1. GREEN TEAAntioxidants decrease an average of 32% after 6 months on the shelf, according to a 2009 study in the Journal of Food Science. These antioxidants, known as catechins, may decrease your risk of several types of cancer, but they are sensitive to both oxygen and light. Sadly, tea, unlike wine, does not improve with age. Make it last: “Buy tea in airtight packages such as tins, rather than cellophane wraps, which air can penetrate,” advises Rona Tison of ITO EN, the world’s largest supplier of green tea. Store your tea bags in sealed, opaque canisters in a cool spot. “Green tea is more sensitive to heat than black tea, so place your sealed container in the refrigerator to keep the leaves fresh and healthy for as long as possible,” she says.
  2. TOMATO PRODUCTSMedia Platforms Design TeamThe capsaicin in chili powder decreased continuously during 9 months of storage in one Chinese study. Capsaicin may contribute to weight loss and also help fight certain cancers. “Generally, spices that should be bright in color but have grown dull are also devoid of flavor and nutritional value,” says Jay Bunting, owner of Wayzata Bay Spice Co. Make it last: Air penetrates plastic, so buy in glass jars whenever possible, says Bunting. Better yet, grind your own. Whole spices such as peppercorns retain health benefits and flavor much longer because the inside of each peppercorn is protected from light and air. Store herbs and spices out of direct light and away from the hot stove.
  3. POTATOESVitamin C declined 40%, on average, after 8 months in proper storage (in a place that’s cool, dark, and dry), according to researchers in Holland. You probably wouldn’t keep potatoes that long. But farmers often store them up to 5 months before shipping them to market, says Peter Imle, a potato farmer and plant geneticist in northern Minnesota. Make it last: Look for smaller potatoes (often labeled new), which have a slightly higher vitamin C content to begin with, and buy only what you can eat in a few weeks. Imle also recommends keeping potatoes in paper sacks, rather than plastic grocery bags. “Paper keeps out excess light and oxygen. But it still allows the potatoes to breathe, without trapping in moisture like plastic can,” he explains. MORE: 5 Healthy Veggies You Think Are Bad For You—But Aren’t
  4. OLIVE OILMedia Platforms Design TeamThe potency of antioxidants declined 40% after 6 months, according to a 2009 Italian study of bottled olive oil in the Journal of Food Science. Yet in many households, bottles can sit on the shelf for much longer than that. Make it last: Don’t store oil near the stove or leave it uncapped for long, as it’s sensitive to oxygen, heat, and light, says Doug Balentine, PhD, director of nutrition sciences at Bertolli, an olive oil producer. If you don’t cook with it often, buy smaller bottles. MORE: 5 Fats You Should Be Eating More Of
  5. BERRY JAMSThe anthocyanins in blueberry jam decline by 23%, on average, after 2 months of storage at room temperature, say researchers at the University of Arkansas. Similarly, strawberry jam loses up to 12% of its health-boosting flavonoids after 6 months in a dark cupboard. Experts believe the flavonoids (including anthocyanins) contribute to the antiinflammatory, memory-preserving, antioxidant effects of berries. Make it last: Store jams in the fridge before opening to retain about 15% more of the anthocyanins and their antiaging benefits. Or buy sugar-free blueberry jams. Researchers found that they maintain higher levels of anthocyanins over time. (You can make your own with this 4-step, no-cook jam recipe.)
  6. DRIED HERBS & SPICESMedia Platforms Design TeamThe capsaicin in chili powder decreased continuously during 9 months of storage in one Chinese study. Capsaicin may contribute to weight loss and also help fight certain cancers. “Generally, spices that should be bright in color but have grown dull are also devoid of flavor and nutritional value,” says Jay Bunting, owner of Wayzata Bay Spice Co. Make it last: Air penetrates plastic, so buy in glass jars whenever possible, says Bunting. Better yet, grind your own. Whole spices such as peppercorns retain health benefits and flavor much longer because the inside of each peppercorn is protected from light and air. Store herbs and spices out of direct light and away from the hot stove.
  7. GRAINS & DRY GOODSThe riboflavin in enriched macaroni plummeted 50% after being exposed to light for only a day, according to a Journal of Food Science study. Even dim light can degrade riboflavin by 80% after 3 months, according to another study. The folic acid in enriched flour is also sensitive to both light and oxygen. Make it last: Store grains in opaque ceramic containers, far from the stove’s damaging heat. A dry cupboard is better than the fridge, except in the case of brown rice, which contains a small amount of oil and therefore spoils faster at room temperature.  MORE: 25 Healing Herbs You Can Use Every Day