What causes acne and what factors contribute to making acne worse?

By Dr. Ari Kasprowicz-Calhoun ND

Acne’s Prevalence is on the Rise:

The prevalence of acne (acne vulgaris) is on the rise, affecting up to 90% of individuals at some point in life. While acne used to be considered a disease of adolescence, it is becoming increasingly more common in adults as well – particularly among women. Acne has been considered a “western disease,” as the link with lifestyle factors is becoming more evident.

90% of people have acne at some point, it's becoming more common, particularly among adult women, and the modern Western lifestyle is to blame. Click To Tweet

Pathogenesis of Acne Vulgaris

There are 4 main factors that contribute to acne in the skin

Increased sebum production: Sebum is the fatty secretion released from sebocytes. Sebum contributes to skin hydration and barrier function. Excessive sebum production contributes to oily skin, commonly accompanying acne.

Follicular hyperkeratinization: Increased proliferation of keratinocytes leads to obstruction of the follicle, essentially plugging the sebocyte with dead cells.

Propionibacterium acnes within follicle:P. acnes,’ is the main bacteria involved in the pathogenesis of acne. It is an anaerobic bacteria that thrives in the lipid-rich environment of sebum. Colonization of P. acnes triggers the immune system and leads to inflammation.

Inflammation: Acne progression often happens due to inflammation from a small comedo to an inflammatory papule or nodule.

Three Types of Acne Lesions:

What are the types of acne lesions? When we refer to acne lesions, we group them into 3 main types.

Open comedo (whiteheads): These lesions occur with an accumulation of sebum and keratin within a sebaceous follicle.

Closed comedo (blackheads): Oxidized lipids contribute to the dark color.

Nodule or Papule: These are follicular ruptures with subsequent inflammation leading to redness, pain, and growth of lesions. This is also the type that becomes “cystic acne”.


Acne Susceptibility:

What makes you more susceptible to acne?

Family History: Genetics influence the size and activity of sebocytes; additionally, several DNA polymorphisms in genes controlling both hormonal activity and inflammation have recently been identified as potential contributors.

Hormonal influences: Androgens, especially dihydrotestosterone (DHT), are known to promote proliferation and activity of the sebocyte. This accounts for why acne arises during puberty, when the concentration of androgens drastically increases in both males and females. DHT, the most potent androgen, is formed from testosterone and is mediated by the enzyme 5 alpha reductase. Acne-Prone (acneic) individuals often have increased activity of these enzymes. Additionally, those with increased susceptibility to acne are found to have a greater density of androgen receptors within the skin.

Genes may predispose you to acne, but diet, gut health, stress, and skincare control the outcome. Click To Tweet


Lifestyle Influences:

What lifestyle and health choices can we make to lessen acne?

Diet: The Western diet plays a major role in the increased prevalence of acne. Refined carbohydrates (sugar), milk and dairy products, along with saturated fats, have been linked to increased inflammation, excess androgens, and comedogenesis. Furthermore, deficiencies in common nutrients, such as linoleic acid, zinc, vitamin D, vitamin C, vitamin A are recognized as risk factors for the development of acne. A nutrient-rich low glycemic diet, such as the Paleolithic diet – packed with plenty of vegetables and fish – is currently considered helpful to promote clear skin. See a discussion of acne-promoting foods below.

Microbiome: Acne is an inflammatory disease and much of our inflammation is mediated by poor gut health. The number of bugs in our intestines far outnumber the cells in our body – creating a complex ecosystem which constantly interacts with our own physiology. The harmony, or disharmony, of these bugs has great influence on our overall health – with many researchers pointing to imbalances in the gut as the root cause of much of modern disease. If the normally protective gut walls are inflamed, food molecules and toxins are able to enter the blood and make contact with our immune tissue. This triggers the immune system to respond – propagating a cascade of inflammatory signals. In naturopathic medicine, we consider the restoration of a healthy gut ‘microbiome’ as an essential component of clearing acne. We work diligently to identify your personal imbalance and associated triggers with the goal of removing pathogenic bacteria and restoring harmony.

Psychological/Emotional Stress: It is well recognized that stress can be a trigger for an acne flare-up. Furthermore, it has been found that those with acne exhibit a particular personality with a greater degree of OCD, anxiety and depression. This association continues despite improvements in skin condition; therefore, it has been proposed that a state of psychological distress precedes and contributes to the state of acne. Additionally, it has been found that sebocytes contain a receptor triggered by stress hormones.

External factors: Although most acne patients have been warned about the dangers of “over-cleansing,” lack of proper hygiene CAN increase exposure to ‘P. acnes.’ This is why it is typically encouraged to shower after working out, avoid touching the face with dirty hands, and wash pillowcases regularly. Mechanical trauma, such as wearing a helmet, scrubbing with astringents, and shaving, can irritate the follicle and contribute to inflammatory lesions. This form of acne is sometimes referred to as acne mechanica.

Acne Triggers in Food:

Three main acne-promoting food groups

Acne is believed to be a disease of modern civilization, with increasing evidence pointing to the western diet as the main culprit. Acne is not found in Indigenous cultures who maintain a hunter-gatherer type of diet. However, acne begins to arise as those cultures are introduced to the western diet, a diet high in sugar, processed foods, saturated fat, dairy, and a low intake of fiber, fish, and vegetables. This has lead researchers to further investigate the main acne offenders within our Western diet.

1. High Glycemic Index

It has long been thought that chocolate may increase acne; however, on further review, it seems that sugar may be the true culprit. Glycemic load (GL) and glycemic index (Gi) are objective quantities which measure the rise in blood sugar and subsequent rise in insulin after the consumption of an individual food. For instance, a piece of white bread would have a much higher GL/GI than an avocado. Insulin is the hormone responsible for getting the molecule of sugar into the cell, so that the body is able to use it as fuel, and the rise in insulin is proportional to the GL/GI.

Elevated insulin levels contribute to acne, by stimulating the secretion of androgens. Androgens are a class of “male” hormones, which most notably includes testosterone and dihydrotestosterone (DHT). Androgens are known to increase sebum production and are thought to be the reason why males tend to experience more severe acne.

Additionally, increased circulating insulin further contributes to acne by increasing cellular proliferation of keratinocytes through dampening of the retinoid pathway. The keratinocyte is the predominant cell in the outer layer of the skin. In acne individuals, keratinocytes are overproduced and not effectively shed, clogging the pilosebaceous unit. A white-head is the most typical result of this process. Retinoids are a class of chemical compounds that are derived from vitamin A. Retin-A and Accutane are two examples of frequently used retinoids in the treatment of acne. The goal of retinoids in acne therapy is to help decrease cellular proliferation and increase shedding; effectively unclogging pores. In our diet, vitamin A and vitamin A derivatives, such as carotenoids, work in a similar manner to help fight acne. Moreover, high GL/GI foods increase insulin and increase the risk of clogged pores by essentially blocking the protective benefits of retinoids.

2. Dairy

It’s time to start rethinking that skinny laté, as dairy products, especially skim milk, have been clearly shown in the literature to exacerbate acne severity. The mechanism behind dairy’s acne-promoting effects is multifactorial.

IGF-1: Milk has been shown to increase insulin-like growth factor 1 (IGF-1), the main hormone believed to be responsible for the rise in acne in puberty. IGF-1 both acts directly on the pilosebaceous unit, as well as indirectly, by stimulating androgen production.

IGF-1 stimulates the proliferation of sebocytes: the gland responsible for secreting sebum. Sebum is an oily lipid secretion which is a crucial component of acne pathogenesis.

IGF-1 stimulates keratinocyte proliferation: As mentioned previously, keratinocyte overproduction without proper shedding contributes to clogged pilosebaceous glands and formation of comedones.

IGF-1 increases androgens: DHT is the most potent androgen and is responsible for the majority of acne effects. IGF-1 stimulates 5-alpha reductase, the enzyme responsible for converting testosterone into DHT.  IGF-1 has also been shown to decrease the proteins that bind androgens, thereby, increasing the free androgens in the blood and subsequent androgen activity within the body.

Hyperinsulinemia: Although dairy is not a dense source of carbohydrates, the glycemic index and subsequent insulin response in milk is three to six times higher than other foods containing the same carbohydrate load. This high glycemic response not only contributes to the mechanisms mentioned above, but also increases IGF-1.  Interestingly, skim milk has been found to have a greater influence on acne than whole milk. One theory is that the extra whey and casein within skim milk contribute to this difference, as whey protein strongly contributes to postprandial hyperinsulinemia and casein increases IGF-1 concentrations.

Hormones within milk

Milk available in most stores is high in placenta-derived progesterone, precursors to dihydrotestosterone (DHT), and IGF-1, all of which are hormones known to contribute to acne pathogenesis.

Skim milk contains less estrogen than whole milk, a hormone typically thought to reduce the occurrence of acne; therefore, this may also contribute to the increased risk of acne with skim milk.

3. Oxidized Fats

Over the last 30 years, the beneficial vs harmful health effects of fats in our diet have been heavily debated. The role of fats in the pathogenesis of acne is no different; however, increasing evidence indicates that the effects of fats on acne are highly dependent upon the type of fat consumed.

Going back to the concept of acne as a westernized condition, we must consider the fat content in the diet of the indigenous cultures where acne is nonexistent. In their “hunter-gatherer” type of diet; omega 3 to omega 6 ratio is 1:1; while the ratio among most westernized diets is approximately 1:20. Omega 3’s are essential fatty acids considered to be highly anti-inflammatory. They are most notably found in fish, but also can be found in some nuts and seeds, as well as high-quality red meat. Omega 6’s are also essential fatty acids; however, they are considered to be inflammatory. Common sources of omega 6’s include safflower oil, soybean oil, canola oil, corn oil, poor quality meat, and many processed foods. The danger of omega 6’s increases as they are subjected to heat, as they are not “stable” and easily oxidized. Most are aware of the role oxidized fats play in the development of cardiovascular disease, but oxidized fats also present a major risk for acne sufferers.

Most of the fats in our diet are inflammatory. Focus on Omega 3 fats like flax, fish, nuts and seeds. Click To Tweet


Sebum is a lipid (fat) rich material that is present in everyone to some degree. It is an essential component of healthy skin, as it helps the skin maintain proper moisture. Acne individuals, however, tend to overproduce sebum and have a slightly different sebum makeup. The sebum of those with acne tends to have significantly more squalene, a lipid that is highly sensitive to oxidation. Oxidized sebum creates a perfect environment for the proliferation of Propionibacterium acnes, the main bacteria that causes the development of inflammatory acne papules.

The consumption of oxidized fats, saturated fats, and trans fats have all been shown to increase the oxidation of squalene, thereby, increasing the inflammatory nature of an individual’s acne lesions. Furthermore, a blackhead is simply a pore that has been clogged with oxidized sebum. Thus, acne sufferers are likely to benefit from a reduction in dietary intake of oxidized fats, as well as, increased intake of antioxidants.

Tips to Avoid Dietary Fat oxidation:

  • Avoid deep-fried foods, especially at restaurants, as they tend to use vegetable oils with low smoke points.
  • When cooking on the stove-top, choose a cooking fat with a high smoke point, such as ghee, refined coconut oil, avocado oil, etc.
  • Choose raw or sprouted nuts over roasted nuts, as the natural oils may partially oxidize in the heat. Opt for whole, as they will maintain freshness longer than those that are chopped and ground. Store nuts in the fridge or freezer for optimal shelf-life.
  • Choose organic grass-fed meats over conventionally raised meats.
  • Refrigerate polyunsaturated oils, including, fish oils, nut oils, and flaxseed oils
  • Choose monounsaturated oils that are packaged in tinted glass containers. If they come in clear bottles, it is a good idea to wrap them in foils.
  • Make sure that all oils are recapped immediately after use and stored in a dark place away from heat.

Healthy is as healthy does

Our skin is an excellent indicator of our internal health. Topical treatments can often effectively deal with acne breakouts, but true health starts from within. We encourage an acne strategy that emphasizes both effective skincare and a healthful diet and lifestyle.

We Can Help:

North County Natural Medicine has collected many powerful natural approaches under one roof, here in Encinitas. Our naturopathic MDs can get you healthy from the inside out. Our caring acupuncturist specializes in skin health and anti-aging. Our naturopaths offer medical-grade facial services (including PRP therapy) and IV nutrition supplementation that can break the acne cycle, diminish scars and grow new collagen.

Schedule a consultation and let us customize a treatment plan for you.

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