Omega 3 - DHA
The human body, unlike fish, is not able to generate any form of the fatty acid. Therefore, Omega-3 is considered essential in any diet.
Omega -3 can be divided into distinct components: ALA (alpha-linolenic acid), EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid). ALA is found in plants and converted into DHA and EPA in the body, meaning tuna contain only DHA and EPA.
The consumption of Omega-3 is known to have beneficial effects on the body. Research has found that Omega-3
- positively influences the cognitive and behavioral performance, due to improving neurotransmission
- eases symptoms of mental disorders such as bipolar disorder and depression. It also reduces general mood change.
- reduces the risk of dementia. Studies show that people who eat fish regularly are three to five times less likely to develop Alzheimer’s disease, though other experts believe the influence is limited.
- is likely to benefit people with known cardiovascular problems by reducing blood pressure and stimulating the blood circulation.
- reduces the risk of early birth.
- eases the pain of people with inflammatory diseases such as arthritis.
Apart from the proven effects of Omega-3, there are many subjects that have been investigated, but results have been found inconclusive, due to expert’s contradicting conclusions. Among others, a large amount of research is conducted on:
- cancer. Though prior research continuously showed curing effects, the latest studies concluded no influence. Different components increase and decrease the risk for prostate cancer, making study outcomes unreliable. Breast cancer tissue can be blocked from growing according to some, but results are again inconclusive.
- preventing cardiovascular disease. Evidence does not support this, but the idea was caused by the fact that Omega-3 reduces blood pressure and stimulates the blood circulation.
- ADHD and autism. Though often used as a “medicine”, evidence is again inconclusive.
There are also effects of Omega-3 that are only seen in big tuna eaters, linking some evidence mainly to DHA and EPA, but also to other tuna characteristics. In people who regularly eat tuna, research found:
- significantly lower average heart rates and a lower chance of ‘sudden death’.
- that memory loss associated with aging slowed by 10% a year.
- a better development of the babies brain, preventing disorders due to premature birth.
Notable is the amount of researchers suggesting we should stop thinking about Omega-3 as either good or bad and no gray area, implying Omega-3 is essential, but no magic cure.
Nevertheless, there is a big market promoting the positive influences of the fatty acids and consumers are aware of the importance of Omega-3 in their diet. Tuna oil is often used as a source and is made of the head of the fish and therefore often shorter in supply. The specific chemical composition of the form of EPA and DHA present in tuna oil differs from other oils and are said to be digested more easily, which is why the effects are significantly more positive.
The long chain omega-3 content in canned tuna does vary because of the following reasons:
- There are different species of tuna that have different levels of long chain omega-3s. Seasonal variations and the age of the tuna also affect the levels of long chain omega-3s.
- Some cleaning and cooking processes prior to canning can cause some of the oil to be lost from the fish. The oil that is lost is often collected, refined and re-enters the food supply as fish oil.
- The Omega-3 rich part of the tuna - the dark meat – is frequently not included in canned tuna as many consumers do not like the look or taste of the dark tuna meat; therefore manufacturers do not include this part in specific canned tuna products.
Prices of fish oil/Omega-3 supplements have gone up by 15% in 2012, reaching an all time high. The market was estimated at about USD 19 billion in 2011.