Every week, we’re bringing you a roundup of the latest health and wellness news to hit the wire. This week, we cover new research on optimism and longevity, advice from world health officials on microplastics in water, and a government move to expand medical marijuana research.

Cheer up, you’ll live longer

Here’s one more compelling reason to look on the bright side—you’ll live longer. Scientists, combining data from two large, long-term studies covering more than 70,000 men and women, found that optimistic people live as much as 15 percent longer than pessimists, according to this Science post.

Men and women filled out questionnaires assessing their feelings about the future. After controlling for health conditions, as well as behaviors around diet and exercise and other demographics that would influence longevity, scientists were able to show that the most optimistic women (top 25 percent) lived an average of 14.9 percent longer than their pessimistic peers. For men, the most optimistic lived 10.9 percent longer on average.

Published in the Proceedings of the National Academy of Sciences, the research showed that the most optimistic women were also 1.5 times more likely to reach the age of 85 than the least optimistic women. The most optimistic men were 1.7 times more likely to make it to that age.

Researchers speculate that the optimistic mindset may help encourage healthy diet and exercise habits and help individuals better handle stress while discouraging unhealthy impulses such as smoking and drinking.

Microplastics in water: Not a human health risk?

You’ve probably seen the startling pictures of tiny, colorful pieces of plastic littering beaches and bodies of water. And while this surge of tiny plastic trash is having a devastating effect on some wildlife, World Health Organization officials said this week that the levels of microplastics in drinking water don’t appear to be risky for human health, although they acknowledged more research is needed.

Microplastics are created when man-made materials, such as plastic water bottles, storage containers and toys, break down into pieces of less than 5 millimeters or about one-fifth of an inch.

The U.N. health agency said that while these plastics have become “ubiquitous” in the environment and have been found in both tap and bottled drinking water, it doesn’t mean “we have a risk to human health.” Bruce Gordon, the WHO’s coordinator of water, sanitation and hygiene, says that consumers shouldn’t “necessarily be concerned” about these materials, which many of us have been ingesting for decades. Still, he acknowledged that the data available on microplastics is admittedly “weak” and that scientists in this Associated Press article on NBC News say more research is needed to really understand the long-term consequences for smaller organisms and humans.

Did medical marijuana research just get a boost?

Research on marijuana’s medical benefits has long been hampered by restrictions on cultivating the plant, even in a laboratory.

This week, the federal government said it would begin processing dozens of pending applications for permission to cultivate the plant for scientific research. The U.S. Drug Enforcement Administration’s decision comes after several years of delay for some applicants and a lawsuit by one cannabis researcher, according to NPR.

Despite the legalization of marijuana for recreational and medicinal use in many states, scientists who wanted to study the plant have had only one place to get it: a facility at the University of Mississippi, which contracts with the National Institute on Drug Abuse. It’s an arrangement that Dr. Sue Sisley of the Scottsdale Research Institute, who filed that federal suit, has called a monopoly. The decision to move forward with processing the applications comes right before a deadline for the government to respond to Sisley’s suit.

Marijuana’s status as a Schedule 1 controlled substance by the government, reserved for drugs with “no currently accepted medical use and a high potential for abuse,” has hindered research that could potentially find promising new treatments for chronic conditions.

But just how soon researchers will get the green light to begin growing is unclear, and the DEA says it still needs to roll out rules for those growing for scientific research, which has some researchers speculating that there could be more foot-dragging ahead.

Moreover, it could take years for researchers to begin producing cannabis in their labs that meets research standards. But scientists say it could be an important first step in figuring out whether cannabis is indeed a cure.

Photo credit: Kyle Glenn, Unsplash