The state of your skin can reflect your overall health, according to accredited dietician Geraldine Georgeou.
We often dismiss breakouts and rashes as insignificant, but, she says, changes in the skin can often be the first sign of an underlying health issue.
"Just as the eyes are said to be the window to the soul," she says in her new book, The Australian Healthy Skin Diet. "I consider your skin to be the window to your health."
She likens the skin, the body's largest organ, to the layers of a cake. Each of the three main layers – the epidermis, the dermis and subcutaneous fat – has its own form and role to play. "It's our barrier to the outside world," she tells SBS Food.
Georgeou's interest in the relationship between skin and nutrition sprang from years spent struggling with polycystic ovarian syndrome (PCOS), a hormonal issue that can impact skin and hair health.
In The Australian Healthy Skin Diet, Georgeou provides meal plans and recipes to support skin health, with individual sections devoted to specific conditions including psoriasis, dermatitis herpetiformis, eczema, and rosacea.
Her book is not a diagnostic tool, she stresses, but a guide for readers who want to understand possible connections between their skin and their diet.
The relationship between your skin and what you eat
Macronutrients like protein and healthy fats play an integral role in skin health, as do Vitamins A, C, B7, D and E, and minerals such as calcium, iron and selenium.
Carbohydrates often get a bad rap in wellness circles, but Georgeou advises against cutting out this important macronutrient that is essential for energy. Not all carbohydrates are equal, she notes. If you want to cut out carbs, it should be the refined variety that scores high on the glycaemic index, a sliding scale that reflects the absorption of glucose in the bloodstream.
Low-GI foods release glucose into the bloodstream slowly, providing more sustained energy. High-GI carbohydrates break down quickly after digestion, which results in spikes in insulin in the blood that can contribute to hormone imbalances and inflammation associated with skin conditions such as psoriasis.
"It's our barrier to the outside world."
High sugar intake also disrupts the microbiome, the vast colonies of bacteria that populate our digestive tract. A destabilised microbiome can lead to 'dysbiosis', a state of imbalance that causes inflammation associated with a raft of skin conditions. "By managing our diet so that it feeds the right balance of good and bad bacteria in the gut, we are enabling a cascade of signals that supports healthy skin," Georgeou writes.
Probiotics – live bacteria consumed in food or taken as a supplement – can improve gut health. "Different strains of probiotic can be used to target different skin conditions," writes Georgeou. "L. acidophilus and bulgaricus are recommended for acne; rhamnosus for UV damage; reuteri, delbrueckii and salivarius for atopic dermatitis."
Also contributing to a healthy microbiome are prebiotics, a type of non-digestible fibre found in starchy vegetables, fruit, legumes and whole grains. Prebiotic fibre ferments in the gut, producing a short-chain fatty acid called butyrate that reduces intestinal permeability and inflammation.
Should you go gluten-free?
When it comes to skin health, it's also important to take into account food allergies and intolerances, which are on the rise in Australia. Georgeou notes that in Australia there has been a 41 per cent rise in anaphylaxis reported between 2009 and 2014. While it's important to be aware of allergies, Georgeou advises against adopting a restrictive diet that eliminates certain foods without first seeking medical advice. Coeliac disease and non-coeliac gluten sensitivity are associated with skin conditions such as itching, hives, eczema ad psoriasis, but gluten must be present in the body for a diagnosis to be made.
Other triggers for skin conditions include chemicals that naturally occur in food, such as salicylates, amines (a by-product of fermentation found in chocolate, cheese, wine, beer and fish) and glutamate, which is often added to food to enhance natural flavours.
When it comes to diet, Georgeou's key message is balance. "It's not about no carbs, it's not about fasting, it's not about Keto diets; it's about understanding how to look after our whole health," she says.
"We want to consume a good variety of fibres, so prebiotics, whole grains, low-GI carbohydrates, plant-based proteins, legumes and nuts; we want to make sure we've got lean protein, and we've got good fats – think olive oil."
In addition, some people might need extra immune support, such as specific probiotics. "With any skin condition, you need to be working with your medical team…Make sure you're using the creams you've been given," she says. "It's got to be a multidisciplinary approach to manage your skin condition."
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