A recent study published in the Journal of Clinical Medicine reviewed skin disorders and inflammatory conditions associated with nutritional deficiencies in vegan diets.

Study: Vegan Diet in Dermatology: A Review. Image Credit: RONEDYA/Shutterstock.com

Background

Excess or inadequate consumption of nutrients might be associated with skin disorders, such as psoriasis, acne vulgaris, atopic dermatitis (AD), and hidradenitis suppurativa (HS).

Diet contributes to the diversity of gut microbiome, and dysbiosis is associated with altered immune responses, promoting skin disorders.

A vegan diet excludes animal-derived products and comprises plant-based foods (fruits, vegetables, grains, nuts, legumes, and seeds). As such, vegan diets may elevate the risk of specific nutritional deficiencies. However, sufficient intake of nutrients and vitamins, along with relevant supplementation, can prevent nutrient deficiencies.

A recent review on skin disease and nutritional deficiency listed only the vegan diet as a risk factor for the deficiency of vitamins A and B2 (riboflavin) and decreased protein intake.

Therefore, in the present study, the authors summarized nutritional deficiencies causing dermatological manifestations, with the vegan diet as a risk factor.

Nutritional deficiencies

Although studies have demonstrated reduced riboflavin intake with a vegan diet relative to non-vegan diets, clinical deficiency of riboflavin in adults has not been reported.

However, a case report described a newborn with life-threatening hypoglycemia and lactic acidosis due to maternal riboflavin deficiency. The mother had a strict vegan diet and occasionally took supplements of folic acid, omega-3, and vitamins B12 and D.

One study reported keratomalacia in a child on a vegan diet and suggested that the diet may put children at risk of anemia, protein or zinc deficiency, and osteopenia. Protein deficiency is one of the common concerns about veganism.

True protein deficiency results in kwashiorkor. A vegan diet can easily provide the recommended daily protein intake, and a study concluded that there was no evidence of protein deficiency among people following a plant-based diet.

Inflammatory skin disease

The relationship between acne and diet has been historically contentious. Consumption of specific dairy products (e.g., cow’s milk) correlates with acne.

Moreover, increased skim milk consumption among male adolescents has been associated with higher acne prevalence; in contrast, significant associations have been reported for low-fat, whole, and skim milk among female adolescents.

Moreover, high-glycemic index (GI) foods exacerbate acne. A trial observed a significant decline in acne lesions in individuals on a low GI diet relative to those on a high GI diet.

Other studies have corroborated the positive correlation between acne and high-GI foods. Evidence supports the pro-acnegenic effect of high-GI foods and some dairy products.

Thus, a low-GI diet or dairy avoidance may benefit acne patients. As such, veganism may enhance anti-acnegenic effects. Indeed, soy-based products have been shown to reduce acne lesions. Fruits and vegetables with low GI may be protective due to their anti-inflammatory effects, and a balanced vegan diet may help prevent or decrease acne lesions.

Plant-based diets may also benefit psoriasis, improving skin health and preventing associated comorbidities.

They are high in omega-3 fatty acids and antioxidants but low in arachidonic acid, trans-fat, and saturated fat. Omega-3 fatty acids and soy isoflavones are anti-inflammatory and could protect against psoriasis.

Although whether diets could limit HS severity remains unclear, studies suggest that dietary interventions for weight loss, bariatric surgery, and brewer’s yeast exclusion diets may improve HS. Fruits and vegetables have been reported to alleviate HS, whereas carbohydrates, sweets, high-fat foods, and dairy products aggravate HS.

Nevertheless, the associations between HS and veganism are yet unexplored. The contribution of diet to AD is less clear; however, the gut microbiome and dietary exposure are reportedly implicated in AD pathogenesis.

Diets rich in vegetables and fruits have elevated amounts of flavonoids, which are anti-inflammatory and antioxidant and can be beneficial against AD.

Targeting the gut microbiome helps regulate immune responses and improve AD lesions, given that skin and gut communicate. As such, plant-based diets can effectively promote gut microbial diversity and support overall skin and gut health.

Concluding remarks

The data on the relationship between skin disease(s) and vegan diets are limited. Evidence suggests that well-balanced vegan diets can easily provide the recommended daily amounts of protein and vitamins and thus can be beneficial against inflammatory skin diseases and associated comorbidities.

Overall, more large-scale studies are required to understand the implications of vegan diets on skin disorders.

Journal reference:

• Lee, H. et al. (2023) "Vegan Diet in Dermatology: A Review", Journal of Clinical Medicine, 12(18), p. 5800. doi: 10.3390/jcm12185800. https://www.mdpi.com/2077-0383/12/18/5800