While watermelons are an excellent source of vitamin C, what makes them a standout among fruits is their lycopene—a red pigment and an antioxidant, most famously found in tomatoes, closely related to beta-carotene. Gram for gram, red-fleshed watermelons actually provide more lycopene than tomatoes, and the lycopene in watermelons, unlike the lycopene in tomatoes, can be used by the body without any processing. Lycopene has attracted the interest of researchers due to its apparent importance in heart health. Here's a few things researchers have discovered about lycopene and heart health:

• In some research, a high dietary intake of lycopene has been associated with a lower risk of heart attack and heart failure.
• Low blood levels of lycopene have been linked to increased risks of high blood pressure, stroke, heart attack, and death from any cause.

So, when watermelon season comes around, there's good reason to choose watermelons with flesh that is the deepest red—they have more lycopene than the yellow and orange varieties.

Source: Diabetes Care

Following the USDA’s Dietary Guidelines for Americans is good for your health, and, according to a large study, it may also be beneficial for the planet. The findings were published in the Proceedings of the National Academy of Sciences and compared the average diets of 37 middle- to high-income nations (64% of the world’s population) to their respective nationally recommended diets. Researchers gathered information about each nation’s recommended diet from national organizations responsible for dietary advice. Each nation’s actual average diet was taken from Food Balance Sheets–detailed reports on national food systems calculated by the UN’s Food and Agriculture Organization. Researchers then calculated greenhouse gas emissions, eutrophication (water pollution due to nutrient runoff), and land use resulting from each diet using a database of the environmental impacts of various product categories, including twelve food groups. After assessing the environmental impacts of each nation’s recommended and average diets, researchers determined that, compared with average diets:

• Recommended diets in high-income nations were associated with 13 to 24.8% lower greenhouse gas emissions, 9.8 to 21.3% less eutrophication, and 5.7 to 17.6% less land use. Of these reductions, approximately 54% were due to reduced calorie intakes and 46% were due to differences in intakes of specific foods.
• Recommended diets in upper middle-income nations were associated with reductions of 0.8 to 12.2% in greenhouse gas emissions, 7.7 to 19.4% in eutrophication, and 7.2 to 18.6% in land use.
• Recommended diets in lower middle-income nations were associated with increases of 12.4 to 17% in greenhouse gas emissions, 24.5 to 31.9% in eutrophication, and 8.8 to 14.8% in land use.

Higher animal product consumption largely explains the lower reductions–or even increases–in environmental damage associated with recommended diets of middle-income nations. Animal products account for a large proportion of all three aspects of environmental impact considered in this study: greenhouse gas emissions, eutrophication, and land use. Even with these increases, researchers found that if every nation adopted their respective recommended diet, the overall environmental impact would be positive. While large-scale dietary changes won’t happen overnight, gradually shifting our eating to align with national recommendations could help reduce our environmental footprint.

Source: Proceedings of the National Academy of Sciences

Research from 2015 found an association between drinking coffee and a reduced risk of malignant melanoma of the skin. Published in the Journal of the National Cancer Institute, the research looked at data from 447,357 people, ages 50–71, who participated in the National Institutes of Health-AARP prospective cohort study, which started in the mid-1990s. The participants filled out a questionnaire regarding their diet, which included questions about their coffee intake. Researchers followed up with the participants, on average, about 10.5 years later. Here’s what the researchers concluded:

• People who drank four or more cups of coffee per day reduced their risk of malignant melanoma (but not melanoma in situ) by 20%, even after adjusting for risk factors such as alcohol intake, smoking, and physical activity.
• The association between drinking coffee and a reduced risk of malignant melanoma was only statistically significant for caffeinated coffee.

The findings are consistent with some experimental evidence showing that compounds in coffee may protect against ultraviolet radiation-induced skin carcinogenesis. Nevertheless, the study had several limitations. As an observational study, it only showed a correlation, not a cause-and-effect relationship. For example, there may have been differences in metabolism or lifestyle between the coffee drinkers and the non-coffee drinkers that weren't taken into account by the researchers. Some of these differences, rather than coffee drinking per se, might have been responsible for the observed association with melanoma. In addition, other observational studies have been inconsistent when it comes to finding a relationship between coffee and melanoma. More research is needed, therefore, to confirm the possible protective role of coffee.

Source: Journal of the National Cancer Institute

Melatonin, a hormone produced by the pineal gland that helps regulate sleep cycles, occurs naturally in some foods. For this reason, it’s sold and regulated in the US as a dietary supplement rather than a drug. And it’s a hugely popular supplement at that: according to the most recent National Health Interview Survey (NHIS), conducted in 2012, 3.1 million US adults took melatonin. The NHIS also found that 419,000 children took melatonin, an astounding increase of 332,000 children since 2007.

But how safe is it? Recently, concerns have been raised that, in adults, chronic melatonin use could throw off the body’s own melatonin production. Of equal or greater concern, is melatonin’s long-term effects in children. According to an article in the New York Times, some experts fear that long-term use of melatonin could be more disruptive to children, as their bodies are still developing reproductive, cardiovascular, immune, and metabolic systems. While there’s currently no good evidence that long-term use has these negative effects, and, in fact, melatonin has been found to be helpful for jet lag and certain sleep disorders, parents should have a healthcare practitioner supervise their children’s melatonin intake. It’s also important to purchase melatonin from reputable brands, as the wide range in quality among some supplements may lead to dosages in the bottle that differ from what’s listed on the label.

Source: New York Times

Probiotics may deserve a place alongside your sunscreen and anti-aging moisturizer. Research has found that the probiotic Lactobacillus plantarum HY7714 may improve skin hydration and the appearance of wrinkles. The double-blind trial was published in the Journal of Microbiology and Biotechnology and included 110 women, ages 41 to 59, with dry skin and wrinkles. The women were randomly assigned to receive either a probiotic powder containing 10 billion colony-forming units of L. plantarum HY7714 or a placebo every day for 12 weeks. Researchers measured the women’s skin hydration, wrinkles, skin gloss, and skin elasticity every four weeks during the study. Here’s what they found at the end of the study:

• Women taking the probiotic had significantly more facial and skin hydration, and less water loss through the skin, than women taking the placebo.
• Women taking the probiotic had a greater reduction in wrinkle depth, enhancement in skin gloss, and improvement in skin elasticity than women taking the placebo.

This study supports previous research that has found L. plantarum HY7714 may be beneficial for skin hydration and appearance, although more research is needed to understand this relationship. Taking supplements for anti-aging skin benefits is by no means a new idea: alpha-lipoic acid and vitamins C and E, among others, have also been associated with better skin health.

Source: Journal of Microbiology and Biotechnology