Switching to organic is tough for many families who don’t want to pay higher prices or give up their favorite foods. But by choosing organic versions of just a few foods that you eat often, you can increase the percentage of organic food in your diet without big changes to your shopping cart or your spending.

The key is to be strategic in your organic purchases. Opting for organic produce, for instance, doesn’t necessarily have a big impact, depending on what you eat. According to the Environmental Working Group, commercially-farmed fruits and vegetables vary in their levels of pesticide residue. Some vegetables, like broccoli, asparagus and onions, as well as foods with peels, such as avocados, bananas and oranges, have relatively low levels compared to other fruits and vegetables.

So how do you make your organic choices count? Pediatrician Dr. Alan Greene, whose new book “Raising Baby Green” explains how to raise a child in an environmentally-friendly way, has identified a few “strategic” organic foods that he says can make the biggest impact on the family diet.

1. Milk: “When you choose a glass of conventional milk, you are buying into a whole chemical system of agriculture,'’ says Dr. Greene. People who switch to organic milk typically do so because they are concerned about the antibiotics, artificial hormones and pesticides used in the commercial dairy industry. One recent United States Department of Agriculture survey found certain pesticides in about 30 percent of conventional milk samples and low levels in only one organic sample. The level is relatively low compared to some other foods, but many kids consume milk in large quantities.

2. Potatoes: Potatoes are a staple of the American diet — one survey found they account for 30 percent of our overall vegetable consumption. A simple switch to organic potatoes has the potential to have a big impact because commercially-farmed potatoes are some of the most pesticide-contaminated vegetables. A 2006 U.S.D.A. test found 81 percent of potatoes tested still contained pesticides after being washed and peeled, and the potato has one of the the highest pesticide contents of 43 fruits and vegetables tested, according to the Environmental Working Group.

Go organic with kid favorites like peanut butter. (Lars Klove/The New York Times)

3. Peanut butter: More acres are devoted to growing peanuts than any other fruits, vegetable or nut, according to the U.S.D.A. More than 99 percent of peanut farms use conventional farming practices, including the use of fungicide to treat mold, a common problem in peanut crops. Given that some kids eat peanut butter almost every day, this seems like a simple and practical switch. Commercial food firms now offer organic brands in the regular grocery store, but my daughter loves to go to the health food store and grind her own peanut butter.

4. Ketchup: For some families, ketchup accounts for a large part of the household vegetable intake. About 75 percent of tomato consumption is in the form of processed tomatoes, including juice, tomato paste and ketchup. Notably, recent research has shown organic ketchup has about double the antioxidants of conventional ketchup.

Organic apples are readily available. (The New York Times)

5. Apples: Apples are the second most commonly eaten fresh fruit, after bananas, and they are also used in the second most popular juice, after oranges, according to Dr. Greene. But apples are also one of the most pesticide-contaminated fruits and vegetables. The good news is that organic apples are easy to find in regular grocery stores.

For a complete list of Dr. Greene’s strategic organic choices, visit Organic Rx on his website.

转换为有机对许多家庭来说很难，因为不愿意付出更高价格或放弃他们自己喜欢的食物。但通过选择你经常吃的仅仅一些食物的有机形式，你可增加日常饮食中的有机食物的百分比例，而不会对购物篮或消费支出产生很大变化。

关键是对有机采购要有策略。例如，选择有机农产品，并不必然有很大影响，而取决于你吃什么。根据《环境工作组》的研究，作为经济作物的水果和蔬菜其杀虫剂残留水平各不相同。有些蔬菜，如花椰菜、芦笋和大蒜，以及带皮的食物，如梨、香蕉和橘子，与其它水果蔬菜相比，其残留水平相对较低。

因此，怎么样才能使你的有机选择有效呢？儿科医师Alan Greene博士，在其新书《绿色喂养小孩》中解释了怎样按环境友好方式来喂养小孩，他鉴定了一些战略性的有机食物，他认为可以对家庭日常饮食构成最大的影响。

1.牛奶

“当你选择一杯传统牛奶时，你正在买进完全的化学农业体系，” Greene说。转向有机牛奶的人们往往会这样做，因为他们关心商业乳品加工业中使用的抗生素，人工合成激素和杀虫剂。美国农业部的最新调查发现，在大约30％的常规牛奶样品中都有一定量的杀虫剂，而只有一个有机样品中含量较低。与其它食品相比牛奶中的杀虫剂水平相对较低，但许多孩子牛奶消费量很大。

2.土豆

土豆是美国人饮食中的常见食品，一项调查发现土豆占我们总蔬菜消费量的30％。仅仅转向有机土豆就可能有极大的影响，因为经济种植的土豆是一种杀虫剂含量最高的蔬菜，2006年美国农业部U.S.D.A.检测发现，检测的土豆中81％在经洗涤和削皮后仍含有杀虫剂，在43种检测的果蔬中，土豆是杀虫剂含量最高的，环境工作组称。

3.花生酱

根据美国农业部的统计，花生种植面积比其它水果、蔬菜和坚果种植面积都要大。99％以上的花生种植农场使用常规种植方法，包括使用杀菌剂治疗霉变，这在花生作物中是一种常见问题。假定有些小孩几乎每天都吃花生酱，这似乎是一个简单可行的转变。经济食物公司现在在一些日用品店出售有机品牌，但我女儿一溜烟是喜欢到健康食品店去磨制她的花生酱。

4. 蕃茄酱

对一些家庭来说，蕃茄酱占了家庭蔬菜摄取量的大部分。大约75％的蕃茄消费是加工形式的，包括蕃茄汁，蕃茄酱或调味番茄酱等。值得注意的是，最近研究已表明，有机蕃茄酱的抗氧化剂含量是常规调味蕃茄酱的两倍。

5.苹果

苹果是第二最常食用的鲜果，仅次于香蕉，同时还是第二最常用的果汁，仅次于橙，Greene博士说。但苹果也是农药污染最严重的果蔬之一。好消息是日常食品杂货店就可以方便买到有机苹果。