Vitamins and Supplements

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:

Is it possible to take too many vitamins?

DEAR DOCTOR K: I take vitamin and mineral supplements. Do I need to worry about getting too much of certain nutrients?

DEAR READER: Many people take individual vitamin and mineral supplements in addition to a powerful multivitamin. But ingesting too much of certain micronutrients can be dangerous.