The front page headline of The Sunday Times in Singapore on 8th October read “Haze anger, but Jakarta can’t do more”. The Pollutant Standard Index (PSI) was an unhealthy 150 at 9PM the night before and was the highest PSI reading in nine years! The high PSI reading over the last few days even prompted the Department of Health to send a reminder to all medical practitioners to warn all their patients with cardiovascular and respiratory diseases to refrain from vigorous exercise.

The haze problem is an annual problem affecting Indonesia, Malaysia and Singapore. This is due to the annual practice of burning the forests on the Sumatra island and in Kalimantan (the Indonesian part of the Borneo island) by farmers and plantation owners in the dry season to clear the land for growing crops. For several months each year, one is able to notice a veil of grayness hanging over the sky. While the sun still shines most of the time, everything just looks a touch gray and the colours are less vibrant. When the haze situation is bad, there is a corresponding increase in the number of people complaining of respiratory problems and eye irritation. The long term health implication of this unique problem in the region is still unknown. However, we might be able to glean some information on published studies on the deleterious health effect of second hand smoke from smoking tobacco.

A recent study from Austria looked at the effect of parental smoking and the children’s respiratory health in 53,879 children in 12 countries (Tobacco Control 2006; 15: 294 – 301). Three types of exposure were studied – mothers who smoked during pregnancy, parental smoking during the first two years of life and current parental smoking. Wheezing and coughing in the night were associated with all 3 patterns of smoke exposure. The risk of having wheezing was increased 17% in children who were exposed to smoke during the first two years of life, while children born to mothers who smoked during pregnancy had a 25% increased risk of wheezing. In addition, a mother who smoked during pregnancy increased the risk of the child developing asthma by 18%. Children who lived with parents who continued to smoke had a 12% increased risk of being woken by a wheezing attack. Increased risk of bronchitis was associated with smoke exposure during the first 2 years of life and persistent parental smoking.

A study from China looked at the effect of second hand smoke (from a husband who smokes or at work) on 72,829 non-smoking women living in Shanghai (BMJ 2006; 333: 376 - 379). The cumulative mortality (death) from all causes was significantly higher in women whose husbands smoked than in those whose husbands did not smoke. Similarly, the cumulative mortality due to cardiovascular disease was also significantly increased in women whose husbands smoked. Women who were exposed to smoke at work had a 19% increased risk of dying from all types of cancer and for lung cancer it was an increase of 79%. Women exposed to smoke from family members in their early life had a 26% increased risk of dying from cardiovascular disease.

Nature’s giant smoke in Sumatra and Kalimantan is driven by economic considerations. The drive to get people to smoke is again driven by economic considerations. While it is not possible to stop manufacturers from making cigarettes in a free market economy, it is possible for a government to enact smoke-free laws banning smoking in pubic places, such as restaurants, worksites and pubs. Indeed, the effectiveness of smoke-free laws in reducing disease incidence has been well documented. During a 6-month period in Helena, Montana, USA, a smoke-free workplace rule was put into effect (BMJ 2004; 328: 977 -980). In that 6-month period, the hospital admission rate for acute myocardial infarction (heart attack) was reduced by 40%. When the rule was suspended, the hospital admission rate for heart attacks returned to the previous levels!

Nature’s giant smoke exposes everyone in the region to second hand smoke for 24/7 for several months each year. While no long-term studies have been published yet, I would hazard a guess that the second-hand smoke effect from the forest fires is just as bad as being married to a husband or wife who smokes!

“NYC mayor lures Robert DiNiro into trans fat debate”  This headline caught my attention the other day. I was wondering what the connection was between trans fat and a famous actor. The article reported on the intention of the New York City Department of Health to force the city’s 20,000 restaurants to drastically reduce the amount of trans fat used in the kitchen. Robert DiNiro owns several restaurants in the city and those kitchens do not use trans fat. The mayor of NYC referred to DiNiro’s good example.

trans Fatty acids (TFAs) are unsaturated fats with at least one double bond in the trans configuration. They are formed during the industrial hydrogenation of vegetable oils. In simpler terms, trans fats are made when manufacturers add hydrogen molecules to vegetable oils. TFAs are primarily used in fast foods, bakery products, packaged snacks and margarines. Humans cannot manufacture TFAs and thus all TFAs in the body are from the diet.

The potential health hazards of consuming TFAs was raised in 1993 when Willett and his co-workers of Harvard Medical School published an article in the prestigious medical journal, The Lancet (Lancet 1993; 341: 581 – 585). In it they reported that women who regularly consumed margarine as part of their diet had a significantly increased risk of coronary heart disease (CHD). The risk of CHD was increased by 67%.

Fifty healthy men were given a diet containing TFAs and the inflammatory markers in the body were monitored. Over a short period of 5 weeks, several inflammatory markers including e-selectin and IL-6 became elevated. Patients with established heart disease often have higher concentrations of blood markers of systemic inflammation. The degree of systemic inflammation in these patients is known to influence the outcome of the heart disease. Those with higher degrees of inflammation have poorer outcomes. In another study involving 150 patients with chronic heart failure, the researchers found that the TFAs level in cell membranes was positively correlated with increased levels of inflammatory markers such as tumour necrosis factor alpha (TNF-α), interleukin 6 (IL-6) and interleukin 1-β (IL-1β). TNF is known to stimulate macrophages, vascular endothelial cells (cells lining the blood vessel) and arterial smooth muscle cells (SMC), leading to the secretion of various protein molecules that mediate fibrosis. This leads to replication of SMC and contributes to elaboration by these cells of a dense extracellular matrix, characteristic of the more advanced atherosclerosis (hardening of blood vessels) lesion. Heart attack is a consequence of a blockage in the diseased blood vessel that supplies the heart muscle. The diseased blood vessel has an atherosclerotic lesion which causes the blood vessel lumen to narrow. When the lumen becomes occluded, a heart attack ensues.

A group of researchers from Copenhagen (Atheroscler Suppl 2006; 7: 47 – 52) assessed the potential exposure of consumers to TFAs by analysing 55 servings of French fries and chicken nuggets, 87 packages of microwave popcorn and 393 samples of biscuits/cakes/wafers. These food stuff, with ‘partially hydrogenated vegetable fat’ listed high on the food label, were purchased between November 2004 and February 2006 in Denmark and in 25 other countries. A ‘high trans menu’ was defined as a large size serving of French fries and nuggets, 100g of microwave popcorn and 100 gm of biscuits/wafers/cakes. The amount of TFAs in a ‘high trans menu’ was 20g in 2001 in Denmark. With legislation against the use of TFAs by the Danish government, this was reduced to less than 1 gm in 2005! In contrast, a ‘high trans menu’ provided more than 20 gm in 17 out of 18 countries, with Hungary, Czech Republic, Poland, Bulgaria and USA ranking highest with 42, 40, 37, 37 and 36 gm respectively.

The health authority in NYC is trying to enact a law requiring restaurants and eateries to stop using TFAs by July 2008. These establishments are reluctant to support this measure, citing higher cost and less tasty food if the use of TFAs is banned. Is it so difficult to limit the use of TFAs in all eating establishments? The Danes have shown the world that this can be achieved without compromising on the taste of the food and without escalating the cost of the manufactured food. For those interested, you could read the article ‘The trans fatty acid story in Denmark’ by A Astrup (Atheroscler Suppl 2006; 7: 43 – 46).

I mentioned the news about NYC’s intended legislation on TFAs to a friend who oversees research and development in a big US food company (which, by the way, has switched out of using TFAs in their snacks) at the weekend. His response was ‘good luck’. He was of the opinion that it would be easier to reduce portion size than to ban TFA use. While reducing portion size would be a good start, I am not sure how many customers would agree to smaller portions. Just imagine that one day, when you walk into a McDonald or Burger King outlet to order a burger meal, the counter staff would automatically say “Downsize?”. That would certainly help but drastically reducing the use of TFAs in the food industry will definitely help the increasing the number of obese people worldwide as well.

The next time you pick up a packet of your favourite snack in the supermarket, just stop and have a look at the food label and see if you can find the words “hydrogenated vegetable oil, shortening or trans fatty acid”. If you see any of those words, it means TFAs.