If you have ever worked with cancer patients, you know they often develop an aversion to foods eaten right before chemotherapy or radiation treatment because the food is associated with the sickness that follows. Well, a similar aversion to cow’s milk may develop in people who have experienced gastrointestinal symptoms as a result of lactose intolerance. Makes sense, right? But if you haven’t experienced it yourself, you may not relate. The most important thing to know is that lactose intolerance is very individual and people often tolerate varying amounts of lactose.
We can point to evidence demonstrating that most people who have low levels of the lactase enzyme needed to digest lactose can drink a cup of milk with a meal without symptoms of intolerance. But will this information encourage people who have experienced lactose intolerance want to try milk again? Maybe, but maybe not.
Dr. Dennis Savaiano, a renowned expert in lactose intolerance from Purdue University, hypothesized that since a food aversion is learned through classical Pavlovian conditioning, it can be unlearned. To reverse or lessen food aversions, research shows that repeat exposure is key. Previous research by Dr. Savaiano and others have demonstrated that the human digestive system is capable of adapting to increasing amounts of lactose – even in those who are lactose intolerant or perceive themselves to be. Since milk is a valuable source of calcium and other nutrients that many people need, he wondered whether a taste preference for milk was adaptable as well.
In a study recently published in the Journal of Nutrition Education and Behavior, Dr. Savaiano and colleagues tested whether a small group of 27 people who avoided cow’s milk – some of whom were lactose intolerant and some who were not – could learn to add cow’s milk to their eating plans and improve their calcium consumption.
Participants drank cow’s milk for 21 days in increasing amounts:
- Week 1: ½ cup of milk with a meal twice per day
- Week 2: 2/3 cup of milk with a meal twice per day
- Week 3: 1 cup of milk with a meal twice per day
Results showed that symptoms of intolerance decreased over 21 days for both lactose digesters and maldigesters when milk was added to the eating plan. Most importantly, they found that adding milk to the eating plans of these milk avoiders significantly increased the degree to which they liked milk and improved their calcium intake and diet quality. The degree to which participants liked milk was associated with greater milk consumption and was maintained for three to six months compared to the start of the study.
The authors explained that aversion is a dislike that leads to avoidance and intolerance is a physiological response. They found the physiological response (digestive malabsorption measured by a hydrogen breath test) to milk was not a significant factor in reversing milk aversion among the milk avoiders in this study. While improved tolerance could not be ruled out as a contributing factor, the authors conclude that participants’ taste preference changed and they were able to enjoy milk again.
Check out this handout for your clients on lactose intolerance and the benefits of cow’s milk written by Dennis Savaiano is available from the Purdue Extension website.