Whether you’re a sport superstar or a gentle jogger, your diet has a role to play – before, during and after exercise. And you may find that consuming dairy products may give you a welcome extra boost to your performance.
Initial research has suggested that lactose – the sugar that is naturally present in milk and dairy products – may provide a valuable source of energy for athletes and for people who just want to keep fit.
Lactose isn’t mentioned specifically in sports nutrition guidelines, probably because there hasn’t been much research on it. But athletes may consume more dairy products than most people, so it’s important to look at the effects of lactose on their health and performance, say the authors.
Lactose is a disaccharide sugar that is digested in the gut, by the lactase enzyme, releasing glucose and galactose that can then be absorbed into the body. Ultimately, these simple sugars are broken down to release energy or are used to build up stores of glycogen in the muscles and liver that can be used as an energy source when the body needs it.
Lactose or sucrose – which is best during exercise?
In a recent study the authors investigated whether lactose could be broken down quickly to release energy during exercise.
They compared it with sucrose (‘table sugar’), another disaccharide, made up of glucose and fructose. Participants consumed lactose or sucrose at a rate of 0.8 grams per minute, or water, while they cycled at a moderate intensity for 2.5 hours. The rates at which lactose and sucrose were broken down during exercise were found to be very similar.
This study suggested that lactose may be as good as sucrose as an energy source during exercise. Lactose seemed to show an advantage because it was associated with greater breakdown of fat and less breakdown of stored glycogen.
‘Dairy foods such as milk or yoghurt may offer an additional benefit over isolated lactose, as the dairy matrix (as seen in yoghurt) is known to improve GI [gastrointestinal] comfort and deliver relevant nutrients such as protein and electrolytes.’ – Odell, 2021.
What if you’re lactose intolerant?
Even people with lactose intolerance are generally able to consume 12–15 g of lactose (equivalent to a glass of milk) without symptoms. In order to consume the recommended daily intake of calcium among others, lactose intolerants can consume other forms of dairy products such as cheeses that contain low or no lactose, and more specifically yogurts that contain live bacteria. Indeed, yogurt is often better tolerated than milk, because it contains live bacteria that can break down lactose.
The lactose ending up in the large intestine might act as a food source for beneficial bacteria that live there and have favourable effects on health. These potential prebiotic effects of lactose haven’t yet been studied, say the authors.
According to the authors, more research is needed in this area before any recommendations can be made.