Olive oil is considered as a "healthy" edible oil. In addition to the "high content of monounsaturated fatty acids" which makes it have certain advantages in composition, cold pressed olive oil also contains more vitamin E and other polyphenols. These trace ingredients make cold pressed olive oil have certain antioxidant capacity. In addition to eating, many people also use it to smear their skin, and many skin care emulsions use olive oil, claiming that it can bring beauty and skin care functions that ordinary oil does not have.
Such ideas and claims are not new. In ancient Europe, people used olive oil to resist wrinkles, moisturize and protect skin. The oil itself helps to moisturize, and the antioxidants in it also have a certain protective effect on oxidation loss such as ultraviolet light when used externally. Therefore, it is not surprising that some people think that olive oil skin care products are "effective".
However, the experience of the ancients was often just a subjective "feeling", and the legendary effect was often the result of "believing is spiritual". To know exactly whether it is effective, we need modern scientific methods to test it.
[Is olive oil good for skin?]
Many studies have evaluated the effect of olive oil on skin protection. For example, Pediatric in 2008
Dermatology) magazine published a randomized controlled trial in Australia to study the skin treatment of premature infants. In the experiment, 173 preterm infants were randomly divided into three groups: one group used a special ointment in the market, one group used a emulsion made of 30% olive oil and 70% lanolin, and the other group did not use drugs as a control. Within 2-4 weeks after the start of the experiment, the evaluator will score the skin condition of the infants without knowing which group they belong to. As a result, the group using olive oil emulsion had the best skin condition and the control group had the worst skin condition. Such experiments can show that the emulsion of olive oil and lanolin is better than nothing, and that it is better than the selected "companion student", but whether olive oil is as "particularly effective" as the legend still cannot be explained.
If there is only this research, it can also be said that "nothing is better than nothing". Olive oil emulsion, even if not so effective, will not be worse. However, another study published by the magazine in 2013 had a serious impact on this attitude. The objective of this study was to compare the effects of olive oil and sunflower seed oil on the skin. Nineteen adult volunteers with normal skin were divided into two groups. The first group applied olive oil to the forearm of one arm twice a day, 6 drops each time, while the other was not treated, lasting for a total of 5 weeks. The second group also applied 6 drops of olive oil on one forearm and 6 drops of sunflower seed oil on the other forearm twice a day for 4 weeks. Finally, the skin condition was evaluated by measuring the integrity and cohesion of the stratum corneum, moisture retention, pH value of the skin surface, erythema and other indicators. The results showed that olive oil decreased the integrity of the cuticle and caused mild erythema, while sunflower oil maintained the integrity of the cuticle and did not cause erythema. Therefore, the researchers believe that olive oil will damage the barrier function of the skin, so it should not be used for dry skin and infant massage.
As far as the strength of scientific research evidence is concerned, these two items can only be regarded as "preliminary studies", and cannot be said to "prove" or "deny" the effect of olive oil on skin. Considering the low affordability of infants and young children, the author of the second study suggests that more attention should be paid if we proceed from a cautious perspective.
However, for fashionable women, they are more concerned about whether olive oil can help freckles. For example, many skin care lotion products use olive oil, claiming to prevent or treat stretch marks.
[Olive oil is powerless to remove stretch marks]
Striae gravidarum arises from the dermis in the middle of the skin. The dermis contains collagen and elastin, so it is elastic and can maintain the shape of the skin. However, if the deformation of the dermis is too large or lasts for a long time, it may lead to the fracture of the dermis, which may lead to the appearance of stripes. During pregnancy, the continuous growth of the fetus in the body makes the abdominal skin subject to continuous traction, which is easy to form such stripes. In Chinese, such stripes are called stretch marks. In addition to pregnancy, other factors that cause the skin to stretch continuously may also form such stripes. For example, men who have significantly increased their weight in the short term may also have "stretch marks".
The early stretch marks are light red, and then gradually turn white. According to statistics, about 50% to 90% of women will appear stretch marks during pregnancy. Its existence will bring psychological anxiety to many women, which makes the prevention and treatment of stretch marks particularly attractive.
Because of the long history of skin treatment, "treatment of stretch marks" has become one of the selling points of olive oil and emulsion products containing olive oil. Unfortunately, this is basically an urban legend and has not been supported by clinical trials. In November 2012, the Evidence Based Medical System Evaluation Database (CDSR) published a review, summarizing six medical trials that can be found to treat striae gravidarum with various emulsions, with a total number of about 800 people. The results were very disappointing, including olive oil, cocoa butter and other common "effective ingredients" of the emulsion, compared with placebo without "effective ingredients" and without any treatment, there was no statistical difference. This result can be expressed in plain words: whether olive oil or placebo is used, or nothing is used, some people have stretch marks, and some do not grow long. The result of statistical analysis is that whether stretch marks grow or not, and how serious they grow, has nothing to do with whether to use emulsion or what kind of emulsion to use!
Of course, as pointed out by the author of the review, the scale of these studies is limited and the design is not completely strict. To make a more definitive description of the relationship between olive oil and stretch marks, further research on a larger scale is needed. We can only say that based on the current evidence, the prevention and treatment of stretch marks with olive oil is just a good wish without scientific evidence.
(Fruit shell net: http://www.guokr.com/article/439331/ ）
