3 Top Supplements for Colds and Flu

Tod Cooperman, MD, President of ConsumerLab.com, shares the supplements that may help prevent you from getting sick.

Posted on | By Tod Cooperman, MD

There is an endless list of natural approaches which people use to prevent or treat colds and flu, but not all have clinical evidence behind them. The following supplements, however, have shown an ability to help prevent or shorten a cold in most studies, and, in the case of vitamin D, to even reduce the risk of flu and pneumonia when it is used to correct a vitamin deficiency. In each case, you need to take the right supplement, at the right time, and in the right way to have the best chance of success. As I have said on the Dr. Oz Show in the past, you don’t always get what you want with dietary supplements, but my top picks, based on ConsumerLab.com’s latest tests, are listed below.

To find out more about the supplements you’re taking, ConsumerLab is offering a 24-hour free pass to Dr. Oz viewers. Visit ConsumerLab.com/DoctorOz now and get immediate access to ConsumerLab.com’s unbiased testing of echinacea, zinc, and vitamin D supplements. (This list may change over time based on the latest results shared by ConsumerLab.com on Dr. Oz.) Remember to let your doctor know if you take or are planning to take any supplements. Some may interact with medications and nutrients.

Echinacea
Echinacea has a long history of use for treating respiratory infections. It’s not well understood how it works, but several studies show that echinacea can help you get over a cold faster and reduce symptoms.

My top picks are: 

  1. Swanson Superior Herbs Elderberry Echinacea Goldenseal Immune Complex 
  2. Gaia Herbs Echinacea Supreme Liquid 
  3. A. Vogel Echinaforce

You need to be extra careful when choosing supplements with echinacea. Some herbal formulas list echinacea as part of a "blend" or "proprietary formula," but fail to specify the amount or type of echinacea. All three of the products above list the right amount of extract from the types of echinacea which have been well studied.

The Swanson and Gaia products have also been checked by ConsumerLab.com to be sure they're not contaminated with heavy metals, microbes and chlorinated pesticides. They also include ingredients, such as elderberry in the Swanson product, which may further help with colds. The A. Vogel product has not yet been tested by ConsumerLab.com, but a clinical study published after we completed our tests found it to reduce the number of cold episodes and their duration by 26% if taken throughout the cold season.

You should start using echinacea at the first sign of a cold, taking a total of about 900 mg of extract divided into two or three doses per day for one to two weeks. Echinacea should not be given to children under 12 and has not been well studied for use by pregnant or breastfeeding women. People taking immunosuppressants or with progressive systemic diseases like tuberculosis or multiple sclerosis or autoimmune conditions should consult a doctor before use.

Zinc
Zinc can be helpful for colds in two ways: First, your immune system needs zinc, so you want to be sure you’re not deficient – which is not uncommon in older people. Second, when taken as a lozenge, zinc works on the throat and can reduce the duration and severity of cold symptoms. However, when used to treat a cold, zinc has to act directly on your throat where it may kill viruses. Just swallowing or even chewing a zinc supplement defeats the purpose. In fact, getting too much zinc may actually reduce your immunity.

ConsumerLab.com found the following three supplements contained the zinc they claimed without unwanted contamination from lead, a heavy metal which sometimes contaminates mineral supplements. Cold-Eeze has been clinically tested and found to work, providing 13.3 mg of zinc per lozenge and proper instructions on how it should be used. The ZAND lozenge has about half the zinc as Cold-Eeze, although it includes herbs which may be soothing on the throat. The last product is a zinc pill which would only be appropriate for treating zinc deficiency diagnosed by your doctor.

  1. Cold-Eeze Cold Remedy
  2. Zand Lemon Zinc Herbal Lozenge
  3. Vitamin World Chelated Zinc 50 mg

The Cold-Eeze lozenge should be taken at the first sign of a cold and allowed to dissolve in the mouth every two hours during the day. The lozenges should not be taken one after the other like candy, and should not be used for more than a week because the total daily dose of zinc is fairly high and would be unsafe if taken for too long. Note that recommended dosing may be different for children and pregnant women.

Vitamin D
Taking vitamin D is unlikely to help people who are not deficient in it. However, when vitamin D is given to people who are deficient, which is the case for as much as 40% of Americans, it does amazing things including reducing the risk of the flu and respiratory infections, including pneumonia. You’re more likely to be deficient if you don’t get out in the sun much (or if your extremities are totally covered with clothing or sunscreen when you do) and don’t consume much dairy or other foods with vitamin D. People with dark skin, the elderly, and those who are obese are more likely to be deficient.

You also don’t want to overdo it with vitamin D and, unfortunately, our tests have found some popular supplements to contain as much as 80% more vitamin D than listed. ConsumerLab has found the following to contain what they claim, plus, the dosage is moderate, they’re easy to take, and they cost just one to three cents per day.

  1. Vitacost Baby D’s (400 IU per drop)
  2. Source Naturals Vitamin D-3 Drops (400 IU per drop)
  3. Spring Valley (Wal-Mart) D-3 (1,000 IU per soft gel)

The Baby D drops have no taste and it’s easy to add one or two drops (400 IU to 800 IU) to a food or beverage. By taking vitamin D with food, particularly those with fats or oils, you increase its absorption by as much as 50%. For people who normally don’t get enough vitamin D, 400 IU to 1000 IU daily may be needed year-round, and even higher amounts may be required to initially get levels up, such as 2,000 IU per day for several weeks – but check with your doctor. Ideally, your blood plasma level of vitamin D (25-hydroxyvitamin D) should be 20 to 30 ng/mL. Each 100 IU should boost your level by 1 ng/mL, although, if you are obese, 200 IU is required for the same rise, as vitamin D is fat soluble. There is growing evidence that some of the benefits of vitamin D start being lost as levels rise past 35 ng/mL and may not be safe above 50 ng/mL. People with hypercalcemia or hypercalciuria as well as heart disease should be particularly sure to consult their doctor before use.

More details about echinacea, zinc, and vitamin D supplements, including test results for many brands not mentioned above, are included in ConsumerLab.com’s online reports, which you can access for a limited time with 24-hour pass for Dr. Oz viewers at ConsumerLab.com/DoctorOz.

Article written by Tod Cooperman, MD
President of ConsumerLab.com