Adult Acne—The Connection Between Diet, Insulin, and Your Skin
Acne is commonly thought of as a teenage affliction, compounding for young sufferers the often self-conscious awkwardness of adolescence with the embarrassment of unattractive skin eruptions. When acne persists into later stages of life, or shows up unexpectedly in older adults, the often unsightly rash can be no less socially distracting and awkward. Severe outbreaks of this skin condition have caused sufferers to avoid life-fulfilling social situations, even work, to skirt their embarrassment.
A variety of medicines are available to fight the condition, but as is the case with many dermatological afflictions, the underlying causes are not, as yet, well understood. For this and other reasons, the efficacy of acne medications is not assured, with limited applications and attendant risks also of concern.
Cell-level mechanisms that clog skin follicles, producing either the non-inflammatory comedones (whiteheads and blackheads) or unsightly red and inflamed pustules, are not well defined and are likely overlapping. Hormonal changes, diet, stress, heredity, vitamin deficiency, and resistant strains of bacteria are all thought to play a role in the onset of acne, in teenage sufferers, as well as adults.
Over the past 30 years primarily two studies involving a limited set of food products had informed dermatologists' proclamations to patients that acne is not caused by the foods they eat. More recent research, however, puts this assumption under considerable scrutiny. Researchers at the 67th Annual Meeting of the American Academy of Dermatology (AAD) presented data that support a hypothesis that a low-glycemic diet has contributed to the low or zero incidence of acne in populations with non-Westernized diets. In this article we will take a look at recent research into the possible cellular pathways involving diet in the incidence of adult acne, and how maintaining a healthy, low-glycemic diet may help.
Insulin, the Mediterranean diet and adult acne
The regular consumption of plentiful, unprocessed fresh fruits and vegetables, along with lean meats, fish and seafood, the traditional diet of people in the Mediterranean region, may contribute to an improvement in skin conditions. Apart from what's present in the Mediterranean diet and those of other nonindustrialized populations, certain foodstuffs that are absent could be key to minimal acne occurrence.
Indeed, wherever one sees diets commonly free of heavily processed foods, cereal grains, refined sugars and saturated and trans-fatty oils, these populations are commonly also observed to be free of acne. To what degree the low incidence of acne in these people can be attributed to diet, or, alternatively, to genetic makeup, is a matter for further research.
However, the role diet plays in a particular condition—hyperinsulinemia—elicits a hormonal response that supports unregulated epithelial growth and increased sebum secretion, suggesting it is likely that diet also helps regulate acne.
In the case of diet-induced hyperinsulinemia (or, excess levels of insulin in the bloodstream), research has suggested that this condition triggers a hormonal cascade and endocrine response, further triggering unregulated growth and keratinization of epithelial cells, as well as hormonally (androgen) mediated sebum secretion.
The study of hyperinsulinemia affords us insight into how a low-glycemic diet may positively affect acne. The hypothesis goes something like this: One primary function of the pancreas is to produce insulin in direct response to increased blood sugar levels; a low-glycemic diet does not contribute a significant excess of sugars to the blood, resulting in lower blood insulin levels, and an inhibition of the epithelial cell growth and additional sebum secretions that occur with increased insulin in conditions such as hyperinsulinemia.
Conversely, high-glycemic diets, with their higher carbohydrate and sugar contributions, generally do give rise to increased plasma levels of insulin. High-glycemic diets also promote increased blood levels of another substance: free insulin-like growth factor (IGF-1).
IGF-1 is thought to promote acne in a similar way to insulin, by promoting follicular obstruction through inducing androgen-mediated sebum production, but also hyperkeratosis, a thickening of the outer layers of skin, and epidermal hyperplasia, a proliferation of skin cells. A study of post-adolescent women, ages 20–25 years, found increased levels of IGF-1 in those suffering from acne.
In another study, a cohort of young men aged 15 to 25 were separated into a control group, which maintained a conventional Western high-glycemic diet, and a low-glycemic diet group, and followed for 12 weeks. The low-glycemic diet group showed decreased androgen levels, and increased IGF-binding protein levels (IGFBP-1, which removes free IGF-1 from circulation); they also experienced a greater decrease in total acne lesion count than the control group.
An additional compound mediating IGF-1 levels in the blood likewise appears to be involved with mechanisms at the root of acne. Patients with acne have exhibited lower blood concentrations of IGFBP-3, a second and primary binding protein that removes IGF-1 from circulation. Of note is the fact that the receptor on IGF-1 that is targeted by pharmaceutical retinoids, compounds successfully used in the treatment of acne, is the same receptor used by IGFBP-3. Mediation of IGF-1, as well as insulin, appears to have some function in the underlying cause of acne outbreaks. Because diet directly impacts insulin levels, as well as exerts an influence on blood levels of IGF-1, IGFBP-1 and IGFBP-3, diet must also play some role in the occurrence and management of acne.
Insulin, acne vulgaris, and polycystic ovarian syndrome
The confluence of disease, insulin, and acne is seen also in women suffering from polycystic ovarian syndrome (PCOS), a common endocrine condition linked to insulin resistance. These patients have shown improvements in their acne when treated with pharmaceuticals prescribed to enhance insulin metabolism. PCOS sufferers have been shown to have increased plasma levels of the three substances also elevated in acne sufferers: androgen, insulin, and IGF-1. To date no studies have been conducted to evaluate the therapeutic effect of drugs prescribed for insulin metabolism on acne patients not suffering from PCOS.
Low-glycemic diet—a sensible start for acne sufferers
In the past decade or so, evidence contradicting the long-held view that diet does not affect the occurrence of acne has been mounting. Recent research suggests that diet certainly does have an effect, and a low-glycemic, Mediterranean-style diet may provide one of the safest options in the management of a condition with many social implications.
Acne affects as many as 50 million people in the US—a problem on a scale that has prompted development of a list of brand name compounds from A–Z. Those frustrated by the embarrassing skin eruptions of adult acne can opt for a broad range of pharmacological solutions for its treatment. Among this array of drugs, results vary for individuals as to effectiveness while subjecting patients to a variety of side effects—some severe enough to have warranted removal of the product from the market.
Meanwhile, of all the treatments available to us today, focusing on maintaining a healthy diet, particularly one rich in fresh fruits and vegetables, fish and seafood, with moderate amounts of lean meat, is likely to prove an excellent starting point in any personal regimen for the treatment of adult acne. The research indicates a low-glycemic dietary approach simply makes sense.