Acne & diet: What is the connection?


What is acne?

We all know it’s the worst, and very frustrating, but how is it defined in the scientific literature. In research literature it is referred to as a chronic (long-lasting) inflammatory disorder.

Tiny glands in the skin called sebaceous glands are affected by a variety of factors that can cause acne.

Sebaceous glands produce sebum. Sebum is an oily, waxy substance, and its main function is to moisturise our skin as well as make it water proof (-ish). Acne affects sebaceous glands that respond to hormones.

Unfortunately not just hormones affect our skin. Stress, environment, genetics, body weight as well as our diet has an impact. I’ll briefly touch on all of these aspects.


Why is acne an issue?

The long and short of it. Acne, spots, pimples, whatever you call them can effect our mental health long term. They are common during teen years and annoyingly linger in to adult hood for some people.

Whether it is from having ‘bad’ skin as a teenager, throughout adult life, or the scars some people are left with. Acne/pimples etc aren’t fun to deal with.

Almost half of high school students with acne (45%) have social phobia (anxiety) according to a systematic review. Having acne leads to a significant increase in depression and anxiety. Learning about evidence-based ways of dealing with acne could be beneficial.

Current evidence behind what effects skin

·      Hormones

Adolescents go through lots of ‘fun’ changes due to their hormones, acne is also caused by some of these hormones. Recent literature has pinpointed insulin, insulin-like growth factor-1 and androgens as the main perpetrators.


Hey that sounds familiar! And diet related…. Insulin is the hormone of plenty, or at least that’s how my university lecturer described it. This means insulin is released when you have access to food, aka a time of plenty.

Insulin is released when we eat carbohydrates, and increased production of insulin is associated with the western diet. I will touch on this and the diet connection later.

Insulin-like growth factor-1 (IGF-1)

This guy increases androgen hormone production, it also changes some rather long-winded technical sounding hormones that increase triglycerides (fats) and desaturation of fatty acids in the sebum. This increases inflammation and causes acne to form.

What foods increase insulin and IGF-1?

Foods that increase insulin are all foods containing carbohydrates, while foods that increase IGF-1 include milk and dairy products, this may also include whey protein supplements.

Insulin and IGF-1, both activate something called PI3K. PI3K is an intracellular (inside the cell) pathway, P13K activation leads to the production of androgens. An oversimplification, which leaves out some of the steps, the end result leads to increased production of cells in sebaceous glands.


Considered the main trigger of acne in puberty, androgens and IGF-1 have a close relationship. IGF-1 increases androgen production.

Androgens, according to a 2014 study increase sebaceous glands size, stimulate sebum production. Research has also found that acne prone skin has more receptors for androgens. 

Estrogen, progesterone and polycystic ovary syndrome (PCOS)

Women who live with polycystic ovary syndrome (PCOS) are more likely to experience acne.

 The main hormone perpetrators in PCOS are insulin and too much lutenizing hormone compared to follicle stimulating hormone. These imbalances causes an increase in the production of androstenedione. Androstenedione is an androgen hormone that can be changed into testosterone or some oestrogens.

Women who live with PCOS may also have low progesterone, while the roles of oestrogen in PCOS and acne still remain unclear. More research in this area needs to be done.

Unsurprisingly we can see that sex hormones and hormones we associate with diet are connected.

·      Stress

Whether stress can cause acne is unclear. It can worsen acne, this is especially an issue for western women over 25. Further research in this area needs to be done however researchers acknowledge a link between stress causing and exacerbating acne.

·      Vitamin D and sun exposure

There has been some connection in cohort studies, linking the presence of acne with vitamin D deficiency. The sun is the quickest way to top up vitamin D. However it needs to be done safely.

Oral tablets are very safe, and in some countries like Australia and New Zealand may be safer than UV exposure. Most weather apps let you know when the UV is at the lowest, this is the best time to expose your skin to the sun. 

·      Genetics

There are suggestions of a link between coeliac disease, a genetic autoimmune and auto-inflammatory disease and acne. However further research in this area needs to be done. 

·      Obese and overweight

Directly linked with PCOS, and insulin resistance, obesity is also linked with increased prevalence of acne.


According to a very recent systematic review, a high glycaemic load is the most likely reason for an acne flare up.

It also points to weaker evidence connecting dairy intake and acne. Some studies suggest the dairy connection is due to skimmed milk alone, while others suggest it is because dairy products increase IGF-1. 

Another review points to saturated fat also causing acne flare-ups.

A 2017 study in the journal Medicine points to the Western diet as a cause of acne. What does the Western diet look like?

High intakes of:

·      meats and processed meats

·      prepackaged foods higher in salt, sugar and fat

·      fried foods

·      high fat dairy products

·      eggs

·      refined grains

·      potatoes

·      corn and high fructose corn syrup

·      high sugar drinks

Is all of this bad for you? Not at all, it is important to note that the study specifies ‘high intakes’. Eggs and lean meats are not a problem when eaten in moderation alongside whole foods such as vegetables, and at least two serves of fruit a day.

High fat dairy is usually not an issue when included in a healthy diet, and low fat options are readily available. People should always check low fat dairy products in case any sugar has been added.

Processed and pre-packaged foods will usually be higher in sugar, saturated, trans fat and salt as well as the refined grains. Foods that contain added sugars, or foods that have had extra processing are digested very quickly, causing a persons blood glucose levels to rise. To counter the western diet, people adopt a low glycaemic diet.

Insulin and blood glucose

As mentioned recent evidence suggests there is a link between acne and insulin. What does insulin actually do to our blood glucose?

When our blood glucose levels rise, our body produces insulin, to drive the glucose into tissues that need energy. If the body cannot use the glucose for energy, it is then stored as fat.

The release of insulin happens every time we eat, and is normal. However in people who eat too much, too often or are insulin resistant, the body is in fact producing too much insulin, to normalise lower blood glucose levels. This can lead to insulin resistance 

What is insulin resistance?

Insulin resistance is when a persons body becomes resistant to insulin. All tissues in the body that require glucose for energy have special insulin receptors on the outsides of their cells, insulin resistance causes some of these receptors to become faulty. Which means when insulin is released from the pancreas, it cannot bind properly to receptors.

The receptors are faulty, and the cells don’t know there is lots of glucose that needs to come in, even if they need the energy. As such these tissues cannot activate glucose transporters, which would bring glucose out of the blood and into the tissue. This whole process leads to elevated blood glucose levels.

So we have a two fold issue, either people are eating a western diet, and perhaps too much and lots of insulin is being dumped into the body to deal with the raised blood glucose which then starts a chain of chemical reactions that leads to overactive sebaceous glands.

Or, people are insulin resistant or become insulin resistant and the body ahs to produce more and more insulin to deal with the blood glucose and then the chemical reactions leading to acne occur. It can also be both!

What if you are insulin resistant or your diet isn’t great?

Change of diet.

Following a low-glycaemic diet as well as exercise will help in this area. The low glycaemic diet will make sure the release of glucose into the blood stream happens at a slow and steady pace, allowing insulin to deal with it, and hopefully reducing the bodies need to dump loads of insulin into the blood stream.

Acne is considered a risk indicator for people who are insulin resistance and obese. Adults with acne may find it useful to get their fasted blood glucose checked to see if insulin resistance is a concern, or if it is hormone related acne. 


What does exercise do, well when we exercise, it stimulates glucose transporters to the surface of muscle tissue, and as such the muscles can take glucose from the blood. No insulin required (magic).

Exercises that specifically build muscle are especially good for this, as it increases muscle mass and muscle cells. By exercising more and including resistance exercises (with weights), people can build insulin sensitivity (the opposite of insulin resistance).

How to reduce androgens

Androgens include testosterone, and the precursor for the hormone oestrogen. A study looking at people with elevated androgens found a low glycaemic diet helped lower androgen levels to a normal range. This study is from 2008 so it is quite old. As a low glycaemic diet seems to be the recommendation for treating acne it at least seems consistent with the evidence.

Another option is to increase foods that contain dietary phytoestorgens, as they can reduce testosterone levels. Phytoestrogens are found in these foods:

·      soy products in the form of isoflavones

·      chaste tree from the vitex genus, can be found in supplements (check with a doctor before taking)

·      alfafa

·      flaxseeds

·      most fruits and vegetables and whole grains



What does all this mean? Overwhelmingly, when acne is not entirely hormone related, the evidence points to a low glycaemic diet and low dairy.

Before cutting out dairy products such as milk, there are some important considerations. Milk is an excellent source of calcium, which is an important mineral for our bones and bone density 

Some populations groups will become vulnerable if they cut out dairy completely:

·      pregnant and breastfeeding mothers

·      infants, children and teenagers, as this is the most important period for developing good bone density

·      anyone with osteoporosis or a below average bone density

·      women who have had a hysterectomy or been through menopause

·      older adults, due to age related de-mineralisation of bone


If acne is an issue but you are included in one of these groups, think before cutting out milk. Other options also include taking a calcium supplement, always consult a doctor before adding any supplements to the diet.

The evidence around diet and acne is not always clear, however some simple lifestyle changes may help reduce acne flare-ups 

A low glycaemic diet is essentially a very healthy diet, focussing on lots of whole foods, especially vegetables, fruits, legumes and whole grains, as well as lean proteins, some dairy as well as nuts and seeds. 

Other lifestyle factors such as managing stress, getting enough vitamin D and maintaining a healthy weight will also help.



Abid Keen, M., et al. (2017). Cutaneous manifestations of polycystic ovary syndrome: A cross-sectional clinical study. Indian Dermatology Online Journal, 8(2), 104-110. Retrieved from


Bakry, O. A., et al. (2014). Role of hormones and blood lipids in the pathogenesis of acne vulgaris in non-obese, non-hirsute females. Indian Dermatology Online Journal, 5, 9-16. Retrieved from


Clark, A. K., et al. (2017, May). Edible plants and their influence on the gut microbiome and acne. International Journal of Molecular Sciences, 18(5), 1070. Retrieved from


Jovík, A., et al. (2017, July). The impact of psychological stress on acne. Acta Dermatovenerologica Croatia, 25(2), 1133-1141. Retrieved from


Katta, R. & Kramer, M. J. (2018, January 1). Skin and diet: An update on the role of dietary change as a treatment strategy for skin disease. Skin Therapy letter, 23(1), 1-5. Retrieved from


Kim, K., et al. (2017, November). A comparative study of biological biomarkers between healthy individuals and patients with acne vulgaris. Medicine, 96(45), 8554. Retrieved from


Kumari, R. & Thappa, D. M. (2013, May-June). Role of insulin resistance and diet in acne. Indian Journal of Dermatology, Venereology and Leprology, 79(3), 219-299. Retrieved from;year=2013;volume=79;issue=3;spage=291;epage=299;aulast=Kumari


Nguyen, C. N., et al. (2016 Oct 20). The psychosocial impact of acne, vitiligo, and psoriasis: A review. Clinical Cosmetic and Investigational Dermatology, 9; 383-382. Retrieved from


Smith, R., et al. (2008, June). A pilot study to determine the short-term effects of a low glycemic load diet on hormonal markers of acne: A nonrandomized, parallel, controlled feeding trial. Molecular Nutrition and Food Research, 52(6), 718-726. Retrieved from


Stewart, T. J. & Bazergy, C. (2018 Feb 22). Hormonal and dietary factors in acne vulgaris versus controls. Dermato Endicronology, 10(1), 1442160. Retrieved from


Tan, J. K. L., et al. (2018, June). Current concepts in acne pathogenesis: Pathways to inflammation. Seminars in Cutaneous Medicine and Surgery, 37(3S), S60-62. Retrieved from