The prevalence of acne and other skin conditions has definitely increased as of late. Makes you wonder – is it genetics, diet, antibiotics/prescription abuse…could be a result of a lot of things. Yes, a lot of us with acne are prone to it because of genetics reasons…BUT, my experience has made me believe that my personal diet has a strong influence over the severity and duration of my breakouts (for both seborrheic dermatitis and acne). So, I decided to hit the web and see what I can find. In this post I’m going to check on the research that’s out there documenting the correlation between diet and skin, in my next post I’m going to talk about my specific diet and how it’s helped me (also how hard it was to change and stick to).
The Research
It looks like academia is finally starting to accept that diet has some influence on acne and seborrheic dermatitis. Which is good, I remember bringing up diet to one of my old dermatologists and he dismissed it before I could even lay out my argument. Frustrating to say the least, but that’s an entirely different blog post.
Let’s start with a few scientific reviews where researchers compiled a BUNCH of studies on skin and diet. The first is Diet and Acne: A review of the evidence by Spencer et al. They compiled 27 studies total: 21 observational studies and 6 clinical studies.
Here’s a table which summarizes their findings – straight from the source.
Another review looked at 13 previous studies and found something similar – refined carbohydrates influence skin conditions like acne and seborrheic dermatitis.
Judging from the compilation of 40 studies – I think it’s safe to say that we can make a case that diet does affect skin conditions like acne and seborrheic dermatitis. But, why? Let’s dig deeper into the two main culprits – dairy and refined carbohydrates.
1. DAIRY
In the studies above, some authors found a direct link between dairy (specifically cow’s milk) and the severity of inflammatory skin conditions. Dairy products like cow’s milk can affect skin through a couple different pathways. Milk we buy in stores most contains hormones. And lots of them. Milk is meant to promote growth and contains a bunch of growth hormones. This study showed that hormones in milk, such as IGF-1, 5α-reduced steroids, and α-lactalbumin can possibly survive commerical processing too. That’s not good. All those growth hormones and steroids in milk are contributing to those not-so-good skin issues we hate.
Here’s another big one – drinking milk increases IGF-1 production. IGF-1 stands for insulin-like growth factor-1…it basically makes us more sensitive to insulin. These guys did a study showing that increased levels of IGF-1 led to increased inflammation and sebum production. More bad signs for skin. Increased sebum production = BAD for seborrheic dermatitis. Here’s quote straight from the American Osteopathic College of Dermatology:
“People with seborrheic dermatitis produce too much sebum (the natural skin oil)”
So…yeah, our sebum production is already higher than average and milk can elevate it even further. I mean I could write pages on how milk can cause inflammation and how it’s linked with skin conditions, but I think you’re starting to get the picture. If you’re serious about treating your seborrheic dermatitis and milk is still a big part of you diet…it’s time to reconsider.
2. CARBOHYDRATES
There’s actually even more evidence out there showing how refined carbohydrates negatively affect seborrheic dermatitis and acne. A lot studies reference how important glycemic index is.
Glycemic index (GI) is a ranking system that assigns a value to a food item, which directly reflects its affect on blood sugar…so a food with a higher GI raises blood sugar more than a food with a lower GI. This is important to keep in mind because insulin acts a lot like IGF-1…they both have similar molecular structures. Lots of studies have found that high levels of insulin are responsible for acne and seb derm pathogenesis as well (this study and this study). So in a nutshell, having a high glycemic load (HGL) diet AKA eating a lot of refined carbs and sugars makes your skin worse.
Here’s a famous study on glycemic load and acne – patients who had a lower glycemic load diet for 10 weeks reduced their acne by 20 – 50%, experienced more balanced hormones (hormones that are linked to skin inflammation that is), and sebum production decreased. Those are some pretty convincing results. The main takeaway here is refined carbohydrates = more insulin, and more insulin = more inflammation, sebum production, androgens. AND all those things are BAD for seborrheic dermatitis.
Sugar is one of the worst culprits. It is a high GI food and remember from your high school biology class, sugar IS a carbohydrate. If you consume a lot of sugar, your inflammation levels will sky rocket. Just look at this study. Basically, some young men were given sugary drinks and the researchers measured a protein associated with inflammation. Well, it went up by ~100% after 3 weeks…sugar = inflammation.
Let’s look at the GI of some foods. If you want more, this is a link to a list of 100 common foods and their GI.
High GI Foods
- Sugar
- Pasta
- White potatoes
- Some fruits: bananas, grapes, cherries, watermelon
- Bread – anything with flour
- Soda
- Chips
Low GI Foods
- Sweet potatoes
- Vegetables
- Steel-cut oatmeal
- Quinoa
- Whole grains (ex. brown rice)
- Legumes, including lentils, chickpeas
- Almonds, peanuts, flax seeds
Honestly, a low glycemic load (LGL) diet is not easy…but it can have a drastic affect on your skin. To summarize here – try to avoid dairy as much as you can (especially milk) and try to maintain and LGL diet, while minimizing the amount of high GI foods you eat.
I wanted to highlight two other important diet related things since they are so prevalent today: Fast Food and Alcohol.
Alcohol
There hasn’t been as much research into the direct linkage between alcohol and skin inflammation (acne and SD). But, I’ve also experienced breakouts after drinking so I decided to dive a bit deeper into it to see what I could find.
Two things jumped out at me – alcohol messes with your blood sugar levels and alcohol interferes with your hormones. See the correlation between blood sugar (insulin) and hormones. What you eat has a big impact on those two things…and keeping both well-regulated means clearer skin and less inflammation.
In addition, too much alcohol can alter the permeability of the membrane associated with your intestines – this has been shown to allow bacteria to slip into the bloodstream and trigger inflammation (see here).
Fast Food
Most fast foods contain a TON of simple, high glycemic carbs and lots of sugar. We already covered how those two things are very bad…and you should avoid them if you want to improve your skin. Fast foods are infamous for containing monosodium glutamate (MSG) and trans fats as well. This study shows how MSG can cause inflammation and lead to dysplasia…aka a stage preceding cancerous growth. Not much research directly links skin conditions to MSG..much like alcohol above, but I think it’s safe to assume that lowering the overall level of inflammation in your body is a plus for your health and ultimately your skin.
In terms of trans fat – they’re horrible. Period. Here’s a couple studies all linking trans fat with inflammation (1,2,3,4). Again, if you really want to change your diet to help our your seb derm or acne…you shouldn’t be coming anywhere near fast food.
Summary
- Avoid dairy – especially milk
- Avoid carbohydrates with a high GI
- Avoid alcohol or drink in moderation (ex. a glass of wine every so often)
- Avoid all forms of fast food
In a post soon to come, I’m going to talk about what you DO want to eat and what a successful anti-inflammatory diet looks like. My personal diet plays a huge role in the severity of my seborrheic dermatitis. My face can definitely tell when I eat/drink some of the bad things we talked about. I’m also going to talk about some important supplements and what impact they can have. Thanks for reading – drop me a line if you have questions.