Diet in acne - the glycemic index


Acne consultations at Skindepth Dermatology always involve a discussion on diet and how any dietary factors may be contributing to acne. And when we talk about acne and diet, we like to talk about Science.

Glycemic Index and Acne

One of the main dietary culprits in acne is the High Glycemic Index (GI) Diet. 

GI measures the rise in blood sugar after the consumption of carbohydrates. 

Low GI carbohydrates are slowly digested, absorbed and metabolized and cause a lower and slower rise in blood glucose/insulin. High GI foods cause a sharp rise in blood sugar/insulin.

So what's the problem with a high glycemic index?

Well, a rise in blood sugar leads to a rise in insulin, This in turn leads to an increase in insulin like growth factor 1 (IGF-1). High levels of IGF lead to insulin resistance and the following:

  • keratinocyte proliferation which leads to skin  inflammation - acne

  • sebocyte proliferation which leads to  comedome (congested pimples) formation

Insulin and IGF-1

Insulin and IGF-1 increase hormone synthesis from our sex organs and adrenals. This then in turn decreases the liver synthesis of sex hormone binding globulin (SHBG), which activates and increases the blood availability of androgens. Androgens are the hormones that act on our skin to produce acne.

So you see, sugar and carbohydrate in the diet cause a direct increase in hormones and inflammation! It all makes sense when you break down the science.

Do keratinocytes cause acne?

Keratinocytes are believed to play a major role in the development of acne called Follicular hyperkeratinization. They are very specialized cells that make up the epidermis (top layer of skin) and are essential in providing protection for the body by forming a tight barrier. 

This barrier prevents foreign substances from entering the body, while also minimizing the loss of moisture and heat. Keratinocytes play an important role in skin injuries, but they also help to regulate the immune system.

On average, humans replace their entire epidermis every month! However, people with acne often have differences in skin turnover meaning that their dead keratinocytes do not shed off like they are supposed to. Instead, the keratinocytes build up and cause a keratin plug to form around the hair follicle. This plug allows for bacteria to become trapped and therefore increases the chances of acne lesions.

What are some causes of acne in adults?

The main causes of acne are typically a combination of one or more of the following:

  • Overproduction of sebum (The oil produced by the skin) 
  • Bacteria P. acnes (type of bacteria)
  • Inflammation
  • Follicular hyperkeratinization 

Deficiencies in common nutrients, such as linoleic acid, zinc, vitamin D, vitamin C, and vitamin A are recognized as risk factors for the development of acne. 

Overproduction of Sebum

The overproduction of sebum is one of the main causes of acne. Sebum is a fatty secretion that comes from the sebocytes. It helps to hydrate the skin and create a barrier. However, when there is too much sebum, it can lead to oily skin and clogged pores. 

The main bacteria involved in causing acne is Propionibacterium acnes (P. acnes). This anaerobic bacteria loves to live in the sebum because it is rich in lipids (fats). When P. acnes begins to colonize, it sets off the immune system which leads to inflammation. 

Inflammation can cause acne to worsen by turning a small comedo (whitehead) into an inflammatory papule or nodule (the big red bumps we know as acne). Follicular hyperkeratinization is another factor that can contribute to acne, and it occurs when there is an increase in the proliferation of keratinocytes. 

This can lead to the obstruction of the follicle, which then traps sebocytes with dead cells.

What food should I avoid if I have acne?

The Western diet's role in the increased prevalence of acne cannot be understated. Consuming refined carbohydrates (sugar) and grains, milk and dairy products, and alcohol, along with saturated fats, leads to increased inflammation, excess androgens, and cosmogenesis. 

Reducing your intake of these foods and beverages may in turn reduce the rate of acne lesions.

What foods help clear acne?

There are a few different things you can eat that may help keep your skin clear and reduce the risk of developing acne. These include:

Omega-3 fatty acids: 

These are anti-inflammatory, and regular consumption has been linked to a reduced risk of acne. Omega-3s have been shown to lower insulin-like growth factor 1. When insulin is high, the body is more likely to produce excess testosterone. This can lead to increased sebum production, which can in turn lead to hormonal acne.


Probiotics promote a healthy gut and balanced microbiome, which is linked to reduced inflammation and a lower risk of acne development 

Green tea and Turmeric: 

These two are not used as treatments though some believe that their properties can aid in the reduction of acne. Green tea contains polyphenols that are known for their anti-inflammatory properties and for reducing sebum production.

Green tea extracts applied to the skin have been shown to reduce acne severity. Tumeric is an anti-inflammatory agent that can help regulate blood sugar, improve insulin sensitivity and inhibit the growth of acne-causing bacteria, which may reduce acne.

Vitamins A, D, E and zinc: These nutrients play crucial roles in skin and immune health and may help prevent acne.

What can I drink to clear acne?

Drinking water can help to flush out toxins and bacteria, which can reduce the likelihood of clogged pores and breakouts.

Secondly, keeping the skin moisturised is important for a number of reasons. It allows the skin to maintain healthy skin cell rejuvenation and collagen production, which in turn helps with acne healing and the reduction of inflammation from acne pimples and acne scarring on the skin.

Finally, increasing your water intake helps reduce blood sugar levels. A high intake of sugar, resulting in higher blood sugar levels is proven to increase acne on the skin. Therefore, balancing and maintaining your blood sugar levels through correct water consumption helps to detoxify the skin.

Which fruit is best for acne?

Fruits that contain Vitamin A or E, are high in antioxidants or Zinc. 

Blueberries, tomatoes and apricots are some great examples. When it comes to acne, everyone's body is different. 

Some people find that they break out more when they eat certain foods. With your doctor's supervision, it can be helpful to experiment with your diet to see what works best for you. Keep any food allergies or sensitivities in mind when planning your diet.

Can drinking water help acne?

Yes, Water can play a big role in improving your skin and treating your acne over time. 

How can I get rid of acne fast?

We offer lots of natural and non-drug-based acne solutions

  • LED light therapy:  can be used as a natural therapy that may help reduce inflammation and redness. 

  • Tea tree: Some evidence shows that tea tree products can help, though care is to be taken due to it sometimes causing irritability and dry skin.
  • Vitamin A creams 

Always speak to your dermatologist about natural treatments before self prescribing at home to avoid adverse reactions. 

Alpha hydroxy acids can help with unattractive dead skin cells by getting rid of the top layer. This process is known as "unplugging" and can also help reduce redness and inflammation. 

Fruit acids are found in many facial treatments and OTC products, such as cleansers and leave-on treatments. Some of these acids include citric, gluconic, and glycolic acids. 

Although there is still some debate surrounding how effective these fruit acids are in treating acne, some studies claim that it does work depending on the type, strength, and formulation of the product. Common side effects of this medication include increased photo-sensitivity and the chance of sunburn, irritation and redness.

What foods trigger hormonal acne?

There are a few things that can cause hormonal acne, and one of them is consuming too much alcohol. Alcohol consumption can influence your body to produce more of the hormones testosterone and oestrogen, which can in turn lead to an increase in sebum production and clogged pores.

Caffeine has been shown to increase the level of cortisol (the stress hormone) in your body. When your body produces too much cortisol, it can have harmful effects, including making your hormonal acne worse.

image source CFTP

How does this happen? 

One way is that too much cortisol can lead to excess sebum production which is a common cause of acne. Another way is that too much caffeine may interfere with your sleep patterns. Lack of quality sleep can lead to your body producing unnecessary amounts of cortisol. So if you're struggling with hormonal acne, it's worth cutting back on caffeine and making sure you're getting enough quality sleep.

When you eat high glycemic index foods (high sugar food and beverages), your body produces more of the hormone insulin, which can lead to increased inflammation and more acne. A low glycemic index diet can help keep your blood sugar levels under control and reduce the risk of hormonal breakouts to help you avoid these problems.

While cow's milk contains both whey and casein proteins which can promote growth in calves, recent research suggests that it also has an effect on human hormones. When we digest the proteins found in milk, our bodies react by increasing insulin levels and blood sugar levels. 

Additionally, cows' milk tells our bodies to release a hormone called IGF-1, which is similar to insulin and has been linked to breakouts.

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