FDA backs safety of artificial sweetener

Editor's note: CNN's Dr. Sanjay Gupta answers medical questions submitted by e-mail on "Your Health" at 2:30 p.m. EDT Saturdays. Questions and answers are posted on CNN.com after the show.

Q: What are the dangers in the sugar substitute aspartame found in various diet products? -- Richard in Anderson, Indiana

A: Having a sweet tooth is perfectly normal. But some people, like diabetics, can't indulge in the sweet stuff, and others are told to cut back in order to lose weight.

That is where artificial sweeteners come in. Among the most popular is aspartame.

While some groups have tried to link aspartame to everything from multiple sclerosis to brain tumors, the Food and Drug Administration says it is completely safe at "normal intake levels."

In fact, the agency says it is one of the most thoroughly tested and studied food additives it has ever approved.

However, there is a small group of people who are sensitive to phenylalanine, one of the two amino acids in aspartame. Those people need to limit their intake.

Q: How can frequent exercise increase overall health? -- Ace in Athens, Pennsylvania

A: Exercise strengthens your heart and cardiovascular system and reduces the risk factors for heart disease, like high blood pressure and obesity.

Among other things, it also improves circulation, which helps your body use oxygen better and helps lower blood pressure.

It helps improve balance and joint flexibility while reducing body fat and strengthening bones.

The biological mechanisms behind all of these benefits are so varied and so complex that we would need a whole show to explain them.

Until then, a good medical textbook should satiate your hunger for knowledge.

"Ask Dr. Gupta" is not intended to address specific questions concerning individual cases. CNN does not directly or indirectly practice medicine or provide medical advice, and nothing contained in the responses of CNN through its correspondents is a substitute for medical advice, diagnosis or treatment. Always contact your doctor if you need medical advice or treatment, or have any questions regarding a medical condition.