Air pollution is a serious health threat that affects the entire world. Previous studies show that it increases the risk of cardiovascular disease, among other things. We need new strategies for protection, and a recent Chinese study conveniently reveals that supplementation with vitamin C can protect the cardiovascular system against oxidative stress and other harmful impacts from air pollution. What we need to find out is how much vitamin C it takes to obtain a therapeutic effect.
Epidemiological studies show a close relation between the tiny particles in air pollution and cardiovascular diseases and increased mortality. The economical and technological development has resulted in increasing levels of air pollution. According to WHO, 90 percent of the world’s population lives in exposed areas. Although politicians try to deal with the problem through legislation and other measures, it is difficult to avoid air pollution so we are in desperate need for other strategies, including ones where each individual is able to make a difference.
Air pollution contains a host of different particles that we breathe in and that eventually end up in our bloodstream. Although we still have a lot to learn about the molecular mechanisms, through which air pollution harms our circulatory system, scientists and experts seem to agree on the fact that inflammation and oxidative stress play a key role.
Inflammation is a natural process in which the immune system attacks microbes, toxins, and harmful particles. Because of daily exposure to air pollution, our immune defense constantly produces pro-inflammatory cytokines such as IL-6, TNf-α, and CRP. Also, a generous quantity of free radicals is produced, which causes oxidative stress. This is a condition where potentially harmful free radicals outnumber the protective antioxidants.
The reason why oxidative stress sets the stage for cardiovascular disease is that the free radicals attack cholesterol in the blood. Cholesterol is an essential compound that is needed to build cell membranes and synthesize steroid hormones, vitamin D, and Q10. Free radicals expose cholesterol to rancidification (lipid peroxidation), which makes it unusable. Instead, the oxidized cholesterol is consumed by white blood cells (macrophages) and embedded in the blood vessel walls where is produces atherosclerotic plaque. Free radicals are also able to cause damage to the epithelial cells that line the inside of blood vessels, including their membranes, mitochondria, and DNA. All of this makes it necessary to find new strategies to combat oxidative stress.
High-dosed vitamin C protects the circulatory system in several ways
Numerous studies have shown that supplements of fish oil and vitamin E have a subclinically positive effect on damage caused by air pollution. The supplements have an anti-inflammatory effect while protecting the function of the endothelial cells in the blood vessels. It has been shown earlier that vitamin C serves as a powerful antioxidant and even delivers a fast effect on blood lipids, blood pressure, and endothelial function. It is also clinically proven that vitamin C has a positive effect on the harmful effects of air pollution. For that reason, a team of Chinese scientists wanted to study this, as air pollution is a particularly large health threat in China.
The study was carried out in the Shijaizhuang metropolis and included 58 healthy young adults. The participants were divided into two groups that received either 2,000 mg of vitamin C daily for one week, or matching placebo. Nobody knew who got what.
The scientists drew blood samples and measured 15 different markers to see how vitamin C affected the participants’ health. It turned out that there was a significant inverse relation between vitamin C and levels of pro-inflammatory markers like IL-6, TNF-α, and CRP. The researchers also discovered that vitamin C had a slightly lowering effect on heart rate and systolic blood pressure. In addition, levels of the powerful, selenium-containing GPX antioxidant were increased by seven percent.
The study indicates that daily supplementation with 2,000 mg of vitamin C can protect young adults against tissue damage in the circulatory system and other sites caused by air pollution and oxidative stress. The new study is published in the journal Ecotoxicology and Environmental Safety.
The dosage (2,000 mg/day) that was used in this study of vitamin C to obtain a positive effect is far beyond the official recommendation for vitamin C (which is 80 mg/day in Denmark). It appears that the need for vitamin C is greater if you are exposed to air pollution, are a smoker, or are exposed to oxidative stress from other sources.
- Fruit and vegetables are good sources of vitamin C
- In order to get 2,000 mg of dietary vitamin C you would have to eat 33 apples. Not only is this an unrealistic goal, it would actually be unhealthy because of the excess intake of sugar (fructose)
- When choosing supplements, it is a good idea to stick with non-acidic forms of vitamin C (e.g., calcium ascorbate) that are gentle on the stomach
Jingyi ren et al. Vascular benefits of vitamin C supplementation against fine particulate air pollution in healthy adults: A double-blind randomised crossover trial. Ecotoxicology and Environmental safety. August 2022
Harlan Krumholz. Inflammation: Is it the New Cholesterol? Pharma & Healthcare Medicine. August 2017
Frida - Parametre (fooddata.dk)
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