Effects of Caffeine

Fact or Myth?

There has been an ongoing controversy surrounding the effects of caffeine. So what is fact and what is fiction? This page will clarify the misconceptions about this common food component.
MYTH: Caffeine is an addictive substance:
FACT: Caffeine is a pharmacologically active substance and works as a mild stimulant drug. Scientists say that moderate consumption of caffeine is safe and should not be classified with addictive drugs of abuse [1]. Some caffeine users report withdraw symptoms, such as headaches, fatigue or drowsiness, but these effects only last a day or so and can be avoided if caffeine intake is reduced gradually. Also, caffeine users do not demonstrate dependent, compulsive behavior that is characteristic of dependency to drugs of abuse [2].
MYTH: Caffeine increases the risk of heart disease:
FACT: A study of 45,589 men conducted by Harvard University researchers concluded that caffeine consumption causes “no substantial increase in the risk of coronary hear disease or stroke” [3]. Also, a study on the effect of filtered coffee consumption on plasma lipid levels was published in 1992. Scientists concluded that coffee consumption actually led to a small increase in the level of HDL or high-density lipoprotein cholesterol, which is believed to protect against and lower the risk of heart disease [1]. Therefore, a moderate caffeine consumption of about 400 mg per day does not associate with cardiovascular effects.
MYTH: Caffeine causes cancer:
FACT: The relationship between caffeine consumption and risk of cancer has been studied, but no associations have been discovered or supported by research.
MYTH: Caffeine is a risk factor for osteoporosis:
FACT: Some studies suggest that the intake of caffeine increase calcium loss in urine. However, this loss has been found to be very minimal and normal levels of caffeine consumption does not significantly affect calcium balance or bone density [4]. In 1994, NIH convened a pane at the Consensus Development Conference on Optimal Calcium Intake. The panel found that caffeine did not affect calcium adsorption or excretion significantly, and any effect was shown to be more than adequately offset by a tablespoon or two of milk [5]. Most coffee drinkers add a milk product to their drink, which can easily offset any negative effects.
MYTH: Caffeine stunts your growth:
FACT: Many parents told their children when they were young that they shouldn’t drink coffee because it would stunt your growth. Well, this is just not true. When coffee or caffeine drinkers were followed over time in different studies, they did not show any effects on their bone growth. Scientific studies do not support this myth. Studies did show a slight limi in how well the gut absorbed calcium, but the studies also showed that the body compensates easily for this change in calcium absorption. How does the body do this? The body decreasing how much calcium it gets ride of in your urine in a 24 hour period. The very slight affect, can be overcome by a tablespoon or two of daily. Some people say that coffee or caffeine drinkers have a lower intake of dairy, but this is a far stretch in claiming that coffee or caffeine stunts your growth.
A study of 81 girls 12 to 18 years old researched the caffeine effect of total body bone mineral gain and hipbone density of a six-year period. The groups ranged from taking 25mg of caffeine per day to greater than 50mg per day. This study found no significant differences in the groups with respect to bone health or growth.
Caffeine is a common drug used in neonatal care when premature babies are cared for. It is used to stimulate them and help with their breathing when their brains are immature. If caffeine really did stunt growth, it would not be used in neonatal care [6].
MYTH: Children are more sensitive to caffeine than adults.
FACT: Children, including ones diagnosed as hyperactive, are no more sensitive to the effects of caffeine than adults [2]. The behavior effects of caffeine in children were examined through 82 published papers, and the results showed that children, not including infants, metabolize caffeine more rapidly than adults, and children in general consume less caffeine than adults. Although there seems to be little solid evidence that children are a risk of negative effects of caffeine, Health Canada recommends that daily intake by children should be limited to 2.5mg/kg body weight [7].