidative stress.

The immune system protects the human body against all types of infections and is designed to mitigate factors that influence its development. For this reason, people seeking to protect themselves against infections use various vitamin and mineral supplements and natural food products, especially herbs. Nutritional status plays an important role in the proper functioning of the immune system. It has been documented that protein, n-3 fatty acids, vitamins D and A, magnesium, calcium, iron, zinc, iodine and selenium are essential for the body's immune response. A well-balanced diet containing foods rich in the nutrients mentioned above may be one of the most important factors in preventing and combating SARS-CoV-2 and other infections. Sprats appear to be natural foods that can improve our nutritional status. They are a rich source of n-3 fatty acids, vitamin D, calcium, magnesium, zinc, selenium, and iodine. The aim of the project was to evaluate the effect of addtion of baked sprats in experimental diets and their influence on selected biochemical parameters related to oxidative stress and inflammation rat organism.

To decrease the risk of metabolic syndrome and other lifestyle-related diseases, the U.S. Environmental Protectional Agency (EPA) and Food and Drug Administration (FDA) advises consuming 2 to 3 servings of fish a week, amounting to approximately 240-320 grams. Fish from the Spratus family are highly recommended for the general adult population, as well as for young children and pregnant women, due to their elevated concentrations of unsaturated fatty acids (particularly omega-3) and minimal mercury levels. Omega-3 fatty acids have beneficial properties, such as reducing metabolic disorders and chronic inflammation. EPA and DHA are particularly well known for lowering serum triglyceride levels by reducing the liver’s production of very low-density lipoprotein (VLDL) particles and accelerating the removal of triglycerides from the bloodstream. This is primarily achieved by reducing hepatic lipogenesis through the inhibition of the SREBP-1c transcription factor, which reduces the activity of enzymes responsible for fat synthesis. Omega-3 fatty acids also stimulate β-oxidation (the breakdown of fatty acids) in mitochondria and peroxisomes, leaving fewer raw materials available for the formation of new triglycerides. Finally, they increase the activity of lipoprotein lipase, an enzyme that accelerates the removal of triglycerides from circulating chylomicrons and VLDL particles. Furthermore, EPA and DHA enhance endothelial and vascular function, mitigate the risk of arrhythmia, enhance insulin sensitivity and lower blood pressure, thereby reducing cardiovascular risk. Fish enhances the immune system through a combination of bioactive peptides, omega-3 fatty acids, vitamins, and minerals. The proteins and omega-3 fatty acids (EPA and DHA) exhibit strong anti-inflammatory and antioxidant effects by inhibiting pro-inflammatory cytokines, stimulating cytoprotective enzymes, and regulating the function of T cells and macrophages. In addition, the fat-soluble vitamins D3 and E support the maturation of immune cells, phagocytosis, and the elimination of pathogens, while minerals such as selenium and zinc protect white blood cells from oxidative damage and maintain essential cellular defense mechanisms.