What is acne?
There are two main types of acne:
1) Acne vulgaris (superficial acne) – the most common type, characterized by blackheads and whiteheads.
2) Acne conglobata (cystic acne) – a more severe type, characterized by severe cysts and scarring.
Acne tends to occur on the face, back, chest, and shoulders because that is where the sebaceous glands are more concentrated.
How common is acne?
Acne most commonly begins during puberty, affecting 79 to 95% of teens in Westernized countries. It tends to affect more males than females (1).
40 to 54% of adults over 25 have acne, while only 12% of women and 3% of men continue to experience it into middle age (1).
What are some of the contributing factors to acne? (2, 3, 4)
- Chronic stress, which can affect gut health and integrity (5).
- High levels of IGF-1 (insulin-like growth factor 1), which increases sebum production and cell growth rates.
- Hyperkeratinization of the hair follicle, which can block pores.
- Inflammation / immune stimulation
- Microbes on the skin.
- Oral and topical antibiotics have been used as treatments for decades, but are no longer recommended as the primary or only treatment due to concerns over antibiotic resistance.
- Overactive androgen hormones (like testosterone) that increase keratin and sebum production.
- Possible genetic predisposition towards more of the enzyme 5-alpha-reductase on the skin, which converts testosterone to its more potent form, DHT.
- Sebum overproduction.
What conditions commonly co-occur with acne?
The following conditions commonly occur alongside acne:
- Depression, anxiety, & other mental health disorders are 2-3x more common in those with acne (6, 7)
- GI symptoms like bad breath, reflux, bloating, constipation are 37% more likely (8)
- Low stomach acid occurs in up to 40% of people with acne (9)
What are some commonly used traditional acne treatments? (4)
Accutane is a prescription acne medication used for severe nodular acne. It is taken by mouth and contains isotretinoin, which is a derivative of vitamin A.
It works by suppressing sebum production and keratinization(10).
However, it cannot be taken by pregnant women due to the teratogenic effects of high-dose vitamin A and has many potential side effects, including high blood pressure in the brain, depression, and suicidal thoughts (11).
2) Benzoyl Peroxide
Benzoyl peroxide is typically used in an over-the-counter topical cream for acne vulgaris.
It works by inhibiting the growth of bacteria on the skin and reducing the amount of fatty acid in sebum (12).
3) Topical Retinoids
Topical retinoid creams can also be used as a treatment for acne. They are often used in combination with benzoyl peroxide.
Adapalene (Differin gel) is available over the counter, while other varieties are available via prescription.
Topical retinoids help reduce the immune response to bacteria on the skin that is involved in acne formation.
How does diet affect acne?
Dietary factors that may affect acne:
- Dairy intake
- High glycemic diet
- Inadequate omega-3 intake
- Alcohol intake
Dairy has the strongest link and strength of evidence (13).
Some research is also investigating how diet can affect acne development on a genetic level, by stimulating FoxO1 and mTORC1 genes, which control androgen hormone signaling, sebum production, immunity, antioxidant responses, and cellular growth – all of which play a role in acne (14, 15, 16).
How does dairy contribute to acne?
Milk can increase insulin levels (beyond the normal amount you would expect from increasing blood sugars) (17, 18, 19).
The amino acids in milk may also stimulate the liver to produce more IGF-1, which boosts sebum production (20, 21, 22).
Lots of studies show correlations between milk & acne, but there’s not really any proof of causation (23, 24, 25, 26, 27, 28).
Why might a high glycemic load worsen acne? (29, 30, 31)
High glycemic foods can increase blood sugar levels, which then increases insulin levels.
Insulin increases the activity of androgen hormones & boosts levels of IGF-1, which spurs acne development.
This is because androgen hormones and IGF-1 boost sebum production and increase cellular growth rates. Too much sebum & too many skin cells lead to clogged pores and a greater chance of acne.
How might low omega-3 intake contribute to acne?
The hypothesis is that low omega-3 intake increases inflammation levels, which can worsen acne (32, 33).
How does alcohol worsen acne?
Alcohol intake can temporarily increase testosterone levels, which can contribute to acne formation (34, 35).
Some alcohol is also excreted through the skin, which may feed acne-causing microbes (36).
Chronic alcohol consumption can also weaken the immune system and increase inflammation, which can contribute to acne (37, 38).
Does chocolate cause acne?
There is no definitive research on whether chocolate causes acne, but some studies have found a link (39, 40, 41).
One study gave acne sufferers a capsule filled with 100% cocoa powder, and found that acne lesions increased… but the “placebo” capsule contained hydrolyzed gelatin… which doesn’t seem like a great control substance since gelatin could potentially improve gut health! (42).
Mechanisms are totally unclear, but one study found that chocolate increased the immune system’s response to acne-causing bacteria on the skin… so perhaps that could play a role (43).
Can nutrient deficiencies affect acne?
Low levels of selenium, vitamin A, vitamin D, vitamin E, and zinc have all been associated with acne severity. May be worth evaluating status & supplementing as needed to replete (44, 75, 76, 77, 78, 79, 80).
What are some potential nutrition considerations for acne?
Here are some possible nutrition interventions for acne:
- Trial a dairy-free diet (46)
- Lower glycemic diet (high glycemic diet may be an acne trigger) (47, 48, 49)
- Consume enough omega-3’s (Want to be in balance with omega-6 intake) (50, 51, 52)
- MRT/LEAP to address possible food sensitivities (53)
- Check topical products as well (lotion, makeup, etc.) for reactive ingredients (based on MRT results)
- Try discontinuing whey protein powder if using, as it may cause acne in some people (54, 55, 56, 57, 58, 59, 60, 61, 62)
- Probiotic to improve gut health (may take 8-12 weeks to see improvements) (63, 64, 65, 66)
- Consider supplements if deficient in important vitamins (see below)
- Rule out PCOS or other hormonal causes (can do a DUTCH test)
- Monitor the relation to the menstrual cycle, to see if it consistently appears at certain times.
- Theoretically, a 30-60 day ketogenic diet may be beneficial by reducing the pathogenic mechanisms of acne and restoring proper hormonal status (67).
- Paleo and Mediterranean style diets have also been beneficial for acne (68, 69).
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What supplements may help acne?
Whether or not a supplement will help reduce acne depends on the root cause, but here are some that have been helpful in certain cases:
1. Curcumin, either in supplement form or applied topically, may help improve acne (70).
There is not enough research to prove its efficacy or suggest a dose. It is hypothesized to work as an anti-inflammatory.
Pure Encapsulation’s Curcumin with Bioperine is a high-quality supplement choice.
2. Fish oil, but the response seems to be very individual. May help some, but make acne worse for others (71).
3g daily, containing 930mg EPA for 12 weeks helped improve severe acne but made mild acne worse in some people.
Nordic Naturals Ultimate Omega is a good option but would need 5 soft gels/day to reach the levels used in the study above.
3. Probiotics – could help some people, or be an acne trigger in others. Very individual.
Can be taken orally or even applied topically. When taken orally, believed to help modulate the gut-brain-skin axis (72).
When applied to the skin, some probiotics can inhibit the growth of the bacteria involved in acne (P. acnes) and increase ceramides that protect the skin barrier and increase moisture (73).
Lactobacillus rhamnosus GG – 3 billion CFU/day orally for 12 weeks improved adult acne by modulating insulin signaling in the skin (74). (This is the strain used in Culturelle.)
4. Zinc gluconate – Both zinc gluconate and antibiotics have been shown to be effective at reducing acne, but antibiotics were 17% more effective than zinc at 3-month follow-up (both groups showed improvements from baseline) (45).
5. Topical green tea extracts may help reduce sebum production, inflammation, & acne severity (81, 82, 83, 84)
6. Topical niacinamide (vitamin B3, also called nicotinamide) gel may also help reduce acne severity by decreasing sebum production and lowering inflammation (85, 86).
Shown to be as effective as topical clindamycin antibiotic gel (87, 88).
May be a better choice than clindamycin for people with oily skin + acne, but does not address other contributing factors, like hyperkeratinization or the presence of P. acnes bacteria on the skin (89).
7. Topical tea tree oil is a natural antibacterial and antifungal.
8. Topical azelaic acid is derived from grains. 15 – 20% topical creams are as effective as 5% benzoyl peroxide creams for acne vulgaris (90).
Erica is a registered dietitian nutritionist and lover of science and learning. She has a never-ending passion for education, and gladly spends her time writing & growing this blog! When she’s not at the computer, she can be found in the kitchen with her family, rocking out to good music and cooking up a storm.