Vitamins and Supplements

Should I eat fish, or take fish oil supplements to prevent heart disease?

DEAR DOCTOR K: Heart disease runs in my family. Should I eat fish, or take fish oil supplements?

DEAR READER: Eating fish regularly reduces a person's risk of sudden death from heart disease. It's also brain-healthy. For that reason, I and most doctors recommend a regular diet of fish for people who have heart disease. And also for people like you where heart disease runs in the family. Fish oils are rich in omega-3 fatty acids, a kind of "healthy fat."

Surprising number of conditions cause vitamin B12 deficiency

DEAR READERS: In yesterday's column I began to answer a reader's question about the different causes of vitamin B12 deficiency, and whether to treat them with shots or pills. Today, we continue a discussion of the many conditions that can interfere with the ability of the small intestine (the part called the ileum) to absorb vitamin B12 from the foods you eat. As we get older, some people have more trouble absorbing the vitamin B12 in their food during digestion. Vitamin B12 in food is like leaves on a tree: It needs to be shaken loose. Stomach acid (and another stomach chemical called pepsin) are what shake vitamin B12 loose from food, allowing it to be absorbed by the ileum.

Can I take a supplement for my vitamin B12 deficiency?

DEAR DOCTOR K: I was recently diagnosed with a vitamin B12 deficiency. Can I take B12 supplements by mouth? Or do I need the shots?

DEAR READER: Tissues throughout the body need vitamin B12, especially in the brain, spinal cord and bone marrow, where blood cells are made. Vitamin B12 in the diet gets absorbed in the part of the small intestine called the ileum. There, it enters the blood. Vitamin B12 deficiency can cause anemia, and problems with the bones, brain and spinal cord. Low vitamin B12 levels in the blood basically have two causes: Either there is not enough B12 in the diet, or the B12 in the diet has trouble getting absorbed by the ileum. B12 is found naturally only in animal products like meat, fish, poultry, eggs and milk. Many cereals are fortified with it.

Can vitamin C boost your immune system and prevent colds?

DEAR DOCTOR K: Whatever happened to the idea that vitamin C can boost your immune system and prevent colds?

DEAR READER: Vitamin C, also known as ascorbic acid, was promoted as a health supplement for decades. It is perhaps best known for its one-time reputation for preventing and treating the common cold. This idea was heavily promoted in the 1970s by one of the 20th century's most celebrated biochemists, Nobel laureate Linus Pauling. But Pauling did not win the Nobel Prize for his theories about vitamin C. Vitamin C is crucial for making collagen, the substance that lends structural support to tendons, ligaments, bones and blood vessels.

Is it possible I’m not getting enough iron in my diet?

DEAR DOCTOR K: I'm a man in my 50s, and I've been feeling run-down. Is it possible I'm not getting enough iron in my diet?

DEAR READER: Many patients ask me this question. I think it has to do with an old commercial for a popular vitamin and mineral supplement to treat iron-poor "tired blood." Iron helps make hemoglobin. That's the molecule that grabs oxygen in the lungs and transports it around the body to release it as a source of energy to the cells in the body. The USDA recommends that adult men get 8 milligrams of iron per day in their diets.

What is difference between vitamin D2 and vitamin D3?

DEAR DOCTOR K: My doctor advised me to take a vitamin D supplement. Why do I need vitamin D? Also, my pharmacy sells vitamin D in two forms: D2 and D3. What is the difference, and which one should I take?

DEAR READER: This is an area full of controversy because not enough research has been done. I typically recommend getting vitamins from food, but vitamin D is found naturally in only a few foods. Fatty fish is the main dietary source, and milk, many juices and breakfast cereals are fortified with it. We get most of our vitamin D from the sun: When sunlight strikes the skin, skin cells make vitamin D. But these days, people get a lot less sunlight than they used to.

Should I have my vitamin D level checked?

DEAR DOCTOR K: I've read several articles about the negative effects of a low blood level of vitamin D, but my doctor said I didn't need to have my level checked. Why not?

DEAR READER: Many of my patients are asking me the same question. Vitamin D has been in the news a lot in recent years, but we still don't have solid answers to many questions, including yours. There is strong evidence that people with a low blood level of vitamin D have higher rates of osteoporosis (thin bones).

How do you treat anemia?

DEAR DOCTOR K: My teenage daughter recently learned that she has iron deficiency and anemia. Why would her iron be low? What is the treatment?

DEAR READER: Anemia means that the blood does not have enough red blood cells. These cells carry oxygen from the lungs to the rest of the body. There are many kinds of anemia. In the United States, iron-deficiency anemia is the most common; it occurs when the body does not have enough iron to make red blood cells.

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.