For many years I was vegan, and now out of choice, eat no meat or dairy, but do eat eggs and fish, especially oily fish. This change happened when I had seen overwhelming evidence of the benefit of omega 3 fats, particularly EPA and DHA, which are highly concentrated in oily fish. However, vegan omega-3 supplements, derived from algae or seaweed and providing significant amounts of EPA and DHA are now available – and they work. A review last month concluded “algal sources of DHA significantly improve [blood] DHA concentrations.”
Both EPA and DHA, which are the key omega-3 fats you want, are derived originally from Alpha-Linolenic Acid, or ALA, which is the kind of omega 3 fat found in flax and chia seeds, as well as pumpkin and hemp seeds and also walnuts. Many strict vegetarians and vegans eat these on a daily basis in thehope of getting enough omega 3. But can you really convert enough ALA – for example in flax seed oil – into EPA and DHA? By the way, the conversion happens in that order, with EPA being cardio-protective and DHA being more important for brain development. Vegetarians have, on average, 60% lower levels of omega-3 in their blood than those who eat fish and much lowerlevels of brain-friendly DHA. The general view is that only about 5% of ALA is converted to EPA, demoting the value of vegetable sources of omega 3. But some research questions this.
A major study carried out by Dr Ailsa Welch and colleagues, from the School of Medicine Health Policy and Practice at the University of East Anglia, rigorously analysed the omega-3 intake in the diets of more than 14,000 people in Norfolk. Blood plasma levels of the more potent long-chain fats (EPA, DPA and DHA) were also assessed in a third of participants to work out how much actually gets through from the diet. One interesting finding was that dark green leafy vegetables also provided a significant portion of omega 3s, as does meat among meat eaters, but not nearly as much as oily fish.
As you would expect, the more fish – especially oily fish – eaten, the higher the blood plasma levels of EPA and DHA, with supplement takers having very high levels. But what was interesting was that the difference in circulating levels between non-fish eating vegetarians and fish-eaters was not nearly as great as might be predicted. This was especially true in women. The implication is that when you are deprived of a direct source of EPA/DPA/DHA, then the body may convert more from vegetable sources of ALA. One possible reason why women may convert vegetarian sources of ALA more effectively is that oestrogen may help the process. This would make sense from an evolutionary point of view since it is in pregnancy that these essential fats are most important.
I asked Dr Welch whether vegetarian sources of omega 3 could be sufficient. “Until we know more about enriched sources of ALA – such as flax seeds, walnut, walnut oils, leafy, dark green vegetables – we should still be cautious as to whether you can really get enough without fish,” she says.
A more recent, but small study compared blood levels of Finnish vegans and non-vegetarians. While they found higher levels of total omega-3, mainly from ALA, in the vegans they found significantly lower levels of EPA (0.63 vs 2.33) and DHA (0.85 vs 2.25) in the vegans versus the non-vegetarians.
Does vegetarian omega-3 keep you healthy?
While this study didn’t look at the health implications as such, there is growing evidence that having a high intake of ALA has positive benefits. A survey of Eastern European countries finds that the higher the intake of ALA, the lower the risk of cardiovascular disease, as does another in Costa Rica. However, studies that have actually given ALA versus fish oils have neither shown cardioprotective effects, nor any significant conversion to DHA. Japan has among the highest levels of fish consumption and very low disease rates; the UK and most other developed Western societies, are the reverse.
One of the measures of cardioprotection is a high heart rate variability (HRV). A high intake of omega-3 is both associated with high HRV and low risk of cardiac death. A recent study in the British Medical Journal compared vegans and omnivores and reported lower HRV in vegans. Whether or not this translates into less cardio-protection remains to be seen.
Conversion to DHA is especially important in pregnancy to build the baby’s brain. A substantial study of women and their children in the Avon area measured the fish intakes of women while pregnant and the subsequent development of their children. Following analysis, the recommendations stated that “consumption of less than 340g/week (three servings of fish a week) in pregnancy was detrimental, that is, increased the risks for low verbal IQ and abnormal behaviours among children.” Lead researcher Commander Joe Hibbeln, in charge of the health of the US navy, concludes: “The optimum level, however, may be even higher and remains to be determined.” In our own 100% Health Survey, significant health benefits were seen in those consuming three or more servings of fish a week.
How much omega 3 do you really need?
According to Hibbeln, one of the world’s leading experts on omega 3 and disease risk, “The majority of thepopulations (98-99%) are protected from… increased risk of chronic illnesses [with an intake of] 2g a day of EPA/DPA/DHA.” A 100g serving of salmon provides about this amount. If you supplement essential omegas on a daily basis, as I do, that gives about 700mg a day, or almost 5g a week. That, plus three servings of oily fish and some vegetarian sources of ALA, such as chia or flax seeds, would appear to be optimum. This is what I aim for.
This is especially important during pregnancy, but also for those with an inflammatory disease such as arthritis, or cardiovascular disease or depression.
Consciously increasing dietary sources of omega 3 compared to omega 6, which is the principle fat found in sesame and sunflower seeds, is also important as the brain’s ratio is 2:1 omega 6 to omega 3, whereas most Western diets have a ratio more like 15:1. Using walnut, chia or flax oil in salad dressings, olive oil as opposed to sunflower oil in cooking, and ground chia, flax or pumpkin seeds, as opposed to sesame or sunflower seeds, on cereals or smoothies is therefore a step in the right direction.
It is unlikely that vegan food sources provide enough omega 3 fats for optimal brain function. And if a vegan who consumes no eggs or fish is pregnant or breastfeeding,
supplementing a direct source of DHA is highly recommended. (DHA supplements, derived
from seaweed, are available.) I’d advise a vegetarian who chooses not to have fish oil supplements to eat a tablespoon of chia or flax seeds on a daily basis, plus have plenty of dark green vegetables, as well as supplementing vegan omega-3 providing at least 500mg of EPA + DHA. In reality this means two capsules a day.
For the rest of us, eating either fish or supplementing fish oils on a daily basis, plus omega 3 rich seeds, is likely to be optimal. If further research shows that we can convert omega 3s from vegetable sources more efficiently then we could eat less fish and have more seeds. From an ecological point of view this may be better with worldwide fish stocks decreasing. An alternative might be omega 3s derived from krill, the tiny organisms that feed fish, farmed in a sustainable way, however their omega-3 concentration is much less than that of oily fish.
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