The Genetics of Taste Lab was host to the fatty acid taste study from November 2014 to August 2015. In that time we enrolled 1020 Museum guests, ages 8-90, as part of the crowdsourced data collection. The study was a true success in both citizen science and crowdsourcing, AND now that the data have been analyzed, we can share that it is a scientific success as well!Assuming humans can detect the taste of fatty acids, how does it happen?
Research suggests that humans can detect the taste of fatty acids, but how this occurs is not known. To look into this question, the Genetics of Taste Lab will open a new research study for public participation. Using an omega-6 essential fatty acid (linoleic acid), the Lab will examine both genetic and environmental factors that might contribute to the ability to taste this important nutrient.
Scientists have long accepted that sweet, sour, salty and bitter are basic tastes. More recently, umami (savory) was added to the list. And now through the findings of our study as well as those of our collaborators, we can finally provide strong evidence that there is a sixth taste: fat, or as it is starting to be known in the land of taste, oleogustus.
There is a thirty year history towards proving that fat is the 6th taste, however the final nail in the coffin came this year when our collaborator, Dr. Richard Mattes of Purdue, and his team published their research "Oleogustus: The Unique Taste of Fat." This finally put fat taste on the map. Now that we know people can detect the taste of fatty acids, we need to figure out how it happens and what it means for human health. That’s where the Genetics of Taste Lab’s work comes in. Using an omega-6 essential fatty acid (linoleic acid), the Lab examined both genetic and environmental factors that contribute to the ability to taste this important nutrient, and the role it has in obesity.
The first published results of the study, No Difference in Perceived Intensity of Linoleic Acid in the Oral Cavity between Obese and Nonobese Individuals, appears in the October 2015 issue of the leading journal Chemical Senses, published by Oxford University Press (free open access!).
The study had dual purposes. The first was to determine whether people can, in fact, discern the presence of linoleic acid. In a survey of 735 subjects, ranging in age from 8 to 90, of white, black, Asian and Latino ethnicity, the answer was definitively yes, people can detect the taste — but to different degrees.
The second was if taste acuity plays a role in obesity. In answer to this question, the researchers found no link between %BF and ability to perceive the taste of the linoleic acid. “We didn’t find that %BF would predict someone’s sensitivity to fat,” our partner and lead author, Robin Tucker-Falconer, RD PhD said. “Now we know we need to explore other areas, like genetics or dietary exposure, for those results.” We are now in the final stages of the genetic analysis, with the goal of finding the gene responsible for fat taste- stay tuned!
The results also revealed an interesting pattern in sensitivity. Women were much better than men at discerning the taste, and young people 17 and under, especially girls, were better than older people. “This was one of the first studies to look at how kids experience fat taste,” Tucker-Falconer said.
What was unusual about the study — and what enabled it to include such a large and diverse set of subjects — was that it was conducted with the help of citizen scientist volunteers that crowdsourced over 1000 Museum guests as human subjects in the Genetics of Taste Laboratory housed within the Museum. Our research partner, Tucker-Falconer adapted the research methods she had used as a graduate student at Purdue, where she tested about 100 participants over four years, to the museum setting, working with our team to design the study and to train the volunteers.
The proof is now I the pudding. “This was far and away the largest sampling that has been done,” said Mattes, a longtime researcher into the biology of taste. “Working with the citizen- scientists is a wonderful scenario,” Mattes continued. “With their interest and willingness to be trained and their commitment, it’s just a perfect situation. It enables us to study large populations in an efficient way.”
This two-year study was led by Nicole Garneau PhD ([email protected]) and Richard Mattes PhD ([email protected]), and made possible by a partnership between the Health Science and Visitor Programs Departments at the Denver Museum of Nature & Science and the Nutrition Science Department at Purdue University.
We love our citizen scientist alumni, and we are incredibly proud of where they take their science careers. This week, we are pleased to share insights from alumnus Michael A. Bagley, an optometric intern at Pacific University College of Optometry.
Michael takes our study on fatty acids to the next level in health in showing the very cool way in which these healthy fats do amazing things for our eyes.
Salmon? Yes, please!
Yo Pearl the Science Girl
Nutrition and dietary supplementation are a fast growing interest and industry in the United States. One family of nutrients gaining notoriety is the polyunsaturated fatty acids (PUFA), like omega-3. Omega-3 PUFAs are considered essential to have in the diet because the body cannot make these nutrients on its own. These molecules are used as structural components in all cells and participate in the growth and function of various body systems including vision, heart, immunity, and the inflammation process.
Two important PUFAs for the eyes are Docosahexaenoic acid (DPA) and Eicosapentaenoic acid (EPA). They have been implicated in the function of the retina, and health of the front surfaces of the eye and cornea. Age-Related Macular Degeneration is a leading cause of blindness in the United States. The Age-Related Eye Disease Study (AREDS) and its follow up, AREDS2, explored the benefit of vitamin, mineral, and omega-3 supplementation effects on macular degeneration. They found that regular intake of their formulation helped slow down the progression of macular degeneration and reduced the risk of developing it in the future. It has now become the standard treatment for this incurable, progressive, and devastating disease.
Another very common condition is dry eye. Many of us have experienced dry, gritty, or uncomfortable feelings on the eye. Protecting the cornea from the dry air is a thin shield made of clear mucous, aqueous (water), and liquid fats/oil called the “tear film”. A study by Rahul Bhargava and his colleagues explored the effects of omega-3 supplementation on people who suffer from this feeling of dryness. They conducted their study in an area of India where the people have very little or no food sources containing this kind of fat. Their findings are very intriguing. The health of the cornea and quality of the protective tear film of their subjects increased dramatically after the supplementation of omega-3 fatty acids. Another trial conducted by Haleh Kangari found the same benefits can be gained right here in the U.S. We should be taking advantage of food sources we already have that contain omega 3, such as fish and dark, leafy green vegetables and fish/krill oil tablets.
Omega-6 fatty acids are another type of PUFAs that are essential to the body’s function and development. These are very common in our diet without even trying. Corn, nuts, and other grains are high in omega-6. It’s so prevalent than some researchers suggest lowering your intake because too much can actually damage cells through triggering unnecessary inflammation. In their article in Review of Optometry magazine, Drs. Paul Karpecki and Diana Shectman suggested a 1:1 ratio of omega-3 to 6. Achieving this ratio usually requires reducing corn and flour product intake while increasing fish and vegetables or taking supplements.
It’s truly amazing how the right nutrients can affect our bodies in dramatic ways. Many of us think of our eyes as separate entities. But they’re as much of a part of our health as a strong heart or a focused mind. Omega-3 PUFAs are gaining stronger support from optometrists, ophthalmologists, and other medical professionals as a part of a healthy diet. These essential nutrients help reduce the risk of macular degeneration in the future and can make eyes feel better right now! As always, ask your optometrist or other medical professional about any concerns you may have.