I hear of a new health benefit of a different food virtually every day as associate nutrition editor of EatingWell Magazine: Broccoli could fight cancer! Coffee may help you live longer! But what I hear about less often is how various foods interact-and, therefore, act-when you eat them together. Some foods, like iron-rich beans and calcium-packed cheese, fight for absorption in your body of their respective key nutrients when you eat them at the same time. But other foods have a synergistic effect-helping their star nutrients work even better in your body. Here are 5 such power pairs, many of which Jessica Girdwain reported about in the May/June issue of EatingWell Magazine:

Broccoli & Mustard

Raw broccoli is a good source of the powerful cancer-fighting compound sulforaphane. But cooking destroys the enzyme (myrosinase) in broccoli that makes sulforaphane available to your body. The fix? Combine broccoli with mustard (yes, the condiment) or another raw cruciferous veggie, such as wasabi or arugula-the extra dose of myrosinase will help you absorb more sulforaphane, according to a 2011 study published in the British Journal of Nutrition.

Coffee & Sugar

If you take your coffee with sugar, good news-it may make you more productive on the job, suggests a small 2010 study published in the journal Human Psychopharmacology: Clinical and Experimental. When study participants drank the two together, researchers found that areas of the brain associated with attention worked more efficiently than when sipped solo. If you don't like coffee, try green or black tea with a drizzle of honey: Just make sure you keep in mind the American Heart Association's recommended limit on added sugars: 6 teaspoons a day for women, 9 for men. Check out these Best & Worst Iced Coffee Drinks.

Adzuki Beans & Raspberries

Pairing adzuki beans-classically used in Japanese desserts-with raspberries may bump up the duo's antioxidant power by 45 percent, according to a 2011 study in the Journal of Agricultural and Food Chemistry. That was the biggest boost researchers saw among 55 combinations of different fruits, veggies and legumes. Top a spinach salad with adzukis; for dessert, dig into fresh raspberries.

Turmeric & Salmon

Curcumin (a component of turmeric) and DHA (an omega-3 fat in oily fish) protect against certain cancers by keeping cancer cells from multiplying. Combining the two may slow tumor growth and the spread of a type of breast cancer cells more so than when the compounds interact with the cancer cells separately, says a 2011 study in BMC Cancer. Researchers think DHA helps cells to utilize curcumin. Rub salmon or trout with turmeric or curry (a spice blend containing turmeric). (Find out what other spices join turmeric as the World's Healthiest Spices.)

Whole Grains & Onions

If, like me, you start off cooking a lot of your meals by sautéeing onion and garlic, you're in luck. Research published in the Journal of Agricultural and Food Chemistry suggests that combining garlic and/or onions with whole grains may help boost the absorption of iron and zinc-minerals found in small amounts in whole grains that are absorbed less easily from plant than animal sources. (Iron helps shuttle oxygen to cells; zinc is needed for healthy immunity and repairing wounds.) Researchers don't know exactly how, but speculate that sulfur compounds in onions and garlic are what help to promote absorption. (They're also what cause garlic breath.)

Beans & Greens

Beans are another plant-based source of iron. Vitamin C helps your body absorb iron, which is particularly important when you're getting iron from plant sources (iron from animal sources is more readily taken into your body). So pairing beans with a vitamin C-rich food, such as greens, is a great way to up your iron absorption.