A well-planned vegetarian diet is a healthy way to meet your nutritional needs.
Find out what you need to know about a plant-based diet.
By Mayo Clinic staff
from:http://www.mayoclinic.com/print/vegetarian-diet/HQ01596/METHOD=print
http://en.wikipedia.org/wiki/Mayo_Clinic
You may follow a vegetarian diet for cultural, religious or ethical reasons. Or you may eat a vegetarian diet to stay healthy and prevent health problems, such as cardiovascular disease. Whatever your reasons for choosing a vegetarian diet, this guide will help you make smart choices to ensure that you meet your daily nutritional needs.
Indeed, a well-planned vegetarian diet can meet the needs of people of all ages, including children, teenagers, and pregnant or breast-feeding women. The key is to be aware of your nutritional needs so that you plan a diet that meets them. If you aren't sure how to create a vegetarian diet that's right for you, talk with your doctor and a registered dietitian.
Types of vegetarian diets
When people think about a vegetarian diet, they typically think about a diet that doesn't include meat, poultry or fish. But vegetarian diets can be further categorized into three types:
Vegan diets exclude meat, poultry, fish, eggs and dairy products — and foods that contain these products.
Lacto-vegetarian diets exclude meat, fish, poultry and eggs, as well as foods that contain them. Dairy products, such as milk, cheese, yogurt and butter, are allowed in a lacto-vegetarian diet.
Lacto-ovo vegetarian diets exclude meat, fish and poultry, but allow eggs and dairy products.
Some people follow a semivegetarian diet — also called a flexitarian diet — which is primarily a plant-based diet but includes meat, dairy, eggs, poultry and fish on occasion or in small quantities.
Vegetarian diet pyramid
A healthy diet takes planning, and a food pyramid can be a helpful tool. The vegetarian pyramid outlines food groups and food choices that, if eaten in the right quantities, form the foundation of a healthy vegetarian diet.
Vegetarian Food Guide Pyramid
Getting adequate nutrition
The key to a healthy vegetarian diet — like any diet — is to enjoy a variety of foods. No single food can provide all the nutrients your body needs. The more restrictive a diet is, the more challenging it is to get all the nutrients you need. A vegan diet, for example, eliminates food sources of vitamin B-12, as well as milk products, which are good sources of calcium. Therefore, you may need to make an extra effort to ensure that your vegetarian diet includes sufficient quantities of the following nutrients:
Calcium helps build and maintain strong teeth and bones. Milk and low-fat dairy foods are highest in calcium. Dark green vegetables, such as turnip and collard greens, kale and broccoli, are good plant sources when eaten in sufficient quantities. Calcium-enriched and fortified products, including juices, cereals, soy milk, soy yogurt and tofu, are other options.
Iodine is a component in thyroid hormones, which help regulate metabolism, growth and function of many key organs, such as the brain, heart, kidney and thyroid. Vegans may not consume enough iodine and be at risk of iodine deficiency and possibly goiter. In addition, foods such as soybeans, cruciferous vegetables and sweet potatoes may promote goiter. Because food manufacturers may not use iodized salt in processed foods, vegans may want to ensure that they use salt with iodine at the table or in cooking. Just 1/4 teaspoon provides a significant amount of iodine.
Iron is a crucial component of red blood cells. Dried beans and peas, lentils, enriched cereals, whole-grain products, dark leafy green vegetables and dried fruit are good sources of iron. Because iron isn't as easily absorbed from plant sources, the recommended intake of iron for vegetarians is almost double that recommended for nonvegetarians. To help your body absorb iron, eat foods rich in vitamin C, such as strawberries, citrus fruits, tomatoes, cabbage and broccoli, at the same time as you're eating iron-containing foods.
Omega-3 fatty acids are important for cardiovascular health as well as eye and brain development. Vegetarian diets that do not include fish and eggs are generally low in active forms of omega-3 fats. Because conversion of the plant-based omega-3 to the types used by humans is inefficient, you may want to consider fortified products or supplements or both.
Protein helps maintain healthy skin, bones, muscles and organs. Eggs and dairy products are good sources, and you don't need to eat large amounts to meet your protein needs. You can also get sufficient protein from plant-based foods if you eat a variety of them throughout the day. Plant sources include soy products and meat substitutes, legumes, lentils, nuts, seeds and whole grains.
Vitamin B-12 is necessary to produce red blood cells and prevent anemia. This vitamin is found almost exclusively in animal products, so it can be difficult to get enough B-12 on a vegan diet. Vitamin B-12 deficiency may go undetected in people who eat a vegan diet. This is because the vegan diet is rich in a vitamin called folate, which may mask deficiency in vitamin B-12 until severe problems occur. For this reason, it's important for vegans to consider vitamin supplements, vitamin-enriched cereals and fortified soy products.
Vitamin D plays an important role in bone health. Vitamin D is added to cow's milk, some brands of soy and rice milk (be sure to check the label), and some cereals and margarines. However, if you don't eat enough fortified foods and have limited sun exposure, you may need supplementation with vitamin D-2 (derived from plants).
Getting started
If you're not following a vegetarian diet but you're thinking of trying it, here are some ideas to help you get started:
Ramp up. Each week increase the number of meatless meals you already enjoy, such as spaghetti with tomato sauce or vegetable stir-fry.
Learn to substitute. Take favorite recipes and try them without meat. For example, make vegetarian chili by leaving out the ground beef and adding an extra can of black beans. Or make fajitas using extra-firm tofu rather than chicken. You may be surprised to find that many dishes require only simple substitutions.
Branch out. Scan the Internet for vegetarian menus. Buy or borrow vegetarian cookbooks. Check out ethnic restaurants to sample new vegetarian cuisines. The more variety you bring to your vegetarian diet, the more likely you'll be to meet all your nutritional needs.
中文译文:
（注：把译文放在下面是因为译文的内容比英文的多了些+少了些。估计是Mayo Clinic 更新过(updated)。请以英文版为准。）
Mayo Clinic团队（Mayo Clinic是美国的一所著名的大学医院）
千叶荷译
http://article.yeeyan.org/view/119243/76415
按：良好计划的素食是能够满足身体营养需求的健康饮食方式。让我们一起来看看关于素食有哪些是你不知道的吧。
保持健康的素食饮食并不是仅仅把肉类从你的餐桌上移开那么简单。你需要采取额外的步骤去满足日常的营养需求。
素食的饮食计划
健康的素食饮食主要由植物类食物构成，如水果，蔬菜，所有的谷物，豆类，坚果和种子。因为素食者获取能量的主要来源是非肉类食物，所以总的来说其饮食构成主要以纤维为主，（与非素食者的饮食相比）包含更少的脂肪和胆固醇。
根据素食者对源自动物的食物的态度，他们可划分成如下几类：
* 严格的素食主义者：他们完全植物类食物。任何源自动物的食物都不会出现在他们的餐桌上，如肉，家禽，鱼，奶，鸡蛋及奶酪。
* 乳类素食主义者：除了植物类食物外他们也食用牛奶及牛奶制品，但不吃鸡蛋、肉类、鱼和家禽。
* 乳蛋类素食主义者：鸡蛋、牛奶以及奶制品如奶酪和酸奶都是可吃的，当然植物类食物也是必不可少。但是他们不吃红色的肉，鱼以及家禽。
*灵活的素食主义者(半素食主义者)：饮食主要以植物类为主，但偶尔也少量吃些肉类、家禽和鱼。
如果你想让素食生活有规律地进行，素食食物金字塔肯定会帮你大忙（金字塔大图请见：http://www.mayoclinic.com/health/medical/IM02769）。
Many vegetarian eating plans exist. At the very least, they exclude red meat, chicken and fish. Some vegetarian diets also exclude eggs and milk products. This Vegetarian Diet Pyramid shows a lacto-ovo vegetarian diet. It features whole grains, legumes, fruits and vegetables and includes moderate amounts of nuts and seeds, soy, egg whites, dairy products and plant oils.
这个金字塔把构成健康素食生活所需要的各种食物进行了分类，当然，即使如此，你也要控制自己的食量。
无论你处于何种年龄阶段或情况，一个良好的素食计划能够满足你的营养需求。无论是儿童还是青少年，老人还是孕妇，甚至处于哺乳期的女性都可以从素食饮食中获益。如果你仍然怀疑自己是否适合素食，请向你的医生或者注册营养师咨询。
·肉类替代品（对照英文版，这一段多了。）
非肉制品将让你的素食饮食更加多样化，如豆腐热狗、大豆汉堡、坚果面包以及来自脉络植物的蛋白质。这些在百货店和健康食品超市随处可见的加工食品有着和肉类相似的口味和肌理，却含有更少的脂肪和更低的卡路里。很多非肉类制品由大豆加工而成，如豆腐和豆豉。
如果要成为一个严格的素食主义者，从健康的角度考虑你需要找到鸡蛋和乳制品的替代品。因此在制定食物清单或者烹饪时你不妨尝试以下替代品建议：
*牛奶：可用强化豆奶，谷物奶或者杏仁奶替代牛奶。
*黄油：炒菜时，使用橄榄油，水，蔬菜汤汁，酒或无脂的炒菜专用喷雾来代替黄油。
*鸡蛋：在制作烘焙类食物时，不妨尝试广告中介绍的鸡蛋替代品吧，即那种由马铃薯淀粉制作而成的干干的玩意儿。或者你也可采用以下的方法：用1/4杯糊状的豆腐或者用1汤匙磨碎的亚麻子混合3汤匙的水来替代鸡蛋。当制作无蛋鸡蛋卷时建议用豆腐代替鸡蛋。
·保证足够的营养
素食越是严格，就越难保证身体需要的营养。比如严格的素食饮食就完全排除了含有维生素B-12的食物和富含钙的奶制品。虽然其他营养物质的摄取（如铁和锌）素食是可以满足的，但是你需要做额外的努力来保证自己获取足够的营养。
以下列出了在素食饮食中可能摄取不足的营养物质，并给出了弥补方法：
（对照英文版，下面内容少了：碘(Iodine)和维他命D(Vitamin D)）
* 蛋白质：你的身体需要蛋白质来维持健康。食用鸡蛋和奶制品的素食者可以从中获取足够的蛋白质。蛋白质也可从豆制品，肉类替代品，豆荚，扁豆，坚果，植物种子和谷物中获得。
* 钙：这种矿物质是牙齿和骨骼健康的重要保证。低脂奶制品和深绿色蔬菜中富含钙质，如菠菜，大头菜，羽衣甘蓝，无头甘蓝，花椰菜等。另外你也可选择食用豆腐，强化豆奶或者果汁。
* 维生素B-12：维生素B-12对制造血红细胞以及预防贫血症至关重要。这种维生素在几乎只存在于动物制品中，如牛奶、鸡蛋和奶酪。严格的素食主义者可从精加工的谷物，强化豆制品或含有维生素B-12的营养补品中获得。
* 铁：与维生素B-12一样，铁是血红细胞的重要组成元素。晾干的大豆和豌豆，扁豆，精加工的谷物，所有谷物制品，深绿色叶类蔬菜以及果干都富含铁。另可以食用富含维生素C的食物以满足身体对源自非动物的铁的需要，如草莓，橘类水果，西红柿，卷心菜以及花椰菜等。同时你也可食用含铁的营养品。
* 锌：这种矿物质存在于身体的多种酶之中，并且在细胞分裂和蛋白质制造过程中扮演重要角色。而所有的谷物，豆制品，坚果和麦芽都富含锌。
维持健康的素食以及任何饮食的关键是学会享受多种多样的食物。没有任何一种食物可以提供身体所需的所有营养，所以饮食的丰富性可以保证你获得必需的营养，并且保持健康的体魄。
·现在就开始吧！
如果你正在考虑转变成一位素食主义者却不知从何入手，那就从饮食目录开始吧！
* 从你知道的开始：列出一个由你已经在食用或者现成的非肉类食品的菜单。
* 把肉类都替换掉：选择那些把其中的一样或几样替换掉后就可以轻松变成素食的菜。例如，你可以制作素食辣椒，并额外加进一个豆腐干。从中你肯定会惊喜地发现一些菜品仅仅是做些简单的替换工作就可完成。
* 尝试新的菜品：可到餐馆品尝新的素食烹饪。总之，越多样化的素食饮食，就越能满足你身体的营养需要。
