Got Milk?


Connie Weaver, distinguished professor and head of the Department of Nutrition Science, serves at the nation’s highest level of her field, including serving on the US Dietary Guidelines Advisory Committee, which advises the federal government on the science to set the nutritional guidelines. Photo by Tom Campbell

Scientist’s research does a whole lot of good for the body

By Amy Patterson Neubert

Do you remember your parents’ nightly nagging to “Drink your milk” or find yourself echoing the same mantra to young kids each night? Well, you can thank Purdue’s Connie Weaver for making the push to drink more milk as part of the American household routine.

Weaver, distinguished professor and head of the Department of Nutrition Science, is the scientist who in the 1990s identified how milk consumption and calcium intake are musts in adolescence because of peak bone development. Her findings determined how much milk is recommended people drink today.

“Connie’s work has transformed thinking about mineral nutrition, especially calcium, in women,” says George P. McCabe, professor of statistics and a collaborator since the 1990s. “She is an excellent example of why universities need to invest in long-term, fundamental research. The impact of her work, while it has played out over the past 20-plus years, will impact people for generations.”

Today, Weaver serves at the nation’s highest level of her field, including working with the Institute of Medicine, the health arm of the National Academy of Sciences. She fields dozens of media calls each year, and national organizations call on her to serve as spokesperson and weigh in on nutrition topics, such as the pros and cons of chocolate milk in schools. In 2005, she served on the US Dietary Guidelines Advisory Committee, which advises the federal government on the science to set the nutritional guidelines. She was part of the team that consulted on the Food Pyramid’s evolution to being known as “My Plate.”

“Translating the discovery into policy that ultimately translates to the consumer is probably the most important aspect of my career,” says Weaver, who came to Purdue in 1978 after earning her doctorate from Florida State University. Her love of nutrition science was inspired by 4-H and helping her mom can more than 2,000 units of vegetables and fruits for their family farm every summer. She was a first-generation college student from Northeast Oregon who studied chemistry, food science, nutrition, and plant physiology.

“I love the discovery but if it just stays in a journal article on the shelf it does not accomplish very much,” she says. “So translating it into policy is the ultimate impact.”

Skimming the surface

Calcium is one of four shortfall nutrients according to the Dietary Guidelines for Americans Advisory Committee. The other nutrients are Vitamin D, potassium, and fiber.

More than 70 percent of calcium in an individual’s diet comes from fluid milk, and the reality is that milk consumption has been on the decline.

“When I grew up you would sit around the table at family meals and milk was the beverage on the table and everyone enjoyed it,” Weaver says. “And that’s disappeared. So if you don’t have the family sitting for meals and pouring glasses of milk, what is it replaced with?”

People are eating out more and on the go. They have options of unlimited refills of soft drinks and it is easier to tote around an iced 44-ounce beverage rather than a glass of milk.

When a person’s body does not consume enough calcium, their bones are more likely to weaken, and possibly develop osteoporosis later in life. The assumption, 30 years ago, was that weak bones was something an older person just had to deal with. So, why would the pediatric perspective matter?

But Weaver, who focused on mineral absorption, wanted to know more about the role calcium played in bone health at younger ages and what that meant for the long-term.

A different kind of lab

To accurately measure how calcium is absorbed, retained, and released by bone, scientists would need to know exactly what someone ate; take regular blood samples; and monitor their excretions. How could scientists accurately collect such data? And, more importantly, who would pay for it? Weaver proposed the research environment, known as Camp Calcium, as a fun summer camp for adoescents.

At this time, about 1989, Purdue Agriculture was refocusing research efforts to support research that was relevant to the needs of people in Indiana and beyond, says Victor Lechtenberg, who was dean of agriculture at the time.

“We were also interested in extending beyond simply agricultural production and paying more attention to end uses of agricultural products, including nutritional aspects,” he says. “Camp Calcium appeared to hit both marks, and was, thus, an attractive project.”

The Camp Calcium format was an ultimate six-week slumber party setting where campers could be observed around the clock. The teenagers lived in a sorority house or residence hall, while enjoying campus entertainment, playing at the recreation center, and learning about college careers. Their food intake would be monitored; blood samples could be taken; and their sweat collected by way of special suits. The camp programming also focused on learning about science.

The data from the first camp of 14 white teenage girls was compared to adults working the camp, and Weaver discovered that bone was built by calcium when people were young: 25 percent of their adult bone mass was built during these teen years of rapid bone growth. In fact, the women, ages 19–30, whose bone mass was measured in comparison, were already starting to lose bone.

That meant that what a 13-year-old girl consumed could affect her risk for osteoporosis when she would be in her 70s. It was novel concept for the time.

“Living side-by-side and on the same diet, we found out how over the hill the counselors were in terms of building bone,” Weaver says. “Nobody over the age of 21 was in positive balance. The best they could do after that was hold onto the bone they had built up by age 21.”

Weaver determined the optical calcium daily intake was 1,300 milligrams for healthy bone mass. Or three cups of dairy a day.

The camp’s legacy

There have been 11 Camp Calciums, the last in 2010, and the research parameters were expanded in later camps to include boys and focus on racial differences. Weaver, as well as her team, collaborating colleagues and visiting researchers, have looked at the role Vitamin D plays in calcium absorption, whether dairy helps regulate weight and the effects of sodium. For example, for every ion of sodium excreted, it pulls out the same amount of calcium excreted through urine. This is why high salt diets are not good for bones.

“Your body’s bones are trying to stay in balance with sodium,” Weaver says. “So the more salt, the more you excrete in urine and the more it is pulling out calcium. We compared this in whites and blacks, and we found out amazingly how different the two races were. The blacks did not excrete all the extra sodium.”

While this is better for bones, it is worse for blood pressure.

“Blacks have higher incidence of hypertension than whites but lower risk for osteoporosis,” Weaver says. “We think this is the mechanism. It’s a characteristic that probably evolved from living at the equator. Their biological need was to hold on to water, so if the body hoards sodium it holds on to water, which was the bigger priority.”

In total, from 11 camps and 381 teenagers participating Weaver has found:

» Even though boys have larger skeletons, they utilize the same amount of calcium — 1,300 milligrams — thanks to their genetics and insulin.

» Blacks use calcium more efficiently than whites and build 12 percent stronger skeletons on average.

» Chinese-American boys and girls achieve maximum calcium retention at a lower daily calcium intake than white boys and girls.

» Calcium needs are influenced by a person’s weight. The more a child weighs, the more calcium they need. If their bones don’t grow to proportion of their body, they are more prone to fractures.

Lechtenberg, who calls Camp Calcium a “home run,” says the return on investment from the initial $50,000 grant to launch the idea can be measured in a variety of ways.

“The most important aspect of return on investment is embodied in the impact that the research has had on people and the way nutrition and medical professionals look at calcium nutrition in young women,” Lechtenberg says. “Much has changed in 25 years — much of the change due to Connie’s programs and her impact nationally and internationally. This sort of return on investment is very difficult to quantify in dollars, suffice it to say that it has been huge.”

It also has attracted more than $20 million in grant money from external funding, including sources like the National Institutes of Health. The funds supported the training of dozens of graduate students and provided employment opportunities for undergraduates as well.

“More directly, we know that every million dollars of research funds coming to Purdue results in employment of 7–10 people for a year. The external funding to this program over the past 25 years has provided hundreds of people years of employment for Hoosiers,” he says.

Weaver and her collaborators are building a foundation for a future Camp Calcium that would be even bigger and focus on both genders and a variety of races to study hypertension, one of today’s greatest chronic health concerns increasing in young people.

And another discovery that Weaver and her team in partnership with Purdue’s PRIME lab is known for in the field is their work on the development of the isotope method for rapid screening of bone loss. This is Calcium-41, and the discovery was funded by the National Institutes of Health as part of the Botanical Research Center. She is one of the pioneers to use this bone tracer, which is measured by accelerator mass spectrometry to study bone turnover in humans and animals.

“When you develop a whole new method that can take testing in hundreds of people for four years down to 50-day interventions in a dozen people, we can change how we do research,” she says.

Fortified in the field

Because of Weaver’s discoveries, she was selected to serve on the two-year federal government committee that would provide recommendations for the 2005 dietary guidelines.

“I thought that was the most important thing I had done to date in my career because the product of that becomes law,” she says. “Every dollar spent in the US on any food nutrition program from the federal government must follow these guidelines. This includes schools, the military, and any nutrition assistance program.”

Weaver’s also been heavily involved in advising industry groups, and she has taught a Purdue undergraduate class since 1984 that brings different food industry representatives to campus to talk to students and meet with faculty. But, there also can be a stigma when researchers are so involved with industry activities.

“My philosophy is if I’ve had this much training and opportunity invested in me, I owe it to all the different stakeholders who should have access to my knowledge and skills. That is government, industry, and academia,” she says. “And that is how I live my life. I train graduate students who will go into any of those three venues. I interact on advisory committees or collaborate on projects. There are some who say it is conflicted if you interact with industry but they are the ones who are going to feed Americans. It’s our duty to provide the best recommendations and knowledge that we can. It has the biggest impact for translation into the food supply. Why would I not work with them?”

Looking at the glass half empty or half full

On campus, Weaver is leading Purdue’s new Women’s Global Health Institute, which is building a foundation of research to focus on prevention related to various women’s health issues such as nutrition, cancer, and Parkinson’s disease. Off campus, she was appointed to the National Institutes of Health’s Women’s Health Research Council, which helps decide priorities and marketing related to women’s health across all the institutes. And, she also will continue her work with the Institute of Medicine.

Looking toward industry, Weaver expects her next spokesperson and advisor role will be on guiding industry, scientists, and advocates on better communicating and understanding regarding the latest trends in labeling of marketing food as organic, natural, and processed foods.

“Everyone is not on the same page so they can’t have a good conversation that will ultimately benefit consumers,” she says.

And of course, she’ll continue working on calcium.

“There has been a lot of imagination into repackaging yogurt, and we need more creativity on healthy foods in general. Dairy of course, but whole grains, fruits, and vegetables too. I feel like I’m part of the messaging to eat healthier, and it feels good to help people who can really make a difference on American health,” she says. “But milk intake is still declining so we’ve got more work to do.”

Amy Patterson Neubert (LA’99, MS LA’08) is a health sciences and news writer for Purdue’s Office of Marketing and Media.