Viva!’s Justine Butler reveals why plants are the best source of omega-3…
The reputation of fish oil has taken a dive. In the late noughties fish oils underwent a meteoric rise in sales when the dreaded cod liver oil was replaced with omega-3 capsules of the new millennium. The fish oil frenzy may well have now died down but confusion remains. Do we need fish oils for health or are we still being sold down the river?
Omega-3 fats explained
Saturated fats, such as lard and butter, tend to be solid and we have no dietary need for this type of unhealthy fat. Unsaturated fats, such as olive and rapeseed oil, and fish oil for that matter, tend to be liquid. It’s the flexible nature of these fats that makes them so biologically useful in fish swimming in cold waters or in the human eye and brain.
Essential fatty acids are unsaturated fats that we cannot make; we must get them from food. They are necessary for cell membranes, the brain and nervous systems and for producing regulators of blood pressure, blood-clotting and immune and inflammatory responses.
Alpha-linolenic acid (ALA) is an omega-3 essential fatty acid found in flaxseeds (linseeds), rapeseeds, soya, walnuts and oils made from them. ALA can be converted in the body into the longer-chain omega-3 fats: eicosapentanoic acid (EPA) and docosahexanoic acid (DHA). EPA and DHA, which are found in oily fish such as herring, salmon and mackerel, are also in some algal supplements, which are suitable for vegans. Conversion rates in the body can be low, hence the controversy. Some people say that vegan diets don’t supply enough EPA or DHA and insist that oily fish are essential – research tells a different story…
Fish oils and disease
Many people still think oily fish are the best source of omega-3 fats, which keep our hearts healthy, children clever and combat allergies and inflammatory conditions such as arthritis. We’re told that fish oils benefit heart health, however, the evidence is inconclusive. A major study in the British Medical Journal found that: “Long chain and shorter chain omega-3 fats do not have a clear effect on total mortality, combined cardiovascular events or cancer”. Further research in the European Journal of Clinical Nutrition revealed that: “Men advised to eat oily fish, and particularly those supplied with fish oil capsules, had a higher risk of cardiac death.”
Another study published in the Journal of the American Medical Association found fish oil supplements increased life-threatening abnormal heart rhythms in patients with implanted defibrillators. The American Heart Association say the findings of these studies can be explained by the “…adverse effects of methyl mercury, an environmental contaminant found in certain fish that may diminish the health benefits of omega-3 fatty acids.”
Fish oils: not so clever
The myth that fish oils boost brain power was reinforced by inaccurate reporting of a study involving children with learning and behavioural problems. The Oxford-Durham study investigated the effects of fish oils versus olive oil in children with developmental co-ordination disorders (DCD), such as attention deficit/hyperactivity disorder (ADHD), dyslexia and dyspraxia.
After three months, results showed improvements in reading, spelling and behaviour among the fish oil group. It was concluded that fatty acid supplements may be a safe, effective treatment for improving academic progress and behaviour among children with DCD. This is not the same as saying fish oil will turn all children into geniuses.
The BBC’s The Human Mind and Child of Our Time covered the story, and consequently omega-3 fish oil supplements sold out across the country. Food companies began slipping fish oils into yogurts and milk drinks to help our kids get smart! St Ivel Advance Omega-3 ‘clever milk’ adverts featured celebrity scientist Professor Robert Winston lending kudos to the claims.
However, the Advertising Standards Authority (ASA) ruled that the adverts were misleading and the claims unproven: “as the children in the trial had learning difficulties, there was no basis to claim there would be an improvement in the concentration of all children”. Dairy Crest withdrew the adverts. The only thing ‘clever’ about it was the huge marketing campaign that got thousands of people running to the shops.
This development in the slippery issue of fish oils adds to the confusion. If the diet provides enough essential fatty acids, fish oils may have no effect on cognitive ability at all. But forcing children to eat oily fish in the pursuit of cleverness may end up causing problems of a far more sinister nature.
All the world’s oceans are contaminated with toxic pollutants such as polychlorinated biphenyls (PCBs), dioxins and methyl mercury. These toxins accumulate, especially in fatty fish, as you move up the food chain and can cancel out any beneficial effects of omega-3s. In March 2006, Seven Seas Ltd withdrew batches of fish oil supplements because of the levels of pollutants present and less than a month later Boots the chemist also withdrew fish oil capsules for the same reason.
Farmed and dangerous
Farmed fish are not the answer as they tend to contain less omega-3s and more toxins than wild fish. A comparison of farmed salmon and wild salmon found that the farmed fish had consistently higher levels of PCBs.
Confused? You will be!
The UK Government say:
Men and boys and women past childbearing age or who cannot or are not intending to have children, can eat up to four portions of oily fish a week.
Girls and women who may become pregnant at some point in their lives can eat between one and two portions of oily fish a week.
Pregnant and breast-feeding women can also eat between one and two portions of oily fish a week. Pregnant women and women intending to
become pregnant should avoid shark, marlin and swordfish and not eat large amounts of tuna.
They say that pregnant and breast-feeding women should eat oily fish because it helps the neurological development of their babies. However, toxic pollutants in oily fish may harm unborn babies and infants. Damned if you do, damned if you don’t! They also extended their warnings to include
non-oily fish, including sea bream, turbot, halibut, dog fish (huss) and sea bass as these might have similar levels of pollutants as oily fish! People are confused.
No magic bullet
Fish is not a popular food and on average, people in the UK eat a third of a portion of oily fish per week and seven out of 10 people eat none at all. We should stop looking for a ‘quick miracle fix’ and focus on the bigger picture – improving our diets by cutting out saturated fatty foods and eating more fruit, vegetables, pulses, wholegrains, nuts and seeds.
Studies show omega-3s from plant foods offer more protection than fish oils.
The Nurses’ Health Study looked at more than 76,000 women over 10 years and found those consuming the most ALA had a 45 per cent lower risk of heart disease. The authors said: “Higher consumption of foods such as oil-based salad dressing that provide polyunsaturated fats,
including ALA, may reduce the risk of fatal heart disease”.
The Health Professionals’ Study looked at more than 43,000 men for six years and found that a one per cent increase in ALA intake lowered the risk of heart attack by 59 per cent.
The National Heart, Lung and Blood Institute Family Heart Study of more than 4,500 people found that men who ate the most ALA had a 40 per cent lower risk of heart disease and women eating the most, a 50-70 per cent lower risk.
The Lyon Diet Heart Study investigated if a Mediterranean diet, rich in ALA, could reduce secondary heart disease compared to a prudent Western diet in 423 adults. Results showed a striking drop in death rates of close to 70 per cent.
Improve conversion rates
To improve the rate at which ALA is converted to EPA and DHA:
• Cut down on cholesterol.
• Avoid or cut down on processed foods, trans-fatty acids from margarines and hydrogenated vegetable oils.
• Avoid or reduce fried foods, alcohol, caffeine, sugar, smoking and stress.
• Make sure that you get the minerals you require including zinc chromium.
Ratio of omega-6 to omega-3
Our bodies may be similar to those of our ancestors, but the way we fuel them has changed. You wouldn’t expect a car to run on a lower grade fuel than it was designed for without experiencing engine problems. Modern diets, rich in fried and processed foods, contain high omega-6 and low omega-3 levels. Both fats compete along the same pathways in the body so it stands to reason if we eat too much omega-6, things may go awry. Humans evolved on a diet with a ratio of omega-6 to omega-3 of around one-to-one. In Western diets the ratio is more like 15 to one! To redress the balance reduce the use of sunflower, safflower and corn oils, while increasing the use of flaxseed, rapeseed and soya bean oils.
The good news is you don’t have to eat neurotoxins and carcinogens to get your omega-3s. Plant foods can provide plenty to keep our hearts healthy and combat allergies and inflammatory conditions such as arthritis. This benefits the environment as well as plant-based sources of omega-3s are sustainable, fish are not.