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Over the last few years, a large number of studies have pointed to a leading factor in most of the top 10 disease-based causes of death: inflammation. Heart disease, diabetes, cancer, stroke, Alzheimer’s – all can be caused by chronic inflammation. It also leads to accelerated aging through free radical damage, atherosclerosis (which causes heart disease and stroke), arthritis, and neurological degeneration.
What causes inflammation in the body? The 1982 Nobel Prize for Medicine was awarded to John Vane, Bengt Samuelsson and Sune Bergelson for their discovery of how the drug aspirin actually works: by changing the levels of certain eicosanoids in the body. Every one of the human body’s 60 trillion cells is able to manufacture eicosanoids, which are molecules that act like localised hormones, which is why altering them can have wide-ranging effects. There are nine known classes of eicosanoids: prostaglandins, thromboxanes, leukotrienes, lipoxins, hydroxylated fatty acids, aspirin-triggered epi-lipoxins, isoprostanoids, epoxyeicosatrienoic acids, and endocannabinoids. Several of these have only been discovered recently, and it is likely that more will be found in the future.
Elevating the levels of some eicosanoids has a beneficial effect on human health, while others have a harmful effect when produced in excess. ‘Bad’ eicosanoids trigger an inflammatory response in the body, while beneficial, or ‘good’ eicosanoids turn off this inflammatory process. ‘Bad’ eicosanoids are not bad per se – they are necessary for the body to live, but harmful when too many of them are produced. Because they are so pervasive in the body, directly altering their levels with drugs (apart from some exceptions such as aspirin) is generally not possible – the drugs would be too powerful, affecting too many systems at once. But because of the way they are made, they are very sensitive to certain components of the human diet, so altering this alone can make an enormous difference.
So, what foods increase the production of the ‘good’ eicosanoids, and decrease the production of the inflammatory ones? All eicosanoids are made from 20-carbon chain fatty acids with a minimum of three double-chain carbon bonds. The body cannot manufacture these on its own, and must use omega-3 and omega-6 fatty acids (which must be obtained through the diet) instead. And here is the crucial point: omega-3 fatty acids produce ‘good’ eicosanoids, while omega-6 fatty acids produce ‘bad’ eicosanoids. Guess what the ratio of omega-3 to omega-6 is in the modern Western diet? It’s between about 1:7 and 1:20. Until recently, it was between about 1:1 and 1:4. This is not good. The constant imbalance leads to chronic inflammation throughout the entire body. No pain is immediately felt, but the damage is slowly being done, and once noticeable problems arise it may be too late.
So what are the best dietary sources of omega-3 fatty acids to restore the balance to where it should be? Fish oil is rich in both EPA and DHA. There is a debate on the benefits of supplementing the diet with EPA, because while it can lower blood triglycerides (which cause heart disease) by 30%, it can also suppress the immune system. DHA, on the other hand, is very important for the brain, eyes, and preventing heart arrhythmia, and so it may be preferable to take straight DHA supplements over fish oil. Mercury. Both perilla oil and linseed oil are rich in linoleic acid, a 16-carbon omega-3 fatty acid, but only a small amount of this is converted by the body to EPA and DHA, and DHA is by the most beneficial of the three overall.
It’s important to keep in mind that because essential fatty acids are polyunsaturated, they are particularly vulnerable to being oxidised. Vitamin E can protect against the oxidation of lipids, so it’s a good idea to take 400 IU per day of vitamin E when consuming essential fatty acid supplements. In one study, the level of vitamin E in the blood halved for participants without supplementation, indicating that it was doing its protective job against oxidation, but needed to be replenished.
But there’s an even more important factor in controlling inflammation: blood glucose levels. Elevated blood glucose increases the production of insulin. The precursor of all pro-inflammatory eicosanoids is arachidonic acid (AA) – and insulin increases the production of AA from essential fatty acids (by activating an enzyme known as delta-5-desaturase). So eating foods with a high glycemic load (such as white bread, rice and cakes), which spike blood sugar and therefore insulin levels up, causes an inflammatory response throughout the body. To keep inflammation down, it is very important to only eat these in moderation, preferably replacing them with wholegrains, fruits and vegetables.
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