Good Fat bad Fat what’s going on?

What are fats?

Fatty acids are derived from triglycerides or phospholipids. When they are not attached to other molecules, they are known as “free” fatty acids. Fatty acids are important sources of fuel because, when metabolized, they yield large quantities of energy in the form of ATP. Many cell types can use either glucose or fatty acids for fuel to generate ATP. In particular, heart and skeletal muscle prefer fatty acids. The brain cannot use fatty acids directly as a source of fuel; it relies on glucose or ketone bodies a breakdown product of fatty acids.

A triglyceride (triacylglycerol) is an ester comprising one molecule of glycerol attached to three fatty acids.  We store our fat as triglyceride in fats cells and we eat fat as triglyceride in the form of animal fat, vegan or fish oils. There are many types of triglycerides: depending on the oil source and fatty acid composition.  The fatty acids are described according to their carbon length (6-22 carbon molecules) and whether the hydrocarbon is fully saturated with hydrogen molecules (saturated fat) or unsaturated where Carbon=Carbon molecules are joined by double bonds using sites where Hydrogen could be bound.  The presence of one double bond labels the unsaturated fatty acid monounsaturated fatty acid (MUFA) and if two or more double bonds are called polyunsaturated fatty acid (PUFA).

 Example of an unsaturated fat triglyceride:  Left part: glycerol; right part from top to bottom; palmitic acid; oleic acid; alpha-linolenic acid (formula C55H98O6)

Unsaturated fats are the main constituents of vegan oils (MUFA & PUFA) whereas animal fats tend to be more saturated.  The double bonds in the fatty acids increase vulnerability to “free radical” attack or oxidation and accounts for the rancidity of these types of fat in room air.  The double bonds also change the shape of the fatty acid and depending on “cis” or “trans” configuration makes the fatty acid bent, kinked and curved rather the densely packed saturated fatty acids accounting for the solid appearance at room temperature.

 

Monounsaturated fatty acids (MUFA) like oleic acid are considered healthy by conventional standards (rich in olive oil) but monounsaturated fatty acids also make up a big portion of animal fat, as much as 44% in pork lard, so it makes sense that we have evolved to process them. So if you want to increase monounsaturated FAs in your diet, fatty chunks of meat will get you much further than a tablespoon of olive oil on your salad.

 

Polyunsaturated fatty acids (PUFA) are subdivided into omega-3, omega-6 and omega-9 fats described by the position of their first double bond if you count from the methyl (or omega) end of the chain. The fatty acid with the first double bond in position 3 is therefore omega-3 PUFA and so on.

Animals do not tend to store large amounts of polyunsaturated fatty acids, mainly because they are not a very good source of energy. Therefore traditional animal fats are quite low in PUFA whilst fish; nuts; seeds and vegetable oil are rich in PUFA but differing amounts and content of omega-3, omega-6 and omega-9 PUFA. 

All PUFA (omega fats) tend to be lumped together in one big “healthy” basket (which is incorrect) as there are significant differences in their effect on the body.

The following table gives the fatty acid, vitamin E and cholesterol composition of some common dietary fats.

PUFA are not the body’s preferred fuel but rather form integral component of cellular membranes (for membrane stability), and are necessary for the synthesis of important cellular messengers called eicosanoids (hormones) controlling and initiating inflammation with other cytokine chemicals.  

PUFA are also involved in two of the most critical processes: oxidation and inflammation and whist both are essential to life, both are dangerous when they get out of control.  Omega-3 alpha-linolenic acid (ALA) and omega-6 linoleic acid (LA) are the two major components of the essential PUFA omega-3 and omega-6 family.

 

ALA taken in the diet is converted to eicosapentaenoic acid (20:5, n−3; EPA), and docosahexaenoic acid (22:6, n−3; DHA). These three polyunsaturated fats (ALA; EPA & DHA) are the typical omega-3 fats to which we refer

EPA concentration in our body is very low as it seems to be converted immediately to its brother DHA. Although EPA and DHA can be synthesized from ALA the conversion in our body is very inefficient for the rate of conversion for ALA to EPA is around 8%. That is out of 1 mg of ALA from flaxseed oil you will only make 0.08mg of EPA. DHA conversion rate is even poorer. It ranges from 0.5% in normal adults to 4% in young women. 

In other words we also need to take in natural EPA and DHA in our diet in various foods  for the important omega-3 benefits.

The health benefits of the long-chain omega-3 fatty acids — primarily EPA and DHA are the best known. These benefits were discovered in the 1970s by researchers studying the Greenland Inuit tribe who consumed large amounts of oily fish & other marine fat (omega-3) & displayed virtually no cardiovascular disease. The high level of omega-3 fatty acids consumed by the Inuit reduced triglyceride, heart rate, blood pressure and atherosclerosis.

By 1979, it seems the picture was clearer as the health benefits of omega fats were found to be due to a family of hormones now known as eicosanoids: Thromboxanes, protacyclines and leukotrienes. The eicosanoids, which have important biological functions, typically have a short active lifetime in the body, starting with synthesis from the omega fatty acids and ending with metabolism by enzymes. Researchers found that omega-3 fatty acids are converted into omega-3 eicosanoids in competition to the omega-6 eicosanoids formed from the omega-6 fat precursor Arachidonic acid (by the same enzymes).

The essential parent fatty acid in the omega-6 family is linoleic acid (LA) and is enzymatically converted to the omega-6 eicosanoids of the arachidonic acid family (pro-inflammatory) .

Arachidonic acid is a central player in the cascade of reactions which promote chronic inflammation and ill-health and disease if the ratio of omega-6: omega 3 intake is high due to important competitive interaction with the omega-3 fatty acids affecting the relative storage, mobilization, conversion and action of the omega-3 and omega-6 eicosanoid precursors. It seems the eicosanoids made from omega-3 fatty acids are produced more slowly and are often referred to as anti-inflammatory, but in fact they are just LESS inflammatory than those made from omega-6 fats.

The point is that if BOTH omega-3 and omega-6 fats are present they will “compete” to be transformed, so the ratio of long-chain omega-3: omega-6 fatty acids directly affects the type of eicosanoids that are produced (anti-inflammatory versus pro-inflammatory).

This competition seems to be the “hall-mark” of chronic degenerative inflammatory based disease (like atherosclerosis; Alzheimer’s dementia; macular degeneration; multiple sclerosis; auto-immune disease; cancer etc.).  These eicosanoids are a complex group of hormones recognized as important when it was found that thromboxane is a factor in the clumping of platelets, which can both cause death by thrombosis and prevent death by bleeding. Likewise, the leukotrienes were found to be important in immune/inflammatory-system response, and therefore relevant to arthritis,lupus, asthma and recovery from infections.

These discoveries have led to greater interest in finding ways to control the synthesis of omega-3 and omega-6 eicosanoids. The simplest way would be by consuming more basic omega-3 fatty acids and fewer omega-6 fatty acids in your diet.

Clinical studies indicate that ratio of omega-3 to omega-6 fatty acids is CRITICAL to maintaining optimal health and good aging with higher omega-3 contributing to the formation of the important omega-3 based eicosanoids such as prostoglandins, leukotrienes and thromboxanes, all tending to dampen down the immune based cascade of cellular and systemic chronic inflammation and thus alter the body’s metabolic function.

In general, grass-fed animals accumulate more omega−3 than do grain-fed animals, which accumulate relatively more omega−6. Remember metabolites of omega−6 based eicosanoids are more inflammatory (particularly arachidonic acid) than those of omega-3. This necessitates that omega−3 and omega−6 fats be consumed in a balanced proportion; healthy ratios of omega-3 to omega 6 range from 1:1 to 4:1 (an individual needs more omega 3 than omega 6). Studies suggest the evolutionary human diet, rich in game animals, seafood, and other marine sources of omega-3 would have provided such a ratio  (paleolithic man).

Typical Western diets have CORRUPTED this ratio to between 10:1 and 50:1 (i.e., dramatically higher levels of omega-6 than omega-3) due to the drastic introduction of vegetable oils: like sunflower oil (no omega-3 fats); cottonseed oil (almost no omega-3); peanuts and peanut oil (extremely high in omega-6); soybean oil (7:1 omega-6 to omega-3); grape seed oil (almost no omega-3) and finally corn oil (46:1 omega-6 to omega-3).

Canola oil tends to be better at (2:1 omega-6 to omega-3); olive oil 3:1 omega-6 to omega-3) and the BEST flaxseed oil (1:3 with more omega-3 than omega-6).

With the much higher ratio of omega-6: omega-3 in the so-called “neolithic” diets; blood triglycerides have been higher; rate of obesity and cardiovascular disease higher ; auto-immune disease and cancer rampant.

In 1999, the GISSI-Prevenzione Investigators reported in The Lancet the results of major clinical study in 11,324 patients with a recent myocardial infarction. Treatment 1 gram per day of omega-3 fatty acids reduced the occurrence of death, cardiovascular death, and sudden cardiac death by 20%, 30%, and 45%, respectively. These beneficial effects were seen from three months onwards.

In 2006 the American Journal of Clinical Nutrition and a second JAMA review; both indicated decreases in total mortality and cardiovascular incidents (heart attacks) associated with the regular consumption of fish and fish oil supplements.

In the March 2007 edition of the journal Atherosclerosis in 81 Japanese men with unhealthy blood sugar levels were randomly assigned to receive 1.8 g daily of EPA, with the other half being a control group. The thickness of the carotid arteries and certain measures of blood flow were measured before and after supplementation. This went on for approximately two years. A total of 60 patients (30 in the EPA group and 30 in the control group) completed the study. Those given the EPA had a statistically significant decrease in the thickness of the carotid arteries, along with improvement in blood flow. The authors indicated that this was the first demonstration that administration of purified EPA improved the thickness of carotid arteries and improved blood flow in patients with unhealthy blood sugar levels.

In a study published in the American Journal of Health-System Pharmacy March 2007, patients with high triglycerides and poor coronary artery health were given 4 grams a day of a combination of EPA and DHA along with some monounsaturated fatty acids. Those patients with very high triglycerides (above 4 mmol/l) reduced their triglycerides on average 45% and their VLDL cholesterol by more than 50%. 

Similar to those following a Mediterranean diet, Arctic-dwelling Inuit – who consume high amounts of omega-3 fatty acids from fatty fish also tend to have higher proportions of increased HDL cholesterol and decreased triglycerides and less heart disease. 

A study of 465 women showed that serum levels of EPA are inversely related to levels of anti-oxidized-LDL antibodies. As you are aware oxidative modification of LDL is thought to play a major role in the development of atherosclerosis through formation of unstable plaque.

Survivors of past heart attacks are less likely to die from an arrhythmia event if they are consuming high levels of omega-3 (membrane stabilisation). These antiarrhythmic effects are thought to be due to omega-3 fatty acids’ ability to increase the fibrillation threshold of the heart electrical and tissue.

Omega-3 fatty acids also have mild antihypertensive effects. When subjects consumed daily systolic blood pressure was lowered by about 3.5-5.5 mmHg and heart rate by 3-5 bpm.

In a study regarding fish oil published in the Journal of Nutrition in April 2007, sixty-four healthy Danish infants from nine to twelve months of age received either cow’s milk or infant formula alone or with fish oil. Those infants supplemented with fish oil were found to have improvement in immune function maturation, with no apparent reduction in immune activation.

Consumption of EPA partially countered memory impairment in a rat model of Alzheimer’s disease and produced a statistically insignificant decrease in human depression.

Flaxseed oil, walnuts, canola oil – all contain high level of ALA, the parent omega-3 molecule.

They are also promoted as equally good sources of omega-3 as fish and other marine products, which are rich in EPA/DHA. Meat, dairy and eggs (grass-fed and pastured) are also sources of omega 3 PUFA but unlike fish source or EPA and DHA, vegan, nut and seed ALA tend to go hand-in-hand with the omega-6 PUFA (LA) and this tends to upset the delicate omega-3: omega-6 balance.  So it is important to have a BASIC understanding of the CONTENT of omega-3 (especially whether EPA or DHA) versus omega-3 ALA and omega -6 LA in various foods.

The implications are particularly important for vegetarians and vegans as the omega-6; omega-3 ratio tends to heavily favour omega-6 PUFA (up to 50:1) and may contribute to ill-health.

Don’t be fooled by marketing as supplementing with “evening primrose” oil is pure omega-6 (LA).

Most of the processed pre-packaged food comes with a surprise high concentration of LA (omega-6) in form of soybean oil, sunflower oil, cottonseed oil, and peanut oil.  These oils were not around 200 years ago but ever since Ancel Keys published the (in)famous 7-Countries study (in the late 1960’s) implicating saturated fat as the villain causing heart disease and the subsequent diet decisions from the McGovern committee driving farming subsidies and industrialisation of food, everything that was processed, packaged, patented and promoted contained high proportion of omega-6 fatty acids in the modern “healthy” diet.

Many health products which contain nuts, peanut butter, seed trail mix, nut bars etc promoted for good heath actually backfired for although the nuts and seeds contained no saturated fat and little omega-3 fat; the problem is that there was an overwhelming load of LA contributing to the pro-inflammatory effects  and effectively shutting down the already-poor conversion of omega-3.  The trend of low-fat vegan diets over the past 50 years has exacerbated the unhealthy omega-6: omega-3 ratio!

 

Evolutionary clues should tell you that eating meat, fish, eggs, pastured dairy and some plants, seed & nuts will give you all the PUFA you need but nuts and seeds needs to be taken in small amount so as not to calorie or omega-6 overload.

Supplementing with daily omega-3 in the form of pure salmon oil is essential (2 g/d) but it is vital to ensure the integrity of the product.  Recently a SA study identified > 50% of the preparations available in SA contained < 90% of the active EPA/DHA advertised on the label.  This highlights the problem of poor regulation of the supplement industry and the need to document your Omega-3 Index of your red cell membrane to ensure adequate omega-3:omega-6 ratios. DO NOT take supplements that has Omega-6 or Omega-9 as this makes no sense when we are trying to correct the already high omega-6 to omega-3 ratio.

So in summary:

  1. Have a BASIC understanding of what fat is in terms of triglyceride; saturated fatty acids and unsaturated acids.
  2. Understand the concept of the essential polyunsaturated fatty acids (PUFA) of the omega-3 and omega-6 family.
  3. Realise that many “healthy” vegan low-fat options tend paradoxically to have HIGH omega-6 intake thus skewing the balance of omega-3 to omega-6 in your diet.
  4. If possible take your omega-3 in “whole foods” that are unprocessed (like fresh fish) rather that from supplement form or take a combination of the two
  5. Do not take omega-6 supplements
  6. Ultimately you have to know what the ratio of these PUFA are in your cellular membranes as you can actively address any deficiency.

I will devote the next blog to all the research available on the Omega-3 Index test looking at the fat content of the red blood cell (RBC) membrane in different population groups; different risk groups and the data we have available to South African’s.

Blessings

Cardiologydoc

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