(Published with the permission of Jean Hailes for Women’s Health)
Fish oil supplements make little to no difference in the prevention of heart disease, according to a recent large research study. But does that mean that eating fish is also no longer a heart-healthy choice?
We find out what the deal is, and whether you still need to be popping that pill – or simply putting fish on your dish.
A question of evidence
Fish oil supplements contain large amounts of omega-3 fatty acids, which have long been promoted to improve heart health and prevent heart disease, the number-one killer of women in Australia.
So, is this recent study one we can just dismiss? Not at all, says Accredited Practising Dietitian Kim Menzies.
“This research study is what is called a ‘meta-analysis’,” explains Ms Menzies. “This is high-quality evidence.”
Rather than just looking at data from one study, a meta-analysis examines data from many independent studies on the same subject – in this case, 79 studies.
“The message, over and over again in this meta-analysis, was that omega-3 supplements show little to no effect on preventing death, heart attacks or strokes,” says Ms Menzies.
So, if you’re at risk of heart disease and you’re taking fish oil pills as your only path to prevention, Ms Menzies urges you to take a different – and more balanced – approach.
“Omega-3 supplements should not be taken as the only preventative measure for heart disease – the evidence is just not there,” she says.
One heart-healthy benefit the research found was that omega-3 supplements can slightly reduce a type of fat – known as triglycerides – in your blood, and increase levels of ‘good’ cholesterol (HDL-cholesterol).
“But the benefit was only slight,” says Ms Menzies. “Plus, this is only one small piece of the ‘heart health puzzle’. It wasn’t found to reduce other important measures such as the ‘bad’ type of cholesterol, LDL-cholesterol.”
Is eating fish still a heart-healthy choice?
When it comes to assessing this study and the place of fish in a heart-healthy diet, Jean Hailes naturopath Sandra Villella says “we should not throw out the baby with the bathwater”.
“Fish and seafood hold a lot of nutritional value – being rich in protein and still a good dietary source of the omega 3 fatty acids,” Ms Villella says. “They also contain smaller quantities of vitamin D, iodine and selenium.
“The vast majority of studies included in this meta-analysis were looking at omega-3 intake in supplement form. There were a very small number of studies which looked at eating fish and how that might prevent heart disease, but they were too small in number to hold any value.
“And some of these studies only tested the impact of dietary advice, rather than the effect of actually eating fish.”
Ms Villella and Ms Menzies both say the current recommendations from the Heart Foundation of Australia – of eating 2-3 servings of fish (including oily fish) per week – still stand.
“Fish is an important part of a heart-healthy diet,” says Ms Villella, “along with a variety of foods including vegetables, legumes, fruit, wholegrain cereals, lean protein, reduced fat dairy, nuts, seeds and other healthy fats such as olive oil.”
“And while this study looked specifically at heart disease, omega-3 fatty acids may still be beneficial for other health issues – such as protecting an ageing brain from Alzheimer’s disease.”
A note on mercury levels
Some types of fish contain higher levels of the metal mercury than other types of fish. Mercury, in high enough amounts, can have toxic effects on the nervous system, so it’s important to limit these types of fish – and not eat them too much or every day.
This is particularly important to note if you are pregnant or planning to become pregnant, as the developing brain of an unborn baby is more sensitive to mercury.
Fish with higher levels of mercury include:
- orange roughy (also known as deep sea perch)
- shark (also known as flake, commonly served in take-away fish and chips)
Food Standards Australia New Zealand state that pregnant women, those planning pregnancy, as well as young children, are recommended to eat 2-3 serves per week of any fish and seafood, except in these cases:
- If you eat one serve per week of orange roughy or catfish, you should eat and no other fish that week, OR
- If you eat one serve per fortnight of shark/flake or swordfish, you should eat no other fish that fortnight.
For the rest of the population, it’s recommended to eat 2-3 serves per week of any fish and seafood, except:
- If you eat 1 serve per week of shark/flake or swordfish, you should eat no other fish that week.
Another good reason to limit your intake of these types of fish is that many are listed as overfished. So choosing sustainably sourced fish such as Australian salmon and barramundi is not only a great choice for your health, but the environment too.
The Heart Foundation also recommends that all Australians should aim for 1 gram of plant-based omega-3s each day.
Plant-based omega-3s are related to the omega-3s found in fish, but are slightly different. Both types, however, are important to a heart-healthy diet.
In fact, evidence from the research study suggested that increasing the plant-based omega-3, alpha‐linolenic acid (ALA) may slightly reduce the risk of heart attacks and death from coronary heart disease.
Foods containing ALA include linseeds, hemp seeds, chia seeds, walnuts and seaweed.
Ms Villella’s latest recipe, Breakfast jar, is rich in ALA – find it in the Jean Hailes Kitchen.
Supplements are not a substitute
Ms Villella says an important lesson to take from this recent study on omega-3s and heart disease is that “supplements cannot replace the important role of healthy wholefoods in our diet”.
“Supplements are often single and separate nutrients, whereas foods are a unique and complex combination of protein, carbohydrate, fat, vitamins and minerals, plus many other potentially beneficial substances such as phytochemicals and antioxidants.”
And as Ms Menzies says, “It is the dietary pattern of eating a wide variety of wholefoods which assists our health, rather than eating individual nutrients.”