Every winter, millions of people suffer with congestion, coughs, fever and other symptoms of the common cold. They may lose days from work. (If they don’t take time off, they spread the virus causing the cold to many other individuals.) But is there a way to prevent colds? One reader thinks he has found one. Q. My wife and I have been taking extra vitamin C after each meal for more than a dozen years. Despite being around people with colds, we have had none. We’ve had no side effects from the vitamin C. A. Health professionals generally dismiss vitamin C to prevent colds. A review of 29 trials of vitamin C for colds concluded that vitamin C doesn’t seem to prevent colds for most people but it consistently reduces their duration and severity (Cochrane Database of Systematic Reviews, Jan. 31, 2013). Perhaps that is because vitamin C can increase the activity of the immune system (Journal of Biological Regulators and Homeostatic Agents, Apr-June, 2013). More than 200 different viruses can cause cold symptoms, so we’re not surprised that vitamin C might not work against all of them.
Along with vitamin C, zinc also enhances immunity and can help reduce the duration of cold symptoms (Annals of Nutrition & Metabolism, 2006). Two preliminary studies showed that supplementation with 1000 mg vitamin C and 10 mg zinc reduced the duration of runny nose significantly more than placebo (Journal of International Medical Research, 2012). Analysis of 34 clinical trials show that the Chinese herb Andrographis paniculata and a preparation of ivy, primrose and thyme are far better than placebo for controlling coughs from colds (Forschende Komplementarmedizin, online Dec. 14, 2015). You’ll find a variety of other natural cold fighters in our Guide to Colds, Coughs and the Flu. You are hereVitamins » Vitamin C Meet the staff of the Micronutrient Information Center. If you value this website, please help by donating to the MIC. The Linus Pauling Institute Micronutrient Information Center provides scientific information on the health aspects of dietary factors and supplements, food, and beverages for the general public.
The information is made available with the understanding that the author and publisher are not providing medical, psychological, or nutritional counseling services on this site. The information should not be used in place of a consultation with a competent health care or nutrition professional. The information on dietary factors and supplements, food, and beverages contained on this website does not cover all possible uses, actions, precautions, side effects, and interactions. It is not intended as nutritional or medical advice for individual problems. Liability for individual actions or omissions based upon the contents of this site is expressly disclaimed. You may not copy, modify, distribute, display, transmit, perform, publish or sell any of the copyrightable material on this website. You may hyperlink to this website but must include the following statement: "This link leads to a website provided by the Linus Pauling Institute at Oregon State University. [Your name] is not affiliated or endorsed by the Linus Pauling Institute or Oregon State University."
Contrary to popular belief, mega-doses of vitamin C are not the best way to get over a cold. While vitamin C supplementation does support the immune system in some people, once you have a cold, it will not help you get over it faster. According to a review by Cochrane of 30 randomized trials involving more than 11,000 adults, for the general population, supplementation with vitamin C doesn't reduce the incidence of colds or upper respiratory tract infections in most adults. However, for people under extreme stress, or who don't consume an adequate amount of fruits and vegetables, supplementation does appear to offer some protective benefits, and lower their risk of colds. Regardless, the review found that once cold symptoms show up, taking a therapeutic dose of vitamin C will not affect the duration or severity of the common cold. (Note that companies like Airborne, which sell therapeutic doses of vitamin C, have been successfully sued for false advertising, and no longer use claims that they can prevent or cure common colds.)
Since colds are caused by viruses, antibiotics, which fight bacteria, won't help either. Instead, turn to these natural remedies to shorten the length or severity of colds and flu: Zinc is an essential mineral that plays an important role in immunity. Those who avoid meat, in particular, can be at risk for a zinc deficiency. The recommended daily intake (RDI) is 15 mg/day. Studies show that adequate zinc consumption, or supplementation, not only prevents the onset of colds and flu, but also decrease the duration of them by a day or more, if taken at the onset of symptoms. Zinc is presently believed to be the most effective remedy against the common cold. Some foods that contain zinc are oysters, crab, pumpkin seeds, sesame seeds, sunflower seeds, pine nuts, cashews, black beans, and shiitake mushrooms. Black elderberry juice can inhibit the growth of influenza viruses and shorten the duration of symptoms, while enhancing antibody levels against the virus. It helps reduce swelling in the sinuses and reduce congestion.
Elderberry can be taken as a liquid, syrup or tincture, as well as a lozenge and in capsule form. Studies have found that fresh ginger effectively fights respiratory viruses. The same results were not found in powdered form, so use ginger in cooking or teas. If you're looking for a good way to boost your nutrient intake this winter, try this Almond Ginger Monkey Smoothie. You can also prepare a simple tea by pouring boiling water over a few slices of fresh ginger and allowing to steep for at least 10 minutes. The jury is still out on whether vitamin C can treat or prevent a cold, but a recent review of the scientific literature suggests that it does have some benefits. While supplementing with vitamin C may not prevent colds, according to the studies reviewed, there’s some evidence that taking vitamin C regularly can help us bounce back from a cold faster. “Supplemental vitamin C may lessen the duration and symptoms of the common cold because of its immune-enhancing effects,” says registered dietitian Lisa Fischer, MS. “It’s not like if you take vitamin C, it’s going cure your cold, but it makes the body more capable of fighting off the virus once you have it.”
In addition to boosting the immune system, Fischer says vitamin C helps repair and regenerate tissue, protect against heart disease and certain cancers, aid in iron absorption, decrease LDL cholesterol (the bad kind), and plays a role in building collagen. It’s also an antioxidant that helps protect cells and DNA against free radicals and other harmful agents that can cause damage to cells. To reap the greatest benefits of supplemental vitamin C, Fischer says it’s best to make it a daily habit. “Any of the research that supports vitamin C says it’s best to take it continuously or consistently, rather than right before you feel like you’re getting sick,” says Fischer, who sees clients at The UltraWellness Center in Lenox, Massachusetts. But don’t rush to order vitamin C pills just yet, as it’s better to get your daily dose from vitamin C-rich foods. According to Fischer, the additional phytonutrients and phytochemicals that foods contain aid in cancer prevention and fighting other diseases.
The best dietary sources of vitamin C may surprise you. “A lot of people assume that vitamin C is found in fruit like oranges, but actually, some of the top sources are vegetables such as bell peppers, broccoli, brussels sprouts, cauliflower, and squash,” says Fischer. “The best sources from fruit would be papaya, strawberry, pineapple, orange, kiwi, and cantaloupe.” (These vitamin C-rich foods are natural fat burners.) The only people who should rush to pop a pill, Fischer says, are those who are deficient in vitamin C (here are the silent signs you might be low on key vitamins). If you’re considering supplementation, studies show that consuming between 250 and 1,000 mg of vitamin C a day is considered safe, but more than that could lead to potential gastrointestinal symptoms such as diarrhea and gastritis and other issues. “The higher doses of vitamin C, which would be considered anything above 1,000 mg or one gram, can interfere with the effects of blooding thinning medications including warfarin (Coumadin), oral contraceptives, barbiturates, aspirin, and acetaminophen (Tylenol), as well as chemotherapy drugs,” Fischer says.