During a presentation at the 2018 Western Canadian Dairy Seminar, Harvey Anderson said the original food guides were designed to maintain nutrient adequacy. However, by narrowly focusing on nutrients, the physiological functionality of certain foods (particularly dairy) may be overlooked.
As Health Canada looks to revise the current food guide, it published some guiding principles last year. These principles mentioned the consumption of “protein-rich foods” with an emphasis on plant-based sources and did not explicitly include dairy and other animal-based foods.
“That, of course, has a lot of people upset. We’re not even sure if we’re going to have a meat group or dairy group, or how it fits in this movement to more plant-based protein,” said Anderson, a professor of nutritional sciences and physiology at the University of Toronto.
The primary reason dairy has had its place in the food guide for many years is because it is well-known as a rich source of nutrients. “It has made a great contribution to the health of Canadians, including as a carrier of vitamin D,” he said.
Plant-based milk alternatives are not nutritionally equivalent to milk. The amount and quality of protein is typically less than cow’s milk, and the alternatives are not required to be fortified with vitamin D.
Dr. Jonathon Maguire, a professor in the departments of pediatrics and nutritional sciences at the University of Toronto, in studying 5,034 children ages 2 to 6, found for each daily cup of non-cow’s milk they drank, children were 0.4 centimetres shorter than average for their age.
“I think Health Canada has got to think very carefully about these substitutes and any decision to change the number of servings in the milk,” Anderson said.
U.S. dairy research has found regular consumption of dairy to be associated with healthier bodyweight and composition, lower incidence of type II diabetes and obesity, and lower incidence of childhood obesity.
Anderson’s research has also concluded dairy is more than a nutrient source: It is a functional food to help control food intake and blood glucose.
“If you just think about milk in appetite and glucose control, it contains low-glycemic sugar so you don’t get much of a blood glucose response; the whey has quick response for energy, the casein lasts for a couple of hours, and fats slow stomach emptying,” Anderson said.
He conducted a number of studies with single servings of skim milk, whole milk, Greek yogurt and cheddar cheese.
In one study, Anderson found single servings of dairy products to be a healthy snack option, as they can suppress appetite within 15 minutes and last a couple of hours.
In another study, a single serving of water, skim milk, whole milk, yogurt or cheese was given to young men 15 minutes before they consumed a pizza meal that averaged 1,000 calories. Those who had water before the meal had an extreme rise in blood glucose after eating. The blood glucose levels of participants who were given yogurt or cheese were not even half as high as those with water. Whole milk and skim milk were also beneficial in curbing a rise in blood glucose.
Similar results were found when dairy products were included with breakfast. A breakfast consisting of a single serving of milk or yogurt beverage consumed by young adults with a high-glycemic cereal increased satiety and lowered blood glucose response by 30 percent compared to water with the cereal.
“Experimental studies of the effect of dairy foods show the physiological functionality of dairy is beyond its nutrient content,” Anderson said. “That accounts for many positive outcomes associated with its consumption, including improved glucose metabolism and appetite suppression.”
Dairy is a rich source of important nutrients; it is consistently associated with reduced risk of chronic diseases and has been shown to have many positive physiological functions. Therefore, Anderson said, “I think it would be inconsistent to stop emphasis of dairy in the food guide.”
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