Comparing Antioxidant Levels in Tomatoes of Different Color

Naturally occurring antioxidants have been of great interest in recent years due to their recognizable health benefits. A study out of Universidad Autónoma Metropolitana in Mexico has clarified differing antioxidant levels by focusing on eight tomato genotypes with different-color fruit.

Laura Pérez-Flores led a team of researchers in an evaluation of the variation in carotenoid, polyphenol, and tocopherol content among selected hybrid and native tomato lines as well as assays for antioxidant capacity of the fruit. In addition, the expression of isoprenoid metabolism-related genes and two pigmentation-related transcription factors were determined.

Pérez-Flores explains, “Tomatoes are the major dietary source of antioxidants; however, little is known about their contents and regulation in genotypes of different colors, shapes, and sizes. The association of greater levels of specific antioxidants with particular colorations of tomato fruit suggests a ‘balance’ between these compounds.”

The findings of these researchers are illuminated in their article “Antioxidant Balance and Regulation in Tomato Genotypes of Different Color”, found in the current issue of the Journal of the American Society for Horticultural Science.

Tomato fruit are an excellent source of antioxidants and contribute significantly to human health because of their anti-inflammatory, antiallergenic, and antithrombotic properties. The results of this study support either the direct commercialization of tomatoes with different color fruit or use of their genotypes in breeding programs to increase antioxidant levels among existing cultivars.

Carotenoids and tocopherols are among the major lipophilic antioxidants present in tomatoes. Polyphenols are powerful antioxidants that have been reported to interfere with the initiation, promotion, and progression of cancer. The main tomato polyphenols are hydroxycinnamic acids, flavanones, flavonols, and anthocyanins.

In recent years, the biosynthetic pathways of carotenoid, tocopherol, and chlorophyll have been studied because of their importance in understanding the regulatory cross-talk that contributes to the nutritional quality of tomato fruit.

The study was conducted in Mexico, which is a center of diversification and domestication of tomato and thus offers a wide range of native genotypes with fruit of different colors, shapes, and sizes. These genotypes could be integrated into breeding programs aiming to increase the nutraceutical properties of commercial cultivars and recover antioxidant compounds that have been lost through the selection process.

All genotypes used in this study were part of the Mexican Network of Plant Genetic Resources. The studied lines, native and hybrid, were planted in a completely randomized block design with three replications, and each experimental unit comprised 10 plants.

The researchers found that greater levels of specific antioxidants were associated with particular colorations of tomato fruit. These genotypes could be used either directly as food or in breeding programs to recover greater levels of functional compounds such as carotenoids, tocopherols, anthocyanins, and vitamin C.

Source: American Society for Horticulture Science


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American Heart Association Launches +color to Help Transform the American Diet

In a landmark nationwide effort, the American Heart Association (AHA) is announcing a new initiative called +color, focusing on the positive health impact of fruits and vegetables. The health impact of +color may be simple yet significant: It is estimated that if Americans ate the recommended amounts of fruits and vegetables every day, approximately 39,900 deaths would be prevented from cardiovascular diseases, stroke and diabetes and $7.6 billion in medical costs could be saved annually.

The American Heart Association (AHA) and SUBWAY® restaurants, with support from Hass Avocado Board (HAB), is launching +color in New York City. This on-going initiative will encourage Americans to add more fruits and vegetables to their diet and better understand the critical health benefits this change can mean.

+color is also critical to helping the AHA achieve its 2020 health impact goal of improving the health of all Americans by 20 percent by 2020. According to a 2015 study in Circulation, young adults who eat more than five daily servings of fruits and vegetables may have less atherosclerosis than those who do not. According to the Dietary Guidelines for Americans 2015-2020, the average intake of fruits and vegetables for adults under 50 years of age is about half of the recommended intake ranges. Adding one more cup of fruits or vegetables per day closes the gap by approximately 50 percent.

“Through +color, we’ll empower communities and consumers of all ages, especially millennials, to eat more fruit and vegetables. We want to push the perceived limits and perceptions around what people think is healthy to what is actually going to help them improve their diet. It’s about adding colorful, nutritious and vitamin-packed fruit and vegetables to meals instead of choosing unhealthier options,” stated Rachel Johnson, Ph.D., MPH, RD, Professor of Nutrition, The University of Vermont and Past Chair, American Heart Association Nutrition Committee. “It’s about showing America how easy it is to get more of these vital foods into their diet each day and how easy it is to share this information everywhere they go with everyone they know. This information has the power to help save lives.”

A diet rich in fruits and vegetables has also been shown to reduce risk of stroke, certain types of cancer and risk of death from all causes. That’s why the AHA and SUBWAY® restaurants are inviting Americans to join in this transformative effort by encouraging everyone to start today.

As the inaugural national sponsor of +color, SUBWAY® restaurants continues their long-term commitment to healthier eating by uniting in this effort with the AHA. SUBWAY® restaurants will ensure consumers understand how their vegetable offerings contribute to the +color initiative by highlighting how the vegetable options available at SUBWAY® restaurants can help them add more fruits and vegetables to their meal. In addition, SUBWAY® restaurants will support this new initiative through an in-store promotion in 2017.

“SUBWAY® restaurants is inspired to join the American Heart Association on this exciting journey to encourage Americans to eat more vegetables and promote healthier eating,” said Lanette Kovachi, RDN, SUBWAY® restaurants Global Dietitian. “At SUBWAY® restaurants, Americans can choose from millions of our handcrafted sandwich combinations to create their own custom sandwich, which can offer up at least two extra servings of vegetables to their diet. Each of the six fresh vegetable varieties offered at SUBWAY® are a perfect compliment to the +color initiative.”

The centerpiece of +color is an extensive series of entertaining videos, social media events and digital interactive information that make it easy to adopt these healthy changes. This can be accomplished by watching and sharing +color content, and adding more fruits or vegetables each day. As a national supporter of +color, HAB’s Fresh Avocados – Love One Today® will be a part of the launch as the official “recipe host.” HAB will help expand the initiative’s reach with avocado heart-check certified recipes and tips about the nutrition benefits of avocados.

Expansion of the initiative will kick off at AHA Heart Walks nationwide this fall. Additional elements of +color will include content for fun kids, as well as opportunities for worksites to engage with its employees.

For more information about +color and how to start adding more color to your day, visit Heart.org/pluscolor.

Source: American Heart Association


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Lighting Color Affects Sleep and Wakefulness

A research team from Oxford University have shown how different colours of light could affect our ability to sleep.

The researchers, led by Dr Stuart Peirson from Oxford’s Sleep and Circadian Neuroscience Institute were aiming to understand why exposing mice to bright light caused two – physically incompatible – responses.

Dr Peirson explained: ‘When we expose mice to light during the night, it causes them to fall asleep. Yet, at the same time, it also increases levels of corticosterone, a stress hormone produced by the adrenal gland that causes arousal – wakefulness. We wanted to understand how these two effects were related and how they were linked to a blue light-sensitive pigment called melanopsin, known to play a key role in setting our body clock.’

The team exposed mice to three different colours of light – violet, blue and green. Based on the existing data about the role of melanopsin in sleep, they expected that the blue light would induce sleep fastest as the wavelength of the blue light (470 nanometres – nm) was closest to the peak sensitivity of the pigment (around 480nm).

However, it was green light that produced rapid sleep onset – between 1 and 3 minutes. Blue and violet light delayed sleep – the onset of sleep taking between 16 and 19 minutes for blue and between 5 and 10 minutes for violet.

Dr Peirson said: ‘The results meant that mice exposed to blue light had less sleep than those exposed to violet and green light. We confirmed the effect by testing mice using green and blue light at a time when they would usually be less active.’

To investigate the role of melanopsin, the team performed the same test on mice lacking the pigment. For these mice, the colours had opposite effects – blue caused rapid sleep onset, while green and violet significantly delayed sleep, showing that melanopsin is necessary for the substantial wavelength-dependent effects of light on sleep.

The researchers also found that while exposure to all three colours of light increased the level of corticosterone stress hormone in ordinary mice, blue light caused a much higher rise. In mice without melanopsin, the response to blue light was greatly reduced. Blocking the effect of corticosterone reduced the sleep-delaying effect, suggesting that the production of this hormone in response to light actively inhibits sleep.

Dr Peirson said: ‘This study shows that there are different pathways from the eye to the brain – one directly regulating sleep and the other increasing arousal. Melanopsin has a more complex role than previously thought, affecting both pathways. This is the first time that it has been shown to regulate adrenal stress responses.

‘An obvious caveat of this study is that mice are a nocturnal species that are active during the night. As such, green light may be expected to increase wakefulness rather than increasing sleep in humans. We would therefore predict that blue light will further enhance the wake-promoting effects of light by elevating adrenal stress hormones.

‘The results also add to our understanding of the effects of light emitting devices on humans, where recent studies have shown that the blue light from these devices delays sleep. However, as we have shown that there are different pathways in the brain, by which different colours of light have different effects on sleep or wakefulness, we need to understand how the overall colour balance of artificial light could affect people’s alertness and sleep.’

Source: EurekAlert!