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.

轉換為有機對許多家庭來說很難，因為不愿意付出更高價格或放棄他們自己喜歡的食物。但通過選擇你經常吃的僅僅一些食物的有機形式，你可增加日常飲食中的有機食物的百分比例，而不會對購物籃或消費支出產生很大變化。

關鍵是對有機采購要有策略。例如，選擇有機農產品，并不必然有很大影響，而取決于你吃什么。根據《環境工作組》的研究，作為經濟作物的水果和蔬菜其殺蟲劑殘留水平各不相同。有些蔬菜，如花椰菜、蘆筍和大蒜，以及帶皮的食物，如梨、香蕉和橘子，與其它水果蔬菜相比，其殘留水平相對較低。

因此，怎么樣才能使你的有機選擇有效呢？兒科醫師Alan Greene博士，在其新書《綠色喂養小孩》中解釋了怎樣按環境友好方式來喂養小孩，他鑒定了一些戰略性的有機食物，他認為可以對家庭日常飲食構成最大的影響。

1.牛奶

“當你選擇一杯傳統牛奶時，你正在買進完全的化學農業體系，” Greene說。轉向有機牛奶的人們往往會這樣做，因為他們關心商業乳品加工業中使用的抗生素，人工合成激素和殺蟲劑。美國農業部的最新調查發現，在大約30％的常規牛奶樣品中都有一定量的殺蟲劑，而只有一個有機樣品中含量較低。與其它食品相比牛奶中的殺蟲劑水平相對較低，但許多孩子牛奶消費量很大。

2.土豆

土豆是美國人飲食中的常見食品，一項調查發現土豆占我們總蔬菜消費量的30％。僅僅轉向有機土豆就可能有極大的影響，因為經濟種植的土豆是一種殺蟲劑含量最高的蔬菜，2006年美國農業部U.S.D.A.檢測發現，檢測的土豆中81％在經洗滌和削皮后仍含有殺蟲劑，在43種檢測的果蔬中，土豆是殺蟲劑含量最高的，環境工作組稱。

3.花生醬

根據美國農業部的統計，花生種植面積比其它水果、蔬菜和堅果種植面積都要大。99％以上的花生種植農場使用常規種植方法，包括使用殺菌劑治療霉變，這在花生作物中是一種常見問題。假定有些小孩幾乎每天都吃花生醬，這似乎是一個簡單可行的轉變。經濟食物公司現在在一些日用品店出售有機品牌，但我女兒一溜煙是喜歡到健康食品店去磨制她的花生醬。

4. 蕃茄醬

對一些家庭來說，蕃茄醬占了家庭蔬菜攝取量的大部分。大約75％的蕃茄消費是加工形式的，包括蕃茄汁，蕃茄醬或調味番茄醬等。值得注意的是，最近研究已表明，有機蕃茄醬的抗氧化劑含量是常規調味蕃茄醬的兩倍。

5.蘋果

蘋果是第二最常食用的鮮果，僅次于香蕉，同時還是第二最常用的果汁，僅次于橙，Greene博士說。但蘋果也是農藥污染最嚴重的果蔬之一。好消息是日常食品雜貨店就可以方便買到有機蘋果。