Nutrients for healthy lungs

Concerned about increasing your immunity to airborne toxins, bacteria, and viruses? Then this article is a must-read. Your lungs are at the forefront of immunity. While healthy lungs are a key part of optimal health, we rarely talk about ‘feeding our lungs’. The truth is that our lungs need certain nutrients to perform at their best, and with respiratory diseases, airborne allergies, and air pollution on the rise, it’s never been more important to ensure an optimal intake of key nutrients for healthy lungs.

Let’s dig into some of the most important vitamins, minerals, and other nutrients for lung health. We will start with vitamin D, then take a quick look at vitamins A and C, and finish with a look at two nutrients that may surprise you: nitric oxide, and glutathione.

Vitamin D and lung health

The human body is pretty adept at making its own vitamin D when skin is exposed to the sun’s rays or other source of ultraviolet B radiation. This form of vitamin D is inactive though and has to be activated in the kidneys by the enzyme 1-alpha-hydroxylase. Once that’s done, the active vitamin D can perform all its important functions including supporting calcium absorption and bone health as well as promoting various aspects of immune function.

Did you know, though, that the kidneys aren’t the only place in the body that can convert vitamin D into its active form? The lungs can do it to! That’s right, researchers recently discovered that the 1α-hydroxylase enzyme is not only expressed in the kidneys, but also in the airway epithelium, alveolar macrophages, dendritic cells and lymphocytes.[i]

So, why would the lungs need a way to activate vitamin D on-site?

One reason seems to be that vitamin D is important for immune function in the lung. Indeed, serum (blood) levels of 25-hydroxyvitamin D (25OHD) above 20 ng/mL appear to lower the risk of infections, including tuberculosis.[ii] [iii] In one meta-analysis of 25 randomized, double blind, placebo-controlled trials, people who took vitamin D supplements had a far lower incidence of acute respiratory tract infection compared to those who didn’t supplement with the nutrient.[iv]

Low levels of vitamin D have also been linked with obstructive lung diseases like asthma and COPD.[v] [vi] This might be because vitamin D supports healthy lungs by helping to prevent the undesirable increase in smooth muscle cells in the airway seen in people with asthma. Vitamin D appears to inhibit levels of MMP-9, the most relevant gene or enzyme in airway remodeling. It also inhibits the expression of the ADAM 33 , ‘a disintegrin and metalloproteinase-33’ gene linked to increased susceptibility to asthma.[vii]

Vitamin D and CoVID-19

Vitamin D deficiency is now widely seen as an important factor in a variety of health conditions, and an editorial published online in the April in the journal of Alimentary Pharmacology & Therapeutics linked low vitamin D to increased mortality from COVID-19.

Jonathan Rhodes and colleagues looked at the mortality per million plotted against latitude and found that “all countries that lie below 35 degrees North have relatively low mortality. Thirty‐five degrees North also happens to be the latitude above which people do not receive sufficient sunlight to retain adequate vitamin D levels during winter.^[viii]

Why the connection? Well, while vitamin D might not directly protect against infection with SARS-coronavirus-2, in the words of the Rhodes et al, vitamin D, “could be very important in preventing the cytokine storm and subsequent acute respiratory distress syndrome that is commonly the cause of mortality.”

And this is where it gets super interesting and relevant for our current coronavirus plight: vitamin D has been seen to decrease the inflammatory response to viral infections in the airway without jeopardizing the eradication of a virus.[ix] This means that ensuring optimal vitamin D status could help reduce excessive inflammation in the lungs, i.e. the cytokine storms everyone’s talking about, which can help reduce severe disease while still supporting the body’s ability to fight viral infection.

What you can do to boost your vitamin D levels and lung health right now

Given that sunlight is an important source of vitamin D and many of us get little daily exposure to sunlight, especially right now, a good dietary or supplemental source of this nutrient is essential to support your ability to conquer infection (one of the 4 actions to healing).

Bearing in mind that vitamin D is a fat-soluble nutrient, it’s best to take vitamin D with a source of fat. And, of course, correcting digestion is going to be key to ensuring your gut can absorb that fat and maintain a healthy balance of bacteria, which itself helps support good immune function and lung health.

The Institute of Medicine suggest an average daily intake of 400-800 IU vitamin D is sufficient for the majority of adults, but some functional medicine doctors recommend a far higher dose for anyone without regular sun exposure or who may have other risk factors for deficiency.

In one study, healthy adults required an average daily intake of 1120-1680 IU to maintain sufficient blood levels of vitamin D.[x] Some participants in this study needed up to 5000 IU daily to correct vitamin D deficiency. In other studies looking specifically at women who were post-menopause, an intake of 800-2000 IU was required to raise blood levels of vitamin D to 20 ng/mL, which many health professionals consider the minimum adequate level.[xi] [xii]Higher doses were needed to reach 30 ng/mL in these studies.

So, depending on individual circumstances, a daily intake of 1000-4000 IU of vitamin D may be a good option for some people to achieve and maintain a healthy level of vitamin D in the blood. The Institute of Medicine set a safe upper limit of 4000 IU for daily intake for adults, so anyone considering taking a higher amount should consult a health care practitioner first.

Vitamin A and lung health

Vitamin A is a fat-soluble vitamin that plays a role in the expression of more than 500 genes.[xiii] It is essential for healthy vision, cellular growth, wound healing and tissue repair, and has free radical scavenging potential. It also plays a role in immune system activity and is important for the health of mucosal passages and epithelial surfaces.[xiv] Vitamin A plays a key role in the development and differentiation of white blood cells, including lymphocytes that fight infection, and it also has an effect on the levels of other immune system cells such as natural killer cells and cytokines such as interleukin 1.[xv]

Most of the vitamin A we store in our bodies is stored in the liver, but we also store some in the retina, kidneys, adrenal glands, fat, and… in the lungs (Kowalski et al., 1994). Low levels of vitamin A, then, may not only affect eye health but also the health of the lungs and how well prepared we are to handle respiratory infection.

There’s even some indication that vitamin A deficiency can lead to an excessive reaction to oxidative stress in the lungs, with greater production of pro-inflammatory cytokines. This has been linked to bronchial spasm and more severe asthma symptoms.xiii In some health conditions, including infection, low levels of vitamin A seem to prevent proper tissue repair and may lead to the formation of scar tissue in the lungs, affecting lung health for far longer than the initial infection.[xiii]

Before you rush to stock up on vitamin A supplements, though, be aware that you can take too much of this nutrient, leading to vitamin A toxicity. Your best bet to keep your vitamin A levels happy is to eat a diet rich in vitamin A and avoid smoking (which depletes vitamin A).

Vitamin A is present “preformed” in some animal-derived foods such as liver, kidney, eggs, and dairy. Most of us can also make our own vitamin A from the “precursor form” called beta-carotene, which is a pigment present in a variety of plant foods such as dark leafy greens and brightly colored vegetables like kale, carrots, and sweet potatoes.

However, if you have variants in the BCO (also known as the BCMO1) gene your ability to convert beta carotene into vitamin A can be significantly reduced (by as much as 60% for some people!). If you’re struggling to maintain a good level of vitamin A, it can help to consume food source of preformed vitamin A, such as beef, lamb or goose liver and salmon. Vitamin A supplements and even capsules of freeze-dried, grass-fed liver (from companies like Ancestral Supplements) are also a convenient way to ensure a good intake of this essential nutrient.

Even if you have a genetic polymorphism that affects your ability to convert beta-carotene to vitamin A, it’s still a good idea to eat those brightly colored vegetables. Why? Because these foods are also a great source of vitamin C, another key nutrient for lung health.

Vitamin C and lung health

Vitamin C is a water-soluble antioxidant, meaning it can go where vitamin A can’t (and vice versa) and can help fight off free radicals. Vitamin C is also essential for immune function, with levels of vitamin C up to 100 times higher in key immune system cells such as phagocytes and lymphocytes than in plasma.[xvi] It may also protect healthy lung tissue against reactive oxygen species produced by phagocytes during a viral infection.[xvii]

Vitamin C can also reduce the activity of bacteria during an infection and increase levels of interferon, a protein that can stop viruses from entering healthy cells.[xviii] Vitamin C also helps increase the activity of T-lymphocytes, the mobility of leukocytes, and the production of antibodies.[xix]

This vitamin is also essential for the healthy production of collagen, the connective tissue that makes up a lot of lung tissue. In cases of lung infection, you’re going to need sufficient vitamin C to help support healthy collagen production and minimize the formation of scar tissue (fibrosis) in the lungs, which has a long-term detrimental effect on lung health.

Glutathione, nitric oxide and lung health

In addition to vitamins A, C, and D, nitric oxide (NO) and glutathione are also important for lung health. These nutrients are often overlooked in discussions about respiratory function, but they are no less important for keeping your lungs healthy!

NO helps blood vessels to relax, supporting better blood flow and tissue oxygenation. It also supports wound healing, detoxification, immune function, and hormone production, including the synthesis of insulin and growth hormone. Low levels of NO are associated with a range of health concerns, including diabetes, heart disease, high cholesterol, high blood pressure, obesity, and aging, as well as erectile dysfunction.

NO can also inhibit platelet aggregation and smooth muscle proliferation. This has ramifications for lung health as it means NO could help reduce bronchial spasm and asthma symptoms as well as the formation of blood clots in the lungs.[xx]

As for glutathione, this compound is one of the body’s main antioxidants and can help detoxify chemical pollutants, drugs, and those toxins we produce as a normal part of metabolism.[xxi] Glutathione can help keep inflammation in check and support immune function, with benefits for lung health.[xxii] Instead of having inflammation narrow the airways in the case of infection or asthma, glutathione is like the body’s natural bronchodilator, combining with NO to form nitrosoglutathione.

If you have asthma, you might be interested to know that there’s a strong chance you have very low levels of glutathione in your lungs compared to folks without asthma. And during an asthma attack, glutathione can become completely depleted in the lungs.[xxiii] This is why glutathione supplementation, especially in combination with an increase in NO, has been seen to help with asthma.[xxiv]

Interestingly, simply taking a few good deep breaths can increase circulating levels of nitric oxide.[xxv] Eating fermented foods can also help increase levels of NO, especially if you eat fermented beets which are naturally high in nitrates that the body converts into NO. Other foods rich in nitrates include arugula, cabbage, and garlic. One of our favorite recipes is made with red cabbage and beets. We also include fennel and onion.

Two amino acids, L-arginine and L-citrulline can also boost NO levels. This helps explain, in part, why L-arginine and L-citrulline both have a reputation for supporting healthy heart function and circulation, immune activity, and healing, and are popular supplements for erectile dysfunction.

L-citrulline is a naturally occurring amino acid. It is found in some foods like watermelons and is also produced naturally by the body. L-citrulline is used for Alzheimer’s disease, dementia, fatigue, muscle weakness, sickle cell disease, erectile dysfunction, high blood pressure, and diabetes.

The takeaway

Whew, we covered a lot in this article!

In short, if you’re looking to support healthy lungs, you’ll want to ensure you have a good intake of:

• Vitamins A, C, and D
• Nitrates (from fermented beets, cabbage, garlic, and apples)
• Glutathione (from asparagus, avocado, cabbage, Brussels sprouts, garlic, almonds, and walnuts)
• L-arginine (from walnuts, hazelnuts, and most other nuts, oats, brown rice, animal products, and chocolate!)
• L-citrulline (from watermelons, pumpkin, cucumbers, bitter melon, and gourds).

The foods that are in italics are high in oxalates and nuts, oats and brown rice are high in phytates, which can inhibit the absorption of a whole host of nutrients including calcium and iron. Fortunately, fermentation helps to reduce both oxalic acid and phytic acid in foods, making them easier to digest. Fermentation also increases levels of certain nutrients, including nitric oxide and improves the availability of important antioxidants such as vitamin C as well as amino acids. (Nuts, seeds, oats, brown rice and chocolate are not fermented.) Together, these nutrients can help your lungs fight off infection faster and stay healthier!

PS: If you’re a practitioner, you might be interested to learn a bit more about how vitamin D affects cytokine storms. Vitamin D increases secretion of the antimicrobial peptide cathelicidin LL-37, decreases chemokine production, inhibits the activation of dendritic cells, and can alter T cell activation.[xxvi] All of these effects are key to our ability to fight infection and to control allergic lung diseases such as asthma. Vitamin D influences key innate immune processes in the lungs, playing a vital role in how the lungs recognize and respond to invading pathogens like viruses and bacteria.

Cathelicidin LL-37 is known as an antimicrobial peptide, levels of which are increased by vitamin D through increased expression of the gene that controls cathelicidin production. Interestingly, vitamin D-mediated increases in LL-37 help to kill Mycobaterium tuberculosis[xxvii], and viral infection increases activation of vitamin D and increases cathelicidin production accordingly.viii

References:

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[ii] Martineau AR, Wilkinson RJ, Wilkinson KA, et al. A single dose of vitamin D enhances immunity to mycobacteria. Am J Respir Crit Care Med. 2007;176(2):208‐213. doi:10.1164/rccm.200701-007OC

[iii] Bouillon R, Van Schoor NM, Gielen E. (2013). Optimal vitamin D status: a critical analysis on the basis of evidence-based medicine. J Clin Endocrinol Metab, Aug;98(8):E1283-304.

[iv] Martineau A, Jolliffe D, Hooper R, et al. (2017). Vitamin D supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data. BMJ, 356, i6583.

[v] Janssens W, Lehouck A, Carremans C, Bouillon R, Mathieu C, Decramer M. Vitamin D beyond bones in chronic obstructive pulmonary disease: time to act. Am J Respir Crit Care Med. 2009;179(8):630‐636. doi:10.1164/rccm.200810-1576PP

[vi] Sutherland ER, Goleva E, Jackson LP, et al. (2010). Vitamin D levels, lung function, and steroid response in adult asthma. American journal of respiratory and critical care medicine, 181(7), 699–704. https://doi.org/10.1164/rccm.200911-1710OC

[vii] Song Y, Qi H, Wu C. Effect of 1,25-(OH)2D3 (a vitamin D analogue) on passively sensitized human airway smooth muscle cells. Respirology. 2007;12(4):486‐494. doi:10.1111/j.1440-1843.2007.01099.x

[viii] Rhodes JM, Subramanian S, Laird E, Kenny RA. Editorial: low population mortality from COVID-19 in countries south of latitude 35 degrees North supports vitamin D as a factor determining severity. Aliment Pharmacol Ther. 2020;51(12):1434‐1437. doi:10.1111/apt.15777

[ix] Hansdottir S, Monick MM, Lovan N, et al. (2010). Vitamin D decreases respiratory syncytial virus induction of NF-kappaB-linked chemokines and cytokines in airway epithelium while maintaining the antiviral state. Journal of immunology (Baltimore, Md.: 1950), 184(2), 965–974. https://doi.org/10.4049/jimmunol.0902840

[x] Aloia JF, Patel M, Dimaano R, et al. (2008). Vitamin D intake to attain a desired serum 25-hydroxyvitamin D concentration. Am J Clin Nutr, 87(6):1952-1958. doi:10.1093/ajcn/87.6.1952

[xi] Gallagher JC, Sai A, Templin T 2nd, Smith L. (2012). Dose response to vitamin D supplementation in postmenopausal women: a randomized trial [published correction appears in Ann Intern Med. 2012 May 1;156(9):672]. Ann Intern Med, 156(6):425-437. doi:10.7326/0003-4819-156-6-201203200-00005

[xii] Talwar SA, Aloia JF, Pollack S, Yeh JK. (2007). Dose response to vitamin D supplementation among postmenopausal African American women. Am J Clin Nutr, 86(6):1657-1662. doi:10.1093/ajcn/86.5.1657

[xiii] Timoneda J, Rodríguez-Fernández L, Zaragozá R, et al. (2018). Vitamin A Deficiency and the Lung. Nutrients, 10(9):1132. doi:10.3390/nu10091132

[xiv] Stargrove, M.B., & Stargrove, L.B. (2008). Herb, nutrient and drug interactions: clinical implications and therapeutic strategies. St. Louis, Missouri: Mosby Elsevier.

[xv] Food and Nutrition Board, Institute of Medicine. (2002). Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. Washington, DC: National Academy Press, 2000. Available at: https://www.ncbi.nlm.nih.gov/books/NBK222310/

[xvi] Hemilä H. (1997). Vitamin C intake and susceptibility to the common cold. Br J Nutr, 77:59-72.

[xvii] Hemilä H, Herman Z. (1995). Vitamin C and the common cold: a retrospective analysis of Chalmers’ review. J Am Coll Nutr. Apr;14(2), 116-23.

[xviii] Iqbal K, Khan A, Khattak M. (2004). Biological significance of ascorbic acid (vitamin C) in human health – A review. Pakistan J of Nutr, 3(1):5-13.

[xix] Leibovitz B, Siegel BV. (1981). Ascorbic acid and the immune response. Adv Exp Med Biol, 135:1-25.

[xx] Horowitz RJ, Freeman PR, Bruzzese J. (2020). Efficacy of glutathione therapy in relieving dyspnea associated with COVID-19 pneumonia: A report of 2 cases. Respiratory Medicine Case Reports. Volume 30, 2020, 101063. https://www.sciencedirect.com/science/article/pii/S2213007120301350

[xxi] Glutathione WebMD Medical Reference. What You Should Know About Glutathione? https://www.webmd.com/vitamins-and-supplements/qa/what-should-you-know-about-glutathione

[xxii] Core Med Science. 14 Benefits of the Master Antioxidant. https://coremedscience.com/blogs/wellness/glutathione-3a-14-benefits-of-the-master-antioxidant-plus-diet-26-supplements

[xxiii] Masterjohn C. (2018, October 16). Glutathione for Asthma. https://chrismasterjohnphd.com/lite-videos/2018/10/16/glutathione-for-asthma

[xxiv] Sahiner UM, Birben E, Erzurum S, et al. (2011). Oxidative Stress in Asthma. World Allergy Organ J4, 151–158. https://doi.org/10.1097/WOX.0b013e318232389e

[xxv] Pramanik T, Sharma HO, Mishra S, et al. (2009). Immediate effect of slow pace bhastrika pranayama on blood pressure and heart rate. J Altern Complement Med, Mar;15(3):293-5.

[xxvi] Hansdottir S, Monick MM, Hinde SL, Lovan N, Look DC, Hunninghake GW. Respiratory epithelial cells convert inactive vitamin D to its active form: potential effects on host defense. J Immunol. 2008;181(10):7090‐7099. doi:10.4049/jimmunol.181.10.7090

[xxvii] Adams JS, Chen H, Chun R, et al. Substrate and enzyme trafficking as a means of regulating 1,25-dihydroxyvitamin D synthesis and action: the human innate immune response. J Bone Miner Res. 2007;22 Suppl 2:V20‐V24. doi:10.1359/jbmr.07s214