By Bahar Gholipour, Staff Writer

Published: 09/12/2013 07:56 AM EDT on LiveScience


It has been a mystery why some people love some vegetables like broccoli, while others find it to be bitter, even though most people have the same genes for bitter taste receptors.


Now scientists may have found the missing link -- it's not only people's genetic makeup that determines people's reaction to broccoli's bitter taste, but also how these genes are instructed to make taste receptors, according to a new study published today (Sept. 11) in the American Journal of Clinical Nutrition.


The most-studied gene for bitter taste receptor[1] , TASR38, comes in two types. People who have only one type or the other may be at the extremes -- they are either very sensitive to bitterness, or don't taste it unless it's very strong. But most people are somewhere in between, having one copy of each type.


However, even within this group of "moderate tasters" who have the same genes, there is greatly varied sensitivity to bitterness. [Tip of the Tongue: The 7 (Other) Flavors Humans May Taste[2] ]


In the study, 18 people with the same bitter taste genes rated the bitterness[3] level of several beverages, including broccoli juice and carrot juice.


The researchers took small samples of tissue from the participants' taste buds. Taste buds, small bumps that cover the tongue, contain taste receptors. The researchers measured the amount of a molecule in the taste buds, called messenger RNA (mRNA), which contains instructions for making bitter taste receptors.



The results showed a direct relationship between how much mRNA people's cells made, and their bitterness ratings of broccoli juice. People who had the most mRNA for bitter taste receptor rated the juice as most bitter.


"The amount of messenger RNA that taste cells choose to make may be the missing link in explaining why some people with 'moderate taster' genes still are extremely sensitive to bitterness in foods and drinks," said study researcher Danielle Reed, a geneticist at Monell Chemical Senses Center in Philadelphia.


The findings shows a new level of complexity in taste perception, and may ultimately lend insight into individual differences in food preferences and dietary choices[4] , the researchers said.


Although the finding has solved one mystery, it has opened the door to new questions.



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  • Not every step toward a more nutritious diet has to taste like one. Forget the steamed broccoli and try incorporating more <a href="http://www.huffingtonpost.com/2012/03/11/colorful-fruit-and-vegetables_n_1323881.html" target="_hplink">great-for-you greens</a> into your favorite meals you're already making. We asked the experts to share with us some of their favorite sneaky ways to get more greens. Here are some of their most drool-worthy suggestions.




  • Baked Goods


    Try pureeing greens and adding them to muffins, suggests <a href="http://elisazied.com/" target="_hplink">Elisa Zied</a>, MS, RDN, CDN. When paired with other flavorful ingredients, like blueberries or <a href="http://www.food.com/recipe/chocolate-cupcakes-with-spinach-and-blueberries-260924" target="_hplink">chocolate</a>, you won't notice the <a href="http://recipes.sparkpeople.com/recipe-detail.asp?recipe=2236275" target="_hplink">spinach hidden in the mix</a>. "You won't even feel like you're eating vegetables," says <a href="http://www.huffingtonpost.com/heather-bauer-rd-cdn/" target="_hplink">Heather Bauer</a>, RD, CDN. This trick even works with <a href="http://family.go.com/food/recipe-281285-deceptively-delicious-brownies-t/" target="_hplink">brownies</a>! (Just remember this isn't a free pass to eat the whole pan.)




  • Eggs


    <a href="https://www.facebook.com/pages/MyPlate-for-Moms-How-to-Feed-Yourself-Your-Family-Better/196841697040535" target="_hplink">Elizabeth M. Ward</a>, MS, RD, swears by greens in omelets, especially <a href="http://www.huffingtonpost.com/2013/03/17/more-green-superfoods_n_2868810.html" target="_hplink">kale</a>, which you can easily buy frozen and throw into the mix whenever you're in the mood to make breakfast.




  • Pasta


    As you're just about finished cooking your favorite noodle dish, around the time when you might typically add some fresh basil, try adding heartier greens to the mix, says <a href="http://www.appforhealth.com/about-us/julie-upton/" target="_hplink">Julie Upton</a>, MS, RD, CSSD. Spinach works particularly well, she says. Greens also work in lasagna, says Zied, or instead of basil in homemade pesto, says <a href="http://www.huffingtonpost.com/cheryl-forberg-rd/" target="_hplink">Cheryl Forberg</a>, RD. (You can even try the pesto as a yummy condiment to serve on sandwiches, she says.)




  • Smoothies


    To change up your morning routine, try mixing spinach or kale into those homemade fruit smoothies, says Ward. A handful of leaves doesn't have to make your sip look -- or taste -- green!




  • Pizza


    There's no reason you can't add a little green to your favorite homemade slice. A handful of leaves can add a refreshing factor to that warm and gooey cheese. Upton suggests baking your dough with just fresh mozzarella. Then when it comes out of the oven, cover the entire pie with a mix of arugula, cherry tomatoes, olive oil and vinegar.




  • Beans


    "When I'm making black beans (with tomato, garlic, onion, cumin, etc.), I love to stir in a couple cups of chopped, blanched greens like spinach, chard or kale at the end," says Forberg. "Adds great color, texture and flavor!"




  • Soups


    Just about any green can be pureed to make a thicker soup, helping to camouflage a distinct health-promoting taste, says Bauer. Whipping up a greens-based soup or sauce is an especially good trick for the severely veggie-averse, she says, who might not even want to see vegetables.