DEAR DR. BLONZ: Could you please tell me about Crohn's disease and how vitamin B-12 might be involved? I have needed occasional shots of B-12 before, and now my close friend has been diagnosed with Crohn's disease and will need regular B-12 shots. What are these shots for? Supposedly, they give energy, but I want to know more. -- G.C., San Jose, Calif.

DEAR G.C.: Crohn's disease involves a chronic inflammation of the intestines and it exists in varying levels of severity. Researchers have yet to unravel the cause, and, unfortunately, there is no cure at the present time. However, new medications and therapies are helping provide some relief. The National Library of Medicine has an information page (tinyurl.com/4f5xgw4), and there is more available from the Crohn's and Colitis Foundation of America (ccfa.org).

Vitamin B-12 is essential for the creation of cells, and is present almost exclusively in foods of animal origin. It's prevalent in most meats (especially organ meats), dairy products (especially yogurt) and eggs, and can be added to certain vegetarian foods.

It takes two separate components for vitamin B-12 to be absorbed into the body. The first component is the vitamin itself, ingested from foods or supplements. The second is a protein manufactured by the body, referred to as the "intrinsic factor." This factor bonds with the vitamin and serves as an essential escort to allow passage through the absorptive surface of the intestines. Without its intrinsic factor, little if any dietary vitamin B-12 gets into your system.

People who have ailments or injuries that affect the absorptive surface of the digestive tract are often unable to properly digest and absorb vitamin B-12 or other nutrients. Crohn's disease is an example of this. There are also certain medications that affect vitamin B-12 absorption, and deficiencies can also develop if the body is unable to produce a sufficient amount of the intrinsic factor. Finally, a B-12 problem can develop in the elderly when there is insufficient production of digestive stomach acid. This condition effectively decreases the amount of vitamin B-12 available for absorption, and affects an estimated 10 to 30 percent of the elderly.

One solution in such cases, especially if the absorptive surface is malfunctioning, is to give the B-12 via injection. That way, the vitamin goes directly into circulation, bypassing any need for the intrinsic factor, digestion or absorption.

As stated above, vitamin B-12 is essential for the creation of cells. The cells with the most rapid turnover, i.e., the shortest lifespan, are red blood cells. This explains why one of the first symptoms of a vitamin B-12 deficiency is a reduction in the number of red blood cells, otherwise known as anemia -- in this case, a "pernicious anemia." Red blood cells carry oxygen from the lungs to the working cells, then carry carbon dioxide from the working cells back to the lungs to be eliminated from the body. It makes sense, then, that certain types of anemia are associated with fatigue and weakness. It also makes sense that giving B-12 to a deficient body can help spark energy. If there is no vitamin B-12 deficiency to begin with, however, these shots would not be expected to do much.

Send questions to: "On Nutrition," Ed Blonz, c/o Universal Uclick, 1130 Walnut St., Kansas City, MO, 64106. Send email inquiries to questions@blonz.com. Due to the volume of mail, personal replies cannot be provided.

DEAR DR. BLONZ: I have a child who has periodic constipation, but he is otherwise in good health. Our pediatrician could find nothing wrong and he suggested an over-the-counter stool softener. It works but only as a temporary measure. What is an appropriate amount of fiber for a child? He drinks a lot of milk. Could this be playing a role? -- S.S., Monterey, Calif.

DEAR S.S.: Constipation for anyone is not normal, especially if it persists. As for recommended amounts of fiber, the basic formula is 11.5 grams of dietary fiber for every 1,000 calories. This means that a typical adult taking in 2,500 calories per day should have about 29 grams of dietary fiber per day. Scaling that down for children: a 5-year-old with an average intake of 1,800 calories should have about 21 grams of fiber. Those between the ages of 7 and 10, with an average daily intake of 2,000 calories, should have about 23 grams of dietary fiber every day.

Studies tend to report that children's diets are low in fiber. My solution for fiber-poor diets starts with what I consider to be the most important meal: breakfast. Does your son have breakfast? A morning bowl of high-fiber cereal might do the trick. If he longs for a sugary cereal, have him use it to sweeten the high-fiber cereal. During the day, you should consider giving him dried fruits. Dried blueberries, for example, contain 10 grams of fiber per half-cup serving; figs and dates contain 9 grams; dried apricots, 8 grams; prunes, 7 grams; and raisins, 5 grams of fiber per serving. Not only do these fruits offer unique, sweet flavors, they're all loaded with important nutrients and phytochemicals.

Avoid imposters like "fruit snacks" and other types of pseudo-fruit treats aimed at the young shopper. The apparent aim is to cajole parents into choosing these products as a convenient way of adding fruit to their child's diets. Although these products boast that they are "made with real fruit," many are gummy sugar concoctions that pale in comparison to the genuine article. Read the label.

Milk doesn't contribute to constipation as a rule, but chronic constipation may be a symptom of a milk allergy. It is estimated that food allergies are present in up to 5 percent of children, and about 90 percent of food allergies involve peanuts, milk, eggs, soy, tree nuts, wheat and shellfish. With the exception of peanuts and/or tree nuts, most children outgrow these allergies.

Another side to the milk issue is that it contains no fiber, so if consumed by itself, it does little to move the bulk of food through the system. Parents with children who eat a low-fiber diet may mistakenly think that the milk is responsible for their child's constipation, when the problem is more likely due to the absence of fiber-rich foods in the daily regimen.

Finally, you mention that your son is otherwise in good health. Be alert to the possibility that socialization issues and other stressors can also play a role in constipation. If your son or your family has been subject to an unusual amount of stress, including issues at school or competitive sports, discuss with your health professional whether these factors should be considered.

Send questions to: "On Nutrition," Ed Blonz, c/o Universal Uclick, 1130 Walnut St., Kansas City, MO, 64106. Send email inquiries to questions@blonz.com. Due to the volume of mail, personal replies cannot be provided.

DEAR DR. BLONZ: I have seen numerous sources recently, including TV's Dr. Oz, attributing all varieties of miraculous properties to coconut oil. One went so far as to imply that saturated fats from vegetable sources, particularly coconut oil, were better for your body than unsaturated fats. I have been under the assumption that saturated fats of any kind have no nutritional value and should be restricted to a minimal intake due to their effect on triglycerides and arterial plaque. While I have no doubt that there are compounds in coconut oil that are good for the body, don't the drawbacks outweigh the benefits? Any clarification would be appreciated. -- DR. M.L., via email

DEAR DR. M.L.: Unlike what you've been hearing lately, coconut oil had previously been portrayed as the consummate dietary villain. Coconut oil is a concentrated source of saturated fat, but it's important to note that not all saturated fats behave in the same way.

Food fats and oils tend to be long chains of carbon atoms, and they are packaged in groups of three known as triglycerides. About half the fats in coconut oil are shorter in chain length than many other vegetable fats, and these compounds are known as medium-chain triglycerides (MCTs). These MCTs can be digested and processed differently in the body, and even though they are saturated, the medium-chain fats are often burned as fuel rather than handled in a way that contributes to the risk of heart disease. It all depends on the context in which the MCTs are consumed. If they're part of an otherwise healthful diet, great, but there is no evidence that adding MCTs to an unbalanced diet is going to make things any better.

Coconut can add wonderful flavors and textures to many dishes, but there is nothing miraculous here. Coconut oil does not provide essential nutrients, and there is no scientific basis for any general statement that saturated fats from vegetable sources are better for the body than unsaturated fats. As is always the case, the overall quality of your diet -- and lifestyle -- holds more sway over your health and longevity than any particular ingredient.

DEAR DR. BLONZ: I typically add milk to my tea and coffee, adding enough to represent one serving of dairy during the day. Does heating milk destroy the calcium or protein content? Is there any way in which the milk is otherwise affected as regards nutrition? -- S.T., Tempe, Ariz.

DEAR S.T.: The heating of milk will not affect its calcium content, and unless it has been boiled for extended periods, there will only be a negligible effect on its protein content. Flavor, however, would likely suffer, but this will be disguised by the beverage to which it was added. There would be an effect on some of its vitamins, most notably riboflavin (vitamin B2), thiamin and niacin.

Send questions to: "On Nutrition," Ed Blonz, c/o Universal Uclick, 1130 Walnut St., Kansas City, MO, 64106. Send email inquiries to questions@blonz.com. Due to the volume of mail, personal replies cannot be provided.