Various types of oils have made a lot of headlines when it comes to protecting our health from cardiovascular and neurological risks. Mainly it has been the Omega fatty acids chains (Omega-3, Omega-6 and Omega-9) that have been part of a constant medical research and debate. Among health benefits attributed to Omega fatty acids are lower risk of cardiovascular disease, cancers, depression, multiple sclerosis, Alzheimer’s, neurological disease, chronic pain, osteoporosis, skin disorders. It seems that most medical research is concerned about the Omega-3 (or fish oil) protective benefits, while in a wider community, there remains quite of bit of confusion about Omega-3, Omega-6 and Omega-9 effects on our health.
Here’s what you need to know about these fatty acids and the latest evidence on their health-protective properties.
Fats and oils can be confusing: there are monounsaturated fats, polyunsaturated fats and saturated fats. Just among the latter, there are at least 30 different types, and unless you’re writing a thesis in organic chemistry you don’t need to know their molecular structural differences.
Monounsaturated fatty acids or MUFAs:
There has never been any doubt among the medical community that monounsaturated fatty acids are excellent for our health. These fats constitute the main pillar of the Mediterranean diet and are found in nuts, avocados, olives, olive oil, pumpkin and sesame seeds, they are also present in some quantities in animal source foods, such as butter, lard, skin of chicken and duck. These fatty acids have been shown to reduce oxidative stress due to the high content of antioxidants in them, and thus protecting us from heart disease (https://pubmed.ncbi.nlm.nih.gov/31616932/), stroke, hypertension, they balance cholesterol and improve insulin sensitivity.(https://www.frontiersin.org/articles/10.3389/fphys.2021.659551/full)
It is their ‘sister’ fatty acids - polyunsaturated fatty acids, or PUFAs, that are more complicated when it comes to medical research and doctors’ recommendations worldwide.
PUFAs are considered essential fatty acids, as they are needed for human growth and development, however, our body does not produce them, we need to obtain them from food sources. There are many types of polyunsaturated fatty acids, but the most researched and known to common folks are the Omega-3 fatty acids - ALA, EPA and DHA - alpha-linolenic acid, eicosapentaenoic acid and docosahexaenioc acid. In plain words, ALA is often called the fatty acid for vegetarians (as it is present in plant foods, such as walnuts and cashews), whereas EPA and DHA together are termed fish oil (even though, lately as a supplement form, they can come from algae or other animal sources).
ALA - one of the most abundant fatty acid is converted into EPA and DHA in the body, but the conversion is quite inefficient: between 1-10% is converted into EPA and up to 5% is converted into DHA.
Aside from the fish oil - Omega-3 fatty acids, the other most important PUFA is Omega-6.
For a long while, the health community advised people to include both of these in their diet, without specifying the quantities or ratios. They were not entirely wrong, as both Omega-6 and Omega-3 need to work in unison to provide long-term health. But it is the ratio of these two when it comes to their critical importance for our health. It is believed that our ancestors consumed foods rich in Omega-6 and Omega-3 at the ratio of 1:1. The modern western diet has this ratio close to 20:1.
Omega-3 are abundant in natural whole foods, such as fatty fish - salmon, sardines, anchovies, mackerel, and also eggs and shellfish. Omega-6 are found in grains, beans and vegetable oils. For a long while, many doctors worldwide advised patients to switch from ‘unhealthy saturated fat’ to a ‘healthy vegetable oil’, such as sunflower oil, safflower oil, soybean oil, rapeseed oil, corn oil, etc. It is the proliferation of these vegetable oils in our daily eating and in a wide variety of foods that is mainly to blame for the heavily lopsided Omega-6 to Omega-3 ratio. (Remember, our ancestors had it at 1:1, the Western diet has it at about 20:1). The Omega-6 vegetable oils are refined and bleached, often with strong chemicals added to deodorise them due to bad smell obtained after processing. Exposed to high heat (they are typically used for frying in fast-food chains and many households) they become oxidised, breaking down into unstable molecules that are toxic and disruptive in the body.
There is a strong body of evidence that the Omega-6 fatty acids from vegetable oils cause inflammation in the body tissues and lead to the onset of many diseases, including cardiovascular disease, hypertension, diabetes, neurological diseases (the very diseases they were meant to be protective against when they first came into the health discourse). https://pubmed.ncbi.nlm.nih.gov/17243087/
https://www.sciencedirect.com/science/article/abs/pii/S0753332202002536
Some researchers go as far as calling the Omega-6 vegetable oils “the driver of coronary heart disease” https://openheart.bmj.com/content/5/2/e000898
One of the top nutrition authorities - Dariush Mozaffarian - in one of his studies found that a higher concentration of saturated fat (previously labelled as the main culprit of heart disease) showed less coronary atherosclerosis progression in postmenopausal women, whereas the intake of polyunsaturated fatty acids was associated with a decline in coronary artery health. https://pubmed.ncbi.nlm.nih.gov/15531663/
Many of us are not even aware that we are consuming high quantities of inflammatory vegetable oils, as they lurk into many every-day supermarket foods - packaged snacks, cereal and protein bars, soups, salad dressings, pastries, muffins, pies, breads, sauces and many more.
Leaving the inflammatory Omega-6 vegetable oils aside, let’s switch to Omega-3 fatty acids or fish oil. There have been big advances in recent years in our understanding of the protective role of the Omega-3 in the prevention of cardiovascular disease, stroke and hypertension, but research on this topic has remained to produce conflicting findings.
A recent VITAL study https://www.nejm.org/doi/full/10.1056/nejmoa1811403 published in a highly influential New England Journal, examined over 25,000 participants who took a supplementation of both Omega-3 (1g daily) and vitamin Ds (2,000iu daily). The results showed that these supplements did not lower the risk of
cardiovascular events, such are myocardial infarction, stroke, or death from cardiovascular causes, compared to a placebo. One of the criticisms of this study is the relatively small group of subjects and also a potentially low dosage of Omega-3 fatty acids used.
A later study, https://www.bmj.com/content/368/bmj.m456, pooling nearly half a million people in the UK, looked at the effects of habitual use of fish oil supplements and potential outcomes on cardiovascular health. In their analysis the researchers adjusted for age and sex, socio-economic status, ethnicity, household income, fruit and vegetable consumption, BMI, smoking status and alcohol consumption, physical activity, and other factors, and found significant inverse associations of fish oil use with the risk of all cause mortality. Consumption of fish oil lowered the risk of mortality from myocardial infarction and other cardiovascular events. The researchers noted that the protective association of fish oil use against CVD events was stronger in those with established hypertension. The study, however, found no significant association between fish oil supplementation and death from stroke.
A randomised, double-blind placebo-controlled trial https://www.nejm.org/doi/full/10.1056/nejmoa1812792 (the golden standard of medical research) involving patients with established cardiovascular diseases or with diabetes, who were already receiving a statin therapy, found that with a supplement of eicosapentaenoic acid, EPA (received as a 2g of Icosapent ethyl twice a day) the risk of cardiovascular death was significantly lower than among those who received placebo.
In a study https://www.ahajournals.org/doi/10.1161/circulationaha.105.581355
of over 40,000 Japanese middle-aged people with no previously diagnosed cardiovascular disease or cancer those who had a higher consumption of fish were associated with a “substantially reduced risk of coronary heart disease”, mostly from non-fatal cardiac events.
Other clinical results, such as the OMEGA study https://www.ahajournals.org/doi/full/10.1161/CIRCULATIONAHA.110.948562, which was randomised, placebo-controlled and double-blind, when tested the effectiveness of the Omega-3 supplements in sudden cardiac death survivors found no significant difference. The study cited that in addition to the primary treatment given to patients who suffered a cardiac event less than 2 weeks before enrolling in the study, the Omega-3 fatty acids supplement taken for 1 year period did not reduce total mortality or nonfatal cardiac events.
A review published in “Nutrients” in 2016 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5579658/ claimed there was a “high strength of evidence of no effect” of marine oils on the outcome of cardiovascular events, sudden cardiac death or all-cause death and blood pressure and “a low strength of evidence” of no effect of marine oils on the risks of CVD death, myocardial infraction, angina pectoris, congestive heart failure, total stroke incidents.
Omega-3 fatty acids are known for their anti-inflammatory effects on the human body. One of the potential mechanisms of Omega-3 on lowering inflammation is by reducing the tracking of leukocytes (white blood cells) to the site of inflammation, also a further clearance of inflammatory cells and the inhibition of inflammatory cytokines (intercellular chemical messengers).
Another proposed mechanism by which these fatty acids reduce inflammation is that they suppress the expression of inflammatory cytokines (such as C-reactive protein and tumour-necrosis factor, TNF, interleukins IL-2, IL-6) and enhance the expression of anti-inflammatory genes. https://www.frontiersin.org/articles/10.3389/fcvm.2021.802306/full
Both EPA and DHA have been shown to down-regulate the platelet-derived growth factor (PDGF), which prevents thrombosis formation.
Fish oil has long been researched to protect us from cognitive decline associated with ageing. Recent studies demonstrate that fish oil supplements may have a protection against onset of dementia or Alzheimer’s.
In a study https://pubmed.ncbi.nlm.nih.gov/23796946/ of healthy women, aged 50-75, who took a fish oil supplement of 2.2g per day, the researchers analysed their cognitive performance, structural neuroimaging, vascular markers and blood parameters and found that compared to the placebo group, those who took the fish oil supplement had a significant increase in executive functions. The cognitive changes seen provide evidence that Omega-3 fatty acids provide positive effects on brain functions in ageing healthy older adults.
New evidence from the ongoing Framingham study (the Framingham Offspring study) https://www.mdpi.com/2072-6643/14/12/2408/htm published in May this year shows that one of the Omega-3 fatty acids, DHA, may help prevent Alzheimer’s and dementia disease. In 1,490 healthy, dementia-free participants, over the age of 65, red blood cell (RBC) status was examined in relation to the incidence of Alzheimer’s. RBC is an objective measure of long-term dietary DHA intake. Risk for the onset of Alzheimer’s was half in those with high DHA levels. People with the higher DHA also had an estimated 4.7 extra years of life free from Alzheimer’s compared to people with low DHA in their blood.
Whether you decide to eat more fish and shellfish or add more nuts and seeds into your daily eating, there seems to be no doubt of the protective benefits of Omega-3 fatty acids for our long-term health. And the best part for me is that the health-protective benefits of the Omega-3 fatty acids come in the form of some of the most delicious foods out there - just thinking of my roast salmon with grated ginger and soy sauce or coconut-oil pan toasted mixed nuts. Yum!
Here’s what you need to know about these fatty acids and the latest evidence on their health-protective properties.
Fats and oils can be confusing: there are monounsaturated fats, polyunsaturated fats and saturated fats. Just among the latter, there are at least 30 different types, and unless you’re writing a thesis in organic chemistry you don’t need to know their molecular structural differences.
Monounsaturated fatty acids or MUFAs:
There has never been any doubt among the medical community that monounsaturated fatty acids are excellent for our health. These fats constitute the main pillar of the Mediterranean diet and are found in nuts, avocados, olives, olive oil, pumpkin and sesame seeds, they are also present in some quantities in animal source foods, such as butter, lard, skin of chicken and duck. These fatty acids have been shown to reduce oxidative stress due to the high content of antioxidants in them, and thus protecting us from heart disease (https://pubmed.ncbi.nlm.nih.gov/31616932/), stroke, hypertension, they balance cholesterol and improve insulin sensitivity.(https://www.frontiersin.org/articles/10.3389/fphys.2021.659551/full)
It is their ‘sister’ fatty acids - polyunsaturated fatty acids, or PUFAs, that are more complicated when it comes to medical research and doctors’ recommendations worldwide.
PUFAs are considered essential fatty acids, as they are needed for human growth and development, however, our body does not produce them, we need to obtain them from food sources. There are many types of polyunsaturated fatty acids, but the most researched and known to common folks are the Omega-3 fatty acids - ALA, EPA and DHA - alpha-linolenic acid, eicosapentaenoic acid and docosahexaenioc acid. In plain words, ALA is often called the fatty acid for vegetarians (as it is present in plant foods, such as walnuts and cashews), whereas EPA and DHA together are termed fish oil (even though, lately as a supplement form, they can come from algae or other animal sources).
ALA - one of the most abundant fatty acid is converted into EPA and DHA in the body, but the conversion is quite inefficient: between 1-10% is converted into EPA and up to 5% is converted into DHA.
Aside from the fish oil - Omega-3 fatty acids, the other most important PUFA is Omega-6.
For a long while, the health community advised people to include both of these in their diet, without specifying the quantities or ratios. They were not entirely wrong, as both Omega-6 and Omega-3 need to work in unison to provide long-term health. But it is the ratio of these two when it comes to their critical importance for our health. It is believed that our ancestors consumed foods rich in Omega-6 and Omega-3 at the ratio of 1:1. The modern western diet has this ratio close to 20:1.
Omega-3 are abundant in natural whole foods, such as fatty fish - salmon, sardines, anchovies, mackerel, and also eggs and shellfish. Omega-6 are found in grains, beans and vegetable oils. For a long while, many doctors worldwide advised patients to switch from ‘unhealthy saturated fat’ to a ‘healthy vegetable oil’, such as sunflower oil, safflower oil, soybean oil, rapeseed oil, corn oil, etc. It is the proliferation of these vegetable oils in our daily eating and in a wide variety of foods that is mainly to blame for the heavily lopsided Omega-6 to Omega-3 ratio. (Remember, our ancestors had it at 1:1, the Western diet has it at about 20:1). The Omega-6 vegetable oils are refined and bleached, often with strong chemicals added to deodorise them due to bad smell obtained after processing. Exposed to high heat (they are typically used for frying in fast-food chains and many households) they become oxidised, breaking down into unstable molecules that are toxic and disruptive in the body.
There is a strong body of evidence that the Omega-6 fatty acids from vegetable oils cause inflammation in the body tissues and lead to the onset of many diseases, including cardiovascular disease, hypertension, diabetes, neurological diseases (the very diseases they were meant to be protective against when they first came into the health discourse). https://pubmed.ncbi.nlm.nih.gov/17243087/
https://www.sciencedirect.com/science/article/abs/pii/S0753332202002536
Some researchers go as far as calling the Omega-6 vegetable oils “the driver of coronary heart disease” https://openheart.bmj.com/content/5/2/e000898
One of the top nutrition authorities - Dariush Mozaffarian - in one of his studies found that a higher concentration of saturated fat (previously labelled as the main culprit of heart disease) showed less coronary atherosclerosis progression in postmenopausal women, whereas the intake of polyunsaturated fatty acids was associated with a decline in coronary artery health. https://pubmed.ncbi.nlm.nih.gov/15531663/
Many of us are not even aware that we are consuming high quantities of inflammatory vegetable oils, as they lurk into many every-day supermarket foods - packaged snacks, cereal and protein bars, soups, salad dressings, pastries, muffins, pies, breads, sauces and many more.
Leaving the inflammatory Omega-6 vegetable oils aside, let’s switch to Omega-3 fatty acids or fish oil. There have been big advances in recent years in our understanding of the protective role of the Omega-3 in the prevention of cardiovascular disease, stroke and hypertension, but research on this topic has remained to produce conflicting findings.
A recent VITAL study https://www.nejm.org/doi/full/10.1056/nejmoa1811403 published in a highly influential New England Journal, examined over 25,000 participants who took a supplementation of both Omega-3 (1g daily) and vitamin Ds (2,000iu daily). The results showed that these supplements did not lower the risk of
cardiovascular events, such are myocardial infarction, stroke, or death from cardiovascular causes, compared to a placebo. One of the criticisms of this study is the relatively small group of subjects and also a potentially low dosage of Omega-3 fatty acids used.
A later study, https://www.bmj.com/content/368/bmj.m456, pooling nearly half a million people in the UK, looked at the effects of habitual use of fish oil supplements and potential outcomes on cardiovascular health. In their analysis the researchers adjusted for age and sex, socio-economic status, ethnicity, household income, fruit and vegetable consumption, BMI, smoking status and alcohol consumption, physical activity, and other factors, and found significant inverse associations of fish oil use with the risk of all cause mortality. Consumption of fish oil lowered the risk of mortality from myocardial infarction and other cardiovascular events. The researchers noted that the protective association of fish oil use against CVD events was stronger in those with established hypertension. The study, however, found no significant association between fish oil supplementation and death from stroke.
A randomised, double-blind placebo-controlled trial https://www.nejm.org/doi/full/10.1056/nejmoa1812792 (the golden standard of medical research) involving patients with established cardiovascular diseases or with diabetes, who were already receiving a statin therapy, found that with a supplement of eicosapentaenoic acid, EPA (received as a 2g of Icosapent ethyl twice a day) the risk of cardiovascular death was significantly lower than among those who received placebo.
In a study https://www.ahajournals.org/doi/10.1161/circulationaha.105.581355
of over 40,000 Japanese middle-aged people with no previously diagnosed cardiovascular disease or cancer those who had a higher consumption of fish were associated with a “substantially reduced risk of coronary heart disease”, mostly from non-fatal cardiac events.
Other clinical results, such as the OMEGA study https://www.ahajournals.org/doi/full/10.1161/CIRCULATIONAHA.110.948562, which was randomised, placebo-controlled and double-blind, when tested the effectiveness of the Omega-3 supplements in sudden cardiac death survivors found no significant difference. The study cited that in addition to the primary treatment given to patients who suffered a cardiac event less than 2 weeks before enrolling in the study, the Omega-3 fatty acids supplement taken for 1 year period did not reduce total mortality or nonfatal cardiac events.
A review published in “Nutrients” in 2016 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5579658/ claimed there was a “high strength of evidence of no effect” of marine oils on the outcome of cardiovascular events, sudden cardiac death or all-cause death and blood pressure and “a low strength of evidence” of no effect of marine oils on the risks of CVD death, myocardial infraction, angina pectoris, congestive heart failure, total stroke incidents.
Omega-3 fatty acids are known for their anti-inflammatory effects on the human body. One of the potential mechanisms of Omega-3 on lowering inflammation is by reducing the tracking of leukocytes (white blood cells) to the site of inflammation, also a further clearance of inflammatory cells and the inhibition of inflammatory cytokines (intercellular chemical messengers).
Another proposed mechanism by which these fatty acids reduce inflammation is that they suppress the expression of inflammatory cytokines (such as C-reactive protein and tumour-necrosis factor, TNF, interleukins IL-2, IL-6) and enhance the expression of anti-inflammatory genes. https://www.frontiersin.org/articles/10.3389/fcvm.2021.802306/full
Both EPA and DHA have been shown to down-regulate the platelet-derived growth factor (PDGF), which prevents thrombosis formation.
Fish oil has long been researched to protect us from cognitive decline associated with ageing. Recent studies demonstrate that fish oil supplements may have a protection against onset of dementia or Alzheimer’s.
In a study https://pubmed.ncbi.nlm.nih.gov/23796946/ of healthy women, aged 50-75, who took a fish oil supplement of 2.2g per day, the researchers analysed their cognitive performance, structural neuroimaging, vascular markers and blood parameters and found that compared to the placebo group, those who took the fish oil supplement had a significant increase in executive functions. The cognitive changes seen provide evidence that Omega-3 fatty acids provide positive effects on brain functions in ageing healthy older adults.
New evidence from the ongoing Framingham study (the Framingham Offspring study) https://www.mdpi.com/2072-6643/14/12/2408/htm published in May this year shows that one of the Omega-3 fatty acids, DHA, may help prevent Alzheimer’s and dementia disease. In 1,490 healthy, dementia-free participants, over the age of 65, red blood cell (RBC) status was examined in relation to the incidence of Alzheimer’s. RBC is an objective measure of long-term dietary DHA intake. Risk for the onset of Alzheimer’s was half in those with high DHA levels. People with the higher DHA also had an estimated 4.7 extra years of life free from Alzheimer’s compared to people with low DHA in their blood.
Whether you decide to eat more fish and shellfish or add more nuts and seeds into your daily eating, there seems to be no doubt of the protective benefits of Omega-3 fatty acids for our long-term health. And the best part for me is that the health-protective benefits of the Omega-3 fatty acids come in the form of some of the most delicious foods out there - just thinking of my roast salmon with grated ginger and soy sauce or coconut-oil pan toasted mixed nuts. Yum!
