Friday, August 10, 2012

Pollution and nutrition

A recent study 1 of adults with asthma and chronic obstructive pulmonary disease (COPD) found that those with lower levels of certain antioxidants in their blood were more vulnerable to the harmful effects of air pollution. Air pollution can aggravate both asthma and COPD, producing symptoms that can be strong enough to lead to hospitalization. This study is important because it indicates that improved nutrition may protect against the common health threat of air pollution and that the low levels recommended for the average person (RDA/I’s) may not be enough.

The study found smokers and those older than 75 years of age were especially vulnerable to air pollution effects but also participants with low levels of vitamin C in their blood were also more vulnerable to PM10. This effect was not seen with other antioxidants and genes.

Air, water and soil pollution place increased demands on protective nutrients, due to these pollutants’ ability to generate free radicals, oxidation and inflammation. They also have the ability to block nutrient digestion, absorption and utilisation, as well as to drain the body of existing nutrients. In fact, many of the negative effects of toxins influence nutrient cycles in the body. For example, selenium and cysteine are necessary for the production and function of glutathione, which detoxifies and helps eliminate heavy metals such as mercury from the body. An elevated mercury load puts extra demand on the body’s supply of selenium and cysteine, to name just two of its anti-nutrient effects. So considering nutritional needs without considering the toxic load of an individual would seem ridiculous and, incidentally, is the reason for the growing field of nutritional toxicology.

With increasing technology and especially the expanding industrialisation of the last century, humans are exposed to a larger number of new potential toxins at greater concentrations. Living in the world today, it is impossible to avoid exposure to environmental toxins such as xenoestrogens (which include the organochlorine pesticides, heavy metals and plastics), cigarette smoke, pesticides, industrial poisons, heavy metals and even food additives (preservatives, colours and flavours). Inhalation, ingestion and absorption of heavy metals as well as inorganic and organic chemical compounds can lead to a build-up of toxins in the body. This is not to mention the hundreds of toxic ingredients we now have in our homes masquerading as cleaning products, personal care products and cosmetics. This accumulation of toxins can alter biochemical balance by chelating nutrients (making them bio-unavailable), mimicking hormones and altering proteins, resulting in metabolic dysfunction. The most disruptive and dangerous effect upon oestrogen receptors. Furthermore, toxic compounds interfere with each other’s exit pathways. If alternative pathways aren’t available, this will create a metabolic “gridlock.”

Studies suggest that an increased intake of particular nutrients may benefit the body and protect it against damage from pollution. These include beta-carotene, vitamins C, A, E, folic acid and selenium. These nutrients are called antioxidants. For the first stage (phase 1) of detoxification to be effective, high levels of N acetyl cysteine and vitamins B2, B3, B6 and B12, folate, flavonoids, vitamin C and iron are required.

1            Canova C, C Dunster, FJ Kelly, C Minelli, PL Shah, C Caneja, MK Tumilty, P Burneya. 2012. PM10-induced hospital admissions for asthma and chronic obstructive pulmonary disease: The modifying effect of individual characteristics. Epidemiology

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