Health benefits of seafood

Research carried out on seafood consuption has shown compelling evidence of associated health benefits.

Eating seafood can help prevent some diseases and improve the symptoms of others.

Boost brain power
Heart disease
Immune function support
Seafood health benefits for pregnancy and post natal depression
Depression and hyperactivity
Dementia and Alzheimer's disease
Obesity
Eye health
Cancer
Diabetes
Circulation
Joint benefits
Breathing and asthma
Healthy skin
Digestion

Boost brain power
The human brain is almost 60% fat, and much of this is the Omega-3 fat DHA. Studies have shown that people who eat plenty of fish during their lives tend to experience less dementia and memory problems as they get older.

Other research has also suggested that adding more DHA to the diet of children with attention-deficit hyperactivity disorder can reduce their behavioural problems and improve their reading skills, while there have also been links suggested between DHA and better concentration.

Heart disease
The strongest evidence for seafood is for its role in maintaining a healthy heart. Interest in this was sparked when scientists noticed that traditional fish-eating communities, Inuits, Japanese, experienced less heart disease and stroke. This led to a number of studies which compared fish-eaters and non-fish-eaters around the globe. One long-term study of American nurses  found that deaths from heart disease were 50% lower in nurses who ate seafood five times a week. This increased to a 60% lower risk if the nurses had diabetes. A review of the independent studies  showed that eating seafood even one to three times a month reduced the risk of heart attack or stroke, although eating seafood more than once a week gave the best result.

Other studies have looked at the impact of fish or fish oils on risk factors which can lead to a heart attack, e.g. LDL cholesterol or triglycerides. Some blood fats clog up arteries if they get too high. Diets high in saturated animal fat are known to push up levels of LDL cholesterol and triglycerides. In contrast, many studies have shown that habitual fish eaters have a better balance of blood fats, meaning that their risk of a heart attack is lower. Fish also seems to have beneficial effects on risk factors for coronary heart disease e.g. reducing the risk of blood clotting.

Immune function support
The immune system exists in a fine balance. EPA and DHA, the natural Omega-3 fatty acids in oil-rich fish, are thought to have specific properties which calm and normalise the immune system. While eating seafood can't prevent inflammatory or allergic conditions from developing in the first place, it can help symptoms such as swelling and pain.

Seafood health benefits for pregnancy and post natal depression
DHA is vital for normal brain and eye development.It is good for the brain because it makes brain cells more responsive to messages. It helps eyesight by boosting and developing the retina. Breast-fed babies have better eyesight and higher IQs than bottle-fed babies because breast milk is rich in DHA and arachidonic acid (an essential Omega-6 fat). Babies supplemented with DHA and arachidonic acid seems to benefit, particularly if they were born pre-term.  Other supplementation studies have found that women taking fish oil during pregnancy give birth to babies who have sharper eyesight and grow up having a higher IQ than children from unsupplemented women.

But DHA is not just important for infants. Pregnancy is known to deplete mothers' DHA reserves due to it being used to assist with brain development in the foetus, particularly in the third trimester. By the time the baby is born, blood DHA levels in the mother can be very low which impacts on breast milk DHA content. Scientists are already seeing a steady decline in the Omega-3 content of breast milk over the last few decades combined with a rise in Omega-6. As expected, low intakes of seafood and high intakes of vegetable oils and margarine are blamed. These changes in breast milk are likely to have an impact on DHA intake in babies but no one knows what might arise from this. A low DHA status after pregnancy could also increase the risk of post natal depression. Low blood levels of DHA have been found in new mums who didn't develop the condition. Pregnant women should be encouraged to eat more seafood, especially oil-rich fish, but need to avoid certain species such as shark and marlin due to the slight risk of contamination with heavy metals.

Other kinds of depression may have a link with a poor DHA status. Studies have found that people diagnosed with clinical depression have low blood levels of DHA.

Depression and hyperactivity
A study of 3200 Finnish people  discovered a link between low fish intake and symptoms of depression. It is likely that regular fish intake boosts DHA status and protects against depression.

Much has been reported in the media about the impact of fish oils on behaviour. While the evidence is not yet complete, it is clear that fish oils help certain conditions. Hyperactivity (or ADHD) is a learning disorder that often responds to supplementation with fish oils. Around 2 to 4% of children in the UK have ADHD and studies have found sufferers to have imbalances in their blood Omega-3 levels. Supplementation studies don't always give the same result, which suggests that some children respond better than others. Eating more seafood is perhaps a more natural way to ensure that children get enough DHA and EPA.

Dementia and Alzheimer 's disease
Dementia is a common disorder among elderly people and can affect as many as 30% of those aged over 85 years. Two Dutch studies, involving several thousand subjects, have reported that a regular consumption of fish seems to protect against age-related brain impairment and dementia. The figure below shows the results of one of these 5. It can be seen that the risk of dementia (relative risk) is lower when weekly fish intake is higher.

A USA study  found a link between low fish consumption and Alzheimer's disease. No supplementation studies have been done, as yet, in the elderly. However, the idea that fish is helpful for maintaining brain power throughout life is certainly gaining approval amongst scientists.

Obesity
With obesity on the rise, more and more consumers are interested in foods which support weight loss. Many studies have now shown that a high protein, low fat diet is best for aiding weight loss. Protein seems to control appetite, helping people to feel full. Seafood, as a low fat, high protein food, is ideal for this type of diet, particularly if grilled, baked or poached.

Eye health
Eating oil-rich fish regularly can also help keep eyes bright and healthy. According to a recent study, marine Omega-3 fatty acids can help protect the eyesight of people suffering with age-related macular degeneration (AMD), a condition caused by the deterioration of the retina which causes blurred, fuzzy or distorted vision. Scientists recommend that people suffering with AMD should eat oil-rich fish at least twice a week, while some experts have also suggested that an Omega-3 rich diet can cut a person's risk of getting AMD by a third. Fish and shellfish are also known to be rich in retinol - a form of vitamin A that is easily absorbed into the body and helps boost
night vision.

Cancer
Some studies are now linking high intakes of fish with a lower risk of cancer, particularly bowel cancer. No one knows, as yet, why this is the case or what sort of impact fish might have on cancer development.

Diabetes
New research suggests that a regular intake of fish and seafood protects people from developing type 2 (maturity onset) diabetes. This condition, usually controlled by drugs or diet, is now affecting more people in the UK because of our growing waistlines. It is not known for certain why fish consumption helps.

Circulation
Eating seafood regularly can improve your circulation and reduce the risk of thrombosis - painful blood clots in the arteries that can be fatal. This is because fish oils contain a lot of Eicosapentaenoic acid (EPA) and Docosahexaenoic acid (DHA). If a diet is rich in EPA and DHA, the body is less likely to use other fats that produce powerful versions of hormone-like substances called eicosanoids. These powerful eicosanoids make the body more likely to suffer inflammation and form blood clots. So more EPA and DHA means less risk for your circulation. Fish oils are also thought to increase the levels of nitric oxide released by the body into the blood, which helps to relax the blood vessels and improve blood flow.

Joint benefits
Including seafood as a regular part of a balanced diet has been shown to help the symptoms of rheumatoid arthritis - a painful condition that causes joints to swell up, reducing strength and mobility. Studies also show that sufferers feel less stiff and sore in the morning if they keep their fish oil intake topped up. Recent research has also found a link between Omega-3 fats and a slowing down in the wearing down of cartilage that leads to osteoarthritis, opening the door for more research into whether eating more seafood could help prevent the disease.

Breathing and asthma
A number of studies have suggested that fish may help protect lungs. One found that children suffering from asthma were more likely to show an improvement when fish oils were introduced into their diet, while another suggested that children who eat lots of fish may be less likely to become asthmatic. Fish may also help to increase your 'puffing' power, with research showing that people who eat a lot of fish tending to have more powerful lungs in old age than those who eat none.

Healthy skin
Not only do Omega-3 fats help the skin protect itself against harmful effects of the environment such as UV damage, but eating lots of fish oils can also help with the symptoms of skin conditions such as eczema and psoriasis, making skin feel less itchy. Fish is also a rich source of protein - an essential ingredient of collagen, which helps to hold back the years, keeping skin firm and more resistant to the effects of ageing.

Digestion
There is some evidence to suggest that a diet rich in fish oils can help to protect against serious inflammatory bowel diseases (IBD) such as Crohn's disease and ulerative colitis. Studies of the Inuit populations in the Arctic have shown very low levels of IBD, and some scientists believe this may be thanks to Omega-3 fats. There is also some evidence that taking in more Omega-3 fats may help slow the progression of disease in some IBD sufferers, and more research is being done.