Foods And Meds You Shouldn't Mix

(CBS)  If you're taking particular prescription medications, they may not be as effective as they could be if you eat certain foods, says registered dietician and Early Show contributor Keri Glassman.

That's because of the way those drugs interact with the foods, she explains.

Here are a few Glassman says you should steer clear of. Right off the bat is one food group that may surprise you:

GREEN LEAFY VEGETABLES

IF you're taking blood thinners. Your good-for-you greens contain vitamin K, which helps clot blood, the opposite of what thinners do. Your dose is customized to you, so if you eat say a salad a day, continue doing that, but don't all of a sudden become Popeye!

AGED CHEESE

Such as parmesan and blue cheese. IF you're taking MAO inhibitors (antidepressants such as Nardil). These cheeses contain tryramine (also in soy and wine) which, when consumed with MAO inhibitors, can add to a rise in blood pressure.

ALCOHOL

IF you're taking antidepressants, anti-anxiety meds (such as Xanax), diabetes drugs, cold and flu meds, beta-blockers, or sleeping pills. If the label says not to drink alcoholic beverages, DON'T EVEN SNEAK A SIP -- you may end up with your head in the toilet! Also, alcohol will heighten the side effects of the drugS, from upset stomach to drowsniess. Diabetics may have low blood sugar episodes.

COFFEE/CAFFEINATED BEVERAGES

IF you're taking asthma meds, anti-anxiety drugs, or decongestants. You may experience jitters and/or a rapid heartbeat.

DAIRY PRODUCTS

IF you're taking antibiotics. Dairy foods can interfere with absorption. Thus, you won't get the benefits of the meds you're taking!

GRAPEFRUIT JUICE

IF you are taking cholesterol-lowering meds, blood thinners, blood pressure drugs, tranquilizers, or antidepressants. Enzymes in our digestive system destroy meds to a certain degree. Grapefruit juice knocks these enzymes out, increasing the amount of drug that enters your bloodstream, which could cause a stomachache, diarrhea or, in rare cases, kidney failure.