SATURATED AND UNSATURATED FATS

Fats are perhaps the most confusing macronutrient. A lot of people even fear them. I have to admit that before 2014 I also feared them, then after delving into the subject I realized that my fears were totally unfounded. So I would like to start this in-depth study by making a premise: how important are fats for the well-being of our body? I hope it will be useful for you to learn to love fats.

THE FUNCTIONS OF FATS

Fats perform many functions that are essential for the optimal functioning of our bodies:

Energy production: fat is the most efficient macronutrient there is: 1 gram of fat provides 9.45 kcal (conventionally rounded to 9 kcal) while protein and carbohydrates provide less than half that: 3.75 kcal (conventionally rounded to 4 kcal)
Energy reserve: the carbohydrate stores in our copre (glycogen) are 400/500 grams (1600/2000 kcal). Fat reserves, on the other hand, are very large and are what enabled us to survive in times of famine. The glycogen in the body does not provide us with the energy we need to even survive one day, while the fat reserves in a very lean person would allow her to survive for as long as 30 days without food.
Structural function: phospholipids and cholesterol (two types of fats) are the basic components of the cell membrane whose fluidity and permeability they regulate. They are also an important component of the hydrolipid film that covers the skin and of myelin, the substance that coats nerve fibers
Vitamin absorption: there are water-soluble (water-soluble) and fat-soluble (fat-soluble) vitamins. A low-fat diet can cause a deficiency in these important vitamins:
- Vitamin A:: falls under the mechanisms of night vision, enabling us to focus and see well even in low light conditions
- Vitamin D: important for skeletal formation and maintenance, hormone regulation, and strengthening the immune system. Those with endocrine imbalances or autoimmune disorders are deficient in vitamin D: a low-fat diet worsens the condition and symptoms (1)
- Vitamin E: is a very important antioxidant, among the most powerful in our bodies
- Vitamin K: intervenes in blood clotting mechanisms; a deficiency is related to an increased risk of bruising and bleeding of the muscularis (including gums)
Nerve impulses: nerve impulses in the brain travel due to the presence of unsaturated fats, particularly DHA (omega3). Fats are crucial for our brains; in fact, a correlation has been shown between diets rich in fats and prevention of neurodegenerative diseases such as Alzheimer's and Parkinson's; these diets have also been effective in slowing the loss of cognitive function of people already suffering from the disease
Emotional state: fats are also crucial for psychoemotional well-being: scientific studies are investigating this branch of nutrition, finding that low-fat diets predispose to mood disorders, anxiety, obsessions, sadness and melancholy
Hormonal regulation: cholesterol despite its bad reputation is the precursor of both male and female stereoid hormones (testosterone, progesterone, estradiol, cortisol). Also think about the importance of fat in a woman: excessive reduction of body fat (below 10-12%) is generally correlated with alterations in the menstrual cycle (dysmennorea, amenorrhea) and problems of a bone nature (early osteoporosis). If we do not have sufficient body fat reserve, the body is unable to cope with pregnancy, so the cycle stops.
Skin protection: All of our skin is covered with a thin lipid layer, which allows it to defend itself against external attacks from bacteria and weathering, ensures supple and radiant skin, and gives softness and hydration. In fact, fats are a staple of anti-aging diets!
Protection from trauma: fats protect joints and vital organs from possible trauma by, among other things, keeping them in their physiological position
Thermal insulation: fat intervenes in our body's thermoregulation processes (especially brown fat) by acting as a true insulator that can protect the body from low temperatures
Sense of satiety: fats have high satiating power and delay the onset of hunger

By this time you have already fallen in love with fats haven't you??!

But how much fat should we consume per day? The LARNs (which are the Reference Intake Levels of Nutrients and Energy for the Italian population) recommend consuming between 20 and 35% of daily calories through fat (2).

WARNING: Fat contains twice as many calories as carbohydrates and protein, so for those who are trying to lose weight it will be necessary to pay attention to the amount of fat consumed.

MACRO AND MICRO NUTRIENTS

Macronutrients are the main providers of nutrition for our bodies:

Glucides (from Greek glucos, sweet) also called carbohydrates (4 kcal per gram)
Protides (from Greek protos, primary) also called proteins (4 kcal per gram)
Lipids (from Greek lipos, fat) also called fats (9 kcal per gram)

Macronutrients are used by our bodies for different functions:

Fats and carbohydrates: source of energy
Protein: building and maintaining our body

Micronutrients, on the other hand, are used by our bodies in numerous physiological functions:

Mineral salts (example: magnesium is used in more than 600 enzymatic reactions(3))
Vitamins

They are called "macros" because we take in more of them than micronutrients. In fact, for macronutrients the gram (g) is used as the unit of measurement, while for micronutrients the milligram (mg) is used

Fun fact: I knew that the word glucides (carbohydrates) came from the Greek word glucos (sweet) but this is the first time I have discovered that protein comes from protos (primary). The ancient Greeks were really ahead of their time; they already understood that proteins are essential to our bodies and therefore considered them primary. Remember that only two of the macronutrients are defined as essential: protein (essential amino acids) and fat (omega 3 and omega 6). There are no essential carbohydrates.

MACRONUTRIENTS: HOW THEY ARE MADE

Macronutrients are categorized according to their chemical structure:

Carbohydrates: formed from carbon, hydrogen and oxygen atoms
Proteins: formed from chains of amino acids
Fats: mainly formed by a carbonaceous tail (formed by carbon and hydrogen) and a "head" (carboxyl group) where we find carbon, hydrogen and oxygen.

SATURATED AND UNSATURATED FATS

I know the distinction between saturated and unsaturated fats seems like a metaphysical issue, but it is actually super simple you will see! First you must understand that a fat is composed of many different types of fatty acids. The greater presence of saturated, monounsaturated or polyunsaturated fatty acids will determine whether the fat is saturated, monounsaturated or polyunsaturated.

For example, olive oil is composed of approximately (4):

17% saturated fatty acids
70% monounsaturated fatty acids
13% polyunsaturated fatty acids

Because monounsaturated fatty acids are the most prevalent, olive oil is classified as a monounsaturated fat.

But what are fatty acids? Molecules formed by a carbon chain and a head (carboxyl group) The letters correspond to the following elements: C = carbon, O = oxygen, H = hydrogen

The length and characteristics of the carbon tail determine the chemical and physical characteristics of the fatty acid. Most importantly, they will allow us to understand once and for all the distinction between saturated and unsaturated fats: just look at what its tail looks like.

Let's start with saturated fatty acids: as you see in the figure each carbon atom (letter C) in the tail is bonded to two hydrogen atoms (the letters H above and below). This type of bonding is called saturated because the carbon atom is bound to two hydrogen molecules and cannot bind to other molecules: therefore, its chances of binding are saturated. This condition is energetically very stable and is the reason why I love saturated fats (more on this later).

In the unsaturated fat tail, on the other hand, we have a little problem: look at the two Cs bound with the green double line: both are missing a hydrogen atom at the bottom. This condition forces them to "bind" to each other with a double bond, but this is not stable at all, so they are perfect victims for free radicals, which will bind to these carbon atoms and oxidize the fat. And this is the reason why I dislike unsaturated fats.

Unsaturated fats are differentiated into:

monounsaturated (one double bond)
polyunsaturated (two or more double bonds)

Polyunsaturated fats are even more unstable because there are several unstable carbon atoms.

The amount of unstable carbon atoms determines the rate of oxidation (5) of fats:

saturated fat = 1
monounsaturated = 10
polyunsaturated = 100

The oxidation reaction of fats leads to the formation of unpleasant odors in food, that
we call "rancid smell." The molecules that are formed from lipid oxidation, however, do not
are not only smelly but in many cases toxic and carcinogenic.

NPN note for nerds

The number after the C indicates how many carbon atoms the fatty acid is composed of.

The number after the colon indicates how many double bonds are present.

Palmitic acid, C16:0, zero double bonds, therefore saturated

Oleic acid, C18:1, a double bond, so monounsaturated

Linoleic acid, C18:2, two double bonds, therefore polyunsaturated

HOW TO RECOGNIZE SATURATED AND UNSATURATED FATS

Figuring out whether a fat is saturated or unsaturated is really very simple:

saturated fats at room temperature are solid because their tails are straight and therefore
pack neatly forming a solid structure.
Unsaturated fats, on the other hand, at room temperature are liquid because their tails are
"folded" and therefore cannot pack up.

Saturated fats (the most stable)

butter
lard/lard (pork fat)
tallow (cow fat)
coconut oil
palm oil
cocoa butter

Monounsaturated fats

(less stabiii than saturated, but more stable than polyunsaturated)

olive oil
avocado oil
peanut oil
almond oil
hazelnut oil
pecan oil
pumpkin seed oil
sesame seed oil

Polyunsaturated fats

(the most unstable of all)

soybean oil
sunflower oil
walnut oil
corn oil
sesame oil

Polyunsaturated fatty acids also include omega 3 and 6, which are essential fatty acids, meaning we must compulsorily take them in through food. Fish is very rich in these fatty acids, but they are also contained in meat and eggs (although to a lesser extent). If hens and cows are raised according to nature, the level of omega 3 is higher. Too much omega 6 is inflammatory, so be careful.

Among the best-known omega-3s we have: EPA and DHA.

WARNING: Despite some people claiming otherwise, there are no omega 3 and omega 6 in vegetables but their precursors: ALA alpha linolenic acid and LA linolenic acid. The problem is that the conversion of ALA to EPA and DHA is very low:

WING > EPA: 5%
WING > DHA: 0.5%

The only vegetables that contain EPA and DHA are algae, but the amount is very low, so it is difficult for them to provide the necessary amount.

OXIDATION AND ROS

Why do I (but not only I) love saturated fats and dislike unsaturated fats? We have been told for fifty years that saturated fats are the supreme evil and we must replace them with unsaturated fats, yet I do the exact opposite of what the guidelines suggest. How come?

The answer is very simple and has to do with the rate of oxidation of different fats (5):
saturated fat = 1
monounsaturated = 10
polyunsaturated = 100
(these are sample values not actual, just to illustrate the abysmal differences)

Oxidation of fats generates unpleasant odors (rancid smell) and in some cases even toxic and carcinogenic substances.

But what is this oxidation that we often hear about? Oxidation is the reaction that occurs when an atom/substance, such as a free radical, steals an electron from another atom/substance. Antioxidants counteract oxidation because they have an electron available and donate it to the free radical.

ROS (Reactive Oxigen Species) called in Italian "reactive oxygen species" are the most prevalent free radicals in our bodies. Free radicals are molecules that are missing an electron and therefore go looking for it by "oxidizing" other molecules.

What effect do ROS have in our bodies? They compromise protein function, damage DNA and oxidize fats. The molecules most susceptible to free radical attack are fats. The factors that promote oxidation are mainly oxygen, heat and light, but also metals, enzymatic actions and microorganisms.

When there is an overabundance of free radicals in our system, they begin to massively attack our cells causing them to age, which promotes the onset of more or less serious diseases.

Can we protect ourselves from oxidation? Yes and no: One of the main sources of ROS is energy production by the mitochondria, so something we definitely cannot do without. Other sources are stress, inflammation, pollution, smoking, too much physical activity, and many pharmacological substances. And we can definitely work on that here.

Our body itself produces enzymes and antioxidants that can neutralize free radicals, but we can help it too:

Introducing antioxidants through the diet (cocoa powder is by far one of the most antioxidant-rich foods)
Trying to keep inflammation down
Avoiding consuming too many unstable (easily oxidized) polyunsaturated fats
providing our bodies with the glycine necessary for the production of glutathione, one of the most powerful antioxidants produced by our bodies. In this study (7) it is shown that the amount of glycine introduced through diet determines the amount of glutathione that can be produced by our body. This study is one of the reasons why I decided to take collagen and then sell it in Live Better. In fact, collagen is the absolute richest food in glycine.
avoiding smoking
Avoiding being constantly stressed

HYDROGENATED AND TRANS FATS

So far we have talked about naturally occurring fats. A separate discussion must be made about man-made fats: hydrogenated fats. Since polyunsaturated oils go rancid quickly human beings have seen fit to hydrogenate them in order to preserve them longer.

How the hydrogenation process of polyunsaturated fats works Do you remember the double bond of polyunsaturated fats? Each of the two carbon atoms joined by the double bond is missing a hydrogen atom at the bottom, and the hydrogenation process simply provides it. This "straightens out" the tail, and as if by magic the oil becomes solid.An example is margarine, which is composed of a polyunsaturated oil that has been hydrogenated and thus has become solid.

Little problem: After urging people to replace that bad boy butter (full of saturated fats) with margarine in the 1980s, we realized that the hydrogenation process created trans fats (trans fats), which we now know are responsible for: coronary heart disease, atherosclerosis (and thus heart attack), and stroke. (8,9,10)

This is why in 2015 the FDA (Food and Drug Administration the U.S. agency in charge of food safety) banned trans fats in food as of June 2018. In Europe, trans fats are still allowed in foods within the limit of 2 grams per 100 grams of total fat. On fats America has always been ahead of us: think about the fact that as early as 2006 it was mandatory to report the trans fat content in the nutrition table. With us it is not even now 17 years later....

Usually the EFSA, (European Food Safety Authority) is stricter than the FDA, so why not in this case? There is a beautiful story behind it, whose main character is Prof. Fred A. Kummerow, a true change-maker (a person who changes things).

In the 1950s, still a university researcher, Kummerow convinced a local hospital to let him examine the arteries of patients who had died of heart disease. To his surprise he found large amounts of trans fats in the tissues, which were then found in almost all packaged foods.

He later showed that mice that were fed trans fats (trans fats) developed atherosclerosis and that this disappeared when trans fats were removed from the diet.

He published his first research on the link between trans fats and atherosclerosis in 1957. But despite the evidence he continued to accumulate over decades, his alarm went unheeded.

Finally in the 1990s something began to move: in 1995 an association requested the FDA that the trans fat content be listed on the nutrition table, which did not happen until 2006. However, the public was now aware of the dangers of consuming trans fats, so food companies began to voluntarily eliminate them from some recipes. It was not enough, however, because trans fats still remained present in so many products.

Frustrated with the situation in 2009, Kummerow, at age 94, filed a petition with the FDA requesting that trans fats be eliminated from the diets of Americans.

In 2013, having gotten no response from the FDA Kummerow (at age 98!!!) decided to go for the hard way: he sued the FDA and the U.S. Department of Health, and magically three months later the FDA announced its plans to eliminate trans fats as they were not considered safe for human health. As of June 2018, U.S. food manufacturers can no longer use trans fats.

Fred Kummerow was an extraordinary man who fought to the last to change things. He died at the age of 102 and continued to work in his laboratory until the age of 101. In addition to his fight against trans fats, he also helped discover that is the real culprit of cardiovascular risk is oxidized cholesterol. Look at him, he also had light in his eyes.

Please note: the definition of trans fats that are considered harmful is very technical and excludes trans fats found in breast milk, dairy products, and beef, such as vaccenic acid, which we discussed in the in-depth article "Does red meat cause cancer?" Here we discussed a very recent study (11) where it was found that vaccenic acid enhances the ability of CD8+ T lymphocyte to infiltrate and kill cancer cells. Analyzing cancer patients, those with the highest levels of vaccenic acid in the blood responded better to immunotherapy. Vaccenic acid--does the name ring a bell? It is found in the meat and milk of ruminants: cows, sheep, goats, etc. And it is also found in human milk.

POINT OF SMOKE.

Another key aspect to touch on regarding fats is the smoke point, which is the temperature at which an oil begins the process of oxidative degradation whereby it releases visible volatiles, such as smoke, and forms a toxic substance called acrolein. Fats best suited for cooking are therefore those with a high smoke point, which gives good stability at high temperatures.

Clearly, the choice of the appropriate fat depends on the type of cooking to be done. Frying (where the food is completely immersed in the fat) has very high temperatures, so we will have to choose a fat with a smoke point higher than 200 °C (that is why olive oil is not good for frying). If we simply have to sauté a food, the temperatures reached will not be as high as in frying and therefore we can also use a fat with a smoke point below 200°C.

To compile this ranking, I had to consult several sources (12,13,14,15). Unfortunately, there is no official data on this very important parameter. The data refer to fats in their natural state, thus unrefined and unfractionated.

Clarified butter, ghi: 250°C
Beef tallow: 250°C
Lard: 240°C
High oleic sunflower oil: 225°C
Avocado oil: 200°C
Extra virgin olive oil: 190°C
Coconut oil: 180°C

I avoid reporting other fats because in my opinion these should be the only ones used. Clearly if you want to use others you are perfectly free to do so, but I do not feel comfortable recommending them.

Clearly there will be a second installment of this in-depth look at fats that will go into the story behind the condemnation of saturated fats. I anticipate that it has no scientific basis, and there are numerous doctors and researchers who claim that the "saturated fat and cholesterol" issue is one of the greatest hoaxes suffered by humankind.

If you want to learn more about cholesterol, there are three wonderful insights to read on the our site which are translations of three extraordinary lectures by Dr. Paul Mason, to be read in this order.

The dark history of statins
Why your doctor thinks cholesterol is bad for you
The truth about high cholesterol (here it is explained why "triglycerides : HDL" is the best data to assess cardiovascular risk)

Happy reading! And remember: knowledge sets you free!

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