Acne: Connecting Diet and Biology


Everyone has their own health journey, and for many people (myself included) this journey involves our skin. Obviously, physical appearance is a big deal, and for most people, it’s also a big investment. In America, women will spend around $225,000 over their lifetimes on appearance, and men spend around $175,000. And of course, skin care is a big part of this. There’s also a huge psychological cost related to skin health. In this area, acne is a heavyweight, as 80% of Americans will suffer from acne at some point in their lives.

When it comes to therapies for acne, there are a number of potent treatments offered through prescription. But many choose to (either in addition or instead) pursue lifestyle changes as a way of approaching this skin condition. These interventions may not have as much evidence for efficacy, but can be far more appealing for those hoping to minimize side effects from medication. Among these, dietary changes are building in popularity. So how does acne science actually connect to diet? One notable link relates to a specific cell pathway and the dietary choices that influence it.

Let’s start out talking about what might be driving acne, and why that would be important for diet. Though the exact causes of acne are not known, it’s thought that a key pathway involved in acne involves a metabolic pathway known as mTOR. You may have heard of mTOR before, because it’s become very popular in longevity discussions and metabolic conversations. mTOR stands for mammalian target of rapamycin, and the TLDL here is that it’s a key coordinator of a cell’s growth. When we’re in conditions of nutrient excess, mTOR is activated, and directs the cells to create more fats and proteins and overall grow. Research suggests that mTOR, specifically mTOR complex 1, may be overactive in acne.

How does mTORC1 get activated? It’s activated when there’s an abundance of signals for nutrient excess. Some of these that are important here are certain amino acids and high levels of growth factors like insulin and insulin-like growth factor-1. mTOR also regulates the immune system in skin cells and may increase inflammation by decreasing the availability of inflammation suppressing T cells called T regs.

Ok, so let’s tie this into lifestyle factors. Overall, the modern day diet is one that contains a nutrient excess. But this isn’t just a calorie issue. We also consume an abundance of things that seem to act as really potent growth signals. These include dairy, branched chain amino acids and refined carbohydrates. Let’s talk about each.

There’s obviously a lot of controversy around dairy consumption. Whatever your position on dairy, it’s clear that it’s basically a highly anabolic fuel, meaning it’s a superfood for cell growth, which makes sense as to why baby animals and humans are the perfect consumers. But dairy also appears to especially increase levels of the growth factor IGF-1, which activates mTOR. In one study, researchers showed that people with acne had higher levels of IGF-1 than controls. Notably, whey protein, which comes from milk, may have the same effect. Research has shown a connection between dairy consumption and acne, but it seems to most powerfully be linked to milk, and not as much to yogurt or cheese. To back up the science here, research shows cheese and yogurt don’t seem to increase IGF-1 nearly as much as milk.

Next let’s look at the link between refined carbohydrates and acne. In a 2014 paper published in the Journal of Drugs in Dermatology, a review paper came out called Diet and Acne Update: Carbohydrates Emerge as the Main Culprit, where researchers called out the connection between a diet high in refined carbs and acne symptoms. A number of studies reviewed in this paper looked at the connection through markers like glycemic index (which measures the glucose spike after a meal) and acne. Notably, refined carbohydrates tend to have the highest glycemic indexes. The studies often found that diets that elevated the glycemic index were linked to worse symptoms while the opposite was the case for diets that did not increase the glycemic index as much. Connecting this to the mTOR story, higher refined carb intake increases circulating insulin and may increase the binding of this growth factor to skin cells and subsequently increase mTOR signaling.

Lastly, let’s explore the connection between amino acids and acne. To begin, it’s important to understand that proteins are made of amino acids, and that we need to eat amino acids. There are 20 amino acids, some of which are called “essential” because we can’t make them ourselves, and need to get them from our diet. In the acne conversation, a specific group of essential amino acids are key. These are called branched chain amino acids because of their molecular structure. These include leucine, isoleucine and valine. So why pay attention to these? It’s because these are strong growth signals. Leucine in particular seems to act as a stimulus for mTOR in cells, and higher levels of it have been implicated in acne. Foods that are highest in leucine tend to be animal products like beef, pork and chicken. It’s for this reason some have suggested a link between excessive animal protein and acne.

In summary, acne is increasingly seen to be influenced by our lifestyle choices, including our diet. Specifically, the mTOR sensor may represent a unifying pathway by which our dietary choices can influence the pathophysiology of acne. Though it seems we’re still far from universally applicable dietary advice, those trying to improve acne may wish to consider limiting milk, refined carbs and animal protein may make sense in the context of the research presented above.

The above is for general informational purposes, should not be taken as healthcare advice and is not intended to be a substitute for the care of a medical professional.



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