Are omega-3 fatty acids good for skin? Or, do these oils actually damage your skin? This week Randy and I explain what omegas, polyunsaturated oils, and Essential Fatty Acids really do for your skin. Plus – Beauty Science News!
Show notes
Beauty Science News – Are you science savvy?
I found an interesting article on the top 10 scientific terms that scientists wish you’d stop using incorrectly.Randy and I banter about a few of them including:
- “Proof”
- Theory vs hypothesis
- Nature vs nurture
- and more!
Question of the week: Are omega fatty acids good for skin?
Ling asks…I read on Beauty Editor that polyunsaturated oils are the cause of skin aging. They also said that Essential Fatty Acids (like Omega 3s) are not really essential. I’m skeptical but can you tell me if this is all really true?
What are PUFAs?
Way back in 1929, George Burr and his wife Mildred discovered that if rats were fed a fat-free diet, their skin would lose the ability to hold moisture. They’d also develop visible skin abnormalities.
Then the Burrs began reintroducing fats into the rats’ diet one at a time until they determined that oils rich in certain polyunsaturated fatty acids (like corn oil and linseed oil) could completely reverse these skin conditions. Oils containing only saturated fatty acids (coconut oil, butter) did not solve the problem. And that’s how the importance of polyunsaturated fatty acids was discovered. It has since been determined that essential fatty acid deficiency (EFAD) in humans also causes symptoms of dermatitis such as scaling and dryness.
So what are these PolyUnsaturated Fatty Acids (PUFAs)? They’re a class of chemical characterized by the following:
1. A long carbon chain (that’s a defining characteristic of fats and oils.)
This chain ends with a carboxylic acid group which is H-C=0 (This is where it gets the name “acid.”)
2. Two or more of the carbon-carbon bonds in this long fatty chain are double bonds. Remember every carbon atom likes to make bonds to 4 other atoms. In the case of oils, the carbons are bonded to hydrogen atoms. (That’s why oils are called “hydrocarbons.” If the carbon can’t bond to a hydrogen then it forms an extra bond to the carbon next to it. This is called a double bond or an unsaturated bond because it’s not saturated with hydrogen. Conversely, saturated fats have no double bonds because all the carbons are saturated, or bonded with, hydrogen atoms.
- When an oil is saturated it tends to be a solid at room temperature (like butter.)
- When an oil is unsaturated it tends to be a liquid at room temperature (like olive oil.)
What are Essential Fatty Acids?
PUFAs, like other lipids, play a critical role in skin biology. Some PUFAs can be manufactured by the body but some PUFAs can ONLY be obtained through diet – in other words, since your body can’t produce them you have to eat them. These PUFAs that must be eaten in order to maintain health skin called Essential Fatty Acids. So EFAs are a subclass of PUFAs. All EFAs are PUFAs but not all PUFAs are EFAs.
There are only two TRUE EFAs:
- linoleic acid
- alpha-linolenic acid
By the way, some other fatty acids are sometimes classified as “conditionally essential,” meaning that they can become essential under some developmental or disease conditions; examples include docosahexaenoic acid gamma-linolenic acid.
These are the ones that are most important in the context of skin care because from these two parent compounds, the body synthesizes longer chain derivatives that also have important functions in healthy skin. Without them you’ll develop skin problems like dermatitis.
These are NOT the same as Essential Oils which are a type of perfume ingredient. It has nothing to do with being essential to your body, it’s just a perfumery phrase.
What does the “omega” in omega fatty acids mean?
We just said that EFAs consist of long chain of carbon and hydrogen atoms with a carboxylic acid group at the end. When naming carbon chains we start by labeling the carbon next to the carboxylate which is known as the α carbon, the next carbon is the β carbon, and so forth. The carbon in the last position is labelled as the “omega” carbon which is abbreviated with the last letter in the Greek alphabet which looks like a “w.”
This is important because the properties of the molecule are different depending on the location of the double bonds (the unsaturated part of the chain) in relation to the end of molecule.
So, an omega-3 fatty acid has a double bond on the 3rd carbon from the end while an omega-6 fatty acid has a double bond on the 6 carbon from the end. These are loosely called Omega-3s or Omega-6s or sometimes just Omega fatty acids.
What do EFAs do for skin?
When you ingest these fats they’re absorbed across the intestines and are then processed by the liver for delivery to skin. It’s assumed that they accumulate in the sebaceous glands which then deliver them to the skin’s surface. To some extent you can “bypass” the digestive system by applying EFAs directly to skin. That’s because they provide some benefits when applied directly to the stratum corneum but it’s also because they are absorbed through the skin into the blood stream where they can be redistributed.
Once they reach the epidermis they become part of the extracellular lipid matrix that provides the barrier function of skin. How do they do this? Well, you’ve heard of ceramides, right? EFAs, specifically Linoleic acid (LA),is combined with other molecules to create these ceramides that help control the permeability barrier function of the skin. So they are critical to skin health.
PUFA’s gone bad – the free radical hypothesis
So back to Ling’s question, do PUFAs cause skin aging. As we said a minute ago, PUFAs are some what of a controversy in nutritionist circles. In particular, there is one researcher, Ray Peat who claims they do all sort of horrible things to your metabolism when you ingest them. For example, he says PUFAs are responsible for…
“cirrhosis of the liver, diabetes, obesity, stress-induced immunodeficiency, epilepsy, brain swelling, retardation, hardening of the arteries, cataracts, and so on. He says they are “They are possibly the most important toxin for animals.”
We’re not nutritionists so we won’t debate that point but Peat also claims that PUFAs are bad for skin which is relevant to Ling’s question. Peat claims (and we quote) that “Free radicals are reactive molecular fragments that occur even in healthy cells, and can damage the cell. When unsaturated oils are exposed to free radicals, they can create chain reactions of free radicals that spread the damage in the cell, and contribute to the cell’s aging.”
So according to Peat, adding PUFAs to your skin is sort of like pouring gasoline on a fire. You’re adding fuel that can make the UV damage worse. That’s a serious accusation and it is counter to what science has been telling us for years. Is it legit?
Are PUFAs really bad for skin or not?
It is true that these oils oxidize. No question about that. But I couldn’t find any evidence that they are harmful to skin. Peat seems to be the ONLY researcher raising this concern. At least the only one I could find. EVERYTIME I came across an article stating that PUFAs are dangerous to skin the source of their information was one of Peat’s articles. And by the way, as far as I could tell, he hasn’t been published in any peer reviewed scientific journal.
These articles are well referenced – at least regarding nutrition. His articles include dozens of citations for scientific studies going back 70 years or more. But in all his references I could not find a single study that corroborated his claim that polyunsaturated oils are bad for skin. I may have missed it – but I couldn’t find it. In fact, when I reviewed the technical literature all I could were studies that confirmed what we have always been told about these oils which is that they are essential for skin health.
These oils do oxidize and I did find some research addressing this problem. Not from a “ it’s bad for skin” perspective but just a “don’t let the oil go rancid.” I’ll put a link to that study in the show notes but essentially what it says by mixing the polyunsaturates with other types of oils (canola) and with antioxidants you can greatly reduce the amount that the polyunsaturate is oxidized. Here’s one data point in that regard: they measured PUFAs to determine how long it took before the oil showed significant oxidation. They did this at elevated temperature and with exposure to UV and found it only takes about eight hours. But with antioxidants and other oils it lasts hundred hours.
So if oxidation of PUFAs leading to more free radicals really is a problem, the simple solution is to blend them with other oils and antioxidants. Specifically look for tocopherol, which is Vitamin E.
The Beauty Brains bottom line
The current scientific consensus is that certain polyunsaturated fatty acids (the ones we call Essential Fatty Acids) play an important role in maintaining healthy skin. Your body can’t make these EFAs so you have to get them through your diet or by applying them directly to your skin. These oils are prone to oxidation but despite the claims or Mr Peat, there seems to be no credible evidence that they are bad for your skin. But, as always, we love to be proved wrong so if anyone has proof that EFAs are bad for skin, we’d love to see it.
References:
http://lpi.oregonstate.edu/infocenter/skin/EFA/
http://www.aak.com/global/cosmetic_emollients_nov06.pdf
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