Fish represent an excellent source of high-quality proteins and long-chain polyunsaturated fatty acids from the Omega 3 series. However, the growing presence of pollutants (mercury, cadmium, lead, arsenic) often discourages their intake. In this article, we provide useful tips in choosing fish and Omega 3 supplements.
Fish represent an excellent source of high-quality proteins and long-chain polyunsaturated fatty acids of the Omega 3 series (EPA and DHA). In addition, they are rich in minerals and trace elements such as iodine, phosphorus, calcium, copper, zinc, iron and cobalt. In fish, we find good quantities of vitamin A, vitamin D and B vitamins. The guidelines for proper nutrition include two or more portions of fish per week. Unfortunately, only a limited number of individuals meet the recommended requirement. This explains the great success of Omega 3 food supplements.
One of the aspects that most influences this nutritional deficiency is the fear of the presence of pollutants in fish. Many industrial, agro-zootechnical and urban activities pour harmful substances into coastal waters, both directly and indirectly, through the internal basins. This leads to a continuous increase of dangerous waste in the waters populated by fish which, once caught, we find on our tables. The substances that can most accumulate in fish are:
- Mercury. An excess of methylmercury is related to an increased risk of developing cardiovascular and neurological diseases in adults. Furthermore, being able to cross the placenta, high mercury levels expose the fetus to the risk of alterations in the development of the nervous system.
- Cadmium. Chronic exposure to cadmium can lead to kidney and cardiovascular diseases, hypertension, osteoporosis and impaired reproductive capacity in women. This metal is also able to pass from mother to infant during breastfeeding.
- Lead. Excessive lead ingestion can cause poisoning (saturnism) characterized by disorders such as abdominal colic, joint pain, anemia and nervous disorders. In addition, an abundance of this metal can transform the secretion of luteinizing hormone (LH), altering the reproductive capacity of the woman.
- Arsenic. Repeated exposure over time can cause a mutation in the color of the skin, hyperkeratosis, skin lesions, skin tumors. It also increases the risk of developing diabetes, cardiovascular disease and lung and bladder cancer. This substance can cause transformations in fetal development during pregnancy.
- Endocrine disruptors. They are substances that mimic the action of natural hormones, altering the body’s endocrine balance. In fact, hormones control all the body’s processes including growth, metabolism, reproductive capacity, functionality of the nervous system and regulation of the cardio-circulatory system. It is therefore easy to understand the risk that can result from the mutation of hormonal function by endocrine disruptors.
The process of accumulation of toxic substances in fish is regulated by the phenomenon of “bioaccumulation“. Predatory fish have higher levels of these elements because, as they feed, they also take on the share of toxic substances that their prey had collected. This explains the reason why it is often recommended to eat mainly small fish. The people most at risk for fish contamination are the weaker groups (children, the elderly, pregnant women), because they have less efficient detoxification systems, and the segment of the population living on coasts, whose consumption of fish is above average.
Many scientific studies show that the benefit of a fish-rich diet outweighs the risks that can arise from the introduction of contaminants, which are however limited by national regulations. Some tips can help us to minimize the risk, and therefore maximize the benefit, of fish consumption.
- Choose only Omega 3 supplements with certified fish (typically GOED or IFOS) which guarantee the absence of contaminants and heavy metals from the fish used for extraction. To check the quality of such supplements, we must also observe the concentration, the dosages, the ratio between fatty acids and the use of preservatives.
- Do not consume more than one portion per week of predatory fish (swordfish, tuna, shark, greens, grouper, dogfish, marlin, pike), alternating them with less contaminated species such as sardines, mackerel, sea bass, sea bream, sole, trout, and many others.
- The consumption of canned tuna is considered safer, because the fish used are generally smaller and therefore younger.
- Women who have plans to become pregnant, who are pregnant, or breastfeeding should further limit, if not avoid, the consumption of predatory fish.