【營養師Q&A】吃生冷才真正有益？
Q：營養學不是說蔬果要吃生才為之健康嗎？
（T：註冊營養師 @tsheknutrition Tiffany Shek，C：註冊中醫師Cinci EC）
T：不一定，例如番茄生食時雖含有更多的維生素C，但在烹飪過程中其茄紅素（一種天然抗氧化成分）含量會增加，而維生素C卻會流失。水煮蔬菜會使水溶性的營養素浸入水中，如維他命B及C，因此除了生食，如果我們想充分攝取蔬菜的營養素，煮蔬菜後可將菜湯喝掉，又或時選擇蒸製，也是一個保存營養的好方法。此外，有研究指出菠菜和紅蘿蔔經烹調後能提高其胡蘿蔔素的生物利用度，更能轉化為維他命A，所以蔬菜不一定要生食才為之健康。各種顏色蔬果的營養價值不同，我們應該依照彩虹飲食原則，進食紅、橙、黃、綠、青、藍、紫色的蔬果，吸收不同營養素作健康養生之用途。
C：我們先要了解在中醫角度甚麼叫「生冷」，「生」是指未煮過的食物，如沙律、刺身、壽司等；已成熟的水果放置室溫的話，也可適量食用，但就不建議經常飲用果汁。「冷」是指低於室溫的食物，剛從雪櫃取出的食物亦是。中醫理論認為「脾失健運，濕由內生」，生冷食物易傷脾胃，則濕濁內生，影響脾胃吸收營養及運化水份的功能，造成痰濕體質，出現易腹瀉、水腫、面色萎黃、肌肉鬆弛、經常感覺疲憊等的脾胃虛弱症狀。而且過量進食生冷食物及凍飲會損害身體的陽氣，影響氣血循環，令身體呈氣滯及血瘀體質，女性易有痛經及手腳冰冷等問題，因此中醫經常會叫大家少吃生冷。
Is food healthier when it is cold and raw?
(T: Tiffany Shek, Registered Dietitian, C: Cinci EC, Registered Chinese Medicine Practitioner)
T: Not necessarily. For example, raw tomatoes contain more vitamin C, but the cooking process increases the content of lycopene (an antioxidant), while the vitamin C is decreased. Boiling vegetables leaches out water-soluble nutrients, such as vitamins B and C, into the water. Therefore, besides eating them raw, we can consume the soup used to boil our vegetables to obtain the water-soluble vitamins. We can also preserve the nutrients by steaming vegetables. Some studies have also shown that cooking spinach and carrots increases the bioavailability of carotene, which is converted into vitamin A in our bodies. Therefore, not all vegetables are healthier eaten raw. Different coloured vegetables have different nutritional values thus we can eat according to the principle of rainbow diet, by having red, orange, yellow, green, blue,
and purple fruits and vegetables, to absorb different nutrients for better health!
C: We must first understand that what is “cold/raw” from Chinese medicine perspective. “Raw” refers to uncooked food like salad, sashimi or sushi, etc. You can consume ripened fruit at room temperature in moderation but it is not recommended to drink juice too often. “Cold” refers to food which is below room temperature including food that has just been taken out of the fridge. Chinese medicine believes that cold/raw food harms the spleen and stomach, which causes dampness in the body. The absorption and fluid transportation function of the spleen would be affected and cause phlegm body condition. This can lead to asthenic spleen and stomach symptoms such as diarrhea, edema, yellowish complexion, loose muscles and fatigue. Moreover, excessive consumption of cold/raw food and drinks can damage the body's yang qi which affects the blood and qi circulation and lead to qi stagnation and blood stasis body constitutions. Women are prone to menstrual pain and cold limbs, so Chinese medicine often suggests for everyone to eat less cold/raw food.
