Tuna is a fish in the mackerel family and an important source of protein, healthy Omega-3 fatty acids and essential nutrients. As an oily fish, tuna is rich in healthy fats that contribute to brain health, enhancing learning and preserving memory. The fish species provides generous amounts of several essential vitamins and dietary minerals that account for its varied benefits. The top benefits of eating tuna include a stronger immune system, skin and hair benefits, weight loss, bone and teeth health, muscle building, better vision and more energy.
How many tuna species are there? There are about 15 species of tuna. True tunas are classified into bluefin tuna and yellowfin tuna, the first being, for the most part, endangered. Tunas are quite longevous fish, living to an average of 10 years or a maximum of 20 to 50 years for some species. The older and bigger the fish, the more heavy metals it accumulates, notably methylmercury, which it acquires from other fish it eats and their respective sources of food.
How much tuna is it safe to eat? The biggest concern with regards to tuna is its content of mercury. Tuna accumulates this heavy metal more than other fish species. Some types of tuna reportedly have more methylmercury than others. For example, albacore tuna typically has a higher content than other species. Also, tunas with a lower fat content have more mercury than fattier tunas as research shows the heavy metal is present in lesser amounts in fattier fish. Nutrition experts have addressed these concerns by recommending eating one can of tuna per week if you are under 50 kg, two if you are over 50 kg and no tuna for pregnant women and women looking to become pregnant within a year because of its potential to lower fertility.
How long does tuna last fresh in the fridge? Tuna is available in the following forms: fresh, frozen or canned. All conservation methods preserve most of the nutritional value of tuna. Fresh tuna spoils the quickest. Frozen and canned tuna remain suitable for consumption from one to 5 years. How long does tuna last fresh in the fridge? If you have opened a can of tuna but didn’t finish it, know that it remains fresh less than 24 hours in refrigerator conditions. You should notice the solids, chunks or flakes of tuna losing their shiny color, becoming dull and acquiring a certain fishy odor.
Types of canned tuna. Typically, canned tuna is available as follows:
1) Tuna in brine (this is usually salt water).
2) Tuna in oil (usually olive pomace oil, extravirgin olive oil, a blend of the two or sunflower oil).
3) Tuna in sauce (typically tomato sauce).
4) Tuna in water (spring water, more exactly).
5) Tuna with flavors (pesto, garlic, peppers and others).
What are the health benefits of eating tuna? The benefits of eating tuna are a result of a generous and varied nutritional profile providing important micro and macronutrients of the likes of Omega-3 fatty acids, vitamin D, B vitamins, choline, cholesterol, dietary minerals and protein. Here are the top 7 nutrition facts, properties and benefits of tuna:
1) Source of Omega-3. Tuna is overall an important source of healthy Omega-3 fatty acids. DHA is a form of Omega-3 in tuna and other oily fish such as salmon, mackerel, sardines, herring, anchovies, known for its beneficial effects on brain and cardiovascular health. According to research, DHA benefits nervous system and cardiovascular health primarily by reducing inflammation levels.
This form of Omega-3 in tuna is reported to improve memory and learning, promote brain development in babies in the womb and infants and potentially help with depression. A sufficient intake reduces vascular inflammation, preventing lipid oxidation, lowers cholesterol and blood pressure levels and is believed to reduce heart attack risks and positively influence blood clotting processes.
2) High in vitamin D. Tuna provides generous amounts of vitamin D, around half of the recommended daily intake for an average adult. Vitamin D is known for its role in strengthening the immune system by regulating the production of certain antibodies, resulting in enhanced immune system responses as well as benefits for autoimmune disorders. Tuna also provides small amounts of zinc, further boosting immunity.
3) Rich in phosphorus. Like most fish, tuna too is rich in the mineral phosphorus which actively contributes to building new bone and maintaining bone density and integrity. Phosphorus deficiency cause delayed bone growth and rickets. Magnesium, also present in small amounts in tuna, further contributes to good bone density and preventing osteoporosis.
4) Source of protein. Tuna is a fish with a fibrous texture and a generally tough meat. Its texture is indicative of the presence of good amounts of protein, usually between 20 and 30 g per 100 g. Protein helps build and repair muscle as well as provides benefits for nervous system health. More exactly, the amino acids that compose protein regulate the production of neurotransmitters in the brain, contributing to improved mood, appetite and even sleep. Lastly, protein-rich foods like tuna help with weight loss.
5) Benefits for skin. The benefits of tuna for skin and hair are a result of its content of vitamins A and E as well as fatty acids composition. Both vitamins and fats in tuna nourish the skin from within, helping it retain moisture and giving it a plump appearance. Moreover, they exert a strong antioxidant action and help delay the onset of wrinkles. Vitamin A also contributes to better eyesight.
6) Source of B vitamins, iron and choline. Tuna provides a variety of B vitamins, notably vitamins B1, B2, B3, B6, B9 and B12 as well as choline. B vitamins, iron and choline generate energy for the body, contributing to elevated energy levels. Moreover, B vitamins contribute to brain and nervous system health by helping synthesize amino acids that further regulate the synthesis of neurotransmitters involved in improving mood, appetite, sleep and other brain and endocrine functions.
7) Moderate calorie content. Tuna generally has a low to moderate calorie content ranging from around 100 to 250 calories per 100 g. Tuna in water or in brine, fresh or frozen tuna without added sauces or oils are typically the lowest in calories. Tuna canned in vegetables oils has the highest calorie count.