Omega 6 and Cardiovascular Risk – Is Excess Dangerous?

Omega 6 and Cardiovascular Risk - Is Excess Dangerous?

Generality

What are Omega 6s?

Omega 6s are a family of lipids , to which the essential fatty acid linoleic acid (LA) and the semi-essential gamma linolenic acid (GLA), dihomo-gamma-linolenic acid (DGLA) and arachidonic acid (AA) belong.

Does omega 6 increase or decrease cardiovascular risk ?

Omega 6 are essential and semi-essential fatty acids that play a promiscuous role on cardiovascular risk:

  • Positive role: they improve some metabolic parameters, above all lipemia and in particular cholesterolemia, reducing the cardiovascular risk.
  • Negative role: it is possible that some of them, if present in excess and for the reasons that we will explain below, increase cardiovascular risk.

 

Omega 6 and Cholesterol

The right dose of omega 6 decreases cardiovascular risk

Among the effects of omega 6 there is also an improvement in cholesterolemia. Above all, the reduction of total cholesterol
is observed , due to the decrease of the bad one or LDL (Low Density Lipoprotein). In fact, there is no real bad cholesterol ; cholesterol is “more or less” all the same (let’s leave out the details of a purely chemical nature). The intake of omega 6 does not reduce the production of cholesterol by the liver , but the synthesis of LDL. LDLs are particular transporters of fats in the blood , which carry lipids from the liver to the suburbs.If in excess, peripheral cholesterol tends to deposit in the arteries , participating in atherosclerosis . This is why, by reducing LDL, omega 6 can help reduce cardiovascular risk.
The scientific evidence supporting a possible improvement effect of omega 6 on the synthesis of good cholesterol or HDL (High Density Lipoprotein) is less evident, which sometimes even seem to decrease.
On the contrary, HDL increases significantly thanks to motor physical activity .

  • To obtain the maximum metabolic result from the consumption of omega 6 it is necessary that, together with the omega 3, they replace the so-called ” bad fats ” ( saturated , hydrogenated and especially in trans conformation).
  • Furthermore, as we will see later, it is essential to respect the “overall caloric constraint”. A diet that is too rich in fat predisposes to overweight and, even if composed of excellent quality lipids, risks nullifying the protective effect of the latter on cardiovascular risk.

Linoleic acid, as well as omega 3:

  • Decreases blood pressure
  • Decreases the production of PAI (antifibrinolytic molecule)
  • Increases insulin sensitivity

These are all aspects that decrease cardiovascular risk.

Omega 6 and Inflammation

An excess of omega 6 is considered potentially harmful to the body; let’s see why.

Excess arachidonic acid increases inflammation and cardiovascular risk

The excess of AA seems to alter the inflammatory balance of the body.
AGEs are responsible for the production of eicosanoids, some of which are anti-inflammatory (vulgarly called good) and some pro-inflammatory (called bad).
While omega 3 and some omega 6 (GLA) produce good anti-inflammatory eicosanoids , certain omega 6 and in particular arachidonic acid are precursors of bad pro-inflammatory ones (inflammatory cascade). Increased inflammation is a factor that greatly increases cardiovascular risk.

Omega 6s damage Omega 3s

The excess of omega 6 decreases the effect of omega 3 and increases the cardiovascular risk

An excess of omega 6, especially linoleic acid, is harmful for the metabolism of omega 3.
The essential fatty acids (AGE omega 6 and omega 3) are processed in the cells thanks to the effect of the same enzymes . Therefore, the excess of omega 6 tends to “occupy” all these biological catalysts, affecting the metabolism of omega 3 (for example, it reduces the production of eicosapentaenoic acid EPA and docosahexaenoic acid DHA). Furthermore, omega 3s are less present in the diet.

This affects the formation of good anti-inflammatory eicosanoids to the advantage of the bad pro-inflammatory ones.
It should be remembered that, even if omega 3s have a better effect from an inflammatory point of view, they have no significant impact on cholesterolemia; however, they appear to effectively reduce blood triglycerides .
This suggests that both omega 3 and omega 6 play an important but not interchangeable role in reducing cardiovascular risk.

Types of eicosanoids

The tables below summarize:

  1. The types of eicosanoids that can be derived from essential fatty acids
  2. The formation of eicosanoids starting from AGEs.

Table 1 – NB . The function of eicosanoids also varies according to the type of receptor in which they bind.

Eicosanoids Abbreviation
Prostaglandins PG
Thromboxanes TX
Prostacyclins PGI
Leukotrienes LK extension

 

Table 2 – Formation of eicosanoids and role in inflammation

Essential Fatty Acid Abbreviation Formula Series of produced eicosanoids
TX
PG
PGI
LK extension Effects
Gamma linolenic acid GLA 18:3ω6 Series-1 Series-3 Less inflammatory
Diohogamma linolenic acid DGLA 20:3ω6 Series-1 Series-3 Less inflammatory
Arachidonic acid YY 20:4ω6 Series-2 Series-4 More inflammatory
Eicosapentaenoic acid EPA 20:5ω3 Series-3 Series-5 Less inflammatory

Synthesis

Fundamental concepts concerning the correlation between omega 6 and cardiovascular risk

Below we will summarize the most important concepts concerning the effects of omega 6 on the human body:

  1. Omega 6s have a distinctly positive effect on cholesterol levels.
  2. To maximize the benefits from the diet, omega 6 and omega 3 need to replace saturated and hydrogenated (especially trans) fats.
  3. Linoleic acid does not appear to affect triglyceride levels .
  4. Some studies have demonstrated a potential to reduce blood pressure and PAI, two aspects that would make LA more and more similar to omega 3.
  5. High intakes of linoleic acid are associated with improved insulin sensitivity .
  6. In almost all of the studies, the intake of omega 6 is associated with a significant reduction in the risk of heart attack ; in a famous study of US nurses (Nurses’ Health Study), women with a higher intake of linoleic acid had a 30% lower risk of heart attack than the others.
  7. In vivo, omega 6 (all) are demonstrating an almost zero proinflammatory potential, contradicting the results previously obtained in vitro.
  8. By carefully analyzing certain markers (cytokines), the intake of certain omega 6 seems to correlate with good improvements in systemic inflammation parameters.
  9. Diet should favor the intake of foods rich in omega 3 , as they are less frequent and in lower concentrations in foods .
  10. Although the existence of a clear and linear correlation between the linoleic acid content of the diet and the reduction of cardiovascular risk has now been proven, exaggerating with the intake of certain omega 6s (above all arachidonic acid), in the face of a low omega 3, could increase the risk of developing inflammatory /autoimmune diseases.
  11. However, if the diet is characterized by an omega 6/omega 3 ratio slightly higher than normal, it would not seem the case to be too alarmed.

Conclusions

  • On balance, it seems that the alteration of the ratio between omega 3 and omega 6 in favor of the latter is far less important than expected.
  • We also recall that the Italian population is still deficient in essential fatty acids in the diet; therefore, it is advisable to try to increase their consumption by replacing the SATURATED fats of animal origin (and the hydrogenated ones containing trans acids), with the polyunsaturated ones contained in dressing oils (cold extracted) and in oily fish , salmon , cod etc (if possible fished and not farmed ).
  • Ultimately, by varying the type of seasoning oils (in addition to extra virgin olive oil, also soy , corn , grape seeds , walnut , etc.), increasing the consumption of fish , reducing that of egg yolk and derivatives of milk … it is possible to increase the intake of essential polyunsaturated fatty acids , including omega 6.

Recommended dietary intakes of omega 6 : the dietary intake of omega 6 for the prevention of cardiovascular risk should be in the order of 5-10% of total daily calories . These are therefore more generous percentages than those recommended by the LARN (2%).

Decrease Cardiovascular Risk

How can cardiovascular risk be reduced?

To reduce the cardiovascular risk it is necessary to intervene on all the predisposing factors (except obviously for the genetic ones):

  • Being of normal weight
  • Maintain metabolic homeostasis
  • Eat in a balanced way, focusing on the supply of beneficial nutrients
  • Practicing motor physical activity
  • Avoid negative agents such as smoking , alcoholism etc.

What does normal weight mean?

It means normal weight .
Maintaining a normal weight while maintaining the right balance between fat mass and fat-free mass allows you to avoid overweight.
Obesity, a serious form of overweight, is the result of a wrong diet and a sedentary lifestyle.
Obesity worsens metabolism and increases cardiovascular risk.

What does metabolic homeostasis mean?

In medical terms, metabolic homeostasis refers to the balance of all vital parameters and health indicators.
The organism is not in metabolic homeostasis when it suffers from significant variations of parameters such as: cholesterolemia, triglyceridemia , glycemia , homocysteinemia , uricemia and blood pressure.
If these variations become serious and permanent, we speak of metabolic or metabolic or well-being pathologies.
One or more of the following factors may be the cause: incorrect diet, obesity, sedentary lifestyle, negative agents and genetic predispositions.

What does it mean to eat in a balanced way?

The diet is defined as balanced when it is sufficient to support bodily functions and guarantees the maintenance of health.
It is highly specific and changes according to the subject.
For it to be balanced, the diet must provide all the essential nutrients , the necessary ones and the nutritional factors that the body needs.

What are the beneficial nutrients and nutritional factors?

They are obviously the ones that are good for health.
Some of these are essential, i.e. that the body must necessarily introduce with the diet (for example the omega 6s we have talked about) or simply necessary to maintain good overall physical function.
A third category is that of useful nutritional factors, which however cannot be defined as “vital in the short term”. This is the case of fibers , phenolic antioxidants , lecithins , phytosterols, etc. (which seem to have a positive effect on cardiovascular risk).

Practicing motor physical activity and abolishing harmful behaviors

Motor physical activity increases caloric expenditure, improves metabolic efficiency, prevents obesity, optimizes metabolic homeostasis, leads to a healthy lifestyle free from harmful behaviors (smoking, alcoholism, drug use, disordered eating etc).

Fat and cardiovascular risk

It is right to reiterate once again that the type of fat present in the diet is among the most influential elements on cardiovascular risk.
We must also avoid obesity, take care of the nutritional balance and take the right amount of useful molecules, limiting the harmful ones.
In order to reduce the cardiovascular risk it is recommended to prevent hypercholesterolemia , type 2 diabetes mellitus , hypertriglyceridemia and hypertension .
The main measures are:

  • Reducing exogenous cholesterol (in foods): it is contained only in foods of animal origin; it is abundant especially in cheeses , offal and egg yolk .
  • Reduce trans fatty acids , typical of hydrogenated tropical oils , and of all products containing them (packaged sweets, snacks , bakery products , etc.).
  • Reduce saturated fatty acids, typical of animal fats ( meat , egg yolk, dairy products, etc.).
  • Promote the percentage increase of unsaturated fats, especially essential polyunsaturated omega 3 and omega 6 (deriving mainly from fish, oilseeds and related oils).
    N.B. _ The only downside to polyunsaturated fatty acids is “brittleness”; they are more subject to oxidative deterioration and thermolability, therefore it is good practice not to expose them to light, oxygen, temperatures above the smoke point and above all, if you use frying oils with high omega 6 contents, do not use them for longer of 2 or 3 firings .
  • Optimize the ratio between omega 6 and omega 3 (which in the Western diet reaches a ratio greater than 10:1) and avoid excess omega 6: as we have already said, too many omega 6 compromise the metabolism of omega 3. too much AA can have a negative effect on inflammation and cardiovascular risk. It is advisable to eat at least 3 portions of blue fish or fish from cold seas and alternate the oils for dressing (raw) rich in omega 3 with those rich in omega 6.
Main sources of various dietary fatty acids.
Fatty acids food sources
Saturated Animal meats (especially ruminants and pigs), milk and dairy products , butter , egg yolk, animal fats in general
Monounsaturated Olive oil , free-range chicken
Omega-6 Seed oils ( corn , grapeseed, sunflower )
Omega 3 Fish, linseed oil
B.C.
trans unsaturated fats
Old hard margarine blocks, products of the confectionery industry

Thomas

Thomas

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