With age, who would not prefer to avoid poor eyesight, cognitive decline, dementia, cancer, diabetes, or death from a sudden heart attack? People would also prefer to have strong bones resistant to fracture and be looked after by healthy children.
The Inuits of Greenland (Eskimos), the Alaskans and the Japanese seem to enjoy all these benefits. Scientific research has zeroed in on the one thing these populations have in common: their staple diet protein was obtained from fish.
The benefits came from the relatively higher consumption of omega-3 fatty acids, found in fish. Omega-3 fatty acids are a heterogeneous group of long-chain polyunsaturated fatty acids — the “essential fatty acids” (EFAs) composed of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and alpha-linolenic acid (ALA). The recommended intake of ALA is 1.5 grams a day and DHA 0.5-1.0gm a day. EFAs are essential for the healthy development and functioning of the brain. They make up 20 per cent of the brain’s dry weight.
The human body cannot synthesise EFAs. They have to be obtained from dietary sources. Vegetarians get their quota of EFA in the form of omega-6 fatty acids from whole grains, sprouts, flaxseeds, soyabeans, walnuts, leafy green vegetables and legumes like beans. But this is slightly different in chemical composition from the omega-3 fatty acids found in fish.
The benefits of eating fish begin to appear when 60gm of fish are taken at least once a week. The benefits plateau if the consumption is more.
Combined with soya nuggets, nuts and legumes, when both omega-3 and omega-6 fatty acids are obtained, the benefits increase. The optimal ratio for maximal health benefits is 4:1 (omega-6:omega-3).
Fish are also an excellent source of protein. A hundred grams of cooked fish provide 20gm of protein, which is a third of the daily requirement. Fish protein, which is of high quality, is lower in fat content than mutton or chicken, and contains minerals like iron, zinc and calcium.
In pregnant women, seafood provides DHA which decreases the chances of preterm birth, improves visual acuity and helps optimise the development of the nervous system in the unborn child. During lactation, it reduces the incidence of post partum depression and provides DHA to the baby.
We have polluted our earth and the seabeds are contaminated with mercury. This liquid metal is present in fish too. Excess exposure to mercury can harm the development of the nervous system of a baby. Pregnant and lactating mothers should, therefore, limit their intake of fish to 400gm a week.
Not everyone can eat fish. While some are vegetarians, others may be allergic. Or fish may just not be available. The pharmaceutical industry markets supplements of cod liver oil, fish oil and omega-3 fatty acid as capsules and tonics. These, along with other lipid lowering medicines like statins, can be taken to potentiate (enhance) their effect. DHA has also been added to health drinks and to fortified infant formulae. The claim is that the benefits are provided without the toxins, to improve outcome in heart disease, lower blood pressure, optimise lipid levels, reduce inflammation and improve immunity. The claim extends to helping in chronic diseases like diabetes, epilepsy and rheumatoid arthritis, fighting depression, relieving asthma, preventing eczema and producing intelligent children with good visual acuity.
Capsulated EFAs are processed and bottled basically for convenience and commercial advantage. The purity, strength or safety of the products and their effects may vary. Product labels therefore must be read carefully. Prescribed medication should not be discontinued in favour of these supplements. People who are allergic to fish or nuts should exercise caution if they are planning to take these products.
Omega-3 fatty acids should be used only as an adjunct and not as a substitute for a healthy diet and regular exercise. Their actions in the prevention of cardiovascular disease are still controversial. Their superiority to current drugs is also disputed. Despite all the hype about these capsules and supplements, studies have not yet conclusively proven that they are superior to natural sources of EFAs. The superiority of breast milk is undisputed and it remains the best for the baby.
An overdose of these supplements can be dangerous, as it can produce vitamin D toxicity, bleeding, diarrhoea and leg cramps. This can also potentiate the effects of diabetic medications and insulin, causing blood sugar levels to drop.
Fish do make a difference. Research has proved that even if you don’t eat fish, keeping an aquarium reduces stress and blood pressure, helps in Alzheimer’s and calms hyperactive children with attention deficit disorder. It does not even have to be a real aquarium. Watching a virtual one, a DVD with moving fish or even having a screen saver with fish has equal benefits at home and in the work place.
There is a clear medical benefit to association with fish, whether you are a “fish eater” or a “fish watcher”.
Sources:The Telegraph (Kolkata, India)