This list isn’t about charity or the oft-touted “corporate social responsibility” initiatives that companies engage in and promote with gauzy ads and Ed Sheeran covers or coffeehouse folk music. Rather, this is the worthwhile stuff they manage to accomplish while also making a buck—which can have the useful side effect of making the efforts sustainable.

This year we found a slew of companies taking on challenges of health and wellbeing. Mighty drug giant Merck and Aucma, a smaller Chinese refrigeration company, are each trying to halt the spread of Ebola—the first, by co-developing an experimental vaccine against the virus; the second, by manufacturing the portable storage containers that keep this sensitive vaccine at ultra-low temperatures in equatorial Africa, even in rural villages without electricity.

Weight Watchers, meanwhile, is taking on an epidemic of a different sort: obesity. And it’s doing it without fad diets or other unsustainable regimens. What’s Weight Watchers’ secret plan? Eating well and exercising. Go figure.

In India, where there are nowhere near enough doctors to serve the nation’s 1.3 billion residents, Johnson & Johnson is helping local health care workers learn how to do essential, but minimally invasive, surgeries. Insurer Humana is testing an initiative to address loneliness and food insecurity among its covered members, hoping to improve health outcomes and reduce its own costs in the process. Dental supply company Henry Schein is working with dental schools to bring oral care to places that never had it—from refugee camps in Africa to poor Caribbean communities.

Abbott is teaching smallholder dairy farmers how to produce better milk. Why? Because the company’s $7 billion nutrition business requires a steady stream of high-quality milk. And then there’s Dexcom, a San Diego medtech company that connected continuous glucose monitoring with a smartphone—making life better and easier for a huge number of people living with diabetes.

That’s what we call changing the world.

For more, please read our fourth annual list on Fortune.com—and while you’re at it, check out our previous years’ rosters. You can find our Change the World lists going back to the inaugural one in 2015 here as well.

DIGITAL HEALTH

Gene editing for... depression? The prospect of CRISPR gene-editing has led to an onslaught of breathless futurist predictions about what the tech may eventually be able to do. It's best to take most of those with a grain or ten of salt; but that's not to say the genome-twisting technique doesn't have fascinating implications. The latest? A joint effort by Washington University School of Medicine in St. Louis and the Boston-based biotech Sage Therapeutics to harness CRISPR to fight depression in an entirely new way from existing therapies. "Most antidepressant drugs target serotonin receptors, aiming to boost serotonin, a chemical thought to regulate mood and social behavior," the researchers explain. "Using CRISPR technology, the scientists have been able to target an altogether different type of receptor called delta-type GABA receptors. They think that natural mood-boosting substances in the brain can target these receptors." If the method actually does work out, it would be a significant advance given that antidepressants have a fairly low level of efficacy.

INDICATIONS

HHS Secretary Azar flexes on the drug rebate debate. Health and Human Services (HHS) Secretary Alex Azar (a former pharmaceutical executive from Eli Lilly) is talking some tough talk on drug rebates for pharmacy benefits managers. Azar claims that his agency essentially has the power to unilaterally eliminate these rebates—rebates which have been one of the Trump administration's major targets in an effort to fight high drug prices. PBMs, it goes without saying, have pushed back hard against that line of argument. (Reuters)

THE BIG PICTURE

The big business of Vitamin D. Kaiser Health News' Liz Szabo is out with a fascinating piece about Dr. Michael Holick, the physician whose dedication to talking up the benefits of Vitamin D helped lead to an uptick in its sales and, in the process, his own personal wealth. It's a nuanced piece about the interplay of medicine and its myriad financial undercurrents, and well worth your read. (Kaiser Health News)

REQUIRED READING

How a Big Bank Fueled the Green Energy Boom, by Matthew Heimer

PepsiCo Is Acquiring SodaStream for $3.2 Billion, by Beth Kowitt

German Researchers Have Built a Quantum Transistor Using Just a Single Atom, by David Z. Morris

How Shareholders Win When Companies Change the World, by Clifton Leaf