Adding milk to coffee is a divisive topic when it comes to taste preferences. While some people enjoy the added creaminess, others wonder if it’s a healthy habit. Does adding milk to coffee dilute its caffeine-boosting effects? Is coffee with milk a reasonable choice for digestion? Here are some insights.
No known effects on caffeine
Coffee on its own is known to have many documented health benefits. It contains caffeine, a molecule known for its stimulating and protective properties against cognitive decline. Coffee also contains valuable antioxidants, such as polyphenols, which have a hypotensive effect on the heart and protect cells from aging. They limit DNA breakage and reduce tissue inflammation.
But what happens when milk is added to coffee? To date, no studies indicate any potential deleterious effects on caffeine. It is the initial coffee dosage that affects caffeine boosting, not milk. Whether with or without milk, it is essential to respect the recommended doses. Excessive caffeine intake can lead to nervousness, sleep disturbances, and cardiovascular problems. According to the European Food Safety Authority (EFSA), a healthy adult should not exceed 400 mg of caffeine per day (200 mg for pregnant women), equivalent to four to five cups of filtered coffee throughout the day.
A better anti-inflammatory effect?
The interaction between milk and the antioxidant properties of coffee is still a matter of scientific debate. Recently, researchers from the University of Copenhagen published a study in the Journal of Agricultural and Food Chemistry on January 30, 2023, suggesting that coffee with milk has better anti-inflammatory effects than a plain black coffee. After conducting an in-vitro study, the researchers found that the antioxidant power of coffee polyphenols was twice as effective when associated with amino acids contained in milk.
This hypothesis remains to be confirmed since it has not been studied on animals or humans. Research by the Swiss Nestlé Research Center published in February 2010 showed that adding whole milk did not alter the bioavailability of coffee polyphenols by examining the composition of blood plasma after ingestion of different coffee recipes.
Satiating but not always digestible
After drinking a noisette or latte, one can feel hunger disappearing. This is because milk contains proteins that have a satiating effect.
However, some people experience digestive discomfort, bloating, nausea, or even accelerated transit along with this sensation of fullness. These discomforts may indicate lactose intolerance. This sugar, present in milk, is usually absorbed in the small intestine by an enzyme called lactase. However, this enzyme decreases progressively with age and disappears if milk consumption is stopped. Digestion of lactose then becomes less easy.
Coffee, by stimulating colon movements, is often blamed for causing digestive discomfort. However, we overlook its beneficial effects on digestion. Coffee contains insoluble fibers that improve the quality of the intestinal microbiota. It improves bile and pancreatic secretions, which promote better digestion of macronutrients (lipids, proteins, and carbohydrates).
An alternative to table sugar but to be consumed in moderation
For those who consume milk as adults, such as Nordic populations, and who do not experience digestive discomfort, it can even be an asset, according to the doctor. The sweetening power of lactose provides a healthier alternative to table sugar and artificial sweeteners.
However, experts advise moderation for heavy milk drinkers. Scientific research advocates for dietary variety, suggesting an average consumption of 2 servings of dairy products per day for adults (3 to 4 for children and seniors), such as a glass of milk, as well as a yogurt or a piece of cheese, which are rich in probiotics and calcium.