Experts say the right diet may be the key to treating skin disorders.

Up to 90 per cent of Australians - or 18 million people - will suffer from skin ailments at some time in their lives, including acne, eczema, skin cancer and psoriasis , according to figures from the Australasian College of Dermatologists. Almost one-quarter of children have eczema, compared with about 10 per cent a decade ago and about 85 per cent will have acne. Although most acne clears after adolescence, up to 20 per cent of adults may continue to be affected.

It is no surprise, then, that the medicated skin care market is experiencing unprecedented growth, but some practitioners believe what we put inside our bodies is more important than smearing our skin with expensive treatments. Nutritionist and author Patrick Holford says: "Your skin is affected by how well you are internally and is therefore a remarkable barometer of your overall health. Getting your body's systems working optimally is crucial to addressing skin problems. Diet is key - eating foods that nourish your body while limiting those that contribute no nutritional value is important."

Many skin conditions are thought to be a reflection of hormone imbalances and the inability to absorb nutrients and eliminate the byproducts of digestion. Helen Sher, founder of the natural skin care company Sher, says: "The majority of our clients have been on courses of antibiotics to banish spots and rosacea, but this is not a long-term solution." She points out that antibiotics kill good bacteria as well as bad, which can damage the digestive and immune systems.

In the case of rosacea (an inflammatory condition that affects 45 million people worldwide, in which the face becomes flushed and itchy), there is evidence that many sufferers produce insufficient stomach acid and the resultant incomplete digestion of food is the main factor.

If skin disorders are the body's way of expressing its imbalances, then treating a skin problem using topical creams and gels is the equivalent of applying a hot flannel to the tip of an iceberg. Robin Logan, author of The Homoeopathic Treatment Of Eczema, explains why it is important to view the body as a whole: "Suppressing eruptions [topically] can lead to the development of more serious internal complaints. This is typically seen in the eczema/asthma syndrome."

According to Michael Franklin, founder of Britain's Allergy and Nutrition Centre, food allergies play a considerable part in many skin complaints. "Psoriasis is usually extremely difficult to treat, yet if more patients and practitioners knew of the links with bowel toxicity, there would be fewer problems. Liver detoxification is an important part of treatment. With rosacea, a lack of B vitamins may play a role."

Not everyone subscribes to the idea of treating your biggest organ from the inside out. Nina Goad, of the British Association of Dermatologists, says: "In general, diet has little influence on skin, though there are a few exceptions. Alcohol and spicy foods seem to make rosacea worse.

"As for acne, there is some evidence that foods with a high glycaemic index [which measures the effects of carbohydrates on blood glucose levels] may worsen the condition in some people."

What to avoid

Dr Jonathan Wilkin, of Britain's National Rosacea Society, says foods that might trigger flare-ups include liver, yoghurt, cheese (except cottage cheese), chocolate, vanilla, vinegar, spicy foods, coffee or tea.

The most documented reactive foods for eczema sufferers are milk, eggs, peanuts, soybeans, wheat, seafood and seeded fruits. Nutritionist Patrick Holford suggests that with skin complaints you should limit your intake of sugary foods, refined carbohydrates (such as white bread) and anything fried.

What to eat

The skin is the last place nutrients will arrive after they have serviced the rest of your body so it is vital to get enough of the things we know help the skin to heal and regenerate.

Proper hydration is vital to a healthy system. Helen Sher recommends drinking six or seven glasses of water daily. Vitamins C and E are important for skin health - mainly as antioxidants - so include organic fruits and vegetables in your diet, especially black grapes and blueberries. Apricots, oranges, peppers, carrots, strawberries and broccoli are rich in the carotenoid pigments, which your body converts to vitamin A.

Nutritionist and author Michael van Straten says: "Carrot juice is bursting with beta carotene; one glass a day, fresh if possible, works wonders for the skin and is a powerful antioxidant."

The naturopathic nutritionist Charlotte Fraser suggests increasing your intake of essential fatty acids to help treat dry skin conditions and acne. Eczema and psoriasis sufferers will benefit from the anti-inflammatory effect of omega 3 found in oily fish.

Evening primrose oil is a source of gamma linoleic acid, which promotes healthy skin, hair and nails.

The most important B vitamin for the skin is biotin, which is found in bananas, eggs and rice. Zinc deficiency can be a factor in psoriasis and acne. Good sources of zinc are sesame, sunflower and pumpkin seeds.

有專家認為，合理的飲食是治療皮膚問題的關鍵。

澳大利亞皮膚病專科學院的調查數字顯示，近90%的澳洲人（-約180萬人）-一生中都曾為各種各樣的肌膚問題所困擾，比如說痤瘡、濕疹、皮膚癌和牛皮癬。大約四分之一的兒童患濕疹，與十年前10%的比例相比，痤瘡患者的比例達85%。盡管大多數痤瘡癥狀在青春期之后就會慢慢消失，但是近20%的成年人仍然被其困擾。

因此，藥物護理產品的走俏也就不足為奇了。但是一些醫師認為，內部的調理比用高檔化妝品涂抹更重要。營養學家作者帕特里克·霍夫德說：“你體內的環境決定你的皮膚狀況，你的皮膚就像你健康情況的晴雨表。調整你的內循環是解決肌膚問題的關鍵。飲食至關重要-要注意多吃有營養的食物，控制垃圾食品的攝入量。”

很多的皮膚問題都被認為是荷爾蒙失調、吸收不好及代謝問題導致的。自然肌膚護理公司的創始人海倫·謝爾說：“我們大多數的客戶都曾使用過抗生素怯斑除痘，但是這并不能解決根本的問題。”她指出，抗生素在殺死細菌的同時也會殺死有益菌，會影響人體的消化系統和免疫系統。

以紅斑痤瘡（一種影響全球4500萬人的肌膚炎癥，患者皮膚會發紅發癢）為例，經證實，大多數紅斑痤瘡患者的主要病因都是胃酸不足和消化不良。

如果肌膚是體內系統失調的表現，靠使用眼下流行的各種面霜和凝膠來解決肌膚問題無異于雪上加霜（加熱的法蘭絨放到冰山角上）。《濕疹順勢療法》一書的作者羅賓·羅格闡釋了全面關注身體的重要性：“抑制出疹（當前流行的辦法）只會使其內部更加惡化，濕疹/哮喘綜合癥的表現更明顯。

根據英國過敏和營養衷心的創始人米歇爾·富蘭克林認為，食物過敏與所多肌膚疾病也密不可分，“牛皮癬難治愈，但是如果患者和醫師了解牛皮癬和患者腸內毒素的關系的話，問題就簡單得多了，治療牛皮癬有效的方法是驅除肝臟內的毒素。對于紅斑痤瘡患者來說，可能是因為缺乏B族維生素。”

并不是每個人都認為皮膚病是由內因導致的。英國皮膚病協會的妮娜·戈爾德認為：“一般說來，飲食對皮膚的影響并不大，盡管也有些特例。酒精和刺激性食物也會使紅斑病情加重。”

“至于痤瘡，有證據顯示含高血糖指數（衡量血液葡萄糖中碳水化合物作用情況的指數）可能會使某些患者的病情加重。”

飲食禁忌

英國國家紅斑痤瘡協會的約翰遜·威爾金博士認為，肝臟、酸奶、奶酪（松軟干酪除外）、巧克力、香草、辛辣刺激食物、咖啡或茶都可能引發皮膚問題。

濕疹患者應注意不要食用牛奶、雞蛋、花生、大豆、小麥、海鮮和有籽果 ，營養學家帕特里克·霍夫德建議皮膚病患者注意不要攝入太多含糖的食物，精煉碳水化合物（如白面包）以及煎炸食品。

飲食貼士

肌膚是營養輸送的最后一站，營養在到達全身其他部位后才輪到肌膚。因此，補充足量的物質以促進肌膚的恢復和再生就顯得至關重要。

健康系統需良好的水和作用。海倫·謝爾女士建議每天飲用6-7杯水。維生素C和維生素E對皮膚極其關鍵—主要是它們的抗氧化功能-黑葡萄和藍莓富含這兩種維他命元素。杏、桔子、青椒、蘿卜、草莓和甘藍都含有大量的類胡蘿卜素色素，這種色素可在你體內轉化為維生素A。”

營養學作家邁克爾·萬·斯達特說：“胡蘿卜汁富含β 胡蘿卜素。一天喝一杯，新鮮的效果更好，這會對皮膚有著神奇的效果，因為它是絕佳的抗氧化劑。”

自然療法營養學家夏洛特·弗蘭茲建議，攝入足量的脂肪酸可有效解決皮膚干燥和痤瘡等問題。魚油中的omega 3（歐米茄）元素所具有的消炎作用對濕疹和牛皮癬有顯著療效。

月見草油富含gamma(伽馬)亞油酸，它可以改善你的肌膚、發質和指甲。

皮膚最重要的B族維生素是生物素，香蕉、雞蛋和大米中都富含這種生物素。缺鋅也是導致牛皮癬和痤瘡的一個因素。芝麻、葵花子和南瓜子都含有豐富的鋅。