Vitamins and Supplements

What can I do about my vitamin D deficiency?

DEAR DOCTOR K: I had some blood work done recently and was surprised to learn that I am deficient in vitamin D. How is this possible? What can I do about it?

DEAR READER: Vitamin D is an unusual vitamin. We get most vitamins from the foods we eat; our body can't make them. Unfortunately, vitamin D isn't found naturally in many foods. Fatty fish and milk (which is fortified with vitamin D) are the main food sources.

What could cause iron deficiency anemia?

DEAR DOCTOR K: I have iron deficiency anemia. What could have caused it? Also, my doctor wants me to take a daily 325 mg iron sulfate supplement. Is that dangerous? The recommended daily dose of iron is much lower.

DEAR READER: Most iron in the body is stored in red blood cells. If you don't have enough iron, it can lead to a low red blood cell count. Doctors call this iron-deficiency anemia, and it's more common in women.

Should I take extra folic acid to boost my immune system?

DEAR DOCTOR K: I'm a healthy woman in my 40s. Should I take extra folic acid to boost my immune system?

DEAR READER: Folic acid is, essentially, a vitamin. We all need vitamins. Indeed, the word "vitamin" was coined to refer to a substance that was essential to human life. The natural form of folic acid, folate, occurs in some foods, including vegetables, fruits, and dried beans and peas.

Do products claiming to boost immunity actually work?

DEAR DOCTOR K: I've seen many product labels that claim to boost immunity. Could they really help? Or should I be skeptical?

DEAR READER: Your immune system does a remarkable job of protecting you from bacteria, viruses and other microbes that can cause disease, suffering, even death. So it seems logical to want to give your immune system a boost. But the concept of boosting immunity actually makes little sense scientifically.

What are antioxidants?

DEAR DOCTOR K: What is an antioxidant? Should I be taking an antioxidant supplement?

DEAR READER: Something terrible often happens to medical scientists: A beautiful theory is murdered by a brutal gang of facts. The theory that vitamin pills with antioxidant powers — primarily vitamins A, C and E — could slow aging, fend off heart disease, improve flagging vision and curb cancer was beautiful and very plausible. As a result, some doctors urged their patients to take such vitamin pills daily.

Do vitamin C or milk have an effect on colds?

DEAR DOCTOR K: My mom always told me to take vitamin C and not to drink milk when I had a cold. Is this true or just an old wives' tale?

DEAR READER: The idea that vitamin C supplements might prevent the common cold, or shorten the duration and reduce its symptoms, was popularized by the biochemist Linus Pauling. Randomized controlled trials involving thousands of people were conducted. My interpretation of the results of those studies is that they showed no evidence that vitamin C supplements reduced the duration or severity of the common cold. There was weak evidence that they might reduce the risk of catching it.

What are some non-dairy sources of calcium?

DEAR DOCTOR K: I need to get more calcium, and I'd like it to come from foods rather than supplements. I'm a vegan, so dairy products aren't an option for me.

DEAR READER: When most people think of food sources of calcium, they think of milk and cheese. Vegans can't eat food that comes from animals, so those sources of calcium aren't available to you. But getting calcium from food sources is becoming easier for vegans. There are many vegan foods that are naturally rich in calcium, and more foods than ever are fortified with calcium, including some cereals and orange juices.

Can supplements help boost my energy?

DEAR DOCTOR K: Many herbs, vitamins and supplements claim to boost energy. Do any of them actually work?

DEAR READER: Unfortunately, there is not much scientific evidence to support the claims. Here is my best current assessment of the published evidence: