Probiotics such as Klaire Labs Vital-Plex can help support the immune system. Several studies in recent years suggest that the regular daily consumption of lactobacillus and bifidobacterium strains of probiotics can help reduce frequency of colds and flu-like symptoms.

If you feel "something coming on," vitamin A can be very useful. It appears to prevent viral penetration by supporting antibody response and mucous membranes. We are not talking about beta carotene or mixed carotenoid supplements here. Carotenes can be turned into vitamin A in the body, but this is not an efficient conversion. Carotenes are best derived from such foods as carrots, green beans, and winter squashes. For supplemental vitamin A, try Now Foods Vitamin A from Fish oil, in higher therapeutic doses (10,000 to 50,000 IUs) twice a day, for short term use (3-7 days) in people with normal liver function.

Vitamin D is also important. Epidemiological studies show an inverse relationship between D blood levels and frequency of respiratory infections: those with the highest D blood levels had the least infections. Research now shows us that most people need to supplement with 2,000-5,000 IUs of vitamin D3.

For a quick immune response, try the top-selling remedy in Europe for over 70 years, Esberitox chewable tablets from Enzymatic Therapy. More powerful than echinacea alone, it contains two types of echinacea, plus a dynamic blend of immune-enhancing herbs to boost natural defenses. It has over 30 clinical studies supporting health benefits its safety for all ages.