People’s Pharmacy: Does vitamin C really prevent colds?

Q. I have been taking a gram a day of vitamin C for years and have not had a cold or the flu in all that time. The most important effect for me was that my constant postnasal drip stopped. This ended years of discomfort and bad breath.

The only time the drip returns is when, as an experiment, I halt my vitamin C. I have considered the possibility that this is the placebo effect.

I find these experiments (during which the only change to my diet is the lack of supplemental vitamin C) to be very convincing. Since the minimum daily adult requirement is roughly the amount required to prevent scurvy, it may be too low.

I was curious about science’s judgment of Dr. Linus Pauling’s theories. An article published in the Scandinavian Journal of Infectious Diseases (1994) seems to be mostly positive. What is your opinion?

A. There is scientific evidence supporting the use of vitamin C, not so much to prevent colds as to treat them (BMC Public Health, Dec. 11, 2023). This meta-analysis of 10 randomized, double-blind trials found that vitamin C reduced the severity of colds.

In addition, research shows that children and teens with higher levels of vitamin C circulating in their bloodstreams have a lower chance of suffering respiratory infections (Frontiers in Nutrition, June 5, 2025). If you would like to learn more about vitamin C against colds, you might want to listen to our interview with Dr. Harri Hemila, the author of the review you found. It is “Show 1431: Vitamin C Studies on Colds & CANCER Vindicate Linus Pauling.” Dr. Pauling was the biochemist who first recommended the value of vitamin C against infection.

Q. I am thriving in retirement, an avid road cyclist touring with fellow cyclists for up to 150 miles per week. Additionally, I subscribe to a Mediterranean-type diet plan for a healthy lifestyle.

Through my ongoing personal nutritional scholarship, I learned that dark chocolate rich in flavonoids is an effective substance for relaxing one’s blood vessels, thus allowing more oxygen to be supplied to muscles. In addition, it lowers blood pressure.

I also consume beets along with a variety of other vegetables and fruits routinely, per the Mediterranean diet. I believe this has contributed to having my blood pressure under control currently. In times past, I exhibited elevated blood pressure likely due to my affinity for fine wines. I have reduced my consumption of wine, although when offered a glass of fine wine, I will not decline the offer.

A. Thanks for your entertaining testimonial. You are correct that cocoa flavanols from dark chocolate, as well as the natural nitrate in beets, can help with blood pressure control. No doubt your exercise regime is also beneficial.

A recent review concluded that the apparent cardiovascular protective effects of light-to-moderate drinking are probably an illusion (Journal of Clinical Medicine, Dec. 30, 2025). Even though wine may have antioxidant activity, you are probably better off keeping your consumption to a minimum, as you describe.

Others who would like to follow your natural approach to maintaining healthy blood pressure may wish to read our “eGuide to Blood Pressure Solutions.” This online resource may be found under the Health eGuides tab at www.PeoplesPharmacy.com.

In their column, Joe and Teresa Graedon answer letters from readers. Write to them in care of King Features, 300 W. 57th Street, 41st Floor, New York, NY 10019, or email them via their website: www.PeoplesPharmacy.com. Their newest book is “Top Screwups Doctors Make and How to Avoid Them.”