If you do a just a cursory search of the body of research on fats in nutrition and their effects on human health – even if it’s only of the subset of research that’s published or referred to on the Internet – what immediately strikes you is the lack of consensus on what’s good and what’s bad. While it’s generally accepted among established medical institutions that saturated fats are not so good for cardiovascular health and that unsaturated fats are better, there are enough factors (and permutations and combinations of them), brought out by innumerable conflicting studies, that confound the situation immensely, making you wonder if the oils and fats you consume are beneficial or harmful. [After extensive reading, I documented some of my conclusions in the earlier posts titled I Shan’t Get No Saturation and Coconut Oil and Pure Ghee: Good or Bad?]
However, if there’s one subject that almost universally agreed upon by everyone (except, notably, NewScientist), it’s the beneficial effects of the omega-3 class of fatty acids in the diet. Study after study is revealing just how important these molecules are in cell function, brain and nerve function, heart health, reduction of inflammation throughout the body, and many other wonderful things. In fact it is also likely that omega-3 regulates triglyceride synthesis and the storage of fat, while as the same time enhancing a fuel partitioning phenomenon that conserves carbohydrate and burns fat – great for healthy weight loss!
Types of Omega-3
Omega-3 fatty acids are “essential” fatty acids that cannot be synthesised by the human body from scratch and hence
must be obtained from diet. The important ones are alpha-linolenic acid or ALA, which is a polyunsaturated short-chain fatty acid; and the long-chain polyunsaturated fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). ALA can be converted to EPA and DHA (albeit with an efficiency of less than 10 percent), and it is EPA and DHA that have been proven to have all those awesome health benefits.
Great sources of ALA include flaxseed, walnuts and green leafy vegetables; soyabean oil and rapeseed oil (canola) are also decent sources. Direct sources of EPA and DHA include fish such as salmon, mackerel, tuna, herring and halibut, and, to a lesser degree, other seafood such as prawn, crab and lobster. For people who don’t want to eat seafood, or for regions where high contamination by mercury and other pollutants is suspected, fish oil supplements could be used as a substitute (for instance cod liver oil capsules or liquid).
Factoring in Omega-6
One cannot discuss omega-3 without also taking into account the analogous class of unsaturated fatty acids known as omega-6. The one that merits mention is linoleic acid, a component of polyunsaturated vegetable oils. This is also an essential nutrient, but excessive levels of linoleic acid, relative to omega-3 fatty acids, could be detrimental to health. While the optimal ratio of omega-6 to omega-3 is 4 to 1 or lower, many modern diets take this ratio way above 10 to 1. Higher levels of omega-6 may also inhibit the conversion of omega-3 ALA to DHA as they compete for the same enzymes.
Omega-3 and omega-6 fats are both important in the production of prostaglandins, hormone-like substances that help regulate blood pressure, inflammatory and allergic responses, blood clotting, etc. Prostaglandin imbalances may result depending on the mix of fats consumed, and some types of prostaglandins that are unfavourable may be produced in excess as a result of too much omega-6 in the diet.
Conclusions and Recommendations
- While it is advisable not to pig out on fried foods (whether on a weight loss programmed or not), never forget that fats are an essential component of a healthy diet. Limit saturated fats, avoid trans fats, and get a mix of monounsaturated and polyunsaturated fatty acids by varying and rotating the vegetable oils you use.
- The ratio of omega-6 to omega-3 fatty acids is ideal when it is four or less. Unfortunately, urban Indian diets, not unlike western diets, are greatly skewed towards omega-6.
- It’s difficult to reduce omega-6, given the oils that are commonly in use in India (groundnut oil, rice bran oil, soyabean oil, etc).
- Instead it might be easier to increase the levels of omega-3. Green leafy vegetables, walnuts, and flax seed could add to alpha-linolenic acid levels. Flax seed, known as alsi in Hindi, should be available in grocery stores at the local market. It needs to be roasted and ground into a powder before use. Alternatively, more expensive (but convenient) flax seed powder is available as a branded product at health food stores or chemists.
- Or you might like to cut out the middleman and go straight to fish to get your fix of EPA and DHA. Salmon is not available in India, but Indian salmon or rawas (Eleutheronema tetradactylum) does provide decent omega-3. A better source is the Indian mackerel or bangada (Rastrelliger kanagurta). Another option is the Kingfish or Indo-Pacific King Mackerel known locally as surmai (Scomberomorus guttatus). Incidentally, the National Institute of Oceanography’s Bioinformatics Centre maintains a great database of the marine biodiversity of India at www.biosearch.in
- Deep frying of fish is likely to destroy the omega-3; light pan frying would be preferable (in fact some research suggests that this might be the best method). Of course, steaming, baking, or cooking the fish in a curry are also options.
- Val Souza