Evaluate the use of supporting materials in the following speech excerpt. Be sure to deal with all the supporting materials in each paragraph, and be specific in assessing their strengths and weaknesses.

According to the Mayo Clinic, the recommended amount of caffeine is up to 400 milligrams per day for healthy adults. Of course, this "safe" dosage will fluctuate based on overall health, weight and age. Caffeine overdose may occur if you ingest more than this amount. A caffeine overdose occurs when you take in too much caffeine through drinks, foods, or medications.

The symptoms of caffeine overdose range from the mild to the severe. Most people know that coffee can help keep you regular, thanks to its laxative properties. Drink more than two or three cups a day, though, and you might get diarrhea, according to the International Foundation for Gastrointestinal Disorders. The National Institute of Mental Health recommends that people who suffer from anxiety avoid caffeine. Why? Too much coffee can actually worsen the effects of anxiety, either by robbing you of proper sleep or triggering your flight or fight response.

Studies have shown that the population of those most likely to suffer from caffeine overdose are young adults in their 20s and 30s. In a Reddit blog, several college students described their experiences. Sarah stated, "Pulled an all-nighter. 6 cups of coffee followed by a monster in the span of about 4 or 5 hours. I had heart palpitations in my first class and starting having weird hallucinations about my dog." Xyner said, "Had 4 cans of monster energy (144 mg of caffeine) to finish an assignment last minute, didn't sleep for two days. Never doing that again.