DEAR DR. DONOHUE: I just had a colonoscopy, and two polyps were found. One was a 1.2-cm tubular adenoma. The other was a 5-mm hyperplastic polyp. I understand that the hyperplastic polyp is nothing to worry about. I can’t find any information on the other. I would like your help. – L.V.

ANSWER: A polyp is a growth arising from the surface lining of a structure. The nose can have polyps; so can the sinuses; so can many other structures, including the colon. The only thing these polyps have in common is that they fit the definition of the word.

Colon polyps are significant because most colon cancers arise from one kind of colon polyp – the adenoma. Close to 30 percent of middle-age and older adults have an adenoma colon polyp, but only 1 percent of those adenomas ever become cancer. Eliminating all adenomas all but assures a colon whose future is free of cancer.

Hyperplastic polyps don’t become cancer.

This is all the information needed to tell the polyp story, but since you introduced another term – “tubular” – let’s pursue it further.

Adenoma polyps can be subdivided based on their appearance. Polyps that look like drinking straws are “tubular.” Ones that resemble a cauliflower are “villous.” Villous adenoma polyps are three times more likely to evolve into cancer than are tubular ones.

Polyp size is another factor in determining cancer potential. Those less than 0.6 inches in length (1.5 cm) have a less than 2 percent chance of being cancerous. Yours is an example. It was 1.2 cm, and it was not cancerous. Polyps larger than an inch (2.54 cm) have a 10 percent chance of harboring cancer cells.

You are clear on all fronts.

The colon-cancer booklet explains this common malignancy and its treatment. Readers can obtain a copy by writing: Dr. Donohue – No. 505, Box 536475, Orlando, FL 32853-6475. Enclose a check or money order (no cash) for $4.75 U.S./$6.75 Can. with the recipient’s printed name and address. Please allow four weeks for delivery.

DEAR DR. DONOHUE: I was happy to purchase Splenda as a sugar substitute. A friend called me after she heard a warning about it on a TV program. The warning was that Splenda is a no-no. Please comment. – A.W.

ANSWER: Splenda – sucralose – is a sugar substitute that’s made by altering a few atoms in natural sugar. Splenda has no calories. It’s hundreds of times sweeter than ordinary sugar. It has found a place in many commercial products, including salad dressings, fruit juices and baked goods like breads.

One great advantage Splenda has over other sugar substitutes is its ability to be used in cooking and baking.

Did your friend say why-why Splenda was said to be a no-no? I have no information that indicates it presents any health risk. I searched the Internet to see if there was some information I wasn’t aware of. I found many testimonials of people who claimed they had suffered untoward reactions after taking it, but I could not find any scientific proof to support those allegations.

I don’t intend to stop using it.

DEAR DR. DONOHUE: After I had a bone-density test, my doctor advised me to take 500 mg of calcium three times a day. I take a vitamin-D tablet every day too. I also take a multivitamin that has 200 mg of calcium. Is 1,700 mg of calcium too much? – E.L.

ANSWER: The daily calcium requirement for adults is 1,000 to 1,200 mg. The daily upper limit is set at 2,500 mg. You’re far from the upper limit.

Most adults get far too little calcium.

The best natural sources of it are dairy products, and adults tend to eat and drink few dairy products. An 8-ounce glass of skim milk and 8 ounces of yogurt have 300 mg of calcium each.

Neither passes the lips of many adults.

Adults do better with cheese. A serving of 1.5 ounces of most cheeses also has about 300 mg of calcium.

Dr. Donohue regrets that he is unable to answer individual letters, but he will incorporate them in his column whenever possible. Readers may write him or request an order form of available health newsletters at P.O. Box 536475, Orlando, FL 32853-6475. Readers may also order health newsletters from www.rbmamall.com.