Microbes & Human Health

Jim Steele used to be one of the skeptics. He’d be at a conference, listening to early research on the health benefits of probiotics. Steele scoffed at the small experiments. “We would literally try not to laugh in the audience, but we’d laugh pretty hard when we went out that night,” he admits.

But slowly the punch lines gave way to revelation. Steele, a professor in CALS’ Department of Food Science, conducts research on lactic acid bacteria, with a focus on Lactobacillus species. They’re important for human gut health, critical for the production of cheese and yogurts, and are the most common probiotic genus. He knew how incredibly useful they were, but still watched with a humbling disbelief as the data on the health potential of these microbes kept getting broader, deeper and more intriguing.

Our microbiota—what we call the totality of our bacterial companions—is ridiculously complex. Each human harbors a wildly diverse ecosystem of bacteria, both in the gut and elsewhere on the body. They have us completely outnumbered: where the typical body may contain a trillion human cells, your microbial complement is 10 trillion. They have 100 times more genes than you, a catalog of life potential called the microbiome. (The terms “microbiome” and “microbiota” are often used interchangeably in the popular press.)

While our initial, germaphobic impulse may be to freak out, most of these bacterial companions are friendly, even essential. On the most basic level they aid digestion. But they also train our immune system, regulate metabolism, and manufacture vital substances such as neurotransmitters. All of these things happen primarily in the gut. “In many ways the gut microbiota functions like an organ,” says Steele. “It’s extraordinarily important for human health,” with as much as 30 percent of the small molecules in the blood being of microbial origin.

Early research has suggested possible microbiota links to protecting against gastric cancers, asthma, numerous GI disorders, autoimmune disease, metabolic syndrome, depression and anxiety. And the pace of discovery seems to be accelerating; these headlines broke in just a few months last spring:
• Mouse studies suggested that the microbe Akkersmania muciniphila may be a critical factor in obesity;
• Kwashiorkor, a form of severe malnutrition that causes distended bellies in children, was linked to a stagnant microbiota;
• Risk of developing Type 2 diabetes was linked to an altered gut microbiota.

The catch: For all the alluring promise of microbes for human health—and it’s now clear they’re critically important—we have almost no idea how this complex system works.

The human gastrointestinal (GI) tract is a classic black box containing hundreds or thousands of species of bacteria (how many depends on how you define a species). There are viruses, fungi and protozoans. Add to that each person’s distinct DNA and their unique geographic, dietary and medical history—each of which can have short- and long-term effects on microbiota. This on-board ecosystem is as unique as your DNA.

Beyond these singularities, the action is microscopic and often molecular, and even depends on location in the GI tract. Most microbiota studies are done with fecal material. “Is that very informative of what’s going on in the ileum?” asks Steele, referring to the final section of the small intestine, which is thought to be the primary site where immunomodulation occurs. “From an ecosystem perspective, fecal material is many miles away from the ileum. Is it really reflective of the ileum community?”

Coping with the Climate

It’s late May, weeks before southern Wisconsin would be locked into a scorching drought, and Kirk Leach BS’78 is worrying about the weather. The grass around his house is already brittle and yellow. A hose snakes across the driveway, trickling moisture over some sad and thirsty new aspens.

But it’s the corn planted just on the other side of his kitchen garden that troubles him. There are patches—hand-high daggers of green—but there is not enough height, not enough uniformity and just plain not enough of it coming up. “This is the last corn I planted, two weeks ago tomorrow,“ he says. “You’d expect a little more growth than that.” He squats above an empty row, probing through three inches of crumbling earth until he unearths a seed, hard and polished as if just spilled from the bag.

Every farmer has an opinion about the weather. Leach remembers when he was young and everything germinated, even seed just thrown on the ground. But in Leach’s mind it’s these little mini droughts—two or three weeks in a row without rain—that have his attention. “Whether that’s significant enough or evidence of climate change I don’t know,” he muses. “Is it because I was a young, carefree 20-year-old like my sons that I didn’t think about it? Whereas now all the responsibility is mine, and so I’m worrying about every time the next rain is going to come?”

That’s the kind of conundrum that climate change presents to Wisconsin farmers as they’re forced to adapt to wild swings in the weather. Some trust the science, but many have questions, too. They’re all practical scientists with their own, very personal sets of data and research concerns.

The reality is that they’re already adapting to climate change, just as they’ve adjusted to so many other challenges. They’re planting earlier. Schedules for vegetable canneries and cranberry harvest have shifted later to reflect consistently warmer autumns. Even the USDA plant hardiness zone map was updated this year, showing Wisconsin a half-zone warmer than in 1990.

But the forecast calls for a whole lot more, in the way of both opportunity and challenges. The simplest take is that slowly warming temperatures may help boost agricultural production by extending the growing season. But higher temperatures could also reduce corn and soy yields and lead to more pest problems. Higher annual rainfall and more intense storms could mean more soil erosion.

Those broad-brush projections are statistical abstractions for any given farmer. Wherever the weather compass spins, the challenge is to craft a livelihood from sunshine, dirt and water.

The silver lining: a generation of stress in the farm economy has left a population of survivors, farmers who are hungry for information and who are lean and agile enough to act on it. If you have the skill and luck to bring a harvest to market, prices have been good. But with input costs soaring ever higher, extreme climate events can make farming seem more like placing a bet than following a business plan.

The growing season in Wisconsin has lengthened by two to three weeks over the last half-century—a big change over a short time. But because spring can be cold and late one year and early the next, some people tend to chalk it up to variability.

Agronomy professor Chris Kucharik BS’92, PhD’97 has no doubt that it’s climate change. Simply put, the earth is like a giant car, and increasing the amount of carbon dioxide is like rolling up the car windows on a sunny day. But under the hood is a series of massive mathematical models that attempt to mimic and forecast such fundamental earth forces as wind, temperature, evaporation and photosynthesis.

Early in his career Kucharik spent a few years in the far northern boreal forests of Canada helping to fine-tune these climate models. When he grew dissatisfied with the abstraction, he decided to try something closer to home: fit agriculture into the models. Honing in on local, Midwestern problems, he became one of the state’s foremost experts on climate and agriculture, with a joint appointment in the CALS agronomy department and the Nelson Institute for Environmental Studies.

Kucharik knows better than most how dense the science can get, but he is adamant that evidence for climate change is clear and overwhelming. In fact, he can even show how it’s helped agricultural productivity in some locations in Wisconsin over the last few decades. It’s not easy to tease out, because crop genetics and management practices have significantly improved over the same period. But trends in precipitation and temperature during the growing season from 1976 to 2006 explain more than a third of the variability in corn and soybean yield trends, he says.

The bad news is that this productivity trend might be hurt by continued warming without adaptive measures. Indeed, for each additional Celsius degree of future warming, corn and soybean yields could potentially decrease. With luck, modest increases in summer precipitation could offset this. Unless, of course, it fails to rain at all.

Growing Future Farmers

REBECCA CLAYPOOL MS’09 is not color-blind. She knows her house is orange and that the steel shed is blue. Her hands planted the fulsome rows of lettuce and kale and chard—now lush, late-season waves in eight shades of green. She marvels at the funky purple berries in her hedgerow.

But that red barn? “I always wanted a yellow barn,” she explains. But painting is low on the chore list at the Yellow Barn Farm, established in 2010. Claypool’s just finished her second growing season and her mind is already on next year—how much to plant, procuring more compost, relocating a greenhouse. “Some day I will paint it yellow,” she vows.

Born and raised East Coast and urban—in West Philly, to be precise—Claypool is two generations removed from farming. The daughter of a school nurse and an architect, she attended Quaker school and a small liberal arts college in Maine. But on a high school exchange program she caught the farming bug. “I harvested my first potatoes, milked my first cows, gathered my first eggs,” she remembers. “I was looking for something, and it just clicked.”

After college Claypool learned cheese-making and worked on established organic vegetable farms in Pennsylvania and Minnesota. She remembers driving through the Midwestern farmscape for the first time and the revelation of that rich, dark soil unfolding to the horizon. Eventually she wound up studying agroecology at CALS, where she still works as a researcher on the Veggie Compass, a tool that helps farmers determine production costs. A year after finishing her master’s degree she took on 10 acres in Avoca, west of Spring Green.

Claypool’s young operation is pocket change in Wisconsin’s $60 billion ag economy, but it poses a pressing question: Who are our future farmers? Only about 2 percent of Americans now live on farms, and only half of them actually farm. Rural populations continue to age and decline. Farm kids used to be the logical next generation, but that’s now a very small pool of potential applicants to cultivate the farm belt. And agriculture has become so capital intensive that if a farm kid wants to farm, generational transfer is tricky.

Politicians always tout the hiring of more police officers or teachers, but during Farm Bill hearings in 2010, U.S. Secretary of Agriculture Tom Vilsack abandoned his prepared remarks to extemporize on how the country needs 100,000 new farmers. “I think it’s important that we focus an aggressive effort on helping beginning farmers begin,” he argued.

On the state level, Paul Dietmann concurs. “We need people to work the land,” says Dietmann, until recently the director of the Wisconsin Farm Center at the Department of Agriculture, Trade and Consumer Protection (DATCP). “The average age of a farmer in Wisconsin is 55 and keeps getting older and older. At some point we’re not going to have enough people to take over that working land.”

Farm kids are still important players in the future of agriculture, but there’s also a new breed of grower heading for the land. The USDA reports that about one-fifth of all U.S. farms are operated by a beginning farmer, defined as someone who’s been in the business less than 10 years. Demographically speaking, these new farmers—when compared to established agriculturalists—are more likely to be female, non-white or Hispanic. And while they generally are younger, in 2007 nearly a third were 55 or older.

What can be done to support and encourage those who see the opportunity and accept the myriad challenges of farming? People and programs across CALS are trying to answer the call.

In January of 1886, 20 young men gathered on the wintry Madison campus for an innovative 12-week indoctrination in agricultural arts at CALS. They sat through 60 lectures on everything from road building to manure; more than a third of them focused on veterinary concerns. One hundred and twenty-six years and several agricultural revolutions later, the Farm and Industry Short Course is now the longest-running agricultural curriculum in the state.

Its intensive certificate program remains a crash course in essential farm skills, with more than 50 courses ranging from dairy cattle reproduction and business management to pest control and welding. Coursework runs for 15 weeks outside the growing season and helps beginning farmers launch into a challenging, changing business environment. But that’s not the only farmer training on campus. In 1989 CALS opened the Center for Integrated Agricultural Systems (CIAS) as a research center for sustainable agriculture. It offers an array of workshops, most of them two or three days, for beginning dairy and market farmers.