Is the milk in the coffee harmful
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Is the Milk in Coffee Harmful?
Introduction
The addition of milk to coffee is a common practice, but its impact on the nutritional and functional properties of coffee has been a subject of debate. This article synthesizes recent research findings to provide a clear understanding of whether adding milk to coffee is harmful.
Impact on Antioxidant Activity and Bioavailability
Antioxidant Properties
Coffee is a significant source of antioxidants, particularly chlorogenic acids, which are known for their health benefits. The addition of milk to coffee has been shown to have varying effects on these antioxidants. Some studies report that milk can bind to coffee's chlorogenic acids, potentially reducing their bioavailability and antioxidant activity . However, other research indicates that milk addition does not significantly affect the overall antioxidant power of coffee, even though some interactions between milk proteins and coffee phenolics occur.
Bioavailability of Phenolic Compounds
The bioavailability of coffee's phenolic compounds, such as chlorogenic acids, is crucial for their health benefits. Research has shown that the addition of milk can decrease the urinary excretion of these compounds and their metabolites, suggesting a reduction in their bioavailability . Specifically, studies have found that the total recovery of chlorogenic acids and their derivatives in urine is significantly lower when coffee is consumed with milk compared to plain coffee .
Effects of Different Types of Milk and Processing Methods
Whole Milk vs. Skimmed Milk
The type of milk added to coffee can also influence its nutritional properties. Whole milk has been found to offer a better protective effect on the phenolic bioaccessibility of coffee compared to skimmed milk. This suggests that the fat content in whole milk may play a role in preserving some of the beneficial compounds in coffee.
Processing Methods
Various processing methods, such as high-pressure homogenization and thermal treatment, can also impact the antioxidant capacity and phenolic bioaccessibility of coffee with milk. These methods generally result in a decrease or no change in antioxidant capacity after digestion, with whole milk showing a slightly better protective effect than skimmed milk.
Conclusion
The addition of milk to coffee can have both positive and negative effects on its nutritional and functional properties. While milk can bind to coffee's chlorogenic acids and potentially reduce their bioavailability, it does not significantly alter the overall antioxidant power of the beverage. The type of milk and processing methods used can also influence these effects. Therefore, while milk in coffee is not inherently harmful, it may reduce some of the health benefits associated with coffee's phenolic compounds.
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