UW nutritional research focuses on dairy, inflammation
MADISON - There’s a lot of buzz in some parts of the dairy industry — and among consumers — about A2 milk. A CBS News story recently highlighted the push toward A2 milk and how some people think it relieves them of dairy intolerance symptoms.
With DNA testing of dairy cattle, it’s possible to sort out those cows that produce only A2 beta casein protein in their milk rather than the more common A1 protein. Most cattle genetics companies are publishing the results of the A1 or A2 genetic profile on their bulls so herd owners can choose to breed for this protein profile in their cows in case there’s ever a premium to be paid for that kind of milk.
During at presentation at the recent World Dairy Expo in Madison, University of Wisconsin-Madison food science professor Bradley Bolling noted that A2 milk is gaining recognition. He is focusing research on food chemistry, nutrition and inflammation – including fermented dairy products like yogurt and A2 milk. The gut, he said is very important to proper functioning of a human body’s immune system as microbiota there interact with the body’s cells.
Inflammation, he noted, can be a good thing because we need it for our immune systems to function properly -- to produce healing after an injury, for example. But chronic inflammation differs from that “good” kind of inflammation because it continues at low levels and remains unresolved. “It perpetuates the damage in the body,” he said.
Chronic inflammation can be linked to a host of ailments – Alzheimer’s disease, arthritis, multiple sclerosis, diabetes, cancer and cardio-vascular disease, he noted, and these chronic conditions account for up to 90 percent of health costs in the nation’s population.
As the facts about inflammation gain greater acceptance, there has been interest in how food can affect this chronic inflammation in the body. “Nutrition can be confusing,” Bolling said. Often nutritional research gets published and into a national conversation before everything is known.
Epidemiological studies, he explained, are those that survey lots of people and look for biomarkers in those people. The “gold standard” type of research is what are called human intervention studies that group people into two categories and then give them the “treatment” versus a placebo – something so they don’ know they aren’t getting the treatment. “The one drawback to this kind of research is that it’s incredibly expensive.”
Health claims for a food or a supplement must have scientific consensus as in the case of a link between consumption of calcium and prevention of osteoporosis. “Consumption of calcium helps build strong bones,” is a statement that has scientific consensus, he adds.
Recently some foods have started to make claims related to their anti-inflammatory properties. The Federal Trade Commission, says Bolling, has gone after companies for making claims that weren’t scientifically proven. Such was the case for the marketers of “cactus juice” who claimed their product could reduce inflammation and detoxify the body. They were forced to pay a $3.5 million penalty for making false claims, he said.
Bolling has focused his energy on dairy products as they relate to inflammation. There have been more than 25 clinical trials in this area. He and his research group focused on yogurt and inflammation to see if fermented dairy products could have an anti-inflammatory effect.
They had study subjects eat a cup and a half of yogurt per day for nine weeks while the “placebo” group ate soy pudding with the same calories and vitamin D content at yogurt. At the beginning of the study all the subjects were given a large meal to induce inflammation in their gut so response to that inflammation could be observed.
They found results indicating that eating yogurt helped improve the intestinal barrier between food and bloodstream – related to the so-called “leaky-gut” syndrome -- and that eating low-fat yogurt has a modest anti-inflammatory effect.
Bolling also outlined research that has looked into A2 milk and its potential to reduce inflammation. When people consume milk containing the A1 protein, he explained, it releases the peptide beta-casomorphin 7 (bcm-7) which sets up the intestines for inflammation. “This is completely separate from lactose intolerance,” he said.
When the beta casein from A2 cows is digested in the human gut, there is no production of the bcm-7 peptide fragment. This scientifically proven fact has been widely accepted for many years and has led many in the field of nutrition to conclude that A2 milk is less inflammatory than conventional A1 milk.
In one study, Chinese adults with self-diagnosed “milk intolerances” consumed A1/A2 milk for two weeks, then went for two weeks without milk and then consumed only A2 milk for two weeks. In this exploratory study, Bolling said, no difference in inflammation was found.
Some who heard Bolling’s presentation felt that a two-week study wasn’t sufficient to get good results.
In one study A2 milk consumption showed no effect on “digestive comfort” but others show that it does. Plenty of people offer their own unscientific experiences that show a dramatic improvement in their intestinal function when they switch to A2 milk. “It’s really an emerging area,” Bolling said. “It’s a field that’s constantly dynamic.”
In the future, so-called medical foods can be developed, but health claims related to reducing the risk of disease can be tricky. It’s possible that some day there may be foods developed to fit with a person’s specific risk profile based on their genes, lifestyle, medications and environmental risks.
To get the best possible research results, he said, would entail following large numbers of people for at least five years, as was the case in the Mediterranean Diet study. That would be a way to best determine if A1 or A2 milk had an effect on glucose response and intestinal inflammation. “Population makes all the difference in these studies,” he added