Dr. Walter Willett comes from a long line of dairy farmers, yet he says people are drinking more milk than they need.
The Harvard University expert on nutrition says it’s not essential that we have any dairy at all.
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“Most of the world does not consume dairy products and (yet) they grow up and become faculty members at Harvard, too,” says Willett, who will be in Toronto and Montreal next week to receive the 2013 Bloomberg Manulife Prize for Promotion of Active Health, a $50,000 research grant administered by McGill University and awarded annually to an academic whose work has the power to make “real and lasting change to the lives of North Americans.”
The dairy story “is very complex and we don’t have all the answers,” said Willett, chair of the department of nutrition at Harvard School of Public Health.
“But there has been this general belief that we need to consume a lot of milk because that will prevent osteoporosis and fractures. Yet studies that have looked at milk and dairy consumption do not show that people who drink more cow’s milk have lower fracture risk.”
The Boston Globe has described Willett as “the world’s most influential nutritionist,” a quiet-spoken physician and academic who starts most days with whole grains for breakfast and a multi-vitamin, multi-mineral supplement with extra vitamin D. He rides his bike four kilometres to work every day (“I’ve got steel studded mountain bike tires so I can keep riding in the winter.”) He likes to eat — “I could easily weigh 50 more pounds than I weigh now if I wasn’t careful” — although almost never red meat.
Two years ago, Willett, who grew up in the Midwest, where a “good meal” meant roast beef, potatoes and gravy, was part of a Harvard team that published a study linking red meat consumption, especially processed meat, with a higher risk of an early death. He was among the first to warn of the dangers of artery-clogging trans fats and a large focus of his research now is how diet in childhood influences the risk of cancer and other conditions later in life.
“This man has led amazing teams who have made amazing discoveries in nutrition. We are indebted to him for that,” said Dr. David Jenkins, Canada Research Chair in nutrition and metabolism at the University of Toronto.
“Nobody is saying that these foods are toxic,” Jenkins said. “What we’re saying is, is it essential that we should be focusing on them so much?”
“I think that it’s very important that people with the nutritional stature of Dr. Willett make comments about things that we may be getting overenthusiastic about,” Jenkins said. “There’s always a tendency when it doesn’t sound right (to have) a knee-jerk response to reject. But they’ve got an enormously good track record of defining things that end up being important.”
When it comes to controlling weight, Willett says the environment is stacked against us from unsafe streets and parks to a massive food industry that spends billions creating and marketing foods that are “maximally seductive.” Children, especially, he says, are being “massively exploited and encouraged” to eat foods damaging their health. “We can’t let this go on.”
Willett has dedicated much of his research life to challenging food polices he believes aren’t grounded in science.
One of his latest targets is cow’s milk.
“Humans have no nutritional requirement for animal milk, an evolutionarily recent addition to the diet,” Willett and his co-author, David Ludwig, of Boston Children’s Hospital, wrote in an article published last September in the journal, JAMA Pediatrics.
Earlier this month in the same journal, Willett and his colleagues reported on research involving 96,000 women and men from their two long-running, decades-long studies, the Nurses’ Health Study and the Health Professionals Follow-up Study. The team found that high milk consumption during the teen years (13 to 18) didn’t translate into a lower risk of hip fractures when people were older.
‘Nobody is saying that these foods are toxic’
“We know that high milk consumption during childhood leads to greater height,” Willett said, “which is a strong risk factor for some fractures.” High dairy consumption has also been linked with an increased risk of cancer later in life, including breast and colorectal cancer.
Willett is not saying that people should give up dairy. (He doesn’t drink cow’s milk, per se, though, “I do enjoy some cheese and yogurt in moderation.”) The Canada Food Guide recommends adults consume two to three servings of milk and alternatives a day, depending on age. Willett believes that “something in the one to two servings a day (range) would be a better level of consumption.
“We don’t have the final answers, but it looks like that’s probably better,” he said.
“It also looks like yogurt may be one of the better ways to consume dairy products.”