If you are a regular coffee drinker, you may perhaps consider switching to tea instead, especially if you are more conscious of health as you age. Coffee without sugar is too bitter to enjoy whereas tea is much less bitter in taste. The health benefits of tea are more compared to coffee. The side effects of coffee include mouth and body dryness, insomnia, irritability, thirst and more frequent urination. Coffee also inhibits the absorption of iron in foods and iron deficiency can cause fatigue.