If the Covid-19 pandemic hadn’t happened, Professor Louise Burke - the chair in sports nutrition at the Mary MacKillop Institute for Health Research at the Australian Catholic University in Canberra - would be grinding out the kilometres right about now in preparation to run the New York City Marathon in November.
“It’s a tough run, but there’s a real buzz coming around Central Park and having so many people line the street,” Burke says.
Unfortunately, this year’s race has been cancelled. If it had gone ahead, after the race, Burke would, as usual, have met friends at a restaurant uptown for one of her favourite desserts, one “with a milky component, like a mousse, ice cream or a yoghurt”.
This may not seem like the obvious go-to recovery snack after you’ve run all the way from Staten Island, but as Burke is the former head of nutrition, and chief of nutrition strategy, at the Australian Institute of Sport - where she worked for more than 30 years, researching practical nutrition strategies for athletes to achieve optimum performance - we’re not arguing.
Burke’s marathon preparations include a hot chocolate every night before bed as part of her recovery process when in training. In 2019, she and a team of academics from around Australia published a literature review of a range of studies that looked at the role dairy milk plays in the recovery process post-endurance exercise. Results indicated that dairy milk, compared to a carbohydrate replacement beverage, enhances muscle protein synthesis and elicits similar rates of muscle glycogen resynthesis. In other words, building muscles.
“What’s been found is the ability of the muscle to respond to exercise comes from a different pathway to the way it responds to nutrition,” Burke says. “So if you can apply exercise and food - particularly the right sort of protein choices - then you’re amplifying the results and it’s better than doing either of them separately.
“Dairy contains the amino acid sources that are really helpful for the muscle to build protein when combined with a workout. When the muscle has exercised, it sends messages to the body telling it that it can make new proteins, and the leucine (one of the amino acids that is found in high amounts in dairy) content has a specific effect: it turns on the factory inside the muscle that enhances muscle protein synthesis in a way that is additive to the exercise stimulus.
“It’s like having Bob the Builder and Wendy turn up on the job and you get an amplified ability to make new protein.”
Young woman getting ready for morning exercising Photograph: Emilija Manevska/Getty Images
Man preparing milk shake in kitchen. Athletic man adding fruits to jar of milk. Photograph: jacoblund/Getty Images/iStockphoto
Having held the position of team dietitian for the Australian Olympic teams in Atlanta in 1996, Sydney in 2000, Athens in 2004, Beijing in 2008 and London in 2012, Burke has built a career on teaching athletes to understand not only the kind of exercise they’re doing, but how to identify their recovery need. Do they need to refuel? Repair? Rehydrate? Build new muscle? Protect their immune system?
“The beauty of many dairy products is they contain something that hits all these targets,” she says.
Seven studies in the literature review investigated the effect of dairy milk beverages on hydration status, four of which observed a greater net fluid balance after the consumption of dairy milk or a dairy milk-based beverage post-exercise when compared to drinking a carbohydrate-electrolyte beverage and/or water.
“If you’re thinking about rehydrating, you need fluid and electrolytes, which are found in milk,” Burke says. “If you need to refuel, the key nutrient is carbohydrate. High-quality protein is often part of the recovery menu. But in addition to the nutrient targets, practicality also needs to be considered. Sometimes, when rapid recovery is the goal, a useful strategy is to choose a liquid form of nutrition that requires minimal preparation and is easy to consume quickly and absorb. There’s no time lost at any point.
“Having a milk-based drink after training can be a way of combining many or all of these nutrients in quantities that meet a specific recovery goal. It’s not the only choice but it’s the easy and versatile choice.”
In 2012, Burke and her team conducted a study with the Australian women’s cycling team and found that a calcium-rich pre-exercise breakfast meal consumed 90 minutes before a prolonged and high-intensity bout of cycling was beneficial to bone health.
“Cyclists often have poor bone density that can lead to many injuries,” Burke says. “But we had this theory that if we could give the women’s cycling team dairy before they exercised, the calcium that was in the dairy might be able to help the bone metabolism during exercise and overcome some of the negative effects that the non-weight-bearing exercise might have.”
The study involved some of the team eating a non-dairy breakfast while the other members would eat oats with milk and yoghurt. Markers within the athlete’s blood were tested during and post-exercise.
“What we found was the breakfast containing dairy was much better at helping the bone metabolism during the session of exercise. The findings were so influential that the cycling team then went on to have a policy that their athletes should have a dairy-based or calcium-containing breakfast prior to doing their morning training.”
Burke says the same study will be applied this year to rowers, who often experience rib stress fractures due to their non-weight-bearing exercise.
No doubt the findings will be discussed over a hot chocolate.
Visit Dairy Australia’s website to learn more about the health benefits of dairy.
._Patrick_s_Day_Parade_94380.jpg?w=600)
