ACNE AND DIET
How to treat and what to eat!
Dr Mathobela, a leading specialist dermatologist and OXY’s resident skincare expert
Acne vulgaris is one of the most common dermatologic conditions worldwide, characterised by the development of non-inflammatory lesions (comedones) and inflammatory lesions (papules, pustules, or cysts) on the face, neck, trunk, and/or arms. It is seen most frequently in adolescents and young adults with a prevalence rate of up to 85% in those 12 to 24 years of age. About 15% to 20% of affected individuals have moderate to severe acne that can result in permanent scarring.
Precursor lesions for acne are called microcomedones (not visible to the naked eye). It develops when keratinocytes that line the hair follicle peel or flake off. This leads to a small, hyperkeratotic plug in the follicular infundibulum that results in blockage of the hair follicle.
Clinically visible acne lesions result due to the interaction of several factors – follicular hyperkeratinisation, increased sebum production, colonization of skin bacteria, and inflammation in genetically predisposed individuals. Excess sebum production occurs because of increased activity of androgen hormones and IGF-1. The pathophysiology of acne is thought to involve multiple factors, including skin microbiome interactions with an individual’s immune system, hormones leading to excess sebum production, genetics, and environmental factors including diet.
However, the relationship between diet and acne remains somewhat controversial.
In recent years, diet has been revisited as a possible factor in the pathogenesis and treatment of acne. Population-based studies have shown that the incidence of acne is much higher in westernized societies (with diets high in processed foods, dairy and refined sugars amongst others and low in omega-3 fatty acids) than in non-westernized societies.
To fully understand how diet impacts acne, let us look at some of the diet related factors that are implicated in acne pathogenesis and their role in this condition:
Insulin resistance
Insulin resistance (resulting in high insulin levels) leads to increased androgenic hormone production (testosterone, androstenedione, dehydroepiandrosterone/ DHEAS, etc.) and increased levels of insulin-like growth factor-1 (IGF-1), both of which are associated with increased sebum production.
Insulin and IGF-1 play a role in the development, differentiation, and lipogenesis (secretion fatty acids) of the pilosebaceous unit. IGF-1 increases the sensitivity of the adrenal glands to the adrenocorticotropic hormone, thus leading to increased DHEAS production. Increased IGF-1 levels are also associated with increased levels of DHEAS in prepubertal girls and normal puberty. In addition, IGF-1 promotes both testicular and ovarian androgen production.
Milk and dairy products
High milk consumption has been shown to increase IGF- 1 levels, which play an important role in the pathogenesis of acne, as stated above. Milk consumption is also thought to also lead to a more pronounced insulin secretion compared with the equivalent amount of carbohydrate ingestion.
At least 80% of cow’s milk protein is casein, and the remaining 20% is whey proteins. Whey proteins leads to increased insulin secretion (but also IGF-1), and casein stimulates IGF-1 to a greater extent than whey. These milk effects are seen in both skimmed milk and full-fat milk. The addition of a glass of milk to a low glycaemic index diet increases postprandial insulinemia by almost 300%, to the same level as seen with a high glycaemic index diet.
High-glycaemic diets
Diets with high glycaemic index foods produce high blood sugar levels, which in turn lead to increased insulin and IGF- 1 levels.
Fatty acids and other nutrients
Essential fatty acids are divided into omega-3 fatty acids and omega-6 fatty acids.
Omega 6 fatty acids, in general, promote inflammation and will therefore worsen acne if consumption is too high. Omega-3 fatty acids have been shown to decrease IGF- 1 which, as previously discussed, is implicated in sebum production and follicular occlusion.
Omega 3 fatty acids are anti-inflammatory and therefore lead to improvement of acne. Diets that are typically low in omega-3 fatty acids, and have a high glycaemic load, may partly explain the increased incidence of acne in westernized societies.
Increased trans-fat (fried foods, processed foods, cakes, biscuits, pies, etc.) and saturated fat (fatty cuts of meats, bacon, sausages, salami, chorizo, cheese, etc.) consumption was associated with increased acne severity.
Probiotics
Some studies suggest that oral probiotics can improve glucose metabolism and fasting plasma insulin levels which favours improvement in acne. Oral probiotics are also thought to promote a more anti-inflammation state in the body which leads to improvement in inflammatory conditions including acne.
In general, patients prone to acne are advised to make healthy food choice. They are advised to increase consumption of fresh fruits and vegetables, minimise foods that easily raises blood sugar and to limit dairy and fatty foods.
In my practise I have had patients experiencing a worsening of acne with high consumption of the implicated foods mentioned above and an improvement when they try to minimise particularly the consumption of sugary foods and milk.