Tuna

Tuna

A tuna is a saltwater finfish migrate long distances over all the world’s oceans and occupy tropical, temperate, and even some cooler waters. The only two species of relatively limited distribution are the blackfin tuna (western Atlantic) and the longtail tuna (Indo-Pacific region). Tunas feed on fishes, squid, shellfish, and a variety of planktonic organisms. They spawn in the open sea over very large areas. The canned meat of albacore and yellowfin tunas is one of the world’s most popular seafoods. Measures were undertaken in the late 20th century to prevent large numbers of dolphins from being killed by the nets used to catch tuna in the world’s oceans.

Types of Tuna:

The seven species of tunas in the genus Thunnus are the northern bluefin tuna, albacore, yellowfin tuna, southern bluefin tuna, bigeye tuna, blackfin tuna, and longtail tuna. These different species range from moderate to very large in size. The giant of the group is the northern bluefin tuna, which grows to a maximum length and weight of about 14 feet and 800 kg. The yellowfin tuna reaches a maximum weight of about 180 kg, and the albacore grows to about 36 kg.

In Cooking:

Tuna is popular for  salad and sandwich.

Health Benefits of Tuna:

Make tuna your next meal choice. It is loaded with vitamins and nutrients, low in saturated fat and is an excellent source of protein. With talks of the dangers of high mercury content, many have turned away from fish. However, these reports are made in relation to people who eat fish every day. When eaten in moderation, you can reap the healthy benefits of this tasty fish, while avoiding the negative effects of high levels of mercury in your food. If you aren't convinced that tuna is a healthy meal choice, here are 10 nutrition facts that might change your mind:

1. Protein:
You always hear about eggs and various meats being a high source of protein, but what about fish? One of the nutritional highlights of tuna is its high protein content. How high in protein content? Try 23 grams in a serving size of three and a half ounces. Talk about a good source of protein to help keep those muscles strong. Protein is also good for the blood, skin, hair and nails.

2. Stroke:
Tuna can help you avoid the risk of having a stroke. A recent study has shown that adults who include one to four servings of fish as a part of their regular diet had a 27 percent lower risk of having an ischemic stroke. Five or more servings of fish per week reduced the risk of stroke to 30 percent.

3. Blood Pressure:
Tuna has omega-3 fatty acid, which helps prevent high blood pressure. Studies have shown that foods, like tuna, that contain omega-3 fatty acids helped test subjects maintain healthy blood pressure. Those who have yet to develop high blood pressure experience an even stronger beneficial effect from omega-3 fatty acids.

4. Lower Triglycerides:
With just two servings of tuna a week, you can lower your triglyceride levels. Why is that a good thing? Triglyceride in the bloodstream indicates the amount of fat being carried. If you have a high level of triglyceride, you are probably also experiencing high levels of low-density lipoprotein (LDL), or "bad cholesterol," and low levels of high-density lipoproteins (HDL), or "good protein." To make things simple, you basically want more HDL and less LDL, and eating tuna to lower your triglyceride level is one way to accomplish this.

5. Good for the heart:
A measure of heart rate function known as heart rate variability (HRV), can be increased by eating tuna. Again, the omega-3 fatty acids of tuna help improve cardiovascular health by increasing HRV. Omega-3 fatty acids also protect your heart from developing abnormal heart rhythms that can be fatal.

6. Heart Disease:
A moderate and healthy consumption of tuna can lower the risk of coronary heart disease. The fact that tuna can help improve the ratio of HDL to LDL in the body allows it ward off an increased risk of heart disease, especially when substituted for foods high in saturated fat and cholesterol content.

7. Obesity:
Another benefit of the omega-3 fatty acid found in tuna is its ability to reduce the risk of obesity while improving the body's insulin response. Omega-3 fatty acid is able to stimulate a hormone called leptin, which helps the body's metabolism while regulating the body's weight and food intake. Tuna is also low on the glycemic index (GI) with a GI rating of 0, and is low in both calories and fat, making it a good food choice for those struggling with obesity.

8. Immune System:
Tuna is a good source of selenium, an antioxidant that helps improve the body's immune system. The immune system is a vital part of the body that is integral for fighting off sickness, diseases and infections.

9. B Vitamins:
The B vitamins present in tuna help to build and maintain red blood cells and increase energy. These water-soluble vitamins increase the rate of metabolism, strengthen the immune system and help keep the skin healthy.

10. Cancer:
Tuna, and other fatty fish, have been shown in studies to reduce the risk of breast cancer in test subjects who ate it regularly. Other studies have shown that fatty fish, like tuna, have helped reduce the risk of kidney cancer.

When looking for a source of lean protein, tuna is an excellent choice. The fact that it is low in both fat and calories makes it an excellent substitute for dairy products and meats that have a higher fat content. One thing to keep in mind when eating tuna, aside from the mercury content, is a high sodium intake. A three and a half ounce serving of tuna contains 37 milligrams of sodium. High sodium intake can negate the health benefits of tuna by causing high blood pressure, stroke, kidney problems and heart disease. Keep this in mind when seasoning your tuna to avoid an excess of sodium intake.

Read More at Wikipedia
Recipe for Tuna  Link1     Link 2