Chances are you've had acne at some point in your life. Maybe it was as a teenager when all you were trying to do was be 'normal', or perhaps it sprouted overnight when you hit 22.
Whichever age you get acne, it's one of the most frustrating, disheartening, helpless experiences -- despite how many people tell you "it's not even that bad".
Luckily, we live in a time and country where we have access to dermatologists and an array of acne medications. But can we also treat and prevent acne from the inside out?
To find out all about acne and diet, The Huffington Post Australia spoke to dermatologist Andrew Miller.
"About 85 percent of teenagers are going to get acne that will want some sort of treatment," Miller told HuffPost Australia.
"Teenagers get acne at a time where they're trying to establish individuality -- they're trying to separate themselves from their parents and become independent human beings, and then acne comes along. You can understand why people become frustrated and depressed.
"It's really difficult and I've got a lot of sympathy for people."
On top of this, acne tends to be genetic, meaning that if your mum or dad experienced acne as a teenager, you probably will too.
"There is a very strict genetic correlation in acne," Miller said. "If you look at severe acne cases, so if I look at my patients I treat with roacctuane, a very significant number of those will have a family history of acne. In fact, I'm onto my second generation of roaccutane patients."
Considering just how many of us experience acne, it makes you wonder: is this high incidence a reflection of our diets? Can we take care of our skin from the inside out?
"What a lot of us [dermatologists] believe is that this actually reflects, not so much the function of the skin, but the function of the immune system. This is where things like diet and insulin levels may play a role," Miller said.
If you're unhealthy, your skin will reflect that. If you have a rotten diet, your skin will show it.
"I think the answer is your skin is a really big organ. It's 3-5 kilos in weight in an adult, which is a significant part of your body mass. It's an extremely active organ and is very metabolically active.
Interestingly, because skin is so important, Miller said it's independent of a lot of the control mechanisms that work in other parts of the body.
"Skin will chug along with the rest of the body falling apart around it. It's protected from a lot of the influences that hormones and other things have on functions of other organ systems," Miller said.
"But if you're unhealthy, your skin will reflect that. If you have a rotten diet, your skin will show it."
It goes without saying then, that diet can play a crucial role in the health of your skin.
"My general advice to people with any skin disease is to make sure they're well nourished. Have a good diet -- plenty of fresh food from all the five food groups," Miller explained.
"If you eat food that's prepared fresh -- so not just out of tins and bottles -- you're going to be doing better."
Miller added that the health of our gut may also play an important role in how our skin looks and feels.
"There's a lot of data coming through at the moment about the microbiome, and we know that the skin microbiome is important for a lot of things like atopic dermatitis," Miller said.
"We know that the gut microbiome is involved in a lot of inflammatory skin conditions and there's some evidence to show that these sorts of things can influence, not so much acne, but other related inflammatory disorders that use inflammatory pathways. So, it's not beyond a leap of faith to say that it may have an influence on the skin, as well."
Now, you're probably wondering: are there any foods that make acne worse? According to Miller and his decades of experience, yes, there are.
"Dairy has been implicated in making acne worse," Miller told HuffPost Australia.
"There was a big nurses' study and other studies done (which have all come from the same centre in the U.S. so you would have to view it with a degree of circumspection), but certainly we do observe in young people -- particular those who go to the gym, do weights and take protein supplements -- there is a consensus among colleagues that the whey based protein supplements are probably not good for acne."
The other foods which Miller said has an effect on acne are high glycemic foods, which are essentially highly processed snacks, biscuits and refined grains.
"The other thing is high GI foods. When your insulin levels boost up, insulin has a whole lot of hormonal effects that go way beyond controlling your glucose level," Miller said.
"Hyperproinsulinemia is associated with a tip towards more androgen, male hormone-style metabolism. And so there is also some evidence to suggest that people who have a high GI diet -- a junk food diet -- are more at risk of acne."
Vitamin deficiency -- namely a zinc deficiency -- may also have a negative effect on acne.
"Zinc is important in regulating the activity of a whole lot of enzymes in body functions. It's a vast number of the enzymes involved in keeping us alive which requires zinc to be present," Miller said.
"A lot of them are involved in the immune system, so if you have low zinc levels it can have a direct effect on your immune system."
Some studies have shown that a zinc supplement helps reduce acne. However, Miller said these studies are not strong enough to completely back up this claim.
"When we talk about zinc, we're talking about mild to moderate acne. Now, when these studies were done, none of them showed superiority of zinc over conventional therapy. Some people have suggested, for some people who can't use these medications, then maybe oral zinc might be an alternative," Miller said.
When it comes to the 'best' diet to prevent or help treat acne, Miller's recommendation may not surprise you.
"Interestingly, a number of years ago my wife and I were travelling around Rhodes, the Mediterranean island, and we went to have a look at a castle," Miller said.
"We went down by bus and the bus we caught back from this castle was at 3.30 in the afternoon after school, and so all these school kids piled onto the bus. I noticed it at first and I nudged my wife, who is a GP, and asked her: 'look, what do you see?' And she said 'I see no acne'.
"There were all these adolescent kids on the bus and there was no acne. They were all lean, and every one of them had sporting equipment in their hand -- hockey sticks, tennis rackets, soccer balls -- male and female."
Miller suspects one of the main reasons why there's a lower incidence of acne in adolescents in the Mediterranean is because the diet is rich in fresh, whole foods including fruits and vegetables, whole grains, legumes, nuts, olive oil, fish, herbs and spices.
"I don't think the Mediterranean diet is a big mystery: it's eating local and eating fresh," he explained. "Eating this way and doing activity showed in these kids' skin.
"I saw a few blackheads and a couple of pimples in a whole busload of kids. It's completely the reverse of what you see when you get on buses here."
The reason exercise can play a large role in acne and skin health has all to do with insulin.
"Exercise helps to reduce your insulin levels. If you've got that good diet and you're exercising as well, it helps to reduce your insulin levels," Miller said.
The bottom line here which Miller wants people to know is, regardless of whether you have acne or not, eat a good diet and exercise often, and if you have acne, see a medical professional.
"I think it's always worthwhile mentioning that having acne is complicated and expensive, and that people should seek reputable advice about it, which means speak to their doctor, to their pharmacist and, if it's severe, they should see a dermatologist," Miller said.
"Always be wary of people that have something to sell you at the same time that they're giving you the advice."
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