Air pollution is a major risk to human health.
The World Health Organization estimates that dirty air kills some two million people per year worldwide, and that the number is climbing (WHO 2011).
Voluminous evidence links the air levels of “particulate matter” found in many cities to heart and lung damage (EPA 2009; Brook RD et al. 2010).
Even short-term rises in particulate matter pollution are associated with heart attacks, angina, stroke, blood clots, arrhythmias, and worsening of heart failure … particularly in at-risk populations (U.S. EPA 2009).
According to one study, particulate matter from vehicle (car, truck, bus) exhaust causes some seven percent of all heart attacks, making it the single greatest preventable cause (Nawrot TS et al. 2001).
Alarmingly, it's also been found that air polluted with particulate matter inflames the brain and damages it in ways proven to promote diseases such as Alzheimer's and Parkinson's (Levesque S et al. 2011; Costa LG et al. 2014).
And four years ago, a study in women linked exposure to high air levels of particulate matter to lower birth weights … although babies born to women who ate 3.2 ounces of fish or more per week suffered no pollution-related weight deficit (Jedrychowski W et al. 2010).
Diesel exhaust yields heart, lung, and brain damage
Polluted air contains several components, of which particulate matter – especially ultrafine particulate matter – is cause for particular (excuse the pun) concern.
Most particulate matter, including ultrafine matter, comes from diesel exhaust emitted by trucks and busses.
Other sources include wood smoke, coal burning, vehicle exhaust, fax machines, photocopiers, tobacco smoke, chimney cracks, and vacuum cleaners.
Ultrafine particles can enter the blood and thereby most organs, including the brain, with human population and animal studies alike showing that exposure to air pollution damages the brain.
As well as a variety of behavioral abnormalities, air pollution causes oxidative stress and inflammation in the brain.
And young ones are most at risk.
Air pollution (and diesel exhaust) can damage developing brains and may promote serious “neurodevelopmental” problems, including autism spectrum disorders.
In addition, air pollution exposure is linked to genetic markers for neurodegenerative diseases such as Alzheimer's and Parkinson's.
So if certain foods or supplements could blunt the adverse effects of air pollution, people breathing bad air need to know, urgently.
A pair of studies published nine years ago found that heart rate variability improved after participants who routinely breathed air polluted with particulate matter took omega-3 fish oil supplements (Holguin F et al. 2005; Romieu I et al. 2005).
Six years ago, we reported on a related human trial from one of those teams, which found that omega-3 fish oil raised body levels of key internal antioxidants (SOD and GSH-Px) in people breathing Mexico City's dirty air … see “Omega-3s Help Protect against Pollution Harm
And we just learned about a more recent clinical trial that tested omega-3 fish oil against the adverse cardiovascular effects of air pollution.
Our thanks go to Dr. Walter Crinnion, ND
, who specializes in environmental health and alerted us to this study when we spoke with him at last weekend's Integrative Health Symposium.
Fish oil eased the heart-health impact of breathing dirty air
The clinical trial was conducted by a team of scientists from the University of South Carolina, the U.S. EPA's North Carolina office, and the TRC Environmental Corporation in North Carolina (Tong H et al. 2012).
They recruited 29 participants aged 50 to 72. All were healthy with no history of diabetes, cardiovascular disease, or pulmonary lung disease and had not smoked for at least a year.
The Carolinas-based team randomly assigned the volunteers to one of two month-long supplement regimens:
- Olive oil – 3 grams per day, with no omega-3 fats
- Omega-3 fish oil – 3 grams per day, with 410 mg omega- EPA + 274 mg omega-3 DHA
After 28 days, the participants donned face masks to breathe two different kinds of air in succession (two hours in each session):
- Clean, filtered air
- Air with the very high (PM2.5) levels of particulate matter known to cause heart and lung damage
The researchers then measured several things known to be affected adversely by air containing such high levels of particulate matter.
These measurements were taken before, immediately after, and 20 hours following their exposures to the filtered and polluted air:
- Blood lipid levels
- Heart rate variability (HRV), low levels of which are associated with arrhythmia and sudden cardiac death
- Cardiac repolarization parameters (the time it takes for heart cells to return to their resting state after a heart beat)
Following their exposure to the polluted air, heart rate variability decreased significantly in the participants who ate olive oil supplements … a bad thing.
In contrast, the subjects on fish oil supplements showed little change in heart rate variability.
And, compared to the fish oil group, the olive oil group displayed a longer (unhealthful) cardiac repolarization duration after breathing the polluted air … and an immediate rise in blood levels of two undesirable lipids – very low-density lipoprotein and triglycerides.
What do the results mean?
This was the first controlled study to show that taking fish oil can reduce cardiac symptoms caused by exposure to particulate pollution.
In fact, the results provided the strongest clinical evidence to date that fish oil can drastically diminish cardiovascular health damage induced by short-term exposure to air polluted with particulate matter.
The study identified two ways in which fish oil provided protection:
- Prevented rises in the types of fats linked to atherosclerosis and heart disease.
- Fish oil protected against changes to the electrical signals controlling how often the heart beats and how quickly it can recover.
As the authors wrote, “Our findings suggest that omega-3 supplements may offer protection against the adverse cardiac and lipid effects associated with air pollution exposure.” (Tong H et al. 2012)
The news media – and social media – would do a great service by alerting people and public health officials in air-polluted areas worldwide.
- Brook RD, Rajagopalan S, Pope CA III, Brook JR, Bhatnagar A, Diez-Roux AV, et al. 2010. Particulate matter air pollution and cardio vascular disease: an update to the scientific statement from the American Heart Association. Circulation. 121(21):2331–2378.
- Brunekreef B, Beelen R, Hoek G, Schouten L, Bausch-Goldbohm S, Fischer P, Armstrong B, Hughes E, Jerrett M, van den Brandt P. Effects of long-term exposure to traffic-related air pollution on respiratory and cardiovascular mortality in the Netherlands: the NLCS-AIR study. Res Rep Health Eff Inst. 2009 Mar;(139):5-71; discussion 73-89.
- Costa LG, Cole TB, Coburn J, Chang YC, Dao K, Roque P. Neurotoxicants Are in the Air: Convergence of Human, Animal, and In Vitro Studies on the Effects of Air Pollution on the Brain. Biomed Res Int. 2014;2014:736385. Epub 2014 Jan 12. Review.
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- Levesque S, Surace MJ, McDonald J, Block ML. Air pollution & the brain: Subchronic diesel exhaust exposure causes neuroinflammation and elevates early markers of neurodegenerative disease. J Neuroinflammation. 2011 Aug 24;8:105. doi: 10.1186/1742-2094-8-105.
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- Romieu I, Téllez-Rojo MM, Lazo M, Manzano-Patiño A, Cortez-Lugo M, Julien P, Bélanger MC, Hernandez-Avila M, Holguin F. Omega-3 fatty acid prevents heart rate variability reductions associated with particulate matter. Am J Respir Crit Care Med. 2005 Dec 15;172(12):1534-40. Epub 2005 Oct 6.
- Tong H, Rappold AG, Diaz-Sanchez D, Steck SE, Berntsen J, Cascio WE, Devlin RB, Samet JM. Omega-3 fatty acid supplementation appears to attenuate particulate air pollution-induced cardiac effects and lipid changes in healthy middle-aged adults. Environ Health Perspect. 2012 Jul;120(7):952-7. doi: 10.1289/ehp.1104472. Epub 2012 Apr 10.
- U.S. EPA (U.S. Environmental Protection Agency). 2009. Integrated Science Assessment for Particulate Matter (Final Report). Accessed at http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=216546
- World Health Organization (WHO). Indoor air pollution and health. August 20, 2011. Accessed at http://www.who.int/mediacentre/factsheets/fs292/en/index.html