What Else Can I Do to Prevent Frequent Colds?

Q: It seems like I get sick every couple of months with a cold or other infection. It’s even worse during the winter. I don’t understand it. I eat a very healthy diet and exercise twice a week with a trainer and twice on my own. I also take a multivitamin and a few other supplements. Is there anything else I could be doing?

A: You’ve got the basic lifestyle issues under control. However, you didn’t mention sleep, which is extremely important in maintaining robust immune function. If that’s a problem, consider taking 1–3 mg of melatonin, 500 mg of valerian, or another natural sleep aid at bedtime.

Chronic stress can also wreak havoc on the immune system, so do what you can to “chill out.” And make sure you practice scrupulous hygiene, especially during cold and flu season.

Also take supplemental vitamin D3. Numerous studies demonstrate its immune-enhancing effects. I strongly recommend that you begin taking 2,000–5,000 IU per day, have your blood level tested in three months, and adjust your dose to maintain a level of 50–80 ng/mL.

There are a number of other supplements that do wonders for the immune system. My favorites include high-dose vitamin C (500 mg four or five times a day), Epicor, a yeast extract shown to boost resistance (500 mg per day), echinacea (use as directed), and probiotics (dosages vary depending on brand).

There’s also a fairly new probiotic lozenge containing Streptococcus salivarius K12, which has been demonstrated to protect against infections of the ears, nose, and throat. Regular use of xylitol or saline sprays are helpful as well because they help clear “bugs” out of the nasal passages.

If I were treating you, I’d also prescribe low-dose naltrexone (LDN). Although this powerful immune modulator is most often used to treat autoimmune disorders and cancer, your system could obviously use a boost, and many of my patients swear by its preventive properties. The suggested dose is 3–4.5 mg taken at bedtime. LDN, which requires a prescription and is available from compounding pharmacies, is extremely safe and well tolerated; its only contraindication is narcotic drugs.

Finally, I want to mention intravenous (IV) vitamin C.

When this vitamin is infused into the bloodstream—in doses far higher than could ever be tolerated orally—it produces hydrogen peroxide, which kills bacteria and viruses without harming healthy tissues. Long-time clinic patient Louise recently told me that at the first sign of a sore throat, headache, or any other symptom that foreshadows an infection, she comes in for a 50 g vitamin C drip. Nine times out of 10, this nips it in the bud. I suggest you find a physician in your area who offers this therapy (visit acam.org).