Omega 3s fight high triglycerides!

Excess triglycerides in the blood represent a health hazard being one of the main cardiovascular risk factors, along with "bad" cholesterol, high blood pressure, poor lifestyle habits and particular diseases or genetic predispositions. Cardiovascular disease, including coronary heart disease, is the leading cause of death among adults of in the elderly, in most European countries. Reducing "high triglycerides" is therefore one of the main weapons of cardiovascular prevention and can be achieved not only through medication but also by adopting a healthy lifestyle, particularly through a balanced diet, for example by increasing the consumption of foods rich in omega-3, i.e., fish and some oil seeds. Indeed, the cardioprotective action of omega-3s, which act by various mechanisms on the control of high cholesterol and triglycerides, has been known for several years.

Triglycerides: what are they and what functions do they have?

Triglycerides are found primarily in adipose tissue, in which they are accumulated within specialized cells called adipocytes. Triglycerides can be taken in with food, whether of animal or plant origin, and be formed by the body itself. Chemically they belong to the lipid family, or fats, and are derived from the union of a glycerol molecule with three fatty acids. Fatty acids in turn are differentiated, according to their length and the presence or absence of double bonds, into saturated, monounsaturated and polyunsaturated fatty acids.

Lipoproteins

Like cholesterol, in order for triglycerides to be transported in the blood and reach body tissues, they must bind to particular proteins (Apoproteins), forming structures called lipoproteins. These lipoprotein particles differ in their lipid and protein composition and are classified according to their density inThe triglycerides represent an important energy resource for the human body; in fact, they provide about 9 kcal per gram, compared with 4 Kcal for carbohydrates and proteins. 

• Chylomicrons,
• VLDL (very low density lipoprotein)
• LDL (low density lipoprotein)
• IDL (intermediate density lipoprotein)
• HDL (high-density lipoprotein).

What is the optimal level of triglycerides in the blood? 

The amount of triglycerides in the blood is called triglyceridemia, and it can be detected by a simple blood test performed on an empty stomach. The concentration of triglycerides in the blood is mainly influenced by diet, sex, and age. The normal concentration of triglycerides in the blood is between 60 mg/dl and 150 mg/dl. When the concentration exceeds the latter value, one is in a condition called hypertriglyceridemia, which can be more or less severe:

• Trigliceridi normali:  < 150 mg/dl
• Borderline triglycerides: 150-199 mg/dl
• High triglycerides: 200 to 499 mg/dl
• Very high triglycerides: > 500 mg/dl

The causes of high triglycerides 

Hypertriglyceridemia in most cases, especially when it is between 150 and 199 mg/dl, is due to an incorrect lifestyle, particularly an unbalanced diet and alcohol consumption. In contrast, cases due to genetic disorders, such as familial hypertriglyceridemia, are very rare (about one case in a thousand). In general, the main causes of high blood triglycerides are:

• overweight or obesity
• sedentariness
• cigarette smoke
• poor eating habits
• diabetes mellitus
• alcohol abuse
• kidney disease
• viral hepatitis
• Taking medications (hormonal contraceptives, glucocorticoids)
• genetic factors

Consequences of hypetriglyceridemia

A high concentration of triglycerides in the blood promotes the onset of diseases such as pancreatitis and especially cardiovascular disorders, such as angina, atherosclerosisheart attack, and stroke. In particular, high triglycerides can promote the formation of atherosclerotic plaques, which are thickenings of the inner walls of arteries that obstruct blood flow, causing atherosclerosis and other heart and blood vessel diseases. This relationship is especially true when hypertriglyceridemia is accompanied by other risk factors, such as increased LDL cholesterol ("bad cholesterol") and decreased HDL ("good cholesterol"). The analysis of blood triglycerides is usually paired with that of total cholesterol, LDL cholesterol, and HDL cholesterol, precisely to assess cardiovascular risk.

How to lower triglycerides?

In addition to reducing or, better yet, eliminating risk factors such as smoking, alcohol and being sedentary, much attention should be paid to diet. In cases of high triglycerides, it is good to: 

• Limit calorie intake by correcting any overweight or obesity
• Reduce consumption of simple sugars (sweets, dehydrated fruits)
• Limit consumption of foods high in saturated fat, such as dairy products and red meat
• Avoid hydrogenated fats, found in snacks and baked goods
• Consume foods rich in antioxidants
• Do not overconsume carbohydrates, which, in excess, are converted into triglycerides and stored in adipose tissue
• Consume polyunsaturated fatty acid peaches, at least 2-3 times a week.
   

There are many studies confirming the beneficial effects of fish intake on fat metabolism and cardiovascular risk(read here). It has been shown that to achieve a 30% reduction in triglyceride concentration, it is necessary to take 120 to 320 grams of fish per day.This action is due to the presence of omega-3 polyunsaturated fatty acids. In fact, it has been widely demonstrated that the intake of omega-3 series fatty acids leads to a significant reduction in the concentration of triglycerides in the blood.

Omega-3 against high triglycerides

The 'interest of the scientific world in omega-3 polyunsaturated fatty acids is due to some epidemiological studies carried out around the mid-1970s. In those very years, it was observed that in the populations of Alaskan Eskimos, Greenlanders (Inuit), and Japanese living in coastal areas, the incidence of ischemia was lower than that observed among Eskimos who had migrated to industrialized countries and that of Japanese living inland. Comparison of mortality between the Greenland Inuit and the Danish population showed that the cardiovascular risk in the former was 10 times lower than that in the latter, and that the Inuit had a diet of fatty fish and 5 times higher in omega-3. Since then, numerous research studies have confirmed the link between omega-3 intake and reduced cardiovascular risk.

But what exactly are omega-3 fatty acids?

As mentioned earlier, omega-3s are polyunsaturated fatty acids, that is, containing a long chain of carbon atoms, held together partly by simple bonds and partly by double bonds. Various types of omega-3 exist in nature, the most important of which are alpha linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The latter two are contained in significant amounts in fish species that live in cold seas: salmon, tuna, sardines, anchovies, mackerel, and herring. One ounce of salmon, for example, contains 560 mg of omega-3. The main sources of ALA, on the other hand, are green leafy vegetables such as spinach, legumes, nuts, and vegetable oils such as flaxseed and soybean oil.

ALA an essential fatty acid, that is, one that cannot be synthesized by the body but can only be taken in through food. It is the precursor of DHA and EPA, but in humans the enzymes required to convert alpha linoleic acid into the other two omega-3s appear to be not fully efficient, and this mechanism is only minimally utilized. Therefore, consumption of foods containing EPA and DHA via fish oil, is important to maintain an optimal level of the two molecules.

Ratio of omega-3 to omega-6

The efficiency of conversion of ALA to EPA and DHA is also limited by the presence of high levels of the omega-6 polyunsaturated fatty acids, this is because the enzymes that convert them, "recognize" both omega-3 and omega-6. When the diet is too rich in the latter, the enzymes act on ALA inefficiently, impairing the formation of EPA and DHA. In Western countries this condition is very common, as the ratio of omega-6: omega-3 dietary intake is 15:1. This imbalance is mainly due to the high consumption of foods rich in omega-6, such as seed oil, and the limited consumption of fish, but also to the lower amount of omega-3 in farmed fish compared to caught fish.

The mechanism of action of omega-3 on blood triglycerides

The reduction in triglyceridemia following omega-3 consumption occurs through several mechanisms. EPA and DHA reduce the production of triglyceride-rich lipoproteins (chylomicrons and VLDL) and accelerate their removal. Specifically, at the level of liver cells, omega-3s slow the synthesis of an apolipoprotein, the protein part of VLDL, called ApoB. This results in reduced entry of triglycerides into the bloodstream. The increased removal of triglycerides, on the other hand, is due to the ability of omega-3 to increase the activity an enzyme, called lipoprotein lipase, found in the inner tissue of blood vessels, which promotes the removal of triglycerides from the blood by breaking them down into their individual components (fatty acids and glycerol).

What is the optimal omega-3 consumption to protect heart health?  

In Europe, the new EU Regulation No. 432/2012 of May 16, 2012 states:

• maintenance of normal blood pressure is achievable with a 3 g daily dose of EPA and DHA.
• maintenance of fasting triglyceride concentrations, 2 g per day of EPA and DHA should be taken instead.

In addition, the same regulation states that omega-3s "contribute to normal cardiac function" with an EPA or DHA dosage of 250 mg per day."

Omega-3; better from fish or supplements?

To be sure of consuming the recommended daily doses of EPA and DHA, it is necessary to consume from about 200 grams of fatty fish per day every day, a condition that is not always achievable. High consumption of fish products among other things increases the likelihood of taking in the contaminants they contain, such as heavy metals, including mercury, which is very dangerous to health. This problem can be avoided by taking omega-3 supplementsextracted by purification from fatty fish muscle tissue. The oil in these supplements is therefore free of harmful substances.