Yesterday we talked about polyphenols and today we’ll cover phytosterols. Phytosterols are a group of plant-derived sterols and stanols. According to the National Institutes of Health (NIH) there are in excess of 200 phytosterols occurring in the plant kingdom found in such foods as nuts, vegetable oils and beans. 
They are phytochemicals that are similar to cholesterol in their function and structure. Cholesterol has gotten a bad rap in today’s press. We tend to think of cholesterol as something bad that we don’t want in our system. But that couldn’t be further from the truth. Cholesterol is a critical component of our bodies and we couldn’t live without it. Cholesterol is the main structural component of cell membranes, and when it comes to skin tissue cholesterol makes up about 25% of it. The amount of cholesterol in a type of tissue determines how permeable they are. The skin plays a dual role in our bodies in that it needs to keep the bad stuff out (like bacteria and viruses) but also allow the good stuff in (like fatty acids and sunlight). But plants don’t generally have cholesterol in their structure. Instead they have phytosterols and these phytosterols play a similar role in plant membranes that cholesterol plays in ours.
What does cholesterol do in our skin?
In addition to creating 25% to the structural component of our skin, cholesterol has a very important function in helping us to produce Vitamin D. We can get some of our vitamin D from foods such as cod liver oil, egg yolks and herring, and it is no coincidence that these foods are also high in cholesterol. We can also manufacture Vitamin D in our bodies as a result of the interaction between the sun and the cholesterol in our skin. What happens is that the UV-B radiation from the sun hits our skin and turns 7-dehydrocholesterol (a form of cholesterol) into Vitamin D3. Vitamin D is critical to many of body’s systems including:
- Bone health and calcium metabolism
- Cancer prevention
- Immune system functioning
- Blood sugar regulation
And so perhaps you can see the conundrum- we need cholesterol and the sun in order to produce Vitamin D and be healthy, but the sun can also be damaging to the skin. What to do?
What do phytosterols do for our skin?
In comes phytosterols to the rescue. According to a study done in Germany, topical application of phytosterols actually stimulated new collagen production in skin. This can help to counter the aging effects of the sun. The phytosterols from plants actually penetrate into our skin and help our skin in much the same way that cholesterol does. So why not just put cholesterol on skin? Unfortunately it’s not that easy becaues when cholesterol is applied directly to the skin, it generally causes acne and inflammation. Luckily applying phytoserols to the skin results in the opposite and actually decreases inflammation and increases elasticity. The phytosterols help our skin’s barrier mechanisms by reducing transepidermal water loss (TEWL). This helps keep the moisture and plumpness in our skin so it doesn’t dry out. It can also help repair skin that has been damaged by sun burn or sun damage.