Our bodies need two types of essential fatty acids from our diet, linoleic acid- LA (omega-6 FA) and alpha-linolenic acid- ALA (omega-3 FA), and that too in the right proportions. Our bodies cannot produce these polyunsaturated EFA on its own.
The majority of Malaysians are currently consuming sub-optimal levels of both these EFA. Our LA and ALA consumption is estimated at 7.7 grams (3.0% of energy) and 0.7 grams (0.3% of energy), respectively.
While we're meeting the basic LA/EFA requirements of 3.0% of energy (WHO 1990), the ratio of LA to ALA is approximately 10:1, a far cry from the recommended ratio of 5:1.
Clinical symptoms of EFA deficiency are known to be very rare. The body is only seriously affected when dietary levels of EFA dip below 1% of energy for prolonged periods.
Still, we could do with an improvement to our overall EFA intake as well as the LA (omega-6): ALA (omega-3 FA) ratio. And just how do we do that? Simple. Follow the Food Guide Pyramid for a healthier diet. Choose more pulses ("dhall", long beans, french beans, and "petai"), oilseeds/nuts and soybean products ("tau-hoo", "fucok", and "tempeh") and fish.
In addition, use palm olein-polyunsaturated blends of cooking oil. These should bring your LA intake to above 4.5% of energy and lower the LA (omega 6): ALA (omega 3) FA ratio to a healthier value of 6-8:1.
For those who don't know, our bodies cannot convert LA (omega-6 FA) into ALA (omega-3 FA) and vice versa. They also both compete for common enzymes (desaturases) involved in their respective metabolism. So very high intakes of LA (10% of energy), may upset the fine metabolic balance and raise the LA (omega 6) :ALA (omega 3) FA ratio to above 10.
But don't worry. There is actually an easy way to attain the important ALA omega-3 metabolites (eicosapentaenoic acid or EPA and docosahexaenoic acid or DHA). Just eat more fish! Adult Malaysians, according to estimates, presently consume about 70 grams of fish a day. Just increase that amount to 100 grams.
Good choices would be temperate marine fish such as mackerel, herring and salmon which contain 3 to 4 times higher EPA and DHA than our local varieties. However, if you can only afford the local varieties, don't despair. Aside from the potential health effects of the omega-3 FA content, fish per se has a protective effect on the heart. And there's nothing fishy about that!
Nutrition during pregnancy and lactation is a different ball game altogether. Mothers who are expecting or breastfeeding require more EFA and energy. WHO recommends that dietary EFA should be raised to 4.5% of energy (about 10 grams) during pregnancy, and to 7.5% of energy (about 17 grams) during lactation. Mothers would probably have to make significant changes to their daily diet to achieve these higher levels of EFA.
- By Dr Tony Ng Kock Wai
Research Officer, Division of Human Nutrition, Institute for Medical Research
Hon. Secretary of the Nutrition Society Of Malaysia