Healthy living & lifestyle
“It’s important to realise that we’ve spent the last 50 years investigating omega-3s, but we have spent very little time understanding the other fatty acids,” says Dr Nils Hoem, chief scientist at Aker BioMarine. “Nutritional science is only now beginning its investigations into the deeper biological effects of food.”
Omega-3 is essential for heart, brain, and eye health, but emerging omega fatty acids such as omega-7 offer new benefits.
The alpha and the omega So what actually is omega-3 and how does it compare with the other members of the omega family? Well, its reputation for being ‘essential’ is not unjustified – omega-3 fatty acids form a critical part of our cell membranes, especially within the eyes and brain. However, since our bodies cannot make these fats, we have to obtain them from dietary sources. There are three main subtypes of omega-3: DHA and EPA (found in seafood and certain microalgae) and ALA (found in plants). Omega-6, perhaps the best-known aside from omega-3, is ‘essential’ too, in the sense that the body can’t make it. However, supplementing this fat is generally unnecessary for those consuming a typical Western diet. Present in oils, nuts, cereals, bread and many animal products, omega-6 is very healthy if consumed in appropriate quantities. The problem emerges when the ratio of omega-3 to omega-6 becomes unbalanced. Historically, this ratio stood at 1:4 or less, but modern Western diets provide a ratio closer to 1:20. This ratio is associated with an inflammatory state within the body and ultimately a range of diseases. “Since omega-6s tend to be more inflammatory, and omega-3s tend to be less inflammatory, you need them both in the right ratio,” says Hoem. “Unfortunately since World War Two, the ratio has
gone in the favour of omega 6, meaning most people in the Western world today have an over-eager early immune response.”
Another fatty acid common in supplements is omega-9, although the need for its inclusion is debatable. For one thing, the body can produce omega-9 without outside help; for another thing, this fat is easily obtained from dietary sources such as olive oil and avocado.
If the numeration system seems confusing (where are omegas 1, 2, 4 and 8?) we can chalk that up to a fusion of ancient Greek and modern chemistry. ‘Omega’ is the last letter of the Greek alphabet, and is used in chemistry to refer to the end of a long chain. In the case of omega-3, we are talking about a chain of carbon atoms with a double bond three notches away from the end. Omega-6 would have the bond in the sixth position, omega-11 in the eleventh, and so on. A lesser-known member of the omega family – though one that is starting to rise in prominence – is omega-7. A non-essential fatty acid (one the body can synthesise), omega-7 is present in foods such as salmon, macadamia nuts, full-fat dairy, eggs and olive oil. It is also abundant within the sea buckthorn, which was used in Traditional Chinese medicine as an anti-inflammatory and is now used to make omega-7 supplements. As Hoem explains, omega-7 is particularly interesting from a chemical perspective. Whereas most healthy fatty acids are ‘cis’ fatty acids – meaning their hydrogen bonds are on the same side – that doesn’t apply to a type of omega-7 called vaccenic acid. This is a trans-fat, in which the hydrogen bonds are found on opposite sides of the carbon atoms.
“In trans fatty acids, the double bonds point in a different direction, which can be dangerous as they can rupture the structure of the cell membrane and interact with the enzymes in unproductive ways,” says Hoem. “Vaccenic acid is a natural trans fatty acid, but because it’s a fatty acid we’re all used to, it doesn’t seem to do us any harm.”
Metabolic markers
There are several other types of omega-7 too, including palmitoleic acid (found especially in macadamia plants) and paullinic acids (found in a variety of plant sources). Because these fats can be synthesised by the human body, they didn’t attract much research attention until recently. In 2008, however, a research paper was published showing that palmitoleic acid might have an important role to play in the metabolism. Specifically, it serves as a ‘lipokine’ (a fat- controlling hormone) that is released from fatty
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