Answer
We summarize the main discoveries in the step by step section.
As can be seen, there may be several reasons for the apparent conflicts between these studies:
1. These studies were performed at different times and the technological advancements were different.
2. Different studies may emphasize on different aspects of health issues and they may not be directly comparable.
3. Different substances (tea or coffee) and different amounts were used in the studies.
4. Conclusions of these studies were on different time scales (short term vs life time).
Work Step by Step
In the 1980s, a study linked coffee to a higher risk of heart disease and pancreatic cancer.
In the early 1990s, studies showed that drinking coffee posed minimal health threats.
In 1994, pregnant women (3 or more cups of tea daily) may be at risk for spontaneous abortion.
In 1998, women who drank more than a half-cup of caffeinated tea every day may actually increase their fertility.
In 1998, over a lifetime, a few extra cups of coffee a day can raise blood pressure, heart rate, and stress
