膳食纖維，又名粗纖維，是植物性食物中不能被消化的部分。膳食纖維素驅動我們的消化系統，沿著腸道吸收水份，幫助排便。它會隨糞便排出體外，對我們而言，幾乎是零卡路里，卻只會增加糞便體積。

每天進食超過50克膳食纖維可能妨礙身體吸收礦物質，導致貧血及骨質疏鬆症。

纖維種類：

1. 水溶性纖維 – 是果膠、樹膠及半纖維素的組成部分，能在水果、豆類、燕麥糠及蔬菜中找到。進食含豐富水溶性纖維的食物可預防肥胖、中風、糖尿病、癌症及腸胃失調。
2. 非水溶性纖維 – 不溶於水，不會隨著消化過程改變形態。我們可在蘋果、葡萄、小麥糠及全穀類食物中找到纖維素、半纖維素及木質素，此類非水溶性纖維有助腸道蠕動，增加糞便體積及防止便秘。

每人每日應攝取3-5份蔬菜、2-4份水果及6-11份穀物，這些食物含有豐富纖維、礦物質、維生素及植物化合物。

如何「善」食纖維？

1. 早餐可選擇燕麥片或全麥穀物，伴以少量新鮮水果
2. 蔬果可連皮食用，以攝取更多纖維
3. 如嘴饞時，可選擇以爆米花作為健康零食
4. 可用糙米代替白米
5. 可用全麥意粉代替白意粉，並加入蔬菜

膳食纖維有幾「善」？

1. 膳食纖維屬低卡路里，亦容易增加飽腹感，高纖飲食可助癡肥病人控制體重
2. 攝取纖維可令糖尿病患者延遲胃部排空的時間，對控制血糖能力較弱的人，可有效於降低血脂和血胰島素水平
3. 水溶性纖維可有效降低血液裡膽固醇和低密度脂蛋白膽固醇(LDL)的含量
4. 纖維有助於排走大腸廢物

作者: Geetanjali 營養師

翻譯: Jason Lui

Fiber is the indigestible part of plant foods that pushes through our digestive system, absorbing water along the way and easing bowel movements. It is also known as roughage. Fiber is eliminated from the body in the intestinal waste. Sometimes called roughage or bulk, fiber adds almost no fuel or energy value to the diet, but it does add volume.

Eating more than 50gms of fiber a day can interfere with mineral absorption, leading to problems such as Anemia & Osteoporosis.

TYPES OF FIBER:

1. SOLUBLE FIBER- are the gel forming pectin, gums and some hemicellulose found in fruits, beans, oat bran and vegetables like peas etc. A diet rich in soluble fiber helps in controlling obesity, stroke, diabetes, cancer & gastrointestinal disorders.
2. INSOLUBLE FIBER- does not dissolve in water. As it goes through the digestive tract it does not change its form. Cellulose, Hemicellulose and Lignin are the examples. It can be found in the peel of Apples & grapes, wheat bran & whole grains. It gives stool its bulk and thus, prevent Constipation.

3-5 vegetable servings, 2-4 fruit servings & 6-11 grain servings daily recommended because these are excellent sources of fiber also provide minerals, vitamins & phytochemicals.

Smart Choice of Dietary Fiber:

1. Have oatmeal or whole-grain cereal for breakfast; top with some fresh fruit.
2. Eat fruits and veggies raw and with skins for more fiber.
3. Munch on popcorn when you need a snack.
4. Switch to brown rice from white rice.
5. Replace white pasta with whole-wheat pasta and add vegetables in it.

Benefits of Fiber in the Diet:-

1. High fiber diet decreases weight in obese patients because it is low in calories or due to increased satiety.
2. Fiber ingestion by diabetic patients leads to some delay in gastric emptying, improvement in glucose intolerance and reduction of hyperinsulinemia and hyperlipidemia.
3. Soluble fiber decreases serum Cholesterol & LDL cholesterol levels (Low Density Lipoproteins).
4. Speeds up the elimination of toxic waste through the colon.

Author: Geetanjali

M.Sc. Foods & Nutrition

Dietitian & Nutritionist