Foods And Herbs For Boosting Immunity And Respiratory Health

 by Marcelle Pick, OB/GYN NP

Are you (or the people around you) “coming down with something” — a respiratory bug you’d rather not have? Some of the most convenient and economical sources of immune support can be found right in your pantry, in the form of immune-boosting foods, herbs, and spices. Some of our favorites are those that act on the respiratory tract as well as the immune system, to be used either before you experience symptoms or when you first notice that tickle in your throat or nose. Including foods that act as natural anti-inflammatories in your diet can also benefit the immune and respiratory systems.

Tea. Many types of tea have long been revered for their health-enhancing effects, and much research has focused on its antioxidant effects. But along with its antioxidant effects, drinkers of true tea (Camellia sinensis) — black, green, white, or oolong — are enjoying a range of phytochemicals that can help them avoid infection. One tea ingredient, L-theanine, appears to prime the memory of core T cells in the immune system, teaching them to recognize certain molecular subcomponents of invading bacterial, parasitic, and viral microbes when encountered for the first time, so they can mount a significantly stronger response than “naïve” T cells.

Another group of compounds in tea called catechins are under evaluation for their antimicrobial effects. Green tea extracts rich in epigallocatechin gallate (EGCG), the major polyphenol in tea, have been shown to have antiviral effects against influenza A virus (seasonal flu) in the laboratory, and EGCG and its relatives are considered to be the likely source of this effect. In another recent study on mice, EGCG demonstrated strong effects against the H1N1 virus in particular. The exterior surfaces of influenza viruses are covered with protein-dense knobs responsible for binding to the cells being infected. Studies on EGCG suggest one way it inhibits the virus’s infectivity is by binding to these knobs so as to “preoccupy” them, actually altering the physical properties of the viral membrane.

And staying well-hydrated by drinking tea infusions also helps keep your sinuses, throat, and nasal passages from becoming clogged up — just take care to ensure the caffeine in these teas doesn’t prevent you from getting the sleep you need.

Herbal tisanes. When steeped in boiling water, just about any herb or plant material that is not tea leaves becomes what is known traditionally as a tisane. If left to brew for some time, it becomes an infusion. Whether brewed as single ingredients or in combination, there are countless varieties of these herbal tisanes and infusions, with an equally diverse range of health-enhancing applications. As observed for centuries, studies on herbs are now elucidating the molecular mechanisms underlying these longstanding observations, and we now have a better, albeit still limited understanding of how they enhance our overall well-being.

But you need not brew up a tisane to derive better immunity, as herbs can be compounded in a wide range of forms, including tinctures, extracts, homeopathic and combination preparations. One of the best known and most widely used herbs, Echinacea, has been long considered a source of immune support in traditional medicine but regarded with mixed feelings by conventional practitioners. Laboratory studies on different Echinacea species, plant parts, and preparations have demonstrated a variety of antiviral properties, useful in preventing and fending off respiratory viruses.

These studies also demonstrate, however, that Echinacea preparations can differ greatly, as can their effectiveness. We recommend you look for organically grown or sustainably harvested herbs, and if using supplements, choose high-quality standardized extracts, whether Echinacea or other medicinal herbs. (See the list below of 5 herbs for cold and flu season for our favorites).  For ongoing or more serious immunological or inflammatory concerns, please consult with a qualified professional for the best overall outcome.

Garlic. Used for millennia to combat respiratory and other infections, including viral illnesses, garlic contains a number of compounds, such as ajoene and allicin, that show potent antibacterial and virucidal activity. Scientific data on its proposed antiviral properties are still somewhat limited, but studies have shown that garlic promotes overall immune health, that it is active against specific bacterial infections of the respiratory tract, and that it may bolster the ability of the respiratory tract to defend against viral infection.

Hot peppers. Chili peppers such as jalapeño, poblano, or serrano contain moderate levels of the compound capsaicin, which is what makes peppers burn in your mouth — and clear out your sinuses! Adding these peppers to soups and other dishes can help open up clogged airways and promote better drainage of the sinuses, which in turn helps rid them of infectious bacteria, viruses, and the mucus and cellular debris associated with them. Peppers are also a high-quality source of vitamin C. As with some other natural treatments, the research on vitamin C and cold and flu prevention has been mixed and somewhat controversial. That said, vitamin C (ascorbic acid) is a powerful antioxidant, and it does appear to benefit the immune response, reduce the duration of respiratory symptoms, and may have some direct effects against influenza.

Chicken soup. Mothers and grandmothers have prescribed homemade chicken soup as a remedy for colds and flu for generations — perhaps since ancient Greece — and with good reason! It may not be a cure-all, but chicken soup does have a number of benefits for overall immune health and a healthy respiratory tract, and it certainly is comforting. As part of the natural inflammatory response, respiratory viruses like the common cold and influenza cause immune cells called neutrophils to migrate to the mucosal lining of the airways — this is thought to be what causes the secretion of mucus. Chicken soup has been shown to significantly limit the number of neutrophils that get drawn in. Steam from chicken soup helps open nasal passages, so it also helps remove infectious particles from your airways in that fashion. And if you make a chicken soup with fresh, homemade broth, garlic, and a jalapeño pepper, you’ll have a triple whammy for your respiratory health!

5 Medicinal herbs for cold and flu season

For generations certain herbs were identified as preventives for colds and flu, widely used in various forms and combinations, and regarded as invaluable for warding off infection and decreasing severity and duration of symptoms.

Modern science has placed these medicinal herbs under intense scrutiny, and the research on some has been mixed yet supportive. We now have a growing body of evidence confirming overall lower incidence of flu and cold infection with the use of certain herbs, while other studies demonstrate intriguing immune-stimulating activity. Herbal medicines are thought to neutralize or limit the success of seasonal viruses in myriad ways, but principally by increasing immune cell numbers and function, gene expression, and cell-signaling activity in the body. Others appear to act upon the virus particles themselves.

Most botanical preparations containing these herbs work best when taken as preventives, or as soon as symptoms become evident. Here are 5 for which the science is strong:

  1. Astragalus (A. membranaceous)
  2. Black elderberry (Sambucus nigra)
  3. Cordyceps (C. militaris)
  4. Echinacea (E. angustifolia, E. purpurea, E. pallida)
  5. Eleuthero (Siberian ginseng — Eleutherococcus senticosus)

References