It was poly unsaturated fatty acids ( PUFA) that made news in eighties and nineties and tons of money were made by the health food industry touting their virtues. Then came Linoleic Acid ( ALA) a n-3 fatty acid and Linolenic Acid (LA), a n-6 fatty acid, both branded as essential fatty acids. They were declared as most important PUFAs that humans should have through their diets and more money is made by same health food lobby. Now we have the Omega-3 fatty acids fad and if the emerging reports are to be believed, all the ills of modern world can be overcome if every food is laced with this PUFA from fish, not from any other sources!
The reported recommendations of American Heart Association (AHA) to consume more Omega-6 fatty acids(n-6 acids) make the nutrition related to essential fatty acids topsy turvy. Until recently excessive consumption of n-6 acids in the diet was considered dangerous with an array of diseases being attributed to it. Linoleic Acid, the torch bearer amongst n-6 acids, present in many vegetable oils, tree nuts and plant seeds, is supposed to be converted to physiologically active arachidonic acid which is the precursor for prostaglandins. Palm oil, Soybean oil, Rapeseed Oil and Sunflower seed oil with an annual production of 100 million tons (mt) provide 32 mt of n-6 fatty acids and 4 mt of its n-3 isomer. Hitherto nutritionists were swearing that an ideal diet should have n-6 acids and n-3 acids in the ratio of 4 to 1 where as in a typical western diet the ratio ranges from 10 to 1 at the lower level to as high as 30 to 1 at the other end of the spectrum. The reasoning for the change in the stand of AHA is that n-6 fatty acids give both pro-inflammatory and anti-inflammatory compounds in the body and therefore outweigh any negative consequences that may arise due to any excess consumption. Their recommendation calls for 5-10% of calories to be derived from n-6 fatty acids which works out to 12-22 g intake per day replacing the saturated fats and trans fats in the diet for an adult.
According to those opposing high intake of n-6 fats and espouse more consumption of n-3 fats, all the ills of the modern world can be attributed to drastic changes taking place in the diets of the population as a result of increasing demands for foods. Emphasis seemed to have shifted since the last 5 decades on cutting down carbohydrates, proteins, fats, cholesterol, saturated fats and trans-fats. It is not realized that the key to good health lies not in ruthlessly cutting down on fats in the diet but eating the best possible fats suitable for the human body. Their judgment is that n-3 fats are critically needed for brain functions and protection against CVD and other disorders. n-3 fats, also called Omega-3 fats, is synthesized from CO2, water and sun light in the chloroplasts of terrestrial plants and marine algae. During olden days animals raised in open farms exposed to sun light and feeding on grass and other forage materials yield milk and milk products like butter, cheese etc rich in n-3 fats. But the modern farming systems fatten cows using feed stocks containing grains like corn and soybean and use antibiotics and growth hormones to get them to the slaughter house in 1 year as against 4-5 years under the old open farming system.
n-6 fats are supposed to contain more rigid fatty acids that give the cell its structure while n-3 fats being more fluid help the body fight inflammation better. Oils from Soybean, Corn, Cottonseed and Canola, all seed oils constitute 96% of the edible oils consumed in the US. Seed oils are increasingly being implicated in diseases like Alzheimer's, CVD, Cancer, Diabetes and Obesity. The radical shift in the ratio of n-6 to n-3 fats from 1:1 at beginning of the last century to 20:1 to day is one of the most dramatic changes that accompanied the increased incidence of many modern day diseases. Powerful pleas are being made for including fish as a 'must' component of regular human diet, if we have to reverse the present trend of continuing onslaught of life style disorders. Already the industry is gearing itself to meet the expected demand for Omega-3 acids from the food industry which wants to fortify many processed foods with fish PUFA. With modern edible oil refining technology of decolonization and deodorization, fish oil can be converted into a water like product and further encapsulated for protection from oxidation and incorporation in many dry products. These fortified foods, positioned as 'super foods' in the markets, ranging from fruit juices to every day bread, have become money-spinners in no time!
The layman consumer is totally lost regarding the implications of all these claims and counter claims. There are al least 10 versions of PUFAs available from different foods. Firmly believing in the concept of PUFAs many consumers cultivated the practice of consuming PUFA rich foods including Flax seed which has more than 85% PUFAs. When Omega-3 fatty acid concept emerged, ALA was courted as the savior for keeping good health. The startling claim that only 1-5% of ALA consumed is converted into readily usable form of Omega-3 Acids like docosahexaenoic acid ( DHA) and eicosapentaenoic acid(EPA) by the body further raises alarm in the minds of the consumer. Added to this, the two fatty acids DHA and EPA are readily available only in fish and algae making the life of vegetarians miserable! A moot question is how those not consuming fish or Algae have been surviving for centuries so long without suffering from the tragic health problems of to day? Whether ratio of n-6 to n-3 imply that simple n-3 acid like ALA is not adequate but it has to be in the form of DHA or EPA? Added to this worry is the current belief that n-6 acids are not convertible to n-3 acids while reverse is possible in human body. Probably these mundane questions may not be critical for fish eating populations but are important in addressing the concerns of countries like India where majority of the population is vegetarian by nature or by compulsions. Indian Council of Medical Research, Ministry of Health must bring out clarity on this issue for the benefit of the consumers in the country.