Effects of caffeine: Registered dietitian talks caffeine consumption and our health

MILWAUKEE -- One day coffee is great for you -- the next day -- the worst! What are we to believe? Registered dietitian Lisa Grudzielanek with Metcalfe's Market joins Real Milwaukee to talk caffeine consumption and our health.

• About 80% of adults take some form of caffeine every day.
• It most consumed sources in coffee, tea, soda, or energy drinks and in smaller doses, chocolate.
• Bottom line: While caffeine can give you a temporary mental and physical boost, its impact depends on how much you consume.

How Much Caffeine?
• People who have never had a heart attack or keep their blood pressure well controlled should consume no more than 400 mg per day, which is the amount found in about 4 cups of coffee or up to 10 cups of black tea.
• Coffee About 80-100 mg of caffeine, per 8oz.
• Decaf Coffee Decaf coffee contains about 0 to 7 mg of caffeine per cup
• Soda Most cans have roughly 25-50 mg of caffeine. Unlike coffee, caffeine-free sodas or pops really are free of caffeine.
• Tea A cup of tea contains roughly 5-50 mg of caffeine.
• Energy drinks. Energy drinks contain the most caffeine in the least fluid ounces. For example, a 16-ounce energy drink could contain as much as 300 mg or more of caffeine.
o Energy are potentially dangerous to people with heart problems. Children and teens shouldn`t drink energy drinks, despite the fact that they`re often the specific targets of these products' marketing efforts.

Effects of Caffeine on the Heart
• The stimulant effect of caffeine speeds up the heart rate.
• Research shows that the level of caffeine at which the heart rate is significantly affected is 360mg, the equivalent of about 3 1/2 cups of brewed coffee.
• It is unclear at the moment whether caffeine increases the risk of cardiovascular problems in the longer term.

Effects of Caffeine on Blood Pressure
• Studies have conclusively shown that caffeine consumption raises blood pressure.

Effects of Caffeine on Bone Density
• High coffee consumption has been linked to osteoporosis in men and women.

Effects of Caffeine on Exercise Performance
• Caffeine may enhance physical performance and endurance. This, combined with its effect of fat burning during exercise, can actually enhance workouts and enable you to get in better shape if you take it at the right time.
• The amounts often studied range from about 225 mg to 600 mg, taken about an hour beforehand. However, much of the research involves high-level athletes, so it's not clear exactly how caffeine may help the average person during a workout.

Effects of Caffeine on the Brain
• Caffeine has been shown to improve performance on a range of different tasks, including vigilance, response times and information processing. However, in some it can enhance anxiety, especially in individuals with heart palpitations or heart problems.
• It is not clear if caffeine (coffee) protects against Alzheimer`s, Parkinson`s, or Type 2 Diabetes or if other nutrients in coffee, like antioxidants or some combination, is at play. More research is needed.