WASHINGTON - Patient after patient asked: Is eating organic food, which costs more, really better for me?

Unsure, Stanford University doctors dug through reams of research to find out — and concluded there's little evidence that going organic is much healthier, citing only a few differences involving pesticides and antibiotics.

Eating organic fruits and vegetables can lower exposure to pesticides, including for children — but the amount measured from conventionally grown produce was within safety limits, the researchers reported Monday.

Nor did the organic foods prove more nutritious.

"I was absolutely surprised," said Dr. Dena Bravata, a senior research affiliate at Stanford and long-time internist who began the analysis because so many of her patients asked if they should switch.

"There are many reasons why someone might choose organic foods over conventional foods," from environmental concerns to taste preferences, Bravata stressed. But when it comes to individual health, "there isn't much difference."

Her team did find a notable difference with antibiotic-resistant germs, a public health concern because they are harder to treat if they cause food poisoning.

Specialists long have said that organic or not, the chances of bacterial contamination of food are the same, and Monday's analysis agreed. But when bacteria did lurk in chicken or pork, germs in the non-organic meats had a 33 per cent higher risk of being resistant to multiple antibiotics, the researchers reported Monday in the journal Annals of Internal Medicine.

That finding comes amid debate over feeding animals antibiotics, not because they're sick but to fatten them up. Farmers say it's necessary to meet demand for cheap meat. Public health advocates say it's one contributor to the nation's growing problem with increasingly hard-to-treat germs. Caroline Smith DeWaal, food safety director at the Center for Science in the Public Interest, counted 24 outbreaks linked to multidrug-resistant germs in food between 2000 and 2010.

The government has begun steps to curb the nonmedical use of antibiotics on the farm.

Organic foods account for 4.2 per cent of retail food sales, according to the U.S. Department of Agriculture. It certifies products as organic if they meet certain requirements including being produced without synthetic pesticides or fertilizers, or routine use of antibiotics or growth hormones.

Consumers can pay a lot more for some organic products but demand is rising: Organic foods accounted for $31.4 billion sales last year, according to a recent Obama administration report. That's up from $3.6 billion in 1997.

The Stanford team combed through thousands of studies to analyze the 237 that most rigorously compared organic and conventional foods. Bravata was dismayed that just 17 compared how people fared eating either diet while the rest investigated properties of the foods themselves.

Organic produce had a 30 per cent lower risk of containing detectable pesticide levels. In two studies of children, urine testing showed lower pesticide levels in those on organic diets. But Bravata cautioned that both groups harboured very small amounts — and said one study suggested insecticide use in their homes may be more to blame than their food.

Still, some studies have suggested that even small pesticide exposures might be risky for some children, and the Organic Trade Association said the Stanford work confirms that organics can help consumers lower their exposure.

CSPI's DeWaal noted that difference, but added that the issue is more complicated. Some fruits and vegetables can harbour more pesticide residue than others — she listed peaches from Chile as topping a recent testing list. Overall levels have dropped in North American produce over the last decade as farms implemented some new standards addressing child concerns, she said.

"Parents with young children should consider where their produce is coming from," DeWaal said, calling types grown in the U.S. or Canada "a safer bet" for lower pesticide levels.

As for antibiotics, some farms that aren't certified organic have begun selling antibiotic-free meat or hormone-free milk, to address specific consumer demands, noted Bravata. Her own preference is to buy from local farmers in hopes of getting the ripest produce with the least handling.

That kind of mixed approach was evident in a market in the nation's capital Thursday, where Liz Pardue of Washington said she buys organic "partially for environmental reasons." Pardue said she doesn't go out of her way to shop organic, but if she does, it's to buy mostly things that are hard to wash like berries and lettuce.

Michelle Dent of Oxon Hill, Md., said she buys most of her groceries from regular chain stores but gets her fruit from organic markets: "It's fresh; you can really taste it."

Anna Hamadyk of Washington said she buys only organic milk because she has a young son.

"I would love to buy everything organic, but it's just too much money," said Hamadyk, who also shops at local farmers markets.

ALSO: 45 healthy foods for fall:

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• Apples

  An apple a day should keep the doctor away. According to studies, <a href="http://www.besthealthmag.ca/eat-well/nutrition/15-health-benefits-of-eating-apples" target="_hplink">apples can protect you against Parkinson's disease, decrease your risk of diabetes and keep your teeth stay shiny white</a>, according to Best Health Magazine.

• Asparagus

  Tasty when roasted or grilled, asparagus is a great source of fibre, folate, vitamins A, C, E, and K, and can <a href="http://www.eatingwell.com/blogs/health_blog/5_powerful_health_benefits_of_asparagus_you_probably_didn_t_know" target="_hplink">help our brains fight cognitive decline, according to EatingWell.com. </a>

• Arugula

  Tip: Replace your typical romaine salad with arugula instead. This leafy green is filled with vitamins and minerals, and<a href="http://voices.yahoo.com/the-amazing-health-benefits-arugula-4825552.html" target="_hplink"> has been known to protect our bodies from cancers</a>, according to Yahoo News.

• Artichoke

  Don't choke up on this fact: artichokes can l<a href="http://www.3fatchicks.com/6-health-benefits-of-artichokes/" target="_hplink">ower your cholesterol, improve your liver functions and work as a digestive aid for your body</a>, according to 3FatChicks.com.

• Basil

  This herb tastes amazing on top of anything: Pastas, fried rice and anything infused with Thai flavours. Basil also<a href="http://www.herbcompanion.com/herbal-living/amazing-health-benefits-of-basil.aspx" target="_hplink"> protects our bodies from premature ageing, common skin issues, and even some types of cancer, </a>according to writer Sarah McCabe.

• Beet

  Don't let the slightly strange smell and taste fool you. Beets can be <a href="http://www.herbcompanion.com/herbal-living/amazing-health-benefits-of-basil.aspx" target="_hplink">instant energy boosters and have absolutely zero trans and saturated fats</a>, according to Yahoo News.

• Blackberries

  <a href="http://www.healthdiaries.com/eatthis/8-health-benefits-of-blackberries.html" target="_hplink">Skin health, eye health, bone health and overall women's health</a>: do we need to say more? Blackberries are in season around the end of August and a little bit into September -- so stock up!

• Blueberries

  Blueberries have been known to boost your immune systems and protect our bodies from<a href="http://www.huffingtonpost.ca/2012/08/28/saturated-fats-are-worse_n_1836432.html" target="_hplink"> colds, fevers and other infections. </a>

• Broccoli

  You probably hated broccoli as a kid, but this doesn't mean you can't start developing a taste for it now. Broccoli is <a href="http://home.howstuffworks.com/broccoli3.htm" target="_hplink">low in calories and high in vitamin A, C and calcium.</a>

• Brussels Sprouts

  Hated by most taste buds but loved by your body. Brussels sprouts are full of phytonutrients (a natural plant compound) and are a <a href="http://www.cookinglight.com/food/in-season/in-season-brussels-sprouts-00400000001701/" target="_hplink">good source of potassium, iron and fibre,</a> according to CookingLight.com.

• Beans

  Beans -- or as one writer likes to call them "the undervalued superfood -- are <a href="http://www.huffingtonpost.com/2012/08/16/beans-health-benefits_n_1792504.html#slide=1391241" target="_hplink">low in fat, good for your heart and packed with protein. </a>

• Cabbage

  Cabbage is an excellent natural detoxifier that can help purify your blood and <a href="http://www.organicfacts.net/health-benefits/vegetable/health-benefits-of-cabbage.html" target="_hplink">remove junk (yes, toxins) lingering in your body. </a>

• Carrots

  Poor eyesight? Eat a carrot. This orange vegetable has been known to <a href="http://www.care2.com/greenliving/10-benefits-of-carrots.html" target="_hplink">improve vision, prevent cancer and even give your skin a natural glow. </a>

• Cauliflower

  Cauliflower looks like brain -- probably because it's good for your noodle. Packed with <a href="http://www.livestrong.com/article/410151-the-health-benefits-of-cauliflower/" target="_hplink">vitamin C, cauliflower can help improve your skin and brain. </a>

• Celery

  Want the most of celery? Make a juice. Celery is filled with<a href="http://www.juicing-for-health.com/health-benefits-of-celery.html" target="_hplink"> vitamin A and B vitamins and is known to lower blood pressure. </a>

• Corn

  Corn -- eaten in small amounts -- is great for your <a href="http://www.boldsky.com/health/nutrition/2012/health-benefits-of-corns-029629.html" target="_hplink">skin, packed with fibre and helps control your cholesterol levels. </a>

• Cranberries

  It's acidic for a reason. Studies have shown that <a href="http://www.whfoods.com/genpage.php?tname=foodspice&dbid=145" target="_hplink">cranberries can help with urinary tract infections and can even prevent them. </a>

• Cucumbers

  Cucumbers contain vitamin C and caffeic acid,<a href="http://www.huffingtonpost.ca/2011/08/09/cucumber-water-recipe_n_922703.html" target="_hplink"> two antioxidant nutrients that can help protect the skin from sun damage</a>, according to health and wellness consultant Doug DiPasquale.

• Eggplant

  If you're trying to lose weight, eggplant is the way to go.<a href="http://www.3fatchicks.com/3-health-benefits-of-eggplant/" target="_hplink"> Full of fibre, eggplant can make you full faster. </a>

• Garlic

  It may make your mouth stick but garlic can help fight <a href="http://www.ivillage.co.uk/the-health-benefits-garlic/78921" target="_hplink">common colds and protect your body against heart disease</a>. Just don't eat a lot of garlic before you have to meet someone.

• Green Beans

  The stringy, crunchy bean that is low in calories also helps your <a href="http://www.livestrong.com/article/257290-what-are-the-benefits-of-string-beans/" target="_hplink">body build its immune system and provide you with protein and calcium. </a>

• Kale

  Steamed or baked (as an alternative to chips) kale can help <a href="http://www.canadianliving.com/blogs/health/2011/04/26/the-health-benefits-of-kale/" target="_hplink">lower cholesterol, is full of vitamin K which helps your bones, and offers anti-inflammatory benefits,</a> according to Canadian Living.

• Leek

  Best paired with your stock, leeks are full of vitamins and minerals and provides<a href="http://www.3fatchicks.com/5-nutritional-benefits-of-leeks/" target="_hplink"> folate -- an important vitamin during pregnancy. </a>

• Lettuce

  You've probably seen them in-between your buns or tossed in a summer salad. Lettuce is a <a href="http://www.3fatchicks.com/5-nutritional-benefits-of-leeks/" target="_hplink">super green food that's high in vitamin K and A. </a>

• Onions

  You won't cry about this one, onions are a surprising source of fibre and can <a href="http://home.howstuffworks.com/onions4.htm" target="_hplink">reduce blood pressure and blood cholesterol levels,</a> according to HowStuffWorks.com.

• Melons

  Available in August and September, this often sweet and delicious fruit has <a href="http://www.besthealthmag.ca/eat-well/nutrition/the-health-benefits-of-melons?slide=4" target="_hplink">anti-inflammatory benefits and reduces blood pressure. </a>

• Mushroom

  If you don't like mushrooms -- you're missing out. Besides tasting great on pizzas, pastas and any burger or sandwich, mushrooms are also <a href="http://www.readersdigest.ca/food/diet-nutrition/3-health-benefits-mushrooms" target="_hplink">full of copper and potassium, according to Reader's Digest. </a>

• Pears

  Pears are known to be natural laxatives and can ease the movement of <a href="http://www.livestrong.com/article/496430-are-pears-good-for-constipation-in-infants/" target="_hplink">stool through the intestines if you're dealing with constipation. </a>

• Peppers

  Crunchy and sweet in every colour, peppers are a low-cal food option perfect for those <a href="http://www.examiner.com/article/peppers-the-health-benefits-of-green-peppers-and-hot-peppers" target="_hplink">who are trying to lose a few pounds</a>, according to the Examiner.

• Plums

  In honour of fall, we'd also like to give a shout out to this <a href="http://www.huffingtonpost.com/2011/10/27/plum-walnut-crumble_n_1048905.html" target="_hplink">plum and walnut crumble recipe</a>. Plums are good for <a href="http://www.canadianliving.com/blogs/health/2011/08/10/5-health-benefits-of-plums-plus-4-mouth-watering-plum-recipes/" target="_hplink">your bones, eyesight and can help with easier digestion if you're feeling bloated</a>, according to Canadian Living.

• Potatoes

  To be fair, French fries, mashed potatoes and curly fries (sadly) aren't the best options for enjoying healthy potatoes. One study has shown that eating small amounts of spuds can <a href="http://www.dailymail.co.uk/health/article-1206765/Why-potatoes-suprising-health-benefit-key-lasting-weight-loss.html" target="_hplink">help you with weight loss and make you feel full faster</a>, according to The Daily Mail.

• Pumpkins

  Before you carve them for your kids -- try adding some pumpkin in your diet. Pumpkin seeds are full of<a href="http://www.care2.com/greenliving/13-health-benefits-of-pumpkin-seeds.html?page=2" target="_hplink"> vitamin K, E and B groups and are a good source of protein</a>, according to Care2.com.

• Parsley

  An easy way to add a little kick to your meals, <a href="http://www.whfoods.com/genpage.php?tname=foodspice&dbid=100" target="_hplink">parsley is high in vitamin K and C. </a>

• Radishes

  Yes, again, this is another root vegetable that might not taste the best. <a href="http://www.fatburningfurnace.com/blog/radish-nutrition-facts-%E2%80%93-health-benefits-of-radishes" target="_hplink">But radishes are low in calories and high in vitamin C. </a>

• Raspberries

  Look, the hairy fruit! Raspberries are packed with antioxidants <a href="http://www.canadianliving.com/blogs/health/2011/07/20/4-raspberry-health-benefits-and-4-delicious-raspberry-recipes/" target="_hplink">(at least 50 per cent more than strawberries) that can ward off cancer</a>, according to Canadian Living.

• Rhubarb

  Great in pies or jam, rhubarb is filled with <a href="Rhubarb" target="_hplink">vitamin C that helps build a stronger immune system to ward of common bugs. </a>

• Rosemary

  Another fall herb, rosemary is an easy way to add flavour to your meals instead of relying on salt. According to About.com, rosemary also contains a chemical called quinones, which has been shown in to<a href="http://homecooking.about.com/od/foodhealthinformation/a/rosemaryhealth.htm" target="_hplink"> inhibit carcinogens and preventing cancer. </a>

• Strawberries

  On top of being an essential source of<a href="http://www.huffingtonpost.com/2012/08/06/strawberries-ultraviolet-radiation-uv-rays-skin_n_1739399.html" target="_hplink"> vitamins A, C and B, new lab research suggests strawberries might also play a part in protecting against dangerous UV rays</a>, according to a study by the University of Barcelona.

• Spinach

  Tip: If you're kids can't stand the taste of spinach, blend it with your fruit smoothies. Spinach is an <a href="http://www.chatelaine.com/en/article/23258--one-of-the-health-benefits-of-spinach-is-it-can-help-you-relax" target="_hplink">excellent source of calcium, folate and protein</a>, according Chatelaine Magazine.

• Squash

  A wholesome vegetable for fall, squash can help with <a href="http://www.besthealthmag.ca/eat-well/healthy-eating/6-health-benefits-of-summer-squash?slide=2" target="_hplink">preventing cancer and boost red blood sells,</a> according to Best Health Magazine.

• Shallots

  No, this is not an onion -- shallots actually have <a href="Have more anti-oxidants, minerals, and vitamins on weight per weight basis than onions." target="_hplink">more antioxidants, minerals, and vitamins compared to onions. </a>

• Tomatoes

  Huffington Post blogger Dr. Leo Galland says tomatoes can help fight inflammation and are excellent sources of <a href="http://www.huffingtonpost.com/leo-galland-md/tomatoes-health-benefits_b_886214.html" target="_hplink">potassium and several vitamins including A, C and E. </a>

• Turnips

  About 51 calories per mashed cup, turnips are full of <a href="http://www.livestrong.com/article/408477-the-health-benefits-of-turnips/" target="_hplink">calcium and potassium, according to LiveStrong.com. </a>

• Zucchini

  Known as a hydrating vegetable, <a href="http://www.3fatchicks.com/7-health-benefits-of-zucchini/" target="_hplink">zucchinis are full of protein, fibre, potassium and vitamin C. </a>

• Swiss Chards

  Nerding out? Grab some chards. Swiss chards (which are not actually from Switzerland) are packed with vitamins and <a href="http://www.healthdiaries.com/eatthis/8-health-benefits-of-swiss-chard.html" target="_hplink">minerals to boost brain, bone and hair health</a>, according to Health Diaries.