How yogurt might’ve saved humanity and could again (or something)
The nutritional aspects of yogurt should not be ignored for reducing risk of chronic health conditions and improving nutrient status around the world.
In developed countries, yogurt could help reduce body weight, blood pressure, and metabolic disease, while strengthening bones. In developing countries, it could help correct nutrient deficiencies and improve immune and gastrointestinal health. The potential from yogurt on improving health could save the U.S. and other countries billions of dollars over time.
These were the messages received by those who attended the 1st Global Summit on the Health Effects of Yogurt in Boston on April 24. The full-day event was hosted during American Society for Nutrition’s Scientific Sessions at Experimental Biology 2013 in partnership with Danone, the Nutrition Society, and the Dairy Research Institute.
The summit was organized as part of a new multi-year project, called the Yogurt in Nutrition Initiative, to examine and document the health effects of yogurt and to stimulate new research and communication of scientific findings to health-care professionals and the public.
Looking over the program of the summit, the list of speakers reads like an impressive “who’s who” of dairy nutrition research from all around the world. Each of the scientists addressed different aspects of dairy and yogurt in their talks throughout the day.
“We’ve pulled together a renowned group of experts in public health to help guide this initiative,” said professor of nutrition Sharon Donovan, of University of Illinois at Urbana-Champaign and ASN’s past president, who participated in organizing the summit.
A long history of yogurt’s use
Professor of international nutrition Andrew Prentice, Ph.D., who directs the MRC International Nutrition Group based at the London School of Hygiene and Tropical Medicine (LSHTM), opened the morning session by giving a generalist’s overview about the role that dairy and yogurt play in public health and said that lessons can be gleaned from history.
He said that domestication of milk-yielding animals and the technology for fermenting milk dates back at least eight thousand years. The use of lactic acid bacteria for fermentation kept milk longer without it spoiling and may have been especially useful for the survival of these early dairy consumers.
It’s a familiar story. But what’s really fascinating is the evidence found within the human genome, Prentice said. The ability to digest lactose sugar from milk (lactose tolerance) is now widespread among populations of Europe, the Middle East, India, and in Africa. The story gets more interesting when learning that lactose tolerance has evolved independently at least four different times, he said. And he cited the work of Sara Tishkoff, Ph.D., of University of Pennsylvania, of which I’ve written previously about, who studies the convergent evolution of lactose tolerance in different populations.
“What this tells me is that the ability to digest lactose in older childhood and adulthood has been incredibly important in our evolutionary history,” Prentice said.
Whatever the cause was behind this selection may highlight the reason for dairy’s importance and may be informative for human health. One hypothesis is that dairy and yogurt allowed mothers to wean their babies more quickly, allowing them to become pregnant again, reproducing more often — a tale of fertility selection. Dairy’s use by early humans would’ve also given them a strong advantage for meeting nutrient needs.
Today, there is a large variation in worldwide intakes of dairy. Interestingly, in some populations that have been without dairy, there may exist adaptations for low calcium intakes. But there’s no question that dairy conferred a strong evolutionary benefit over time, Prentice said. After all, dairy is highly nutrient dense in comparison to other natural foods. Milk and eggs, Prentice said, one could say are among the only natural foods uniquely designed by evolution to contain all the nutrients needed to sustain a life.
Better healthcare through yogurt
According to UC Davis adjunct professor of nutrition David McCarron, the healthcare savings today in the U.S. by increasing more dairy foods like yogurt could reach $26 billion in the first year and exceed $200 million in five years. These estimates, which he published with his colleague Robert Heaney, were based on accumulated data from longitudinal studies and randomized controlled trials related to chronic disease, particularly cardiovascular disease.
McCarron also discussed the work of other researchers such as Ashima Kant as well as Dariush Mozaffarian and their colleagues in evaluating how yogurt could affect aspects such as body weight, chronic disease, and premature death. The research suggests dairy foods in general could improve health and longevity and that yogurt consumption, specifically, could predict prevention of weight gain more than any other food.
“Yogurt just sticks out above anything else,” McCarron said, for reducing risk of obesity, diabetes, and so on. There still is a need for randomized controlled trials, he added, but the evidence is enough that government should consider encouraging more yogurt consumption. He recommended getting “Congress on a yogurt diet.”
Yogurt comes out on top for nutritional impact in modern methods of nutritional scoring too, reported Vic Fulgoni, who is the senior vice president of Nutrition Impact, LLC. His consulting firm uses the Nutrient Rich Foods (NRF) Index to identify healthy, affordable foods based on U.S. Department of Agriculture (USDA) nutrient composition and food price data sets. Fulgoni cites Adam Drewnowski’s work in the American Journal of Clinical Nutrition that found NRF scores of milk and, particularly yogurt, ranked highest for being lowest-cost sources of protein and calcium.
Another nutritional scoring method developed by David Katz, M.D., of Yale University is the NuVal Nutritional Scoring System, which uses the ONQI (Overall Nutritional Quality Index) algorithm. Fulgoni said Dr. Katz’s scoring system also finds yogurt to be high and that novel approaches using regression analyses and weight of nutrients are expected to as well.
The event followed with workshops and additional talks about yogurt and gut health, bone health, weight management, and prevention of metabolic diseases. Following the coverage on Twitter of all the benefits that yogurt could bestow on public health was Ottawa University assistant professor and author of the Weighty Matters blog Yoni Freedhoff, M.D., who quipped, “I ate yogurt yesterday and on the way home, I lifted a car!”
Dairy Research Institute president Greg Miller, Ph.D., who attended the full event, shared a few highlights via Twitter. From the talk given by Purdue University Connie Weaver, Ph.D, Miller reported that “The majority of Americans are falling short of meeting dietary recommendations for dairy” (3 servings per day) and that that is a concern, especially for adolescent females. Miller also shared from the talk given by UC Davis professor Bruce German that yogurt’s content of oligosaccharides and Bifidobacteriam could influence the gut microbiome improving GI health. He also shared from nutrition and exercise professor Arne Astrup, M.D., that a recent meta-analysis found that dairy decreased cardiovascular risk while other studies showed it could protect against loss of lean body mass (sarcopenia).
What of flavored yogurt?
A few nutritionists at the summit expressed skepticism over all the focus on yogurt. Among the comments expressed was that nutritional scoring didn’t consider palatability and that yogurt’s added sugars considerably reduced its nutritional score. Donovan compared the topic of added sugars in yogurt to the current controversies surrounding chocolate milk in schools. “The main contention is when it’s flavored with added sugars,” she said, “but the yogurt’s nutritional score is still higher versus other foods. How do we decide if it’s right for children?”
In a conversation with me during the early morning break, registered dietitian David Grotto, who is the acclaimed author of 101 Foods That Could Save Your Life, told me that while researching his book, yogurt also kept coming up on top as one of the best foods to include in a person’s diet for long-term health.
The issue is that we eat so little of it in the United States, Grotto said. Compared to Europeans who eat on average 1 cup of yogurt per day, Americans on average only eat 1 cup of yogurt per week. Older males in the U.S., in particular, didn’t seem to “get the memo of the health benefits of yogurt and yet could benefit the most from it.” Yogurt servings in the U.S. tend to be smaller and not as filling, which Grotto says could help explain why his older male patients decline to consume it.
When I pressed Grotto about the question about added sugars in U.S. yogurts, he said the truth of the matter is that Americans just have high threshold for sugar in comparison to Europeans. “Children will not eat yogurt unless it has sweetness,” he said. “That can also be trained at home. Do we draw the line in the sand and gut all of yogurt with added sugars? If the sugar in yogurt was contributing to the obesity epidemic, I’d say ‘yes, that would make sense’, but if you look at yogurt consumption overall, that is not the smoking gun.”
Grotto added, “I’m not saying we shouldn’t be concerned about added sugars in yogurt. But I’ve got my own bias for natural foods. That sweetness could be added through a berry sauce as well as chunks of fruit. For me, there’s no reason we can’t get consumption up and still meet that American sweet tooth.”
Not someone who enjoys yogurt sweet? You could take a cue from a new study that suggests enjoyment could be enhanced by pairing yogurt with caffeine from a caffeinated beverage such as coffee or tea.