Caffeine, Omega-3s, calories

Question
Hi! I have a few questions. The first one is, does caffeine hurt your bones? I heard that Diet Coke in excess is harmful, but is that the carbonation, or the cola, or the caffeine, or the aspartame, or what? What is a safe upper limit? Also, can someone eat too many Omega-3s? I eat 2 tbsp. of flax seeds every morning, and I usually have 4 or 5 ounces of fish about 5 times a week. Is that too much? Lastly, I've been eating 1200 calories, but don't want to lose anymore weight. I upped it to 1500 for 2 days, but gained weight, and I don't want to gain weight either. My friend told me that my metabolism just had to adjust. If that's true, will my weight drop back down after my metabolism adjusts? How long would that take? By the way, I'm 16, 5'8", and 126 lbs. Thanks for answering my questions; I really appreciate it.

Answer
Emily,
Yes, caffeine has been shown to reduce calcium absorption, which can effect your bones. Caffeine can also act as a stimulant as well as a diuretic. Colas also contain significant amounts of the mineral phosphorus. Studies show that phosphorus can interfere with the ability of bones to absorb calcium, though more research is required. Some leading calcium researchers believe the key problem is not what the soft drinks contain, but that they take the place of nutrient-rich beverages such as milk that are essential for bones.

The best rule of thumb is to drink beverages that are more nutritious more of the time such as water, juice, milk, etc... Research suggests that an intake of about 400 milligrams of caffeine a day is safe for most ADULTS.  Here is some info that may help you:  http://kidshealth.org/kid/stay_healthy/food/caffeine.htmland

Also important to bone health is eating a healthy well balanced diet that includes calcium and vitamin D as well as regular exercise.

Not sure of your reason for eating so much omega 3 fatty acids at your age but if you are eating that much fish, the flax seed isn't really necessary.  You can find out more about omega 3's here:
http://www.wholehealthmd.com/refshelf/substances_view/0%2C1525%2C992%2C00.html

IF you were eating 1200 calories and you are now increasing, give it time.  Your body does need to adjust to the new calorie level.  Just increase your calories very slowly.  
Kim Tessmer, RD LD
www.Nutrifocus.net

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