Vitamins & Supplements

Question: Are there certain foods that interfere with calcium absorption?

Answer: The short answer to your question is no. In fact, some types of calcium supplements should be taken with food to maximize absorption. While foods do not generally inhibit calcium absorption, there are interactions between calcium and certain medications.

Calcium and vitamin D are important for building and maintaining strong bones. To protect against osteoporosis, most people should be getting 1,000-1,200 milligrams of elemental (absorbable) calcium daily, along with 400-800 IU (international units) of vitamin D.

The best way to increase calcium intake is by eating foods rich in calcium, such as dairy products, calcium-fortified orange juice, and green leafy vegetables like broccoli, kale, and collards. However, for people who can't boost their dietary calcium enough, calcium supplements are usually recommended.

Calcium supplements come in two forms: calcium carbonate and calcium citrate. Calcium carbonate is generally less expensive and is available in over-the-counter preparations such as Tums, Os-cal, and their generic equivalents. Ideally, calcium should be taken in several smaller doses during the day (for example, one 400-milligram pill three times daily). Calcium carbonate should be taken with food to maximize absorption. Calcium citrate is generally more expensive and is available in over-the-counter preparations such as Citracal. The main advantage of calcium citrate is that it can be taken any time, with or without food.

The body needs vitamin D to help calcium absorption. The body makes vitamin D when exposed to sunlight, and the vitamin is present in some foods. Milk and other dairy products fortified with vitamin D, egg yolks, liver, and saltwater fish are good dietary sources of vitamin D. Supplements are also available in the form of a multivitamin or in combination with calcium supplements.

If you want to learn more about calcium and vitamin D, talk with your doctor.

Question: I am trying to become pregnant. Can you tell me which vitamins I should be taking, and if there are any vitamins I should avoid?

Answer: A woman who is planning to become pregnant needs to be concerned about nutrition. Pregnancy requires extra energy and nutrients, and proper nutrition plays an important role in the normal development and growth of a fetus.

One of the most important vitamins a woman of childbearing age should take is folate (folic acid). You should take 400-800 micrograms of folate daily, both before and during pregnancy.

Some other important nutrients that often must be taken in supplement form are calcium (1,200 milligrams [mg] daily), iron (30 mg daily), protein, phosphorus, zinc, and magnesium. Most prenatal vitamin formulas provide the necessary vitamins for a healthy pregnancy.

It is important to realize that with vitamin supplements, there can be too much of a good thing. Excess doses of many vitamins can lead to health problems. This is true in pregnancy as well. Generally, pregnant women should take about 800 retinal equivalents (about 2,700 international units [IU]) of vitamin A daily. Most women can get that much from diet alone. In fact, taking supplements may be harmful in doses higher than 10,000 IU daily, which is the dose of vitamin A in many commercial multivitamin supplements. Vitamin A is fat soluble, which means that it can build up in the body and not get washed out in the urine like most of other vitamins do.

If you are planning to become pregnant, you should meet with your doctor to discuss proper nutrition and whether or not you should take a prenatal vitamin supplement. If you have any other questions, ask your doctor.

Question: Can Down's syndrome be treated with piracetam and nutritional supplements?

Answer: Several treatments have been proposed to improve the function of children with Down's syndrome. Unfortunately, little information supports any treatment at this time. Two treatments, however, are currently under investigation. One of the treatments uses very large doses of vitamin and mineral supplements. The other treatment uses a relatively new class of drugs known as nosotropic drugs. These drugs are thought to improve cognitive function. The one now being studied in the treatment of Down's syndrome is called piracetam. The drug is not available in the United States but is sold under the names Nootropyl, Cerebroforte, and Avigilen, in Europe.

The impact of megadoses of vitamins and minerals on Down's syndrome has been studied before. In 1981, a regimen of vitamin and mineral nutritional supplements was reported effective. Later, a more rigorous study using a larger number of children with Down's syndrome found no benefit from large doses of vitamins and minerals. The current study compares a vitamin and mineral regimen with a series of early intervention programs designed to improve cognitive function.

Exactly how piracetam and other nosotropic drugs work remains unclear. In animal studies, piracetam aids learning and memory, and in studies of children with dyslexia, it has been shown to improve reading speed. However, improvements to mental functioning have been difficult to reproduce in people with other conditions. Piracetam has shown to be helpful--to varying degrees--in the treatment of alcohol-related mental disturbances, certain neuromuscular disorders, vertigo (dizziness), and a blood disorder called sickle cell disease. We don't know yet whether children with Down's syndrome will benefit from piracetam.

Question: Are nutritional supplements necessary to ensure a healthy diet?

Answer: Interest in taking daily nutritional supplements has recently increased, possibly because of studies showing that diets high in fruits and vegetables have been linked to increased longevity and a lower incidence of common diseases such as cancer and heart disease. With this knowledge in mind, researchers began to examine the health benefits of specific nutritional supplements like vitamins C, E, and A. Although a few of these later studies showed limited benefits of taking these supplements for patients suffering from specific disorders (like vitamin E for patients with heart disease), global benefits of these supplements were not found. Some doctors speculate that taking one or two vitamin supplements was not particularly useful because food contains a complex array of beneficial chemicals (only some of which are vitamins) that work together to generate health benefits. Put simply, there is no substitute for a healthy diet.

Unfortunately, only a minority of Americans follow this advice. As a society, we consume simple sugars and other carbohydrates in excess, as well as too much fatty food. In addition, few people eat the recommended daily requirement of three to five servings of fruits and vegetables per day. People with poor eating habits would do better if they improved their diet rather than investing in nutritional supplements.

There are, of course, times when nutritional supplements are strongly recommended. For example, women who are pregnant or wish to become pregnant in the near future should add folate to their diet because adequate folate intake in the first 3 months of pregnancy helps prevent some birth defects. It is possible to get enough folate by eating a diet rich in fruits and vegetables, but such a diet can be difficult for pregnant women to maintain. Taking a supplement can insure that a pregnant woman reliably gets enough folate.

Nutrition is a complicated topic. If you see your doctor to discuss your interest in eating well, together you can decide whether a specific nutritional supplement is a worthwhile investment.

Question: I am taking cod liver oil supplements to meet my omega-3 requirements. Is this the best way to get enough omega-3s into my diet?

Answer: Probably not.

Omega-3s are one form of what are called "essential fatty acids." Essential fatty acids play critical roles in our body and we must get some in our diets to survive.

Unfortunately, omega-3s are not present in all foods; even though we need only 650 milligrams of this type of fat each day, some diets do not provide enough. Fish is by far the best source of omega-3 fats: Two servings a week of fatty fish (for example, mackerel, salmon, sardines) provides more than adequate amounts. Free-range meat or eggs from hens fed special diets provide a little omega-3, but not nearly enough to meet daily requirements--unless you want to eat seven eggs a day! Therefore, some people look to supplements to meet their requirement.

Cod liver oil was one of the first omega-3 supplements to become available and does in fact contain large amounts of these essential fats. It also contains vitamin A, however, which can be dangerous when taken in large quantities. Because of this, most experts do not advise taking this supplement. Many other types of fish oil supplements are available that do not contain vitamin A, and they are probably a better bet.

Eating two servings of fatty fish each week is probably the best way to get your omega-3s. If you choose to go with supplements, make sure that they contain at least a small amount of vitamin E, which is necessary to prevent spoilage of these delicate fats. The essential omega-3 oils you should be looking for on the label are abbreviated as DHA and EPA. (Both are good.) Daily intake of DHA and EPA combined should be about 700 milligrams.

Question: Is it possible to overdose on vitamin A from foods?

Answer: Vitamin A is an important part of a healthy diet. We get it from foods containing the vitamin itself or beta-carotene, which the body uses to make vitamin A as needed. Because the body regulates how much beta-carotene turns into vitamin A, it is difficult to eat too much beta-carotene. But it is possible to ingest too much vitamin A.

Vitamin A and beta-carotene are found in orange fruits and vegetables like carrots, butternut squash, pumpkins, mangoes, and dark green vegetables such as spinach and broccoli. Organ meats (liver and kidney) contain very high amounts of vitamin A.

Overdosing on vitamin A can cause headache, irritability, itchiness, and skin rashes-- even liver damage. Severe symptoms can develop in healthy people if they consume more than 500,000 IU (International Units) all at once, but chronic toxicity with equally dangerous symptoms can be caused if a person takes more than 25,000 IU daily. Also, taking more than 15,000 IU during early pregnancy can cause birth defects, so pregnant women and people with kidney disorders should not take vitamin A or beta-carotene supplements unless directed by a medical doctor.

Studies of people who get lots of vitamin A and beta-carotene from fruits and vegetables tend to have lower rates of heart disease and cancer. But taking these nutrients in pill from (either alone or in a multivitamin) does not appear to have the same benefit.

So while it's unlikely that anyone could overdose on vitamin A or beta-carotene through foods alone, it is possible if you eat organ meats or take supplements high in Vitamin A. Discuss your concerns with your doctor or a dietitian/nutritionist.

Question: What are the advantages of taking coenzyme Q10 supplements?

Answer: Coenzyme Q10 is an enzyme found throughout the body. It is an antioxidant that is essential for many important metabolic processes. Coenzyme Q10 is now available as a nutritional supplement, but scientific studies haven't shown much benefit from its use.

Coenzyme Q10 is promoted as a treatment for many medical problems, including male infertility, gum disease, diabetes, congestive heart failure, angina, Alzheimer's disease, high blood pressure. It is also said to improve athletic performance. These recommendations are based on little or no scientific evidence, however.

Investigators also thought coenzyme Q10 might help patients with heart failure. This is based on the fact that coenzyme Q10 is important to heart function and that people with heart failure have consistently low levels of it. Unfortunately, the studies done so far have not had impressive results. Most doctors now believe that coenzyme Q10 holds little or no benefit for patients with heart failure. There is also interest in using coenzyme Q10 for patients with angina. Some studies have shown small benefits, but more definitive studies are needed before any conclusions can be drawn. It is expensive and may interact with other medications, so speak with your doctor before you take it.

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