Monday, July 7, 2014

One ingredient, ten products: Sunflower oil - introduction

In this post - One ingredient, ten products: An introduction - Brandi suggested we take a look at how to use sunflower oil as she had a bunch that was about to expire. (You know you can freeze the oil without any issues, right?)

Sunflower oil is a fantastic oil if you are looking for a high linoleic acid oil. It's light, meaning you can make some very light moisturizers containing great ingredients, and it's inexpensive. It has a shelf life of up to 6 months, one year for the high oleic acid version. (More about this below.)

Its fatty acid make up is...
5 to 7% palmitic acid (saturated, C16)
3 to 6% stearic acid (saturated, C18)
16 to 36% oleic acid (unsaturated, C18:1)
61 to 73% linoleic acid (unsaturated, C18:2)

It can contain up to 700 mg per kg Vitamin E, 500 mg in the form of the alpha tocopherol and 100 mg in the gamma tocopherol. It contains between 3000 to 4500 ppm phytosterols like sitosterol and campesterol, which help reduce inflammation and itching, and can reduce transepidermal water loss.

Unfortunately, with all those double bonds in the linoleic acid, it doesn't have a long shelf life - 3 to 6 months. The high levels of Vitamin E help with oxidation, but not enough to overcome the double bonds. With these high levels of Vitamin E, you're going to get the goodness offered by the vitamin - softening of the skin, alleviation of dry skin, the usual retention of water, plus anti-inflammatory benefits!

Linoleic acid is considered an essential fatty acid, one we can't construct ourselves in our body, so we have to get it from the outside world. It is crucial to normal barrier function in skin, and a deficiency can lead to dry skin and hair, hair loss, and poor wound healing. It is a major component in ceramides - about 14% - which make up about 50% of our stratum corneum or outer layer of skin.

Ceramides are essential for the normal organization of our tissues into structures that are responsible for keeping the barrier function of the skin functioning well, like preventing transepidermal water loss and keeping other things out. They are found in our skin at about 50% by mass. The other components of our skin are fatty acids (10 to 20% by mass) and cholesterol (about 25%). A decrease in ceramides - through aging, exposure to high or low temperatures - can lead to dry skin and itchiness due to a decrease in the efficacy of the stratum corneum's ability to keep water in and other things out. During the winter, a proportion of our ceramide 1 linoleate (acylceramide) decreases, and this can lead to dry and itchy skin. During the summer, our skin has increased levels of palmitic and palmitoleic fatty acids. And people with atopic dermatitis and acne show reduced levels of linoleic acid in their skin.

Studies have shown linoleic acid can restore the barrier function and reduce scaling on your skin. One study showed using linoleic acid on people with acne reduced the pustule size by 25% in one month. It can act as an anti-inflammatory, acne reducer, and moisture retainer.

Oleic acid (C18:1) is another fatty acid that shows up a lot in the oils we use in lotion making. It is found in olive oil at really high rates (78%) and high oleic sunflower oil (74%). It has only the one double bond, so it has a longer shelf life than those oils with really high linoleic fatty acid content.

Oleic acid is not considered an essential fatty acid because our bodies produce it. Although oleic acid is actually found in our human sebum - you'll probably see jojoba and olive oil touted as being very close to sebum as a selling point - it can actually make the effects of the bacteria responsible for some types of acne (P. acnes) worse!

Note that there are two types of sunflower oil we can get from our suppliers. Sunflower oil and high oleic sunflower oil. Sunflower oil has a shelf life of up to six months because that lovely linoleic acid doesn't have a really long shelf life. High oleic sunflower oil has been altered to have more oleic acid in it - between 69% to 80% compared to 16% to 36% in normal oil - which means the shelf life can be up to one year. That's a big difference, so check which one you have and note the expiry date accordingly.

Another bonus of sunflower oil is the cost - it's one of the least expensive oils you can buy at $7 to $10 a pound.

It's not considered a comedogenic oil, so it is good for facial lotions. Not only is it light, but it is also thought to help with acne! (I definitely recommend it for acne - it makes your skin feel moisturized and very soft!)

The skin feel of sunflower oil is light and greasy, which isn't a bonus if you like your products to be less greasy feeling. However, if you're accustomed to store bought products with mineral oil, it's still less greasy feeling than that.

Join me tomorrow as we embark on making our first product, a body oil with sunflower oil. If you simply can't wait that long, take a look at some products we've made in the past...
Facial moisturizer with sunflower oil
Oil based make-up remover
Linoleic acid: Lotion bars
Formulating with oils: Solid scrub bars
Weekend Wonderings: How can we make a nice body oil from an oil cleansing method oil?
Duplicating products: Korres 3 in 1 cleansing emulsion
Newbie Tuesday: Testing the skin feel of our oils

6 comments:

Zink said...

Would be great if you could reference the studies you refer to.

Susan Barclay-Nichols said...

Hi Zink. The concept that linoleic acid helps speed up skin's barrier mechanisms can be found in myriad studies, but here are a few...
Investigation into functions of fatty acids in skin
Permeability barrier in essential fatty acid deficiency
The repair of impaired epidermal barrier function in rats by the cutaneous application of linoleic acid
Lipids and barrier function of the skin
And so on...

Check out this post to see my general references and textbooks.

Zink said...

Only one of those studies are controlled vs. another oil (olive oil) and they're all on rats.

I was specifically looking for the pustule size study btw, sorry for not being more specific, I see you added a link, to bad it doesn't control against other oils either which is too bad.

That being said, I will test Sunflower or maybe even better Safflower seed oil (which is the common carrier oil highest in linoleic acid).

Susan Barclay-Nichols said...

Did you click on the link to the study of pustule size?

Zink said...

Yes, it's a linoleic acid vs water vehicle study. In other words, we don't learn that linoleic acid is better than other fatty acids from it :)

Brandi Yates said...

Thanks Susan. Youre the best!